it.unimi.dsi.fastutil.objects.Object2DoubleFunctions Maven / Gradle / Ivy
Show all versions of fastutil-core Show documentation
/*
* Copyright (C) 2002-2024 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;
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 Object2DoubleFunctions {
private Object2DoubleFunctions() {
}
/**
* 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 AbstractObject2DoubleFunction implements java.io.Serializable, Cloneable {
private static final long serialVersionUID = -7046029254386353129L;
protected EmptyFunction() {
}
@Override
public double getDouble(final Object k) {
return (0);
}
@Override
public double getOrDefault(final Object k, final double defaultValue) {
return defaultValue;
}
@Override
public boolean containsKey(final Object k) {
return false;
}
@Override
public double defaultReturnValue() {
return (0);
}
@Override
public void defaultReturnValue(final double 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. */
@SuppressWarnings("rawtypes")
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 AbstractObject2DoubleFunction implements java.io.Serializable, Cloneable {
private static final long serialVersionUID = -7046029254386353129L;
protected final K key;
protected final double value;
protected Singleton(final K key, final double value) {
this.key = key;
this.value = value;
}
@Override
public boolean containsKey(final Object k) {
return java.util.Objects.equals(key, k);
}
@Override
public double getDouble(final Object k) {
return java.util.Objects.equals(key, k) ? value : defRetValue;
}
@Override
public double getOrDefault(final Object k, final double defaultValue) {
return java.util.Objects.equals(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 Object2DoubleFunction singleton(final K key, double 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 Object2DoubleFunction singleton(final K key, final Double value) {
return new Singleton<>((key), (value).doubleValue());
}
/** A synchronized wrapper class for functions. */
public static class SynchronizedFunction implements Object2DoubleFunction, java.io.Serializable {
private static final long serialVersionUID = -7046029254386353129L;
protected final Object2DoubleFunction function;
protected final Object sync;
protected SynchronizedFunction(final Object2DoubleFunction f, final Object sync) {
if (f == null) throw new NullPointerException();
this.function = f;
this.sync = sync;
}
protected SynchronizedFunction(final Object2DoubleFunction f) {
if (f == null) throw new NullPointerException();
this.function = f;
this.sync = this;
}
@Override
public double applyAsDouble(K operand) {
synchronized (sync) {
return function.applyAsDouble(operand);
}
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
public Double apply(final K key) {
synchronized (sync) {
return function.apply(key);
}
}
@Override
public int size() {
synchronized (sync) {
return function.size();
}
}
@Override
public double defaultReturnValue() {
synchronized (sync) {
return function.defaultReturnValue();
}
}
@Override
public void defaultReturnValue(final double defRetValue) {
synchronized (sync) {
function.defaultReturnValue(defRetValue);
}
}
@Override
public boolean containsKey(final Object k) {
synchronized (sync) {
return function.containsKey(k);
}
}
@Override
public double put(final K k, final double v) {
synchronized (sync) {
return function.put(k, v);
}
}
@Override
public double getDouble(final Object k) {
synchronized (sync) {
return function.getDouble(k);
}
}
@Override
public double getOrDefault(final Object k, final double defaultValue) {
synchronized (sync) {
return function.getOrDefault(k, defaultValue);
}
}
@Override
public double removeDouble(final Object k) {
synchronized (sync) {
return function.removeDouble(k);
}
}
@Override
public void clear() {
synchronized (sync) {
function.clear();
}
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
public Double put(final K k, final Double v) {
synchronized (sync) {
return function.put(k, v);
}
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
public Double get(final Object k) {
synchronized (sync) {
return function.get(k);
}
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
public Double getOrDefault(final Object k, final Double defaultValue) {
synchronized (sync) {
return function.getOrDefault(k, defaultValue);
}
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
public Double 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 Object2DoubleFunction synchronize(final Object2DoubleFunction 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 Object2DoubleFunction synchronize(final Object2DoubleFunction f, final Object sync) {
return new SynchronizedFunction<>(f, sync);
}
/** An unmodifiable wrapper class for functions. */
public static class UnmodifiableFunction extends AbstractObject2DoubleFunction implements java.io.Serializable {
private static final long serialVersionUID = -7046029254386353129L;
protected final Object2DoubleFunction function;
protected UnmodifiableFunction(final Object2DoubleFunction f) {
if (f == null) throw new NullPointerException();
this.function = f;
}
@Override
public int size() {
return function.size();
}
@Override
public double defaultReturnValue() {
return function.defaultReturnValue();
}
@Override
public void defaultReturnValue(final double defRetValue) {
throw new UnsupportedOperationException();
}
@Override
public boolean containsKey(final Object k) {
return function.containsKey(k);
}
@Override
public double put(final K k, final double v) {
throw new UnsupportedOperationException();
}
@Override
public double getDouble(final Object k) {
return function.getDouble(k);
}
@Override
@SuppressWarnings("unchecked")
public double getOrDefault(final Object k, final double defaultValue) {
return ((Object2DoubleFunction)function).getOrDefault(k, defaultValue);
}
@Override
public double removeDouble(final Object k) {
throw new UnsupportedOperationException();
}
@Override
public void clear() {
throw new UnsupportedOperationException();
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
public Double put(final K k, final Double v) {
throw new UnsupportedOperationException();
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
public Double get(final Object k) {
return function.get(k);
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
@SuppressWarnings("unchecked")
public Double getOrDefault(final Object k, final Double defaultValue) {
return ((Object2DoubleFunction)function).getOrDefault(k, defaultValue);
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
public Double 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 Object2DoubleFunction unmodifiable(final Object2DoubleFunction f) {
return new UnmodifiableFunction<>(f);
}
/** An adapter for mapping generic total functions to partial primitive functions. */
public static class PrimitiveFunction implements Object2DoubleFunction {
protected final java.util.function.Function function;
protected PrimitiveFunction(java.util.function.Function function) {
this.function = function;
}
@SuppressWarnings("unchecked")
@Override
public boolean containsKey(Object key) {
return function.apply((K)(key)) != null;
}
@SuppressWarnings("unchecked")
@Override
public double getDouble(Object key) {
Double v = function.apply((K)(key));
if (v == null) return defaultReturnValue();
return (v).doubleValue();
}
@SuppressWarnings("unchecked")
@Override
public double getOrDefault(Object key, double defaultValue) {
Double v = function.apply((K)(key));
if (v == null) return defaultValue;
return (v).doubleValue();
}
@SuppressWarnings("unchecked")
@Deprecated
@Override
public Double get(Object key) {
return function.apply((K)key);
}
@SuppressWarnings("unchecked")
@Deprecated
@Override
public Double getOrDefault(Object key, Double defaultValue) {
final Double v;
return (v = function.apply((K)key)) == null ? defaultValue : v;
}
@Deprecated
@Override
public Double put(final K key, final Double 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
*/
@SuppressWarnings("unchecked")
public static Object2DoubleFunction primitive(final java.util.function.Function f) {
java.util.Objects.requireNonNull(f);
if (f instanceof Object2DoubleFunction) return (Object2DoubleFunction)f;
if (f instanceof java.util.function.ToDoubleFunction) return key -> ((java.util.function.ToDoubleFunction)f).applyAsDouble((K)(key));
return new PrimitiveFunction<>(f);
}
}