it.unimi.dsi.fastutil.ints.Int2IntFunctions Maven / Gradle / Ivy
Show all versions of fastutil-core Show documentation
/*
* Copyright (C) 2002-2021 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.ints;
import it.unimi.dsi.fastutil.Function;
/**
* 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 final class Int2IntFunctions {
private Int2IntFunctions() {
}
/**
* 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 AbstractInt2IntFunction implements java.io.Serializable, Cloneable {
private static final long serialVersionUID = -7046029254386353129L;
protected EmptyFunction() {
}
@Override
public int get(final int k) {
return (0);
}
@Override
public int getOrDefault(final int k, final int defaultValue) {
return defaultValue;
}
@Override
public boolean containsKey(final int k) {
return false;
}
@Override
public int defaultReturnValue() {
return (0);
}
@Override
public void defaultReturnValue(final int defRetValue) {
throw new UnsupportedOperationException();
}
@Override
public int size() {
return 0;
}
@Override
public void clear() {
}
@Override
public Object clone() {
return EMPTY_FUNCTION;
}
@Override
public int hashCode() {
return 0;
}
@Override
public boolean equals(final Object o) {
if (!(o instanceof Function))
return false;
return ((Function) o).size() == 0;
}
@Override
public String toString() {
return "{}";
}
private Object readResolve() {
return EMPTY_FUNCTION;
}
}
/**
* An empty type-specific function (immutable). It is serializable and
* cloneable.
*/
public static final EmptyFunction EMPTY_FUNCTION = new EmptyFunction();
/**
* An immutable class representing a type-specific singleton function. Note that
* the default return value is still settable.
*
*
* Note that albeit the function is immutable, its default return value may be
* changed.
*
*
* This class may be useful to implement your own in case you subclass a
* type-specific function.
*/
public static class Singleton extends AbstractInt2IntFunction implements java.io.Serializable, Cloneable {
private static final long serialVersionUID = -7046029254386353129L;
protected final int key;
protected final int value;
protected Singleton(final int key, final int value) {
this.key = key;
this.value = value;
}
@Override
public boolean containsKey(final int k) {
return ((key) == (k));
}
@Override
public int get(final int k) {
return ((key) == (k)) ? value : defRetValue;
}
@Override
public int getOrDefault(final int k, final int defaultValue) {
return ((key) == (k)) ? value : defaultValue;
}
@Override
public int size() {
return 1;
}
@Override
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
* {@code <key,value>}.
*/
public static Int2IntFunction singleton(final int key, int value) {
return new Singleton(key, value);
}
/**
* 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
* {@code <key,value>}.
*/
public static Int2IntFunction singleton(final Integer key, final Integer value) {
return new Singleton((key).intValue(), (value).intValue());
}
/** A synchronized wrapper class for functions. */
public static class SynchronizedFunction implements Int2IntFunction, java.io.Serializable {
private static final long serialVersionUID = -7046029254386353129L;
protected final Int2IntFunction function;
protected final Object sync;
protected SynchronizedFunction(final Int2IntFunction f, final Object sync) {
if (f == null)
throw new NullPointerException();
this.function = f;
this.sync = sync;
}
protected SynchronizedFunction(final Int2IntFunction f) {
if (f == null)
throw new NullPointerException();
this.function = f;
this.sync = this;
}
@Override
public int applyAsInt(int operand) {
synchronized (sync) {
return function.applyAsInt(operand);
}
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
public Integer apply(final Integer key) {
synchronized (sync) {
return function.apply(key);
}
}
@Override
public int size() {
synchronized (sync) {
return function.size();
}
}
@Override
public int defaultReturnValue() {
synchronized (sync) {
return function.defaultReturnValue();
}
}
@Override
public void defaultReturnValue(final int defRetValue) {
synchronized (sync) {
function.defaultReturnValue(defRetValue);
}
}
@Override
public boolean containsKey(final int k) {
synchronized (sync) {
return function.containsKey(k);
}
}
@Deprecated
@Override
public boolean containsKey(final Object k) {
synchronized (sync) {
return function.containsKey(k);
}
}
@Override
public int put(final int k, final int v) {
synchronized (sync) {
return function.put(k, v);
}
}
@Override
public int get(final int k) {
synchronized (sync) {
return function.get(k);
}
}
@Override
public int getOrDefault(final int k, final int defaultValue) {
synchronized (sync) {
return function.getOrDefault(k, defaultValue);
}
}
@Override
public int remove(final int k) {
synchronized (sync) {
return function.remove(k);
}
}
@Override
public void clear() {
synchronized (sync) {
function.clear();
}
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
public Integer put(final Integer k, final Integer v) {
synchronized (sync) {
return function.put(k, v);
}
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
public Integer get(final Object k) {
synchronized (sync) {
return function.get(k);
}
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
public Integer getOrDefault(final Object k, final Integer defaultValue) {
synchronized (sync) {
return function.getOrDefault(k, defaultValue);
}
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
public Integer remove(final Object k) {
synchronized (sync) {
return function.remove(k);
}
}
@Override
public int hashCode() {
synchronized (sync) {
return function.hashCode();
}
}
@Override
public boolean equals(final Object o) {
if (o == this)
return true;
synchronized (sync) {
return function.equals(o);
}
}
@Override
public String toString() {
synchronized (sync) {
return function.toString();
}
}
private void writeObject(java.io.ObjectOutputStream s) throws java.io.IOException {
synchronized (sync) {
s.defaultWriteObject();
}
}
}
/**
* 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 Int2IntFunction synchronize(final Int2IntFunction 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 Int2IntFunction synchronize(final Int2IntFunction f, final Object sync) {
return new SynchronizedFunction(f, sync);
}
/** An unmodifiable wrapper class for functions. */
public static class UnmodifiableFunction extends AbstractInt2IntFunction implements java.io.Serializable {
private static final long serialVersionUID = -7046029254386353129L;
protected final Int2IntFunction function;
protected UnmodifiableFunction(final Int2IntFunction f) {
if (f == null)
throw new NullPointerException();
this.function = f;
}
@Override
public int size() {
return function.size();
}
@Override
public int defaultReturnValue() {
return function.defaultReturnValue();
}
@Override
public void defaultReturnValue(final int defRetValue) {
throw new UnsupportedOperationException();
}
@Override
public boolean containsKey(final int k) {
return function.containsKey(k);
}
@Override
public int put(final int k, final int v) {
throw new UnsupportedOperationException();
}
@Override
public int get(final int k) {
return function.get(k);
}
@Override
public int getOrDefault(final int k, final int defaultValue) {
return function.getOrDefault(k, defaultValue);
}
@Override
public int remove(final int k) {
throw new UnsupportedOperationException();
}
@Override
public void clear() {
throw new UnsupportedOperationException();
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
public Integer put(final Integer k, final Integer v) {
throw new UnsupportedOperationException();
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
public Integer get(final Object k) {
return function.get(k);
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
public Integer getOrDefault(final Object k, final Integer defaultValue) {
return function.getOrDefault(k, defaultValue);
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
public Integer remove(final Object k) {
throw new UnsupportedOperationException();
}
@Override
public int hashCode() {
return function.hashCode();
}
@Override
public boolean equals(Object o) {
return o == this || function.equals(o);
}
@Override
public String toString() {
return function.toString();
}
}
/**
* 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 Int2IntFunction unmodifiable(final Int2IntFunction f) {
return new UnmodifiableFunction(f);
}
/**
* An adapter for mapping generic total functions to partial primitive
* functions.
*/
public static class PrimitiveFunction implements Int2IntFunction {
protected final java.util.function.Function function;
protected PrimitiveFunction(java.util.function.Function function) {
this.function = function;
}
@Override
public boolean containsKey(int key) {
return function.apply(Integer.valueOf(key)) != null;
}
@Deprecated
@Override
public boolean containsKey(Object key) {
if (key == null)
return false;
return function.apply((Integer) (key)) != null;
}
@Override
public int get(int key) {
Integer v = function.apply(Integer.valueOf(key));
if (v == null)
return defaultReturnValue();
return (v).intValue();
}
@Override
public int getOrDefault(int key, int defaultValue) {
Integer v = function.apply(Integer.valueOf(key));
if (v == null)
return defaultValue;
return (v).intValue();
}
@Deprecated
@Override
public Integer get(Object key) {
if (key == null)
return null;
return function.apply((Integer) key);
}
@Deprecated
@Override
public Integer getOrDefault(Object key, Integer defaultValue) {
if (key == null)
return defaultValue;
final Integer v;
return (v = function.apply((Integer) key)) == null ? defaultValue : v;
}
@Deprecated
@Override
public Integer put(final Integer key, final Integer value) {
throw new UnsupportedOperationException();
}
}
/**
* Returns a (partial) type-specific function based on the given total generic
* function.
*
* The returned function contains all keys which are not mapped to {@code null}.
* If the function already is a primitive function, it is returned without
* changes.
*
* Warning: If the given function is a “widened”
* primitive function (e.g. an {@code Int2IntFunction} given to
* {@code Short2ShortFunctions}), it still is wrapped into a proxy, decreasing
* performance.
*
* @param f
* the function to be converted to a type-specific function.
* @return a primitive view of the specified function.
* @throws NullPointerException
* if {@code f} is null.
* @see PrimitiveFunction
* @since 8.1.0
*/
public static Int2IntFunction primitive(final java.util.function.Function f) {
java.util.Objects.requireNonNull(f);
if (f instanceof Int2IntFunction)
return (Int2IntFunction) f;
if (f instanceof java.util.function.IntUnaryOperator)
return ((java.util.function.IntUnaryOperator) f)::applyAsInt;
return new PrimitiveFunction(f);
}
}