45511fdd15
JsonAdapter is cached per the type of the JsonAdapter class. Added a test to ensure JsonAdapter works on fields of parameterized types Keep track of registered JsonAdapters and JsonAdapterFactorys in ThreadLocal.
989 lines
42 KiB
Java
989 lines
42 KiB
Java
/*
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* Copyright (C) 2008 Google Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.google.gson;
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import java.io.EOFException;
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import java.io.IOException;
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import java.io.Reader;
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import java.io.StringReader;
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import java.io.StringWriter;
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import java.io.Writer;
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import java.lang.reflect.Type;
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import java.math.BigDecimal;
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import java.math.BigInteger;
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import java.util.ArrayList;
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import java.util.Collections;
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import java.util.HashMap;
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import java.util.List;
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import java.util.Map;
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import java.util.concurrent.ConcurrentHashMap;
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import java.util.concurrent.atomic.AtomicLong;
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import java.util.concurrent.atomic.AtomicLongArray;
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import com.google.gson.internal.ConstructorConstructor;
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import com.google.gson.internal.Excluder;
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import com.google.gson.internal.Primitives;
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import com.google.gson.internal.Streams;
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import com.google.gson.internal.bind.ArrayTypeAdapter;
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import com.google.gson.internal.bind.CollectionTypeAdapterFactory;
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import com.google.gson.internal.bind.DateTypeAdapter;
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import com.google.gson.internal.bind.JsonAdapterAnnotationTypeAdapterFactory;
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import com.google.gson.internal.bind.JsonTreeReader;
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import com.google.gson.internal.bind.JsonTreeWriter;
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import com.google.gson.internal.bind.MapTypeAdapterFactory;
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import com.google.gson.internal.bind.ObjectTypeAdapter;
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import com.google.gson.internal.bind.ReflectiveTypeAdapterFactory;
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import com.google.gson.internal.bind.SqlDateTypeAdapter;
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import com.google.gson.internal.bind.TimeTypeAdapter;
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import com.google.gson.internal.bind.TypeAdapters;
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import com.google.gson.reflect.TypeToken;
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import com.google.gson.stream.JsonReader;
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import com.google.gson.stream.JsonToken;
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import com.google.gson.stream.JsonWriter;
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import com.google.gson.stream.MalformedJsonException;
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/**
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* This is the main class for using Gson. Gson is typically used by first constructing a
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* Gson instance and then invoking {@link #toJson(Object)} or {@link #fromJson(String, Class)}
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* methods on it. Gson instances are Thread-safe so you can reuse them freely across multiple
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* threads.
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*
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* <p>You can create a Gson instance by invoking {@code new Gson()} if the default configuration
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* is all you need. You can also use {@link GsonBuilder} to build a Gson instance with various
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* configuration options such as versioning support, pretty printing, custom
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* {@link JsonSerializer}s, {@link JsonDeserializer}s, and {@link InstanceCreator}s.</p>
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*
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* <p>Here is an example of how Gson is used for a simple Class:
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*
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* <pre>
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* Gson gson = new Gson(); // Or use new GsonBuilder().create();
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* MyType target = new MyType();
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* String json = gson.toJson(target); // serializes target to Json
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* MyType target2 = gson.fromJson(json, MyType.class); // deserializes json into target2
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* </pre></p>
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*
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* <p>If the object that your are serializing/deserializing is a {@code ParameterizedType}
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* (i.e. contains at least one type parameter and may be an array) then you must use the
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* {@link #toJson(Object, Type)} or {@link #fromJson(String, Type)} method. Here is an
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* example for serializing and deserializing a {@code ParameterizedType}:
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*
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* <pre>
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* Type listType = new TypeToken<List<String>>() {}.getType();
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* List<String> target = new LinkedList<String>();
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* target.add("blah");
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*
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* Gson gson = new Gson();
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* String json = gson.toJson(target, listType);
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* List<String> target2 = gson.fromJson(json, listType);
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* </pre></p>
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*
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* <p>See the <a href="https://sites.google.com/site/gson/gson-user-guide">Gson User Guide</a>
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* for a more complete set of examples.</p>
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*
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* @see com.google.gson.reflect.TypeToken
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*
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* @author Inderjeet Singh
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* @author Joel Leitch
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* @author Jesse Wilson
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*/
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public final class Gson {
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static final boolean DEFAULT_JSON_NON_EXECUTABLE = false;
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static final boolean DEFAULT_LENIENT = false;
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static final boolean DEFAULT_PRETTY_PRINT = false;
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static final boolean DEFAULT_ESCAPE_HTML = true;
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static final boolean DEFAULT_SERIALIZE_NULLS = false;
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static final boolean DEFAULT_COMPLEX_MAP_KEYS = false;
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static final boolean DEFAULT_SPECIALIZE_FLOAT_VALUES = false;
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private static final TypeToken<?> NULL_KEY_SURROGATE = new TypeToken<Object>() {};
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private static final String JSON_NON_EXECUTABLE_PREFIX = ")]}'\n";
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/**
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* This thread local guards against reentrant calls to getAdapter(). In
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* certain object graphs, creating an adapter for a type may recursively
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* require an adapter for the same type! Without intervention, the recursive
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* lookup would stack overflow. We cheat by returning a proxy type adapter.
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* The proxy is wired up once the initial adapter has been created.
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*/
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private final ThreadLocal<Map<TypeToken<?>, FutureTypeAdapter<?>>> calls
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= new ThreadLocal<Map<TypeToken<?>, FutureTypeAdapter<?>>>();
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private final Map<TypeToken<?>, TypeAdapter<?>> typeTokenCache = new ConcurrentHashMap<TypeToken<?>, TypeAdapter<?>>();
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private final List<TypeAdapterFactory> factories;
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private final ConstructorConstructor constructorConstructor;
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private final Excluder excluder;
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private final FieldNamingStrategy fieldNamingStrategy;
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private final boolean serializeNulls;
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private final boolean htmlSafe;
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private final boolean generateNonExecutableJson;
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private final boolean prettyPrinting;
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private final boolean lenient;
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private JsonAdapterAnnotationTypeAdapterFactory jsonAdapterFactory;
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/**
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* Constructs a Gson object with default configuration. The default configuration has the
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* following settings:
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* <ul>
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* <li>The JSON generated by <code>toJson</code> methods is in compact representation. This
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* means that all the unneeded white-space is removed. You can change this behavior with
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* {@link GsonBuilder#setPrettyPrinting()}. </li>
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* <li>The generated JSON omits all the fields that are null. Note that nulls in arrays are
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* kept as is since an array is an ordered list. Moreover, if a field is not null, but its
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* generated JSON is empty, the field is kept. You can configure Gson to serialize null values
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* by setting {@link GsonBuilder#serializeNulls()}.</li>
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* <li>Gson provides default serialization and deserialization for Enums, {@link Map},
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* {@link java.net.URL}, {@link java.net.URI}, {@link java.util.Locale}, {@link java.util.Date},
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* {@link java.math.BigDecimal}, and {@link java.math.BigInteger} classes. If you would prefer
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* to change the default representation, you can do so by registering a type adapter through
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* {@link GsonBuilder#registerTypeAdapter(Type, Object)}. </li>
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* <li>The default Date format is same as {@link java.text.DateFormat#DEFAULT}. This format
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* ignores the millisecond portion of the date during serialization. You can change
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* this by invoking {@link GsonBuilder#setDateFormat(int)} or
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* {@link GsonBuilder#setDateFormat(String)}. </li>
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* <li>By default, Gson ignores the {@link com.google.gson.annotations.Expose} annotation.
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* You can enable Gson to serialize/deserialize only those fields marked with this annotation
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* through {@link GsonBuilder#excludeFieldsWithoutExposeAnnotation()}. </li>
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* <li>By default, Gson ignores the {@link com.google.gson.annotations.Since} annotation. You
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* can enable Gson to use this annotation through {@link GsonBuilder#setVersion(double)}.</li>
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* <li>The default field naming policy for the output Json is same as in Java. So, a Java class
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* field <code>versionNumber</code> will be output as <code>"versionNumber"</code> in
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* Json. The same rules are applied for mapping incoming Json to the Java classes. You can
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* change this policy through {@link GsonBuilder#setFieldNamingPolicy(FieldNamingPolicy)}.</li>
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* <li>By default, Gson excludes <code>transient</code> or <code>static</code> fields from
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* consideration for serialization and deserialization. You can change this behavior through
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* {@link GsonBuilder#excludeFieldsWithModifiers(int...)}.</li>
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* </ul>
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*/
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public Gson() {
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this(Excluder.DEFAULT, FieldNamingPolicy.IDENTITY,
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Collections.<Type, InstanceCreator<?>>emptyMap(), DEFAULT_SERIALIZE_NULLS,
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DEFAULT_COMPLEX_MAP_KEYS, DEFAULT_JSON_NON_EXECUTABLE, DEFAULT_ESCAPE_HTML,
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DEFAULT_PRETTY_PRINT, DEFAULT_LENIENT, DEFAULT_SPECIALIZE_FLOAT_VALUES,
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LongSerializationPolicy.DEFAULT, Collections.<TypeAdapterFactory>emptyList());
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}
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Gson(final Excluder excluder, final FieldNamingStrategy fieldNamingStrategy,
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final Map<Type, InstanceCreator<?>> instanceCreators, boolean serializeNulls,
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boolean complexMapKeySerialization, boolean generateNonExecutableGson, boolean htmlSafe,
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boolean prettyPrinting, boolean lenient, boolean serializeSpecialFloatingPointValues,
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LongSerializationPolicy longSerializationPolicy,
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List<TypeAdapterFactory> typeAdapterFactories) {
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this.constructorConstructor = new ConstructorConstructor(instanceCreators);
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this.excluder = excluder;
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this.fieldNamingStrategy = fieldNamingStrategy;
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this.serializeNulls = serializeNulls;
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this.generateNonExecutableJson = generateNonExecutableGson;
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this.htmlSafe = htmlSafe;
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this.prettyPrinting = prettyPrinting;
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this.lenient = lenient;
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List<TypeAdapterFactory> factories = new ArrayList<TypeAdapterFactory>();
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// built-in type adapters that cannot be overridden
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factories.add(TypeAdapters.JSON_ELEMENT_FACTORY);
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factories.add(ObjectTypeAdapter.FACTORY);
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// the excluder must precede all adapters that handle user-defined types
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factories.add(excluder);
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// user's type adapters
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factories.addAll(typeAdapterFactories);
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// type adapters for basic platform types
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factories.add(TypeAdapters.STRING_FACTORY);
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factories.add(TypeAdapters.INTEGER_FACTORY);
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factories.add(TypeAdapters.BOOLEAN_FACTORY);
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factories.add(TypeAdapters.BYTE_FACTORY);
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factories.add(TypeAdapters.SHORT_FACTORY);
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TypeAdapter<Number> longAdapter = longAdapter(longSerializationPolicy);
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factories.add(TypeAdapters.newFactory(long.class, Long.class, longAdapter));
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factories.add(TypeAdapters.newFactory(double.class, Double.class,
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doubleAdapter(serializeSpecialFloatingPointValues)));
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factories.add(TypeAdapters.newFactory(float.class, Float.class,
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floatAdapter(serializeSpecialFloatingPointValues)));
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factories.add(TypeAdapters.NUMBER_FACTORY);
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factories.add(TypeAdapters.ATOMIC_INTEGER_FACTORY);
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factories.add(TypeAdapters.ATOMIC_BOOLEAN_FACTORY);
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factories.add(TypeAdapters.newFactory(AtomicLong.class, atomicLongAdapter(longAdapter)));
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factories.add(TypeAdapters.newFactory(AtomicLongArray.class, atomicLongArrayAdapter(longAdapter)));
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factories.add(TypeAdapters.ATOMIC_INTEGER_ARRAY_FACTORY);
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factories.add(TypeAdapters.CHARACTER_FACTORY);
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factories.add(TypeAdapters.STRING_BUILDER_FACTORY);
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factories.add(TypeAdapters.STRING_BUFFER_FACTORY);
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factories.add(TypeAdapters.newFactory(BigDecimal.class, TypeAdapters.BIG_DECIMAL));
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factories.add(TypeAdapters.newFactory(BigInteger.class, TypeAdapters.BIG_INTEGER));
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factories.add(TypeAdapters.URL_FACTORY);
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factories.add(TypeAdapters.URI_FACTORY);
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factories.add(TypeAdapters.UUID_FACTORY);
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factories.add(TypeAdapters.CURRENCY_FACTORY);
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factories.add(TypeAdapters.LOCALE_FACTORY);
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factories.add(TypeAdapters.INET_ADDRESS_FACTORY);
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factories.add(TypeAdapters.BIT_SET_FACTORY);
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factories.add(DateTypeAdapter.FACTORY);
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factories.add(TypeAdapters.CALENDAR_FACTORY);
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factories.add(TimeTypeAdapter.FACTORY);
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factories.add(SqlDateTypeAdapter.FACTORY);
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factories.add(TypeAdapters.TIMESTAMP_FACTORY);
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factories.add(ArrayTypeAdapter.FACTORY);
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factories.add(TypeAdapters.CLASS_FACTORY);
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// type adapters for composite and user-defined types
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factories.add(new CollectionTypeAdapterFactory(constructorConstructor));
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factories.add(new MapTypeAdapterFactory(constructorConstructor, complexMapKeySerialization));
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this.jsonAdapterFactory = new JsonAdapterAnnotationTypeAdapterFactory(constructorConstructor);
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factories.add(jsonAdapterFactory);
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factories.add(TypeAdapters.ENUM_FACTORY);
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factories.add(new ReflectiveTypeAdapterFactory(
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constructorConstructor, fieldNamingStrategy, excluder, jsonAdapterFactory));
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this.factories = Collections.unmodifiableList(factories);
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}
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public Excluder excluder() {
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return excluder;
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}
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public FieldNamingStrategy fieldNamingStrategy() {
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return fieldNamingStrategy;
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}
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public boolean serializeNulls() {
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return serializeNulls;
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}
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public boolean htmlSafe() {
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return htmlSafe;
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}
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private TypeAdapter<Number> doubleAdapter(boolean serializeSpecialFloatingPointValues) {
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if (serializeSpecialFloatingPointValues) {
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return TypeAdapters.DOUBLE;
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}
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return new TypeAdapter<Number>() {
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@Override public Double read(JsonReader in) throws IOException {
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if (in.peek() == JsonToken.NULL) {
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in.nextNull();
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return null;
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}
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return in.nextDouble();
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}
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@Override public void write(JsonWriter out, Number value) throws IOException {
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if (value == null) {
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out.nullValue();
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return;
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}
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double doubleValue = value.doubleValue();
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checkValidFloatingPoint(doubleValue);
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out.value(value);
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}
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};
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}
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private TypeAdapter<Number> floatAdapter(boolean serializeSpecialFloatingPointValues) {
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if (serializeSpecialFloatingPointValues) {
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return TypeAdapters.FLOAT;
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}
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return new TypeAdapter<Number>() {
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@Override public Float read(JsonReader in) throws IOException {
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if (in.peek() == JsonToken.NULL) {
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in.nextNull();
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return null;
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}
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return (float) in.nextDouble();
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}
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@Override public void write(JsonWriter out, Number value) throws IOException {
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if (value == null) {
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out.nullValue();
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return;
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}
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float floatValue = value.floatValue();
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checkValidFloatingPoint(floatValue);
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out.value(value);
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}
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};
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}
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static void checkValidFloatingPoint(double value) {
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if (Double.isNaN(value) || Double.isInfinite(value)) {
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throw new IllegalArgumentException(value
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+ " is not a valid double value as per JSON specification. To override this"
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+ " behavior, use GsonBuilder.serializeSpecialFloatingPointValues() method.");
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}
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}
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private static TypeAdapter<Number> longAdapter(LongSerializationPolicy longSerializationPolicy) {
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if (longSerializationPolicy == LongSerializationPolicy.DEFAULT) {
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return TypeAdapters.LONG;
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}
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return new TypeAdapter<Number>() {
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@Override public Number read(JsonReader in) throws IOException {
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if (in.peek() == JsonToken.NULL) {
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in.nextNull();
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return null;
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}
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return in.nextLong();
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}
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@Override public void write(JsonWriter out, Number value) throws IOException {
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if (value == null) {
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out.nullValue();
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return;
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}
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out.value(value.toString());
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}
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};
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}
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private static TypeAdapter<AtomicLong> atomicLongAdapter(final TypeAdapter<Number> longAdapter) {
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return new TypeAdapter<AtomicLong>() {
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@Override public void write(JsonWriter out, AtomicLong value) throws IOException {
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longAdapter.write(out, value.get());
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}
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@Override public AtomicLong read(JsonReader in) throws IOException {
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Number value = longAdapter.read(in);
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return new AtomicLong(value.longValue());
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}
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}.nullSafe();
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}
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private static TypeAdapter<AtomicLongArray> atomicLongArrayAdapter(final TypeAdapter<Number> longAdapter) {
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return new TypeAdapter<AtomicLongArray>() {
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@Override public void write(JsonWriter out, AtomicLongArray value) throws IOException {
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out.beginArray();
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for (int i = 0, length = value.length(); i < length; i++) {
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longAdapter.write(out, value.get(i));
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}
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out.endArray();
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}
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@Override public AtomicLongArray read(JsonReader in) throws IOException {
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List<Long> list = new ArrayList<Long>();
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in.beginArray();
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while (in.hasNext()) {
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long value = longAdapter.read(in).longValue();
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list.add(value);
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}
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in.endArray();
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int length = list.size();
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AtomicLongArray array = new AtomicLongArray(length);
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for (int i = 0; i < length; ++i) {
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array.set(i, list.get(i));
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}
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return array;
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}
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}.nullSafe();
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}
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/**
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* Returns the type adapter for {@code} type.
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*
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* @throws IllegalArgumentException if this GSON cannot serialize and
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* deserialize {@code type}.
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*/
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@SuppressWarnings("unchecked")
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public <T> TypeAdapter<T> getAdapter(TypeToken<T> type) {
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TypeAdapter<?> cached = typeTokenCache.get(type == null ? NULL_KEY_SURROGATE : type);
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if (cached != null) {
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return (TypeAdapter<T>) cached;
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}
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Map<TypeToken<?>, FutureTypeAdapter<?>> threadCalls = calls.get();
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boolean requiresThreadLocalCleanup = false;
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if (threadCalls == null) {
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threadCalls = new HashMap<TypeToken<?>, FutureTypeAdapter<?>>();
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calls.set(threadCalls);
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requiresThreadLocalCleanup = true;
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}
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// the key and value type parameters always agree
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FutureTypeAdapter<T> ongoingCall = (FutureTypeAdapter<T>) threadCalls.get(type);
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if (ongoingCall != null) {
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return ongoingCall;
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}
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try {
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FutureTypeAdapter<T> call = new FutureTypeAdapter<T>();
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threadCalls.put(type, call);
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for (TypeAdapterFactory factory : factories) {
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TypeAdapter<T> candidate = factory.create(this, type);
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if (candidate != null) {
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call.setDelegate(candidate);
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typeTokenCache.put(type, candidate);
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return candidate;
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}
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}
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throw new IllegalArgumentException("GSON cannot handle " + type);
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} finally {
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threadCalls.remove(type);
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if (requiresThreadLocalCleanup) {
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calls.remove();
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}
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}
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}
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/**
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* This method is used to get an alternate type adapter for the specified type. This is used
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* to access a type adapter that is overridden by a {@link TypeAdapterFactory} that you
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* may have registered. This features is typically used when you want to register a type
|
|
* adapter that does a little bit of work but then delegates further processing to the Gson
|
|
* default type adapter. Here is an example:
|
|
* <p>Let's say we want to write a type adapter that counts the number of objects being read
|
|
* from or written to JSON. We can achieve this by writing a type adapter factory that uses
|
|
* the <code>getDelegateAdapter</code> method:
|
|
* <pre> {@code
|
|
* class StatsTypeAdapterFactory implements TypeAdapterFactory {
|
|
* public int numReads = 0;
|
|
* public int numWrites = 0;
|
|
* public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
|
|
* final TypeAdapter<T> delegate = gson.getDelegateAdapter(this, type);
|
|
* return new TypeAdapter<T>() {
|
|
* public void write(JsonWriter out, T value) throws IOException {
|
|
* ++numWrites;
|
|
* delegate.write(out, value);
|
|
* }
|
|
* public T read(JsonReader in) throws IOException {
|
|
* ++numReads;
|
|
* return delegate.read(in);
|
|
* }
|
|
* };
|
|
* }
|
|
* }
|
|
* } </pre>
|
|
* This factory can now be used like this:
|
|
* <pre> {@code
|
|
* StatsTypeAdapterFactory stats = new StatsTypeAdapterFactory();
|
|
* Gson gson = new GsonBuilder().registerTypeAdapterFactory(stats).create();
|
|
* // Call gson.toJson() and fromJson methods on objects
|
|
* System.out.println("Num JSON reads" + stats.numReads);
|
|
* System.out.println("Num JSON writes" + stats.numWrites);
|
|
* }</pre>
|
|
* Note that this call will skip all factories registered before {@code skipPast}. In case of
|
|
* multiple TypeAdapterFactories registered it is up to the caller of this function to insure
|
|
* that the order of registration does not prevent this method from reaching a factory they
|
|
* would expect to reply from this call.
|
|
* Note that since you can not override type adapter factories for String and Java primitive
|
|
* types, our stats factory will not count the number of String or primitives that will be
|
|
* read or written.
|
|
* @param skipPast The type adapter factory that needs to be skipped while searching for
|
|
* a matching type adapter. In most cases, you should just pass <i>this</i> (the type adapter
|
|
* factory from where {@link #getDelegateAdapter} method is being invoked).
|
|
* @param type Type for which the delegate adapter is being searched for.
|
|
*
|
|
* @since 2.2
|
|
*/
|
|
public <T> TypeAdapter<T> getDelegateAdapter(TypeAdapterFactory skipPast, TypeToken<T> type) {
|
|
// If the specified skipPast factory is not registered, ignore it.
|
|
boolean skipPastFound = skipPast == null
|
|
|| (!factories.contains(skipPast) && jsonAdapterFactory.getDelegateAdapterFactory(type) == null);
|
|
|
|
for (TypeAdapterFactory factory : factories) {
|
|
if (!skipPastFound) {
|
|
skipPastFound = factory == skipPast;
|
|
if (!skipPastFound && factory instanceof JsonAdapterAnnotationTypeAdapterFactory) {
|
|
// Also check if there is a registered JsonAdapter for it
|
|
factory = ((JsonAdapterAnnotationTypeAdapterFactory)factory).getDelegateAdapterFactory(type);
|
|
skipPastFound = factory == skipPast;
|
|
}
|
|
continue;
|
|
}
|
|
TypeAdapter<T> candidate = factory.create(this, type);
|
|
if (candidate != null) {
|
|
return candidate;
|
|
}
|
|
}
|
|
throw new IllegalArgumentException("GSON cannot serialize or deserialize " + type);
|
|
}
|
|
|
|
/**
|
|
* Returns the type adapter for {@code} type.
|
|
*
|
|
* @throws IllegalArgumentException if this GSON cannot serialize and
|
|
* deserialize {@code type}.
|
|
*/
|
|
public <T> TypeAdapter<T> getAdapter(Class<T> type) {
|
|
return getAdapter(TypeToken.get(type));
|
|
}
|
|
|
|
/**
|
|
* This method serializes the specified object into its equivalent representation as a tree of
|
|
* {@link JsonElement}s. This method should be used when the specified object is not a generic
|
|
* type. This method uses {@link Class#getClass()} to get the type for the specified object, but
|
|
* the {@code getClass()} loses the generic type information because of the Type Erasure feature
|
|
* of Java. Note that this method works fine if the any of the object fields are of generic type,
|
|
* just the object itself should not be of a generic type. If the object is of generic type, use
|
|
* {@link #toJsonTree(Object, Type)} instead.
|
|
*
|
|
* @param src the object for which Json representation is to be created setting for Gson
|
|
* @return Json representation of {@code src}.
|
|
* @since 1.4
|
|
*/
|
|
public JsonElement toJsonTree(Object src) {
|
|
if (src == null) {
|
|
return JsonNull.INSTANCE;
|
|
}
|
|
return toJsonTree(src, src.getClass());
|
|
}
|
|
|
|
/**
|
|
* This method serializes the specified object, including those of generic types, into its
|
|
* equivalent representation as a tree of {@link JsonElement}s. This method must be used if the
|
|
* specified object is a generic type. For non-generic objects, use {@link #toJsonTree(Object)}
|
|
* instead.
|
|
*
|
|
* @param src the object for which JSON representation is to be created
|
|
* @param typeOfSrc The specific genericized type of src. You can obtain
|
|
* this type by using the {@link com.google.gson.reflect.TypeToken} class. For example,
|
|
* to get the type for {@code Collection<Foo>}, you should use:
|
|
* <pre>
|
|
* Type typeOfSrc = new TypeToken<Collection<Foo>>(){}.getType();
|
|
* </pre>
|
|
* @return Json representation of {@code src}
|
|
* @since 1.4
|
|
*/
|
|
public JsonElement toJsonTree(Object src, Type typeOfSrc) {
|
|
JsonTreeWriter writer = new JsonTreeWriter();
|
|
toJson(src, typeOfSrc, writer);
|
|
return writer.get();
|
|
}
|
|
|
|
/**
|
|
* This method serializes the specified object into its equivalent Json representation.
|
|
* This method should be used when the specified object is not a generic type. This method uses
|
|
* {@link Class#getClass()} to get the type for the specified object, but the
|
|
* {@code getClass()} loses the generic type information because of the Type Erasure feature
|
|
* of Java. Note that this method works fine if the any of the object fields are of generic type,
|
|
* just the object itself should not be of a generic type. If the object is of generic type, use
|
|
* {@link #toJson(Object, Type)} instead. If you want to write out the object to a
|
|
* {@link Writer}, use {@link #toJson(Object, Appendable)} instead.
|
|
*
|
|
* @param src the object for which Json representation is to be created setting for Gson
|
|
* @return Json representation of {@code src}.
|
|
*/
|
|
public String toJson(Object src) {
|
|
if (src == null) {
|
|
return toJson(JsonNull.INSTANCE);
|
|
}
|
|
return toJson(src, src.getClass());
|
|
}
|
|
|
|
/**
|
|
* This method serializes the specified object, including those of generic types, into its
|
|
* equivalent Json representation. This method must be used if the specified object is a generic
|
|
* type. For non-generic objects, use {@link #toJson(Object)} instead. If you want to write out
|
|
* the object to a {@link Appendable}, use {@link #toJson(Object, Type, Appendable)} instead.
|
|
*
|
|
* @param src the object for which JSON representation is to be created
|
|
* @param typeOfSrc The specific genericized type of src. You can obtain
|
|
* this type by using the {@link com.google.gson.reflect.TypeToken} class. For example,
|
|
* to get the type for {@code Collection<Foo>}, you should use:
|
|
* <pre>
|
|
* Type typeOfSrc = new TypeToken<Collection<Foo>>(){}.getType();
|
|
* </pre>
|
|
* @return Json representation of {@code src}
|
|
*/
|
|
public String toJson(Object src, Type typeOfSrc) {
|
|
StringWriter writer = new StringWriter();
|
|
toJson(src, typeOfSrc, writer);
|
|
return writer.toString();
|
|
}
|
|
|
|
/**
|
|
* This method serializes the specified object into its equivalent Json representation.
|
|
* This method should be used when the specified object is not a generic type. This method uses
|
|
* {@link Class#getClass()} to get the type for the specified object, but the
|
|
* {@code getClass()} loses the generic type information because of the Type Erasure feature
|
|
* of Java. Note that this method works fine if the any of the object fields are of generic type,
|
|
* just the object itself should not be of a generic type. If the object is of generic type, use
|
|
* {@link #toJson(Object, Type, Appendable)} instead.
|
|
*
|
|
* @param src the object for which Json representation is to be created setting for Gson
|
|
* @param writer Writer to which the Json representation needs to be written
|
|
* @throws JsonIOException if there was a problem writing to the writer
|
|
* @since 1.2
|
|
*/
|
|
public void toJson(Object src, Appendable writer) throws JsonIOException {
|
|
if (src != null) {
|
|
toJson(src, src.getClass(), writer);
|
|
} else {
|
|
toJson(JsonNull.INSTANCE, writer);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* This method serializes the specified object, including those of generic types, into its
|
|
* equivalent Json representation. This method must be used if the specified object is a generic
|
|
* type. For non-generic objects, use {@link #toJson(Object, Appendable)} instead.
|
|
*
|
|
* @param src the object for which JSON representation is to be created
|
|
* @param typeOfSrc The specific genericized type of src. You can obtain
|
|
* this type by using the {@link com.google.gson.reflect.TypeToken} class. For example,
|
|
* to get the type for {@code Collection<Foo>}, you should use:
|
|
* <pre>
|
|
* Type typeOfSrc = new TypeToken<Collection<Foo>>(){}.getType();
|
|
* </pre>
|
|
* @param writer Writer to which the Json representation of src needs to be written.
|
|
* @throws JsonIOException if there was a problem writing to the writer
|
|
* @since 1.2
|
|
*/
|
|
public void toJson(Object src, Type typeOfSrc, Appendable writer) throws JsonIOException {
|
|
try {
|
|
JsonWriter jsonWriter = newJsonWriter(Streams.writerForAppendable(writer));
|
|
toJson(src, typeOfSrc, jsonWriter);
|
|
} catch (IOException e) {
|
|
throw new JsonIOException(e);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Writes the JSON representation of {@code src} of type {@code typeOfSrc} to
|
|
* {@code writer}.
|
|
* @throws JsonIOException if there was a problem writing to the writer
|
|
*/
|
|
@SuppressWarnings("unchecked")
|
|
public void toJson(Object src, Type typeOfSrc, JsonWriter writer) throws JsonIOException {
|
|
TypeAdapter<?> adapter = getAdapter(TypeToken.get(typeOfSrc));
|
|
boolean oldLenient = writer.isLenient();
|
|
writer.setLenient(true);
|
|
boolean oldHtmlSafe = writer.isHtmlSafe();
|
|
writer.setHtmlSafe(htmlSafe);
|
|
boolean oldSerializeNulls = writer.getSerializeNulls();
|
|
writer.setSerializeNulls(serializeNulls);
|
|
try {
|
|
((TypeAdapter<Object>) adapter).write(writer, src);
|
|
} catch (IOException e) {
|
|
throw new JsonIOException(e);
|
|
} finally {
|
|
writer.setLenient(oldLenient);
|
|
writer.setHtmlSafe(oldHtmlSafe);
|
|
writer.setSerializeNulls(oldSerializeNulls);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Converts a tree of {@link JsonElement}s into its equivalent JSON representation.
|
|
*
|
|
* @param jsonElement root of a tree of {@link JsonElement}s
|
|
* @return JSON String representation of the tree
|
|
* @since 1.4
|
|
*/
|
|
public String toJson(JsonElement jsonElement) {
|
|
StringWriter writer = new StringWriter();
|
|
toJson(jsonElement, writer);
|
|
return writer.toString();
|
|
}
|
|
|
|
/**
|
|
* Writes out the equivalent JSON for a tree of {@link JsonElement}s.
|
|
*
|
|
* @param jsonElement root of a tree of {@link JsonElement}s
|
|
* @param writer Writer to which the Json representation needs to be written
|
|
* @throws JsonIOException if there was a problem writing to the writer
|
|
* @since 1.4
|
|
*/
|
|
public void toJson(JsonElement jsonElement, Appendable writer) throws JsonIOException {
|
|
try {
|
|
JsonWriter jsonWriter = newJsonWriter(Streams.writerForAppendable(writer));
|
|
toJson(jsonElement, jsonWriter);
|
|
} catch (IOException e) {
|
|
throw new JsonIOException(e);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Returns a new JSON writer configured for the settings on this Gson instance.
|
|
*/
|
|
public JsonWriter newJsonWriter(Writer writer) throws IOException {
|
|
if (generateNonExecutableJson) {
|
|
writer.write(JSON_NON_EXECUTABLE_PREFIX);
|
|
}
|
|
JsonWriter jsonWriter = new JsonWriter(writer);
|
|
if (prettyPrinting) {
|
|
jsonWriter.setIndent(" ");
|
|
}
|
|
jsonWriter.setSerializeNulls(serializeNulls);
|
|
return jsonWriter;
|
|
}
|
|
|
|
/**
|
|
* Returns a new JSON reader configured for the settings on this Gson instance.
|
|
*/
|
|
public JsonReader newJsonReader(Reader reader) {
|
|
JsonReader jsonReader = new JsonReader(reader);
|
|
jsonReader.setLenient(lenient);
|
|
return jsonReader;
|
|
}
|
|
|
|
/**
|
|
* Writes the JSON for {@code jsonElement} to {@code writer}.
|
|
* @throws JsonIOException if there was a problem writing to the writer
|
|
*/
|
|
public void toJson(JsonElement jsonElement, JsonWriter writer) throws JsonIOException {
|
|
boolean oldLenient = writer.isLenient();
|
|
writer.setLenient(true);
|
|
boolean oldHtmlSafe = writer.isHtmlSafe();
|
|
writer.setHtmlSafe(htmlSafe);
|
|
boolean oldSerializeNulls = writer.getSerializeNulls();
|
|
writer.setSerializeNulls(serializeNulls);
|
|
try {
|
|
Streams.write(jsonElement, writer);
|
|
} catch (IOException e) {
|
|
throw new JsonIOException(e);
|
|
} finally {
|
|
writer.setLenient(oldLenient);
|
|
writer.setHtmlSafe(oldHtmlSafe);
|
|
writer.setSerializeNulls(oldSerializeNulls);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* This method deserializes the specified Json into an object of the specified class. It is not
|
|
* suitable to use if the specified class is a generic type since it will not have the generic
|
|
* type information because of the Type Erasure feature of Java. Therefore, this method should not
|
|
* be used if the desired type is a generic type. Note that this method works fine if the any of
|
|
* the fields of the specified object are generics, just the object itself should not be a
|
|
* generic type. For the cases when the object is of generic type, invoke
|
|
* {@link #fromJson(String, Type)}. If you have the Json in a {@link Reader} instead of
|
|
* a String, use {@link #fromJson(Reader, Class)} instead.
|
|
*
|
|
* @param <T> the type of the desired object
|
|
* @param json the string from which the object is to be deserialized
|
|
* @param classOfT the class of T
|
|
* @return an object of type T from the string. Returns {@code null} if {@code json} is {@code null}.
|
|
* @throws JsonSyntaxException if json is not a valid representation for an object of type
|
|
* classOfT
|
|
*/
|
|
public <T> T fromJson(String json, Class<T> classOfT) throws JsonSyntaxException {
|
|
Object object = fromJson(json, (Type) classOfT);
|
|
return Primitives.wrap(classOfT).cast(object);
|
|
}
|
|
|
|
/**
|
|
* This method deserializes the specified Json into an object of the specified type. This method
|
|
* is useful if the specified object is a generic type. For non-generic objects, use
|
|
* {@link #fromJson(String, Class)} instead. If you have the Json in a {@link Reader} instead of
|
|
* a String, use {@link #fromJson(Reader, Type)} instead.
|
|
*
|
|
* @param <T> the type of the desired object
|
|
* @param json the string from which the object is to be deserialized
|
|
* @param typeOfT The specific genericized type of src. You can obtain this type by using the
|
|
* {@link com.google.gson.reflect.TypeToken} class. For example, to get the type for
|
|
* {@code Collection<Foo>}, you should use:
|
|
* <pre>
|
|
* Type typeOfT = new TypeToken<Collection<Foo>>(){}.getType();
|
|
* </pre>
|
|
* @return an object of type T from the string. Returns {@code null} if {@code json} is {@code null}.
|
|
* @throws JsonParseException if json is not a valid representation for an object of type typeOfT
|
|
* @throws JsonSyntaxException if json is not a valid representation for an object of type
|
|
*/
|
|
@SuppressWarnings("unchecked")
|
|
public <T> T fromJson(String json, Type typeOfT) throws JsonSyntaxException {
|
|
if (json == null) {
|
|
return null;
|
|
}
|
|
StringReader reader = new StringReader(json);
|
|
T target = (T) fromJson(reader, typeOfT);
|
|
return target;
|
|
}
|
|
|
|
/**
|
|
* This method deserializes the Json read from the specified reader into an object of the
|
|
* specified class. It is not suitable to use if the specified class is a generic type since it
|
|
* will not have the generic type information because of the Type Erasure feature of Java.
|
|
* Therefore, this method should not be used if the desired type is a generic type. Note that
|
|
* this method works fine if the any of the fields of the specified object are generics, just the
|
|
* object itself should not be a generic type. For the cases when the object is of generic type,
|
|
* invoke {@link #fromJson(Reader, Type)}. If you have the Json in a String form instead of a
|
|
* {@link Reader}, use {@link #fromJson(String, Class)} instead.
|
|
*
|
|
* @param <T> the type of the desired object
|
|
* @param json the reader producing the Json from which the object is to be deserialized.
|
|
* @param classOfT the class of T
|
|
* @return an object of type T from the string. Returns {@code null} if {@code json} is at EOF.
|
|
* @throws JsonIOException if there was a problem reading from the Reader
|
|
* @throws JsonSyntaxException if json is not a valid representation for an object of type
|
|
* @since 1.2
|
|
*/
|
|
public <T> T fromJson(Reader json, Class<T> classOfT) throws JsonSyntaxException, JsonIOException {
|
|
JsonReader jsonReader = newJsonReader(json);
|
|
Object object = fromJson(jsonReader, classOfT);
|
|
assertFullConsumption(object, jsonReader);
|
|
return Primitives.wrap(classOfT).cast(object);
|
|
}
|
|
|
|
/**
|
|
* This method deserializes the Json read from the specified reader into an object of the
|
|
* specified type. This method is useful if the specified object is a generic type. For
|
|
* non-generic objects, use {@link #fromJson(Reader, Class)} instead. If you have the Json in a
|
|
* String form instead of a {@link Reader}, use {@link #fromJson(String, Type)} instead.
|
|
*
|
|
* @param <T> the type of the desired object
|
|
* @param json the reader producing Json from which the object is to be deserialized
|
|
* @param typeOfT The specific genericized type of src. You can obtain this type by using the
|
|
* {@link com.google.gson.reflect.TypeToken} class. For example, to get the type for
|
|
* {@code Collection<Foo>}, you should use:
|
|
* <pre>
|
|
* Type typeOfT = new TypeToken<Collection<Foo>>(){}.getType();
|
|
* </pre>
|
|
* @return an object of type T from the json. Returns {@code null} if {@code json} is at EOF.
|
|
* @throws JsonIOException if there was a problem reading from the Reader
|
|
* @throws JsonSyntaxException if json is not a valid representation for an object of type
|
|
* @since 1.2
|
|
*/
|
|
@SuppressWarnings("unchecked")
|
|
public <T> T fromJson(Reader json, Type typeOfT) throws JsonIOException, JsonSyntaxException {
|
|
JsonReader jsonReader = newJsonReader(json);
|
|
T object = (T) fromJson(jsonReader, typeOfT);
|
|
assertFullConsumption(object, jsonReader);
|
|
return object;
|
|
}
|
|
|
|
private static void assertFullConsumption(Object obj, JsonReader reader) {
|
|
try {
|
|
if (obj != null && reader.peek() != JsonToken.END_DOCUMENT) {
|
|
throw new JsonIOException("JSON document was not fully consumed.");
|
|
}
|
|
} catch (MalformedJsonException e) {
|
|
throw new JsonSyntaxException(e);
|
|
} catch (IOException e) {
|
|
throw new JsonIOException(e);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Reads the next JSON value from {@code reader} and convert it to an object
|
|
* of type {@code typeOfT}. Returns {@code null}, if the {@code reader} is at EOF.
|
|
* Since Type is not parameterized by T, this method is type unsafe and should be used carefully
|
|
*
|
|
* @throws JsonIOException if there was a problem writing to the Reader
|
|
* @throws JsonSyntaxException if json is not a valid representation for an object of type
|
|
*/
|
|
@SuppressWarnings("unchecked")
|
|
public <T> T fromJson(JsonReader reader, Type typeOfT) throws JsonIOException, JsonSyntaxException {
|
|
boolean isEmpty = true;
|
|
boolean oldLenient = reader.isLenient();
|
|
reader.setLenient(true);
|
|
try {
|
|
reader.peek();
|
|
isEmpty = false;
|
|
TypeToken<T> typeToken = (TypeToken<T>) TypeToken.get(typeOfT);
|
|
TypeAdapter<T> typeAdapter = getAdapter(typeToken);
|
|
T object = typeAdapter.read(reader);
|
|
return object;
|
|
} catch (EOFException e) {
|
|
/*
|
|
* For compatibility with JSON 1.5 and earlier, we return null for empty
|
|
* documents instead of throwing.
|
|
*/
|
|
if (isEmpty) {
|
|
return null;
|
|
}
|
|
throw new JsonSyntaxException(e);
|
|
} catch (IllegalStateException e) {
|
|
throw new JsonSyntaxException(e);
|
|
} catch (IOException e) {
|
|
// TODO(inder): Figure out whether it is indeed right to rethrow this as JsonSyntaxException
|
|
throw new JsonSyntaxException(e);
|
|
} finally {
|
|
reader.setLenient(oldLenient);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* This method deserializes the Json read from the specified parse tree into an object of the
|
|
* specified type. It is not suitable to use if the specified class is a generic type since it
|
|
* will not have the generic type information because of the Type Erasure feature of Java.
|
|
* Therefore, this method should not be used if the desired type is a generic type. Note that
|
|
* this method works fine if the any of the fields of the specified object are generics, just the
|
|
* object itself should not be a generic type. For the cases when the object is of generic type,
|
|
* invoke {@link #fromJson(JsonElement, Type)}.
|
|
* @param <T> the type of the desired object
|
|
* @param json the root of the parse tree of {@link JsonElement}s from which the object is to
|
|
* be deserialized
|
|
* @param classOfT The class of T
|
|
* @return an object of type T from the json. Returns {@code null} if {@code json} is {@code null}.
|
|
* @throws JsonSyntaxException if json is not a valid representation for an object of type typeOfT
|
|
* @since 1.3
|
|
*/
|
|
public <T> T fromJson(JsonElement json, Class<T> classOfT) throws JsonSyntaxException {
|
|
Object object = fromJson(json, (Type) classOfT);
|
|
return Primitives.wrap(classOfT).cast(object);
|
|
}
|
|
|
|
/**
|
|
* This method deserializes the Json read from the specified parse tree into an object of the
|
|
* specified type. This method is useful if the specified object is a generic type. For
|
|
* non-generic objects, use {@link #fromJson(JsonElement, Class)} instead.
|
|
*
|
|
* @param <T> the type of the desired object
|
|
* @param json the root of the parse tree of {@link JsonElement}s from which the object is to
|
|
* be deserialized
|
|
* @param typeOfT The specific genericized type of src. You can obtain this type by using the
|
|
* {@link com.google.gson.reflect.TypeToken} class. For example, to get the type for
|
|
* {@code Collection<Foo>}, you should use:
|
|
* <pre>
|
|
* Type typeOfT = new TypeToken<Collection<Foo>>(){}.getType();
|
|
* </pre>
|
|
* @return an object of type T from the json. Returns {@code null} if {@code json} is {@code null}.
|
|
* @throws JsonSyntaxException if json is not a valid representation for an object of type typeOfT
|
|
* @since 1.3
|
|
*/
|
|
@SuppressWarnings("unchecked")
|
|
public <T> T fromJson(JsonElement json, Type typeOfT) throws JsonSyntaxException {
|
|
if (json == null) {
|
|
return null;
|
|
}
|
|
return (T) fromJson(new JsonTreeReader(json), typeOfT);
|
|
}
|
|
|
|
static class FutureTypeAdapter<T> extends TypeAdapter<T> {
|
|
private TypeAdapter<T> delegate;
|
|
|
|
public void setDelegate(TypeAdapter<T> typeAdapter) {
|
|
if (delegate != null) {
|
|
throw new AssertionError();
|
|
}
|
|
delegate = typeAdapter;
|
|
}
|
|
|
|
@Override public T read(JsonReader in) throws IOException {
|
|
if (delegate == null) {
|
|
throw new IllegalStateException();
|
|
}
|
|
return delegate.read(in);
|
|
}
|
|
|
|
@Override public void write(JsonWriter out, T value) throws IOException {
|
|
if (delegate == null) {
|
|
throw new IllegalStateException();
|
|
}
|
|
delegate.write(out, value);
|
|
}
|
|
}
|
|
|
|
@Override
|
|
public String toString() {
|
|
return new StringBuilder("{serializeNulls:")
|
|
.append(serializeNulls)
|
|
.append("factories:").append(factories)
|
|
.append(",instanceCreators:").append(constructorConstructor)
|
|
.append("}")
|
|
.toString();
|
|
}
|
|
}
|