/*
* Copyright (C) 2008 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.annotations.
GwtCompatible;
import com.google.common.annotations.
GwtIncompatible;
import java.io.
Serializable;
import java.util.
Map.
Entry;
import javax.annotation.
Nullable;
/**
* {@code keySet()} implementation for {@link ImmutableMap}.
*
* @author Jesse Wilson
* @author Kevin Bourrillion
*/
@
GwtCompatible(emulated = true)
final class
ImmutableMapKeySet<K, V> extends
ImmutableSet<K> {
private final
ImmutableMap<K, V>
map;
ImmutableMapKeySet(
ImmutableMap<K, V>
map) {
this.
map =
map;
}
@
Override
public int
size() {
return
map.
size();
}
@
Override
public
UnmodifiableIterator<K>
iterator() {
return
asList().
iterator();
}
@
Override
public boolean
contains(@
Nullable Object object) {
return
map.
containsKey(
object);
}
@
Override
ImmutableList<K>
createAsList() {
final
ImmutableList<
Entry<K, V>>
entryList =
map.
entrySet().
asList();
return new
ImmutableAsList<K>() {
@
Override
public K
get(int
index) {
return
entryList.
get(
index).
getKey();
}
@
Override
ImmutableCollection<K>
delegateCollection() {
return
ImmutableMapKeySet.this;
}
};
}
@
Override
boolean
isPartialView() {
return true;
}
@
GwtIncompatible("serialization")
@
Override Object writeReplace() {
return new
KeySetSerializedForm<K>(
map);
}
@
GwtIncompatible("serialization")
private static class
KeySetSerializedForm<K> implements
Serializable {
final
ImmutableMap<K, ?>
map;
KeySetSerializedForm(
ImmutableMap<K, ?>
map) {
this.
map =
map;
}
Object readResolve() {
return
map.
keySet();
}
private static final long
serialVersionUID = 0;
}
}