com.google.common.collect.MutableClassToInstanceMap Maven / Gradle / Ivy
/*
* 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 static com.google.common.base.Preconditions.checkNotNull;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.primitives.Primitives;
import java.io.Serializable;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Set;
import java.util.Spliterator;
/**
* A mutable class-to-instance map backed by an arbitrary user-provided map. See also {@link
* ImmutableClassToInstanceMap}.
*
* See the Guava User Guide article on {@code
* ClassToInstanceMap}.
*
* @author Kevin Bourrillion
* @since 2.0
*/
@GwtIncompatible
@SuppressWarnings("serial") // using writeReplace instead of standard serialization
public final class MutableClassToInstanceMap extends ForwardingMap, B>
implements ClassToInstanceMap, Serializable {
/**
* Returns a new {@code MutableClassToInstanceMap} instance backed by a {@link HashMap} using the
* default initial capacity and load factor.
*/
public static MutableClassToInstanceMap create() {
return new MutableClassToInstanceMap(new HashMap, 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 MutableClassToInstanceMap create(Map, B> backingMap) {
return new MutableClassToInstanceMap(backingMap);
}
private final Map, B> delegate;
private MutableClassToInstanceMap(Map, B> delegate) {
this.delegate = checkNotNull(delegate);
}
@Override
protected Map, B> delegate() {
return delegate;
}
/**
* Wraps the {@code setValue} implementation of an {@code Entry} to enforce the class constraint.
*/
private static Entry, B> checkedEntry(
final Entry, B> entry) {
return new ForwardingMapEntry, B>() {
@Override
protected Entry, B> delegate() {
return entry;
}
@Override
public B setValue(B value) {
return super.setValue(cast(getKey(), value));
}
};
}
@Override
public Set, B>> entrySet() {
return new ForwardingSet, B>>() {
@Override
protected Set, B>> delegate() {
return MutableClassToInstanceMap.this.delegate().entrySet();
}
@Override
public Spliterator, B>> spliterator() {
return CollectSpliterators.map(
delegate().spliterator(), MutableClassToInstanceMap::checkedEntry);
}
@Override
public Iterator, B>> iterator() {
return new TransformedIterator, B>, Entry, B>>(
delegate().iterator()) {
@Override
Entry, B> transform(Entry, B> from) {
return checkedEntry(from);
}
};
}
@Override
public Object[] toArray() {
return standardToArray();
}
@Override
public T[] toArray(T[] array) {
return standardToArray(array);
}
};
}
@Override
public B put(Class key, B value) {
return super.put(key, cast(key, value));
}
@Override
public void putAll(Map, ? extends B> map) {
Map, B> copy = new LinkedHashMap<>(map);
for (Entry, B> entry : copy.entrySet()) {
cast(entry.getKey(), entry.getValue());
}
super.putAll(copy);
}
@Override
public T putInstance(Class type, T value) {
return cast(type, put(type, value));
}
@Override
public T getInstance(Class type) {
return cast(type, get(type));
}
private static T cast(Class type, B value) {
return Primitives.wrap(type).cast(value);
}
private Object writeReplace() {
return new SerializedForm(delegate());
}
/** Serialized form of the map, to avoid serializing the constraint. */
private static final class SerializedForm implements Serializable {
private final Map, B> backingMap;
SerializedForm(Map, B> backingMap) {
this.backingMap = backingMap;
}
Object readResolve() {
return create(backingMap);
}
private static final long serialVersionUID = 0;
}
}