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/*
* Copyright (C) 2007 The Guava Authors
*
* 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.common.collect;
import com.google.common.collect.MapConstraints.ConstrainedMap;
import com.google.common.primitives.Primitives;
import java.util.HashMap;
import java.util.Map;
/**
* A mutable class-to-instance map backed by an arbitrary user-provided map.
* See also {@link ImmutableClassToInstanceMap}.
*
* <p>See the Guava User Guide article on <a href=
* "http://code.google.com/p/guava-libraries/wiki/NewCollectionTypesExplained#ClassToInstanceMap">
* {@code ClassToInstanceMap}</a>.
*
* @author Kevin Bourrillion
* @since 2.0 (imported from Google Collections Library)
*/
public final class MutableClassToInstanceMap<B>
extends ConstrainedMap<Class<? extends B>, B>
implements ClassToInstanceMap<B> {
/**
* Returns a new {@code MutableClassToInstanceMap} instance backed by a {@link
* HashMap} using the default initial capacity and load factor.
*/
public static <B> MutableClassToInstanceMap<B> create() {
return new MutableClassToInstanceMap<B>(
new HashMap<Class<? extends B>, B>());
}
/**
* Returns a new {@code MutableClassToInstanceMap} instance backed by a given
* empty {@code backingMap}. The caller surrenders control of the backing map,
* and thus should not allow any direct references to it to remain accessible.
*/
public static <B> MutableClassToInstanceMap<B> create(
Map<Class<? extends B>, B> backingMap) {
return new MutableClassToInstanceMap<B>(backingMap);
}
private MutableClassToInstanceMap(Map<Class<? extends B>, B> delegate) {
super(delegate, VALUE_CAN_BE_CAST_TO_KEY);
}
private static final MapConstraint<Class<?>, Object> VALUE_CAN_BE_CAST_TO_KEY
= new MapConstraint<Class<?>, Object>() {
@Override
public void checkKeyValue(Class<?> key, Object value) {
cast(key, value);
}
};
@Override
public <T extends B> T putInstance(Class<T> type, T value) {
return cast(type, put(type, value));
}
@Override
public <T extends B> T getInstance(Class<T> type) {
return cast(type, get(type));
}
private static <B, T extends B> T cast(Class<T> type, B value) {
return Primitives.wrap(type).cast(value);
}
private static final long serialVersionUID = 0;
}
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