gson-comments/gson/src/main/java/com/google/gson/ParameterizedTypeHandlerMap...

114 lines
3.3 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 java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.logging.Level;
/**
* A map that provides ability to associate handlers for a specific type or all of its sub-types
*
* @author Inderjeet Singh
* @author Joel Leitch
*
* @param <T> The handler that will be looked up by type
*/
final class ParameterizedTypeHandlerMap<T> {
private final Map<Type, T> map = new HashMap<Type, T>();
private boolean modifiable = true;
public synchronized void register(Type typeOfT, T value) {
if (!modifiable) {
throw new IllegalStateException("Attempted to modify an unmodifiable map.");
}
if (hasSpecificHandlerFor(typeOfT)) {
Gson.logger.log(Level.WARNING, "Overriding the existing type handler for " + typeOfT);
}
map.put(typeOfT, value);
}
public synchronized void registerIfAbsent(ParameterizedTypeHandlerMap<T> other) {
if (!modifiable) {
throw new IllegalStateException("Attempted to modify an unmodifiable map.");
}
for (Map.Entry<Type, T> entry : other.entrySet()) {
if (!map.containsKey(entry.getKey())) {
register(entry.getKey(), entry.getValue());
}
}
}
public synchronized void makeUnmodifiable() {
modifiable = false;
}
public synchronized T getHandlerFor(Type type) {
T handler = map.get(type);
if (handler == null && type instanceof ParameterizedType) {
// a handler for a non-generic version is registered, so use that
Type rawType = ((ParameterizedType)type).getRawType();
handler = map.get(rawType);
}
return handler;
}
public synchronized boolean hasAnyHandlerFor(Type type) {
return getHandlerFor(type) != null;
}
public synchronized boolean hasSpecificHandlerFor(Type type) {
return map.containsKey(type);
}
public synchronized ParameterizedTypeHandlerMap<T> copyOf() {
ParameterizedTypeHandlerMap<T> copy = new ParameterizedTypeHandlerMap<T>();
for (Map.Entry<Type, T> entry : map.entrySet()) {
copy.register(entry.getKey(), entry.getValue());
}
return copy;
}
public synchronized Set<Map.Entry<Type, T>> entrySet() {
return map.entrySet();
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder("{");
boolean first = true;
for (Map.Entry<Type, T> entry : map.entrySet()) {
if (first) {
first = false;
} else {
sb.append(',');
}
sb.append(typeToString(entry.getKey())).append(':');
sb.append(entry.getValue());
}
return sb.toString();
}
private String typeToString(Type type) {
return TypeUtils.toRawClass(type).getSimpleName();
}
}