* @param <V> the type of mapped values
*/
@Beta
-public final class SharedSingletonMap<K, V> implements Serializable, UnmodifiableMapPhase<K, V> {
+public abstract class SharedSingletonMap<K, V> implements Serializable, UnmodifiableMapPhase<K, V> {
+ private static final class Ordered<K, V> extends SharedSingletonMap<K, V> {
+ private static final long serialVersionUID = 1L;
+
+ Ordered(final K key, final V value) {
+ super(key, value);
+ }
+
+ @Override
+ public ModifiableMapPhase<K, V> toModifiableMap() {
+ return new MutableOffsetMap<K, V>(this);
+ }
+ }
+
private static final long serialVersionUID = 1L;
private static final LoadingCache<Object, SingletonSet<Object>> CACHE = CacheBuilder.newBuilder().weakValues()
.build(new CacheLoader<Object, SingletonSet<Object>>() {
private int hashCode;
@SuppressWarnings("unchecked")
- private SharedSingletonMap(final K key, final V value) {
+ SharedSingletonMap(final K key, final V value) {
this.keySet = (SingletonSet<K>) CACHE.getUnchecked(key);
this.value = Preconditions.checkNotNull(value);
}
public static <K, V> SharedSingletonMap<K, V> of(final K key, final V value) {
- return new SharedSingletonMap<>(key, value);
+ return new Ordered<>(key, value);
}
public static <K, V> SharedSingletonMap<K, V> copyOf(final Map<K, V> m) {
Preconditions.checkArgument(m.size() == 1);
final Entry<K, V> e = m.entrySet().iterator().next();
- return new SharedSingletonMap<>(e.getKey(), e.getValue());
- }
-
- @Override
- public ModifiableMapPhase<K, V> toModifiableMap() {
- return new MutableOffsetMap<K, V>(this);
+ return new Ordered<>(e.getKey(), e.getValue());
}
@Override
- public SingletonSet<Entry<K, V>> entrySet() {
+ public final SingletonSet<Entry<K, V>> entrySet() {
return SingletonSet.<Entry<K, V>>of(new SimpleImmutableEntry<>(keySet.getElement(), value));
}
@Override
- public SingletonSet<K> keySet() {
+ public final SingletonSet<K> keySet() {
return keySet;
}
@Override
- public SingletonSet<V> values() {
+ public final SingletonSet<V> values() {
return SingletonSet.of(value);
}
@Override
- public boolean containsKey(final Object key) {
+ public final boolean containsKey(final Object key) {
return keySet.contains(key);
}
@Override
- public boolean containsValue(final Object value) {
+ public final boolean containsValue(final Object value) {
return this.value.equals(value);
}
@Override
- public V get(final Object key) {
+ public final V get(final Object key) {
return keySet.contains(key) ? value : null;
}
@Override
- public int size() {
+ public final int size() {
return 1;
}
@Override
- public boolean isEmpty() {
+ public final boolean isEmpty() {
return false;
}
@Override
- public V put(final K key, final V value) {
+ public final V put(final K key, final V value) {
throw new UnsupportedOperationException();
}
@Override
- public V remove(final Object key) {
+ public final V remove(final Object key) {
throw new UnsupportedOperationException();
}
@Override
- public void putAll(final Map<? extends K, ? extends V> m) {
+ public final void putAll(final Map<? extends K, ? extends V> m) {
throw new UnsupportedOperationException();
}
@Override
- public void clear() {
+ public final void clear() {
throw new UnsupportedOperationException();
}
@Override
- public int hashCode() {
+ public final int hashCode() {
if (hashCode == 0) {
hashCode = keySet.getElement().hashCode() ^ value.hashCode();
}
}
@Override
- public boolean equals(final Object obj) {
+ public final boolean equals(final Object obj) {
if (this == obj) {
return true;
}
}
@Override
- public String toString() {
+ public final String toString() {
return "{" + keySet.getElement() + '=' + value + '}';
}
}