337 lines
12 KiB
Java
337 lines
12 KiB
Java
/*
|
|
* Copyright (C) 2008 Google Inc.
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
package com.google.gson;
|
|
|
|
import com.google.gson.internal.Streams;
|
|
import com.google.gson.stream.JsonWriter;
|
|
import java.io.IOException;
|
|
import java.io.StringWriter;
|
|
import java.math.BigDecimal;
|
|
import java.math.BigInteger;
|
|
|
|
/**
|
|
* A class representing an element of JSON. It could either be a {@link JsonObject}, a {@link
|
|
* JsonArray}, a {@link JsonPrimitive} or a {@link JsonNull}.
|
|
*
|
|
* @author Inderjeet Singh
|
|
* @author Joel Leitch
|
|
*/
|
|
public abstract class JsonElement {
|
|
/**
|
|
* @deprecated Creating custom {@code JsonElement} subclasses is highly discouraged and can lead
|
|
* to undefined behavior.<br>
|
|
* This constructor is only kept for backward compatibility.
|
|
*/
|
|
@Deprecated
|
|
public JsonElement() {}
|
|
|
|
/**
|
|
* Returns a deep copy of this element. Immutable elements like primitives and nulls are not
|
|
* copied.
|
|
*
|
|
* @since 2.8.2
|
|
*/
|
|
public abstract JsonElement deepCopy();
|
|
|
|
/**
|
|
* Provides a check for verifying if this element is a JSON array or not.
|
|
*
|
|
* @return true if this element is of type {@link JsonArray}, false otherwise.
|
|
*/
|
|
public boolean isJsonArray() {
|
|
return this instanceof JsonArray;
|
|
}
|
|
|
|
/**
|
|
* Provides a check for verifying if this element is a JSON object or not.
|
|
*
|
|
* @return true if this element is of type {@link JsonObject}, false otherwise.
|
|
*/
|
|
public boolean isJsonObject() {
|
|
return this instanceof JsonObject;
|
|
}
|
|
|
|
/**
|
|
* Provides a check for verifying if this element is a primitive or not.
|
|
*
|
|
* @return true if this element is of type {@link JsonPrimitive}, false otherwise.
|
|
*/
|
|
public boolean isJsonPrimitive() {
|
|
return this instanceof JsonPrimitive;
|
|
}
|
|
|
|
/**
|
|
* Provides a check for verifying if this element represents a null value or not.
|
|
*
|
|
* @return true if this element is of type {@link JsonNull}, false otherwise.
|
|
* @since 1.2
|
|
*/
|
|
public boolean isJsonNull() {
|
|
return this instanceof JsonNull;
|
|
}
|
|
|
|
/**
|
|
* Convenience method to get this element as a {@link JsonObject}. If this element is of some
|
|
* other type, an {@link IllegalStateException} will result. Hence it is best to use this method
|
|
* after ensuring that this element is of the desired type by calling {@link #isJsonObject()}
|
|
* first.
|
|
*
|
|
* @return this element as a {@link JsonObject}.
|
|
* @throws IllegalStateException if this element is of another type.
|
|
*/
|
|
public JsonObject getAsJsonObject() {
|
|
if (isJsonObject()) {
|
|
return (JsonObject) this;
|
|
}
|
|
throw new IllegalStateException("Not a JSON Object: " + this);
|
|
}
|
|
|
|
/**
|
|
* Convenience method to get this element as a {@link JsonArray}. If this element is of some other
|
|
* type, an {@link IllegalStateException} will result. Hence it is best to use this method after
|
|
* ensuring that this element is of the desired type by calling {@link #isJsonArray()} first.
|
|
*
|
|
* @return this element as a {@link JsonArray}.
|
|
* @throws IllegalStateException if this element is of another type.
|
|
*/
|
|
public JsonArray getAsJsonArray() {
|
|
if (isJsonArray()) {
|
|
return (JsonArray) this;
|
|
}
|
|
throw new IllegalStateException("Not a JSON Array: " + this);
|
|
}
|
|
|
|
/**
|
|
* Convenience method to get this element as a {@link JsonPrimitive}. If this element is of some
|
|
* other type, an {@link IllegalStateException} will result. Hence it is best to use this method
|
|
* after ensuring that this element is of the desired type by calling {@link #isJsonPrimitive()}
|
|
* first.
|
|
*
|
|
* @return this element as a {@link JsonPrimitive}.
|
|
* @throws IllegalStateException if this element is of another type.
|
|
*/
|
|
public JsonPrimitive getAsJsonPrimitive() {
|
|
if (isJsonPrimitive()) {
|
|
return (JsonPrimitive) this;
|
|
}
|
|
throw new IllegalStateException("Not a JSON Primitive: " + this);
|
|
}
|
|
|
|
/**
|
|
* Convenience method to get this element as a {@link JsonNull}. If this element is of some other
|
|
* type, an {@link IllegalStateException} will result. Hence it is best to use this method after
|
|
* ensuring that this element is of the desired type by calling {@link #isJsonNull()} first.
|
|
*
|
|
* @return this element as a {@link JsonNull}.
|
|
* @throws IllegalStateException if this element is of another type.
|
|
* @since 1.2
|
|
*/
|
|
public JsonNull getAsJsonNull() {
|
|
if (isJsonNull()) {
|
|
return (JsonNull) this;
|
|
}
|
|
throw new IllegalStateException("Not a JSON Null: " + this);
|
|
}
|
|
|
|
/**
|
|
* Convenience method to get this element as a boolean value.
|
|
*
|
|
* @return this element as a primitive boolean value.
|
|
* @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link
|
|
* JsonArray}.
|
|
* @throws IllegalStateException if this element is of the type {@link JsonArray} but contains
|
|
* more than a single element.
|
|
*/
|
|
public boolean getAsBoolean() {
|
|
throw new UnsupportedOperationException(getClass().getSimpleName());
|
|
}
|
|
|
|
/**
|
|
* Convenience method to get this element as a {@link Number}.
|
|
*
|
|
* @return this element as a {@link Number}.
|
|
* @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link
|
|
* JsonArray}, or cannot be converted to a number.
|
|
* @throws IllegalStateException if this element is of the type {@link JsonArray} but contains
|
|
* more than a single element.
|
|
*/
|
|
public Number getAsNumber() {
|
|
throw new UnsupportedOperationException(getClass().getSimpleName());
|
|
}
|
|
|
|
/**
|
|
* Convenience method to get this element as a string value.
|
|
*
|
|
* @return this element as a string value.
|
|
* @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link
|
|
* JsonArray}.
|
|
* @throws IllegalStateException if this element is of the type {@link JsonArray} but contains
|
|
* more than a single element.
|
|
*/
|
|
public String getAsString() {
|
|
throw new UnsupportedOperationException(getClass().getSimpleName());
|
|
}
|
|
|
|
/**
|
|
* Convenience method to get this element as a primitive double value.
|
|
*
|
|
* @return this element as a primitive double value.
|
|
* @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link
|
|
* JsonArray}.
|
|
* @throws NumberFormatException if the value contained is not a valid double.
|
|
* @throws IllegalStateException if this element is of the type {@link JsonArray} but contains
|
|
* more than a single element.
|
|
*/
|
|
public double getAsDouble() {
|
|
throw new UnsupportedOperationException(getClass().getSimpleName());
|
|
}
|
|
|
|
/**
|
|
* Convenience method to get this element as a primitive float value.
|
|
*
|
|
* @return this element as a primitive float value.
|
|
* @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link
|
|
* JsonArray}.
|
|
* @throws NumberFormatException if the value contained is not a valid float.
|
|
* @throws IllegalStateException if this element is of the type {@link JsonArray} but contains
|
|
* more than a single element.
|
|
*/
|
|
public float getAsFloat() {
|
|
throw new UnsupportedOperationException(getClass().getSimpleName());
|
|
}
|
|
|
|
/**
|
|
* Convenience method to get this element as a primitive long value.
|
|
*
|
|
* @return this element as a primitive long value.
|
|
* @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link
|
|
* JsonArray}.
|
|
* @throws NumberFormatException if the value contained is not a valid long.
|
|
* @throws IllegalStateException if this element is of the type {@link JsonArray} but contains
|
|
* more than a single element.
|
|
*/
|
|
public long getAsLong() {
|
|
throw new UnsupportedOperationException(getClass().getSimpleName());
|
|
}
|
|
|
|
/**
|
|
* Convenience method to get this element as a primitive integer value.
|
|
*
|
|
* @return this element as a primitive integer value.
|
|
* @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link
|
|
* JsonArray}.
|
|
* @throws NumberFormatException if the value contained is not a valid integer.
|
|
* @throws IllegalStateException if this element is of the type {@link JsonArray} but contains
|
|
* more than a single element.
|
|
*/
|
|
public int getAsInt() {
|
|
throw new UnsupportedOperationException(getClass().getSimpleName());
|
|
}
|
|
|
|
/**
|
|
* Convenience method to get this element as a primitive byte value.
|
|
*
|
|
* @return this element as a primitive byte value.
|
|
* @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link
|
|
* JsonArray}.
|
|
* @throws NumberFormatException if the value contained is not a valid byte.
|
|
* @throws IllegalStateException if this element is of the type {@link JsonArray} but contains
|
|
* more than a single element.
|
|
* @since 1.3
|
|
*/
|
|
public byte getAsByte() {
|
|
throw new UnsupportedOperationException(getClass().getSimpleName());
|
|
}
|
|
|
|
/**
|
|
* Convenience method to get the first character of the string value of this element.
|
|
*
|
|
* @return the first character of the string value.
|
|
* @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link
|
|
* JsonArray}, or if its string value is empty.
|
|
* @throws IllegalStateException if this element is of the type {@link JsonArray} but contains
|
|
* more than a single element.
|
|
* @since 1.3
|
|
* @deprecated This method is misleading, as it does not get this element as a char but rather as
|
|
* a string's first character.
|
|
*/
|
|
@Deprecated
|
|
public char getAsCharacter() {
|
|
throw new UnsupportedOperationException(getClass().getSimpleName());
|
|
}
|
|
|
|
/**
|
|
* Convenience method to get this element as a {@link BigDecimal}.
|
|
*
|
|
* @return this element as a {@link BigDecimal}.
|
|
* @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link
|
|
* JsonArray}.
|
|
* @throws NumberFormatException if this element is not a valid {@link BigDecimal}.
|
|
* @throws IllegalStateException if this element is of the type {@link JsonArray} but contains
|
|
* more than a single element.
|
|
* @since 1.2
|
|
*/
|
|
public BigDecimal getAsBigDecimal() {
|
|
throw new UnsupportedOperationException(getClass().getSimpleName());
|
|
}
|
|
|
|
/**
|
|
* Convenience method to get this element as a {@link BigInteger}.
|
|
*
|
|
* @return this element as a {@link BigInteger}.
|
|
* @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link
|
|
* JsonArray}.
|
|
* @throws NumberFormatException if this element is not a valid {@link BigInteger}.
|
|
* @throws IllegalStateException if this element is of the type {@link JsonArray} but contains
|
|
* more than a single element.
|
|
* @since 1.2
|
|
*/
|
|
public BigInteger getAsBigInteger() {
|
|
throw new UnsupportedOperationException(getClass().getSimpleName());
|
|
}
|
|
|
|
/**
|
|
* Convenience method to get this element as a primitive short value.
|
|
*
|
|
* @return this element as a primitive short value.
|
|
* @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link
|
|
* JsonArray}.
|
|
* @throws NumberFormatException if the value contained is not a valid short.
|
|
* @throws IllegalStateException if this element is of the type {@link JsonArray} but contains
|
|
* more than a single element.
|
|
*/
|
|
public short getAsShort() {
|
|
throw new UnsupportedOperationException(getClass().getSimpleName());
|
|
}
|
|
|
|
/** Returns a String representation of this element. */
|
|
@Override
|
|
public String toString() {
|
|
try {
|
|
StringWriter stringWriter = new StringWriter();
|
|
JsonWriter jsonWriter = new JsonWriter(stringWriter);
|
|
// Make writer lenient because toString() must not fail, even if for example JsonPrimitive
|
|
// contains NaN
|
|
jsonWriter.setStrictness(Strictness.LENIENT);
|
|
Streams.write(this, jsonWriter);
|
|
return stringWriter.toString();
|
|
} catch (IOException e) {
|
|
throw new AssertionError(e);
|
|
}
|
|
}
|
|
}
|