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/* Generic definitions */
/* Assertions (useful to generate conditional code) */
/* Current type and class (and size, if applicable) */
/* Value methods */
/* Interfaces (keys) */
/* Interfaces (values) */
/* Abstract implementations (keys) */
/* Abstract implementations (values) */
/* Static containers (keys) */
/* Static containers (values) */
/* Implementations */
/* Synchronized wrappers */
/* Unmodifiable wrappers */
/* Other wrappers */
/* Methods (keys) */
/* Methods (values) */
/* Methods (keys/values) */
/* Methods that have special names depending on keys (but the special names depend on values) */
/* Equality */
/* Object/Reference-only definitions (keys) */
/* Object/Reference-only definitions (values) */
/*
* Copyright (C) 2002-2016 Sebastiano Vigna
*
* 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 it.unimi.dsi.fastutil.objects;
/**
* A class providing static methods and objects that do useful things with
* type-specific functions.
*
* @see it.unimi.dsi.fastutil.Function
* @see java.util.Collections
*/
public class Object2ObjectFunctions {
private Object2ObjectFunctions() {
}
/**
* An immutable class representing an empty type-specific function.
*
*
* This class may be useful to implement your own in case you subclass a
* type-specific function.
*/
public static class EmptyFunction
extends
AbstractObject2ObjectFunction
implements
java.io.Serializable,
Cloneable {
private static final long serialVersionUID = -7046029254386353129L;
protected EmptyFunction() {
}
public V get(final Object k) {
return (null);
}
public boolean containsKey(final Object k) {
return false;
}
public V defaultReturnValue() {
return (null);
}
public void defaultReturnValue(final V defRetValue) {
throw new UnsupportedOperationException();
}
public int size() {
return 0;
}
public void clear() {
}
private Object readResolve() {
return EMPTY_FUNCTION;
}
public Object clone() {
return EMPTY_FUNCTION;
}
}
/**
* An empty type-specific function (immutable). It is serializable and
* cloneable.
*/
@SuppressWarnings("rawtypes")
public static final EmptyFunction EMPTY_FUNCTION = new EmptyFunction();
/**
* An immutable class representing a type-specific singleton function.
*
*
* This class may be useful to implement your own in case you subclass a
* type-specific function.
*/
public static class Singleton
extends
AbstractObject2ObjectFunction
implements
java.io.Serializable,
Cloneable {
private static final long serialVersionUID = -7046029254386353129L;
protected final K key;
protected final V value;
protected Singleton(final K key, final V value) {
this.key = key;
this.value = value;
}
public boolean containsKey(final Object k) {
return ((key) == null ? (k) == null : (key).equals(k));
}
public V get(final Object k) {
if (((key) == null ? (k) == null : (key).equals(k)))
return value;
return defRetValue;
}
public int size() {
return 1;
}
public Object clone() {
return this;
}
}
/**
* Returns a type-specific immutable function containing only the specified
* pair. The returned function is serializable and cloneable.
*
*
* Note that albeit the returned function is immutable, its default return
* value may be changed.
*
* @param key
* the only key of the returned function.
* @param value
* the only value of the returned function.
* @return a type-specific immutable function containing just the pair
* <key,value>.
*/
public static Object2ObjectFunction singleton(final K key,
V value) {
return new Singleton(key, value);
}
/** A synchronized wrapper class for functions. */
public static class SynchronizedFunction
extends
AbstractObject2ObjectFunction
implements
java.io.Serializable {
private static final long serialVersionUID = -7046029254386353129L;
protected final Object2ObjectFunction function;
protected final Object sync;
protected SynchronizedFunction(final Object2ObjectFunction f,
final Object sync) {
if (f == null)
throw new NullPointerException();
this.function = f;
this.sync = sync;
}
protected SynchronizedFunction(final Object2ObjectFunction f) {
if (f == null)
throw new NullPointerException();
this.function = f;
this.sync = this;
}
public int size() {
synchronized (sync) {
return function.size();
}
}
public boolean containsKey(final Object k) {
synchronized (sync) {
return function.containsKey(k);
}
}
public V defaultReturnValue() {
synchronized (sync) {
return function.defaultReturnValue();
}
}
public void defaultReturnValue(final V defRetValue) {
synchronized (sync) {
function.defaultReturnValue(defRetValue);
}
}
public V put(final K k, final V v) {
synchronized (sync) {
return function.put(k, v);
}
}
public void clear() {
synchronized (sync) {
function.clear();
}
}
public String toString() {
synchronized (sync) {
return function.toString();
}
}
@Override
public V remove(final Object k) {
synchronized (sync) {
return function.remove(k);
}
}
@Override
public V get(final Object k) {
synchronized (sync) {
return function.get(k);
}
}
}
/**
* Returns a synchronized type-specific function backed by the given
* type-specific function.
*
* @param f
* the function to be wrapped in a synchronized function.
* @return a synchronized view of the specified function.
* @see java.util.Collections#synchronizedMap(java.util.Map)
*/
public static Object2ObjectFunction synchronize(
final Object2ObjectFunction f) {
return new SynchronizedFunction(f);
}
/**
* Returns a synchronized type-specific function backed by the given
* type-specific function, using an assigned object to synchronize.
*
* @param f
* the function to be wrapped in a synchronized function.
* @param sync
* an object that will be used to synchronize the access to the
* function.
* @return a synchronized view of the specified function.
* @see java.util.Collections#synchronizedMap(java.util.Map)
*/
public static Object2ObjectFunction synchronize(
final Object2ObjectFunction f, final Object sync) {
return new SynchronizedFunction(f, sync);
}
/** An unmodifiable wrapper class for functions. */
public static class UnmodifiableFunction
extends
AbstractObject2ObjectFunction
implements
java.io.Serializable {
private static final long serialVersionUID = -7046029254386353129L;
protected final Object2ObjectFunction function;
protected UnmodifiableFunction(final Object2ObjectFunction f) {
if (f == null)
throw new NullPointerException();
this.function = f;
}
public int size() {
return function.size();
}
public boolean containsKey(final Object k) {
return function.containsKey(k);
}
public V defaultReturnValue() {
return function.defaultReturnValue();
}
public void defaultReturnValue(final V defRetValue) {
throw new UnsupportedOperationException();
}
public V put(final K k, final V v) {
throw new UnsupportedOperationException();
}
public void clear() {
throw new UnsupportedOperationException();
}
public String toString() {
return function.toString();
}
@Override
public V remove(final Object k) {
throw new UnsupportedOperationException();
}
@Override
public V get(final Object k) {
return function.get(k);
}
}
/**
* Returns an unmodifiable type-specific function backed by the given
* type-specific function.
*
* @param f
* the function to be wrapped in an unmodifiable function.
* @return an unmodifiable view of the specified function.
* @see java.util.Collections#unmodifiableMap(java.util.Map)
*/
public static Object2ObjectFunction unmodifiable(
final Object2ObjectFunction f) {
return new UnmodifiableFunction(f);
}
}