/*
 * 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 java.util.Map;

import javax.annotation.Nullable;

/**
 * Implementation of {@link ImmutableMap} with exactly one entry.
 *
 * @author Jesse Wilson
 * @author Kevin Bourrillion
 */
@GwtCompatible(serializable = true, emulated = true)
@SuppressWarnings("serial") // uses writeReplace(), not default serialization
final class SingletonImmutableMap<K, V> extends ImmutableMap<K, V> {

  final transient K singleKey;
  final transient V singleValue;

  private transient Entry<K, V> entry;

  SingletonImmutableMap(K singleKey, V singleValue) {
    this.singleKey = singleKey;
    this.singleValue = singleValue;
  }

  SingletonImmutableMap(Entry<K, V> entry) {
    this.entry = entry;
    this.singleKey = entry.getKey();
    this.singleValue = entry.getValue();
  }

  private Entry<K, V> entry() {
    Entry<K, V> e = entry;
    return (e == null)
        ? (entry = Maps.immutableEntry(singleKey, singleValue)) : e;
  }

  @Override public V get(@Nullable Object key) {
    return singleKey.equals(key) ? singleValue : null;
  }

  @Override
  public int size() {
    return 1;
  }

  @Override public boolean isEmpty() {
    return false;
  }

  @Override public boolean containsKey(@Nullable Object key) {
    return singleKey.equals(key);
  }

  @Override public boolean containsValue(@Nullable Object value) {
    return singleValue.equals(value);
  }

  @Override boolean isPartialView() {
    return false;
  }

  @Override
  ImmutableSet<Entry<K, V>> createEntrySet() {
    return ImmutableSet.of(entry());
  }

  @Override
  ImmutableSet<K> createKeySet() {
    return ImmutableSet.of(singleKey);
  }

  @Override
  ImmutableCollection<V> createValues() {
    return ImmutableList.of(singleValue);
  }

  @Override public boolean equals(@Nullable Object object) {
    if (object == this) {
      return true;
    }
    if (object instanceof Map) {
      Map<?, ?> that = (Map<?, ?>) object;
      if (that.size() != 1) {
        return false;
      }
      Entry<?, ?> entry = that.entrySet().iterator().next();
      return singleKey.equals(entry.getKey())
          && singleValue.equals(entry.getValue());
    }
    return false;
  }

  @Override public int hashCode() {
    return singleKey.hashCode() ^ singleValue.hashCode();
  }

  @Override public String toString() {
    return new StringBuilder()
        .append('{')
        .append(singleKey.toString())
        .append('=')
        .append(singleValue.toString())
        .append('}')
        .toString();
  }
}

@@ -1142,48 +1142,8 @@
 e;%0A%0A
-  private transient Entry%3CK, V%3E entry;%0A%0A
   Si
@@ -1322,256 +1322,42 @@
 this
-.entry = entry;%0A    this.singleKey = entry.getKey();%0A    this.singleValue = entry.getValue();%0A  %7D%0A%0A  private Entry%3CK, V%3E entry() %7B%0A    Entry%3CK, V%3E e = entry;%0A    return (e == null)%0A        ? (entry = Maps.immutableEntry(singleKey, single
+(entry.getKey(), entry.get
 Value
+(
 ))
- : e
 ;%0A  
@@ -1946,14 +1946,50 @@
 .of(
-entry(
+Maps.immutableEntry(singleKey, singleValue
 ));%0A
@@ -2399,9 +2399,9 @@
 e() 
-!
+=
 = 1)
@@ -2409,36 +2409,8 @@
 %7B%0A  
-      return false;%0A      %7D%0A
     
@@ -2468,24 +2468,26 @@
 xt();%0A      
+ 
+ 
 return singl
@@ -2510,24 +2510,26 @@
 y.getKey())%0A
+  
           &&
@@ -2567,16 +2567,24 @@
 lue());%0A
+      %7D%0A
     %7D%0A  
@@ -2705,244 +2705,7 @@
 %0A  %7D
-%0A%0A  @Override public String toString() %7B%0A    return new StringBuilder()%0A        .append('%7B')%0A        .append(singleKey.toString())%0A        .append('=')%0A        .append(singleValue.toString())%0A        .append('%7D')%0A        .toString();%0A  %7D
 %0A%7D%0A

Eliminate redundant fields and code from SingletonImmutableMap. From Louis: http://codereview.appspot.com/6211080/ ------------- Created by MOE: http://code.google.com/p/moe-java MOE_MIGRATED_REVID=30462649