/*
* Copyright (C) 2012 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.checkArgument;
import com.google.common.annotations.
GwtCompatible;
import java.io.
Serializable;
import java.util.
EnumMap;
import java.util.
Iterator;
import javax.annotation.
Nullable;
/**
* Implementation of {@link ImmutableMap} backed by a non-empty {@link
* java.util.EnumMap}.
*
* @author Louis Wasserman
*/
@
GwtCompatible(serializable = true, emulated = true)
@
SuppressWarnings("serial") // we're overriding default serialization
final class
ImmutableEnumMap<K extends
Enum<K>, V> extends
ImmutableMap<K, V> {
static <K extends
Enum<K>, V>
ImmutableMap<K, V>
asImmutable(
EnumMap<K, V>
map) {
switch (
map.
size()) {
case 0:
return
ImmutableMap.
of();
case 1: {
Entry<K, V>
entry =
Iterables.
getOnlyElement(
map.
entrySet());
return
ImmutableMap.
of(
entry.
getKey(),
entry.
getValue());
}
default:
return new
ImmutableEnumMap<K, V>(
map);
}
}
private transient final
EnumMap<K, V>
delegate;
private
ImmutableEnumMap(
EnumMap<K, V>
delegate) {
this.
delegate =
delegate;
checkArgument(!
delegate.
isEmpty());
}
@
Override
ImmutableSet<K>
createKeySet() {
return new
ImmutableSet<K>() {
@
Override
public boolean
contains(
Object object) {
return
delegate.
containsKey(
object);
}
@
Override
public int
size() {
return
ImmutableEnumMap.this.
size();
}
@
Override
public
UnmodifiableIterator<K>
iterator() {
return
Iterators.
unmodifiableIterator(
delegate.
keySet().
iterator());
}
@
Override
boolean
isPartialView() {
return true;
}
};
}
@
Override
public int
size() {
return
delegate.
size();
}
@
Override
public boolean
containsKey(@
Nullable Object key) {
return
delegate.
containsKey(
key);
}
@
Override
public V
get(
Object key) {
return
delegate.
get(
key);
}
@
Override
ImmutableSet<
Entry<K, V>>
createEntrySet() {
return new
ImmutableMapEntrySet<K, V>() {
@
Override
ImmutableMap<K, V>
map() {
return
ImmutableEnumMap.this;
}
@
Override
public
UnmodifiableIterator<
Entry<K, V>>
iterator() {
return new
UnmodifiableIterator<
Entry<K, V>>() {
private final
Iterator<
Entry<K, V>>
backingIterator =
delegate.
entrySet().
iterator();
@
Override
public boolean
hasNext() {
return
backingIterator.
hasNext();
}
@
Override
public
Entry<K, V>
next() {
Entry<K, V>
entry =
backingIterator.
next();
return
Maps.
immutableEntry(
entry.
getKey(),
entry.
getValue());
}
};
}
};
}
@
Override
boolean
isPartialView() {
return false;
}
// All callers of the constructor are restricted to <K extends Enum<K>>.
@
Override Object writeReplace() {
return new
EnumSerializedForm<K, V>(
delegate);
}
/*
* This class is used to serialize ImmutableEnumSet instances.
*/
private static class
EnumSerializedForm<K extends
Enum<K>, V>
implements
Serializable {
final
EnumMap<K, V>
delegate;
EnumSerializedForm(
EnumMap<K, V>
delegate) {
this.
delegate =
delegate;
}
Object readResolve() {
return new
ImmutableEnumMap<K, V>(
delegate);
}
private static final long
serialVersionUID = 0;
}
}