http://fastutil.di.unimi.it/: fastutil extends the Java Collections Framework by providing type-specific maps, sets, lists and priority queues with a small memory footprint and fast access and insertion; provides also big (64-bit) arrays, sets and lists, and fast, practical I/O classes for binary and text files.
  • Sebastiano Vigna 
/*
	* Copyright (C) 2002-2019 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.ints.IntCollection;
import it.unimi.dsi.fastutil.objects.ObjectSet;
import it.unimi.dsi.fastutil.objects.ObjectIterator;
import java.util.function.Consumer;
import java.util.Map;

A type-specific Map; provides some additional methods that use polymorphism to avoid (un)boxing, and handling of a default return value. 
 Besides extending the corresponding type-specific function, this interface strengthens Map.entrySet(), keySet() and values(). Moreover, a number of methods, such as size(), defaultReturnValue(), etc., are un-defaulted as their function default do not make sense for a map. Maps returning entry sets of type FastEntrySet support also fast iteration. 

A submap or subset may or may not have an independent default return value
(which however must be initialized to the default return value of the
originator).

See Also:
/**
 * A type-specific {@link Map}; provides some additional methods that use
 * polymorphism to avoid (un)boxing, and handling of a default return value.
 *
 * <p>
 * Besides extending the corresponding type-specific
 * {@linkplain it.unimi.dsi.fastutil.Function function}, this interface
 * strengthens {@link Map#entrySet()}, {@link #keySet()} and {@link #values()}.
 * Moreover, a number of methods, such as {@link #size()},
 * {@link #defaultReturnValue()}, etc., are un-defaulted as their function
 * default do not make sense for a map. Maps returning entry sets of type
 * {@link FastEntrySet} support also fast iteration.
 *
 * <p>
 * A submap or subset may or may not have an independent default return value
 * (which however must be initialized to the default return value of the
 * originator).
 *
 * @see Map
 */
public interface Int2IntMap extends Int2IntFunction, Map<Integer, Integer> {
	
An entry set providing fast iteration.

 In some cases (e.g., hash-based classes) iteration over an entry set requires the creation of a large number of Entry objects. Some fastutil maps might return entry set objects of type FastEntrySet: in this case, 
fastIterator() will return an iterator that is guaranteed not to create a large number of objects, possibly by returning always the same entry (of course, mutated), and fastForEach(Consumer<? super Entry>) will apply the provided consumer to all elements of the entry set, which might be
represented always by the same entry (of course, mutated).

/**
	 * An entry set providing fast iteration.
	 *
	 * <p>
	 * In some cases (e.g., hash-based classes) iteration over an entry set requires
	 * the creation of a large number of {@link java.util.Map.Entry} objects. Some
	 * {@code fastutil} maps might return {@linkplain Map#entrySet() entry set}
	 * objects of type {@code FastEntrySet}: in this case, {@link #fastIterator()
	 * fastIterator()} will return an iterator that is guaranteed not to create a
	 * large number of objects, <em>possibly by returning always the same entry</em>
	 * (of course, mutated), and {@link #fastForEach(Consumer)} will apply the
	 * provided consumer to all elements of the entry set, <em>which might be
	 * represented always by the same entry</em> (of course, mutated).
	 */
	interface FastEntrySet extends ObjectSet<Int2IntMap.Entry> {
		
Returns a fast iterator over this entry set; the iterator might return always
the same entry instance, suitably mutated.

Returns:a fast iterator over this entry set; the iterator might return always the same Entry instance, suitably mutated.
/**
		 * Returns a fast iterator over this entry set; the iterator might return always
		 * the same entry instance, suitably mutated.
		 *
		 * @return a fast iterator over this entry set; the iterator might return always
		 *         the same {@link java.util.Map.Entry} instance, suitably mutated.
		 */
		ObjectIterator<Int2IntMap.Entry> fastIterator();
		
Iterates quickly over this entry set; the iteration might happen always on
the same entry instance, suitably mutated.

 This default implementation just delegates to Iterable<Entry>.forEach(Consumer<? super Entry>). 
Params:
  • consumer – 
           a consumer that will by applied to the entries of this set; the
           entries might be represented by the same entry instance, suitably
           mutated.
Since:8.1.0
/**
		 * Iterates quickly over this entry set; the iteration might happen always on
		 * the same entry instance, suitably mutated.
		 *
		 * <p>
		 * This default implementation just delegates to {@link #forEach(Consumer)}.
		 *
		 * @param consumer
		 *            a consumer that will by applied to the entries of this set; the
		 *            entries might be represented by the same entry instance, suitably
		 *            mutated.
		 * @since 8.1.0
		 */
		default void fastForEach(final Consumer<? super Int2IntMap.Entry> consumer) {
			forEach(consumer);
		}
	}
	
Returns the number of key/value mappings in this map. If the map contains more than Integer.MAX_VALUE elements, returns Integer.MAX_VALUE. 
See Also:
Returns:the number of key-value mappings in this map.
/**
	 * Returns the number of key/value mappings in this map. If the map contains
	 * more than {@link Integer#MAX_VALUE} elements, returns
	 * {@link Integer#MAX_VALUE}.
	 *
	 * @return the number of key-value mappings in this map.
	 * @see it.unimi.dsi.fastutil.Size64
	 */
	@Override
	int size();
	
Removes all of the mappings from this map (optional operation). The map will
be empty after this call returns.

Throws:
  • UnsupportedOperationException – 
            if the clear() operation is not supported by this
            map
/**
	 * Removes all of the mappings from this map (optional operation). The map will
	 * be empty after this call returns.
	 *
	 * @throws UnsupportedOperationException
	 *             if the <code>clear()</code> operation is not supported by this
	 *             map
	 */
	@Override
	default void clear() {
		throw new UnsupportedOperationException();
	}
	
Sets the default return value (optional operation). This value must be returned by type-specific versions of get(), put() and remove() to denote that the map does not contain the specified key. It must be 0/false by default. 
Params:
  • rv – 
           the new default return value.
See Also:
/**
	 * Sets the default return value (optional operation).
	 *
	 * This value must be returned by type-specific versions of {@code get()},
	 * {@code put()} and {@code remove()} to denote that the map does not contain
	 * the specified key. It must be 0/{@code false} by default.
	 *
	 * @param rv
	 *            the new default return value.
	 * @see #defaultReturnValue()
	 */
	@Override
	void defaultReturnValue(int rv);
	
Gets the default return value.

Returns:the current default return value.
/**
	 * Gets the default return value.
	 *
	 * @return the current default return value.
	 */
	@Override
	int defaultReturnValue();
	
Returns a type-specific set view of the mappings contained in this map.

 This method is necessary because there is no inheritance along type parameters: it is thus impossible to strengthen Map.entrySet() so that it returns an ObjectSet of type-specific entries (the latter makes it possible to access keys and values with type-specific methods). 
See Also:
Returns:a type-specific set view of the mappings contained in this map.
/**
	 * Returns a type-specific set view of the mappings contained in this map.
	 *
	 * <p>
	 * This method is necessary because there is no inheritance along type
	 * parameters: it is thus impossible to strengthen {@link Map#entrySet()} so
	 * that it returns an {@link it.unimi.dsi.fastutil.objects.ObjectSet} of
	 * type-specific entries (the latter makes it possible to access keys and values
	 * with type-specific methods).
	 *
	 * @return a type-specific set view of the mappings contained in this map.
	 * @see Map#entrySet()
	 */
	ObjectSet<Int2IntMap.Entry> int2IntEntrySet();
	
Returns a set view of the mappings contained in this map.

 Note that this specification strengthens the one given in Map.entrySet(). 
See Also:
Returns:a set view of the mappings contained in this map.
Deprecated:Please use the corresponding type-specific method instead.
/**
	 * Returns a set view of the mappings contained in this map.
	 * <p>
	 * Note that this specification strengthens the one given in
	 * {@link Map#entrySet()}.
	 *
	 * @return a set view of the mappings contained in this map.
	 * @see Map#entrySet()
	 * @deprecated Please use the corresponding type-specific method instead.
	 */
	@Deprecated
	@Override
	@SuppressWarnings({"unchecked", "rawtypes"})
	default ObjectSet<Map.Entry<Integer, Integer>> entrySet() {
		return (ObjectSet) int2IntEntrySet();
	}
	
{@inheritDoc}

 This default implementation just delegates to the corresponding type-specific–function method. 
Deprecated:Please use the corresponding type-specific method instead.
/**
	 * {@inheritDoc}
	 * <p>
	 * This default implementation just delegates to the corresponding
	 * type-specific&ndash;{@linkplain it.unimi.dsi.fastutil.Function function}
	 * method.
	 * 
	 * @deprecated Please use the corresponding type-specific method instead.
	 */
	@Deprecated
	@Override
	default Integer put(final Integer key, final Integer value) {
		return Int2IntFunction.super.put(key, value);
	}
	
{@inheritDoc}

 This default implementation just delegates to the corresponding type-specific–function method. 
Deprecated:Please use the corresponding type-specific method instead.
/**
	 * {@inheritDoc}
	 * <p>
	 * This default implementation just delegates to the corresponding
	 * type-specific&ndash;{@linkplain it.unimi.dsi.fastutil.Function function}
	 * method.
	 * 
	 * @deprecated Please use the corresponding type-specific method instead.
	 */
	@Deprecated
	@Override
	default Integer get(final Object key) {
		return Int2IntFunction.super.get(key);
	}
	
{@inheritDoc}

 This default implementation just delegates to the corresponding type-specific–function method. 
Deprecated:Please use the corresponding type-specific method instead.
/**
	 * {@inheritDoc}
	 * <p>
	 * This default implementation just delegates to the corresponding
	 * type-specific&ndash;{@linkplain it.unimi.dsi.fastutil.Function function}
	 * method.
	 * 
	 * @deprecated Please use the corresponding type-specific method instead.
	 */
	@Deprecated
	@Override
	default Integer remove(final Object key) {
		return Int2IntFunction.super.remove(key);
	}
	
{@inheritDoc}

 Note that this specification strengthens the one given in Map.keySet(). 
See Also:
Returns:a set view of the keys contained in this map.
/**
	 * {@inheritDoc}
	 * <p>
	 * Note that this specification strengthens the one given in
	 * {@link Map#keySet()}.
	 * 
	 * @return a set view of the keys contained in this map.
	 * @see Map#keySet()
	 */
	@Override
	IntSet keySet();
	
{@inheritDoc}

 Note that this specification strengthens the one given in Map.values(). 
See Also:
Returns:a set view of the values contained in this map.
/**
	 * {@inheritDoc}
	 * <p>
	 * Note that this specification strengthens the one given in
	 * {@link Map#values()}.
	 * 
	 * @return a set view of the values contained in this map.
	 * @see Map#values()
	 */
	@Override
	IntCollection values();
	
Returns true if this function contains a mapping for the specified key.

Params:
  • key – 
           the key.
See Also:
Returns:true if this function associates a value to key.
/**
	 * Returns true if this function contains a mapping for the specified key.
	 *
	 * @param key
	 *            the key.
	 * @return true if this function associates a value to {@code key}.
	 * @see Map#containsKey(Object)
	 */
	@Override
	boolean containsKey(int key);
	
Returns true if this function contains a mapping for the specified key.

 This default implementation just delegates to the corresponding type-specific–function method. 
Deprecated:Please use the corresponding type-specific method instead.
/**
	 * Returns true if this function contains a mapping for the specified key.
	 * <p>
	 * This default implementation just delegates to the corresponding
	 * type-specific&ndash;{@linkplain it.unimi.dsi.fastutil.Function function}
	 * method.
	 * 
	 * @deprecated Please use the corresponding type-specific method instead.
	 */
	@Deprecated
	@Override
	default boolean containsKey(final Object key) {
		return Int2IntFunction.super.containsKey(key);
	}
	
Returns true if this map maps one or more keys to the specified value. 
See Also:
/**
	 * Returns {@code true} if this map maps one or more keys to the specified
	 * value.
	 * 
	 * @see Map#containsValue(Object)
	 */
	boolean containsValue(int value);
	
{@inheritDoc}

Deprecated:Please use the corresponding type-specific method instead.
/**
	 * {@inheritDoc}
	 * 
	 * @deprecated Please use the corresponding type-specific method instead.
	 */
	@Deprecated
	@Override
	default boolean containsValue(final Object value) {
		return value == null ? false : containsValue(((Integer) (value)).intValue());
	}
	// Defaultable methods
	
Returns the value to which the specified key is mapped, or the defaultValue if this map contains no mapping for the key. 
Params:
  • key – 
           the key.
  • defaultValue – 
           the default mapping of the key.
See Also:
Returns:the value to which the specified key is mapped, or the defaultValue if this map contains no mapping for the key.
Since:8.0.0
/**
	 * Returns the value to which the specified key is mapped, or the
	 * {@code defaultValue} if this map contains no mapping for the key.
	 *
	 * @param key
	 *            the key.
	 * @param defaultValue
	 *            the default mapping of the key.
	 *
	 * @return the value to which the specified key is mapped, or the
	 *         {@code defaultValue} if this map contains no mapping for the key.
	 *
	 * @see java.util.Map#getOrDefault(Object, Object)
	 * @since 8.0.0
	 */
	default int getOrDefault(final int key, final int defaultValue) {
		final int v;
		return ((v = get(key)) != defaultReturnValue() || containsKey(key)) ? v : defaultValue;
	}
	
If the specified key is not already associated with a value, associates it with the given value and returns the 
default return value, else returns the current value. 
Params:
  • key – 
           key with which the specified value is to be associated.
  • value – 
           value to be associated with the specified key.
See Also:
Returns:the previous value associated with the specified key, or the default return value if there was no mapping for the key.
Since:8.0.0
/**
	 * If the specified key is not already associated with a value, associates it
	 * with the given value and returns the {@linkplain #defaultReturnValue()
	 * default return value}, else returns the current value.
	 *
	 * @param key
	 *            key with which the specified value is to be associated.
	 * @param value
	 *            value to be associated with the specified key.
	 *
	 * @return the previous value associated with the specified key, or the
	 *         {@linkplain #defaultReturnValue() default return value} if there was
	 *         no mapping for the key.
	 *
	 * @see java.util.Map#putIfAbsent(Object, Object)
	 * @since 8.0.0
	 */
	default int putIfAbsent(final int key, final int value) {
		final int v = get(key), drv = defaultReturnValue();
		if (v != drv || containsKey(key))
			return v;
		put(key, value);
		return drv;
	}
	
Removes the entry for the specified key only if it is currently mapped to the
specified value.

Params:
  • key – 
           key with which the specified value is associated.
  • value – 
           value expected to be associated with the specified key.
See Also:
Returns:true if the value was removed.
Since:8.0.0
/**
	 * Removes the entry for the specified key only if it is currently mapped to the
	 * specified value.
	 *
	 * @param key
	 *            key with which the specified value is associated.
	 * @param value
	 *            value expected to be associated with the specified key.
	 *
	 * @return {@code true} if the value was removed.
	 *
	 * @see java.util.Map#remove(Object, Object)
	 * @since 8.0.0
	 */
	default boolean remove(final int key, final int value) {
		final int curValue = get(key);
		if (!((curValue) == (value)) || (curValue == defaultReturnValue() && !containsKey(key)))
			return false;
		remove(key);
		return true;
	}
	
Replaces the entry for the specified key only if currently mapped to the
specified value.

Params:
  • key – 
           key with which the specified value is associated.
  • oldValue – 
           value expected to be associated with the specified key.
  • newValue – 
           value to be associated with the specified key.
See Also:
Returns:true if the value was replaced.
Since:8.0.0
/**
	 * Replaces the entry for the specified key only if currently mapped to the
	 * specified value.
	 *
	 * @param key
	 *            key with which the specified value is associated.
	 * @param oldValue
	 *            value expected to be associated with the specified key.
	 * @param newValue
	 *            value to be associated with the specified key.
	 *
	 * @return {@code true} if the value was replaced.
	 *
	 * @see java.util.Map#replace(Object, Object, Object)
	 * @since 8.0.0
	 */
	default boolean replace(final int key, final int oldValue, final int newValue) {
		final int curValue = get(key);
		if (!((curValue) == (oldValue)) || (curValue == defaultReturnValue() && !containsKey(key)))
			return false;
		put(key, newValue);
		return true;
	}
	
Replaces the entry for the specified key only if it is currently mapped to
some value.

Params:
  • key – 
           key with which the specified value is associated.
  • value – 
           value to be associated with the specified key.
See Also:
Returns:the previous value associated with the specified key, or the default return value if there was no mapping for the key.
Since:8.0.0
/**
	 * Replaces the entry for the specified key only if it is currently mapped to
	 * some value.
	 *
	 * @param key
	 *            key with which the specified value is associated.
	 * @param value
	 *            value to be associated with the specified key.
	 *
	 * @return the previous value associated with the specified key, or the
	 *         {@linkplain #defaultReturnValue() default return value} if there was
	 *         no mapping for the key.
	 *
	 * @see java.util.Map#replace(Object, Object)
	 * @since 8.0.0
	 */
	default int replace(final int key, final int value) {
		return containsKey(key) ? put(key, value) : defaultReturnValue();
	}
	
If the specified key is not already associated with a value, attempts to
compute its value using the given mapping function and enters it into this
map.

 Note that contrarily to the default 
computeIfAbsent(), it is not possible to not add a value for a given key, since the mappingFunction cannot return null. If such a behavior is needed, please use the corresponding nullable version.

Params:
  • key – 
           key with which the specified value is to be associated.
  • mappingFunction – 
           the function to compute a value.
See Also:
Returns:the current (existing or computed) value associated with the
        specified key.
Since:8.0.0
/**
	 * If the specified key is not already associated with a value, attempts to
	 * compute its value using the given mapping function and enters it into this
	 * map.
	 *
	 * <p>
	 * Note that contrarily to the default
	 * {@linkplain java.util.Map#computeIfAbsent(Object, java.util.function.Function)
	 * computeIfAbsent()}, it is not possible to not add a value for a given key,
	 * since the {@code mappingFunction} cannot return {@code null}. If such a
	 * behavior is needed, please use the corresponding <em>nullable</em> version.
	 *
	 * @param key
	 *            key with which the specified value is to be associated.
	 * @param mappingFunction
	 *            the function to compute a value.
	 *
	 * @return the current (existing or computed) value associated with the
	 *         specified key.
	 *
	 * @see java.util.Map#computeIfAbsent(Object, java.util.function.Function)
	 * @since 8.0.0
	 */
	default int computeIfAbsent(final int key, final java.util.function.IntUnaryOperator mappingFunction) {
		java.util.Objects.requireNonNull(mappingFunction);
		final int v = get(key);
		if (v != defaultReturnValue() || containsKey(key))
			return v;
		int newValue = mappingFunction.applyAsInt(key);
		put(key, newValue);
		return newValue;
	}
	
If the specified key is not already associated with a value, attempts to compute its value using the given mapping function and enters it into this map unless it is null. 
 Note that this version of 
computeIfAbsent() should be used only if you plan to return null in the mapping function. 
Params:
  • key – 
           key with which the specified value is to be associated.
  • mappingFunction – 
           the function to compute a value.
See Also:
Returns:the current (existing or computed) value associated with the specified key, or the default
        return value if the computed value is null.
Since:8.0.0
/**
	 * If the specified key is not already associated with a value, attempts to
	 * compute its value using the given mapping function and enters it into this
	 * map unless it is {@code null}.
	 *
	 * <p>
	 * Note that this version of
	 * {@linkplain java.util.Map#computeIfAbsent(Object, java.util.function.Function)
	 * computeIfAbsent()} should be used only if you plan to return {@code null} in
	 * the mapping function.
	 *
	 * @param key
	 *            key with which the specified value is to be associated.
	 * @param mappingFunction
	 *            the function to compute a value.
	 *
	 * @return the current (existing or computed) value associated with the
	 *         specified key, or the {@linkplain #defaultReturnValue() default
	 *         return value} if the computed value is {@code null}.
	 *
	 * @see java.util.Map#computeIfAbsent(Object, java.util.function.Function)
	 * @since 8.0.0
	 */
	default int computeIfAbsentNullable(final int key,
			final java.util.function.IntFunction<? extends Integer> mappingFunction) {
		java.util.Objects.requireNonNull(mappingFunction);
		final int v = get(key), drv = defaultReturnValue();
		if (v != drv || containsKey(key))
			return v;
		Integer mappedValue = mappingFunction.apply(key);
		if (mappedValue == null)
			return drv;
		int newValue = (mappedValue).intValue();
		put(key, newValue);
		return newValue;
	}
	
If the specified key is not already associated with a value, attempts to
compute its value using the given mapping function and enters it into this
map, unless the key is not present in the given mapping function.

 This version of 
computeIfAbsent() uses a type-specific version of fastutil's Function. Since Function has a containsKey() method, it is possible to avoid adding a key by having containsKey() return false for that key. 
Params:
  • key – 
           key with which the specified value is to be associated.
  • mappingFunction – 
           the function to compute a value.
See Also:
Returns:the current (existing or computed) value associated with the
        specified key.
Since:8.0.0
/**
	 * If the specified key is not already associated with a value, attempts to
	 * compute its value using the given mapping function and enters it into this
	 * map, unless the key is not present in the given mapping function.
	 *
	 * <p>
	 * This version of
	 * {@linkplain java.util.Map#computeIfAbsent(Object, java.util.function.Function)
	 * computeIfAbsent()} uses a type-specific version of <code>fastutil</code>'s
	 * {@link it.unimi.dsi.fastutil.Function Function}. Since
	 * {@link it.unimi.dsi.fastutil.Function Function} has a
	 * {@link it.unimi.dsi.fastutil.Function#containsKey(Object) containsKey()}
	 * method, it is possible to avoid adding a key by having {@code containsKey()}
	 * return {@code false} for that key.
	 *
	 * @param key
	 *            key with which the specified value is to be associated.
	 * @param mappingFunction
	 *            the function to compute a value.
	 *
	 * @return the current (existing or computed) value associated with the
	 *         specified key.
	 *
	 * @see java.util.Map#computeIfAbsent(Object, java.util.function.Function)
	 * @since 8.0.0
	 */
	default int computeIfAbsentPartial(final int key, final Int2IntFunction mappingFunction) {
		java.util.Objects.requireNonNull(mappingFunction);
		final int v = get(key), drv = defaultReturnValue();
		if (v != drv || containsKey(key))
			return v;
		if (!mappingFunction.containsKey(key))
			return drv;
		int newValue = mappingFunction.get(key);
		put(key, newValue);
		return newValue;
	}
	
If the value for the specified key is present, attempts to compute a new
mapping given the key and its current mapped value.

Params:
  • key – 
           key with which the specified value is to be associated.
  • remappingFunction – 
           the function to compute a value.
See Also:
Returns:the new value associated with the specified key, or the default return value if none.
Since:8.0.0
/**
	 * If the value for the specified key is present, attempts to compute a new
	 * mapping given the key and its current mapped value.
	 *
	 * @param key
	 *            key with which the specified value is to be associated.
	 * @param remappingFunction
	 *            the function to compute a value.
	 *
	 * @return the new value associated with the specified key, or the
	 *         {@linkplain #defaultReturnValue() default return value} if none.
	 *
	 * @see java.util.Map#computeIfPresent(Object, java.util.function.BiFunction)
	 * @since 8.0.0
	 */
	default int computeIfPresent(final int key,
			final java.util.function.BiFunction<? super Integer, ? super Integer, ? extends Integer> remappingFunction) {
		java.util.Objects.requireNonNull(remappingFunction);
		final int oldValue = get(key), drv = defaultReturnValue();
		if (oldValue == drv && !containsKey(key))
			return drv;
		final Integer newValue = remappingFunction.apply(Integer.valueOf(key), Integer.valueOf(oldValue));
		if (newValue == null) {
			remove(key);
			return drv;
		}
		int newVal = (newValue).intValue();
		put(key, newVal);
		return newVal;
	}
	
Attempts to compute a mapping for the specified key and its current mapped value (or null if there is no current mapping). 
 If the function returns null, the mapping is removed (or remains absent if initially absent). If the function itself throws an (unchecked) exception, the exception is rethrown, and the current mapping is left unchanged. 
Params:
  • key – 
           key with which the specified value is to be associated.
  • remappingFunction – 
           the function to compute a value.
See Also:
Returns:the new value associated with the specified key, or the default return value if none.
Since:8.0.0
/**
	 * Attempts to compute a mapping for the specified key and its current mapped
	 * value (or {@code null} if there is no current mapping).
	 *
	 * <p>
	 * If the function returns {@code null}, the mapping is removed (or remains
	 * absent if initially absent). If the function itself throws an (unchecked)
	 * exception, the exception is rethrown, and the current mapping is left
	 * unchanged.
	 *
	 * @param key
	 *            key with which the specified value is to be associated.
	 * @param remappingFunction
	 *            the function to compute a value.
	 *
	 * @return the new value associated with the specified key, or the
	 *         {@linkplain #defaultReturnValue() default return value} if none.
	 *
	 * @see java.util.Map#compute(Object, java.util.function.BiFunction)
	 * @since 8.0.0
	 */
	default int compute(final int key,
			final java.util.function.BiFunction<? super Integer, ? super Integer, ? extends Integer> remappingFunction) {
		java.util.Objects.requireNonNull(remappingFunction);
		final int oldValue = get(key), drv = defaultReturnValue();
		final boolean contained = oldValue != drv || containsKey(key);
		final Integer newValue = remappingFunction.apply(Integer.valueOf(key),
				contained ? Integer.valueOf(oldValue) : null);
		if (newValue == null) {
			if (contained)
				remove(key);
			return drv;
		}
		final int newVal = (newValue).intValue();
		put(key, newVal);
		return newVal;
	}
	
If the specified key is not already associated with a value, associates it with the given value. Otherwise, replaces the associated value with the results of the given remapping function, or removes if the result is null. 
Params:
  • key – 
           key with which the resulting value is to be associated.
  • value – 
           the value to be merged with the existing value associated with the
           key or, if no existing value is associated with the key, to be
           associated with the key.
  • remappingFunction – 
           the function to recompute a value if present.
See Also:
Returns:the new value associated with the specified key, or the default return value if no value is associated with the key.
Since:8.0.0
/**
	 * If the specified key is not already associated with a value, associates it
	 * with the given {@code value}. Otherwise, replaces the associated value with
	 * the results of the given remapping function, or removes if the result is
	 * {@code null}.
	 *
	 * @param key
	 *            key with which the resulting value is to be associated.
	 * @param value
	 *            the value to be merged with the existing value associated with the
	 *            key or, if no existing value is associated with the key, to be
	 *            associated with the key.
	 * @param remappingFunction
	 *            the function to recompute a value if present.
	 *
	 * @return the new value associated with the specified key, or the
	 *         {@linkplain #defaultReturnValue() default return value} if no value
	 *         is associated with the key.
	 *
	 * @see java.util.Map#merge(Object, Object, java.util.function.BiFunction)
	 * @since 8.0.0
	 */
	default int merge(final int key, final int value,
			final java.util.function.BiFunction<? super Integer, ? super Integer, ? extends Integer> remappingFunction) {
		java.util.Objects.requireNonNull(remappingFunction);
		final int oldValue = get(key), drv = defaultReturnValue();
		final int newValue;
		if (oldValue != drv || containsKey(key)) {
			final Integer mergedValue = remappingFunction.apply(Integer.valueOf(oldValue), Integer.valueOf(value));
			if (mergedValue == null) {
				remove(key);
				return drv;
			}
			newValue = (mergedValue).intValue();
		} else {
			newValue = value;
		}
		put(key, newValue);
		return newValue;
	}
	
{@inheritDoc}

 This default implementation just delegates to the corresponding Map method. 
Deprecated:Please use the corresponding type-specific method instead.
/**
	 * {@inheritDoc}
	 * <p>
	 * This default implementation just delegates to the corresponding {@link Map}
	 * method.
	 * 
	 * @deprecated Please use the corresponding type-specific method instead.
	 */
	@Deprecated
	@Override
	default Integer getOrDefault(final Object key, final Integer defaultValue) {
		return Map.super.getOrDefault(key, defaultValue);
	}
	
{@inheritDoc}

 This default implementation just delegates to the corresponding Map method. 
Deprecated:Please use the corresponding type-specific method instead.
/**
	 * {@inheritDoc}
	 * <p>
	 * This default implementation just delegates to the corresponding {@link Map}
	 * method.
	 * 
	 * @deprecated Please use the corresponding type-specific method instead.
	 */
	@Deprecated
	@Override
	default Integer putIfAbsent(final Integer key, final Integer value) {
		return Map.super.putIfAbsent(key, value);
	}
	
{@inheritDoc}

 This default implementation just delegates to the corresponding Map method. 
Deprecated:Please use the corresponding type-specific method instead.
/**
	 * {@inheritDoc}
	 * <p>
	 * This default implementation just delegates to the corresponding {@link Map}
	 * method.
	 * 
	 * @deprecated Please use the corresponding type-specific method instead.
	 */
	@Deprecated
	@Override
	default boolean remove(final Object key, final Object value) {
		return Map.super.remove(key, value);
	}
	
{@inheritDoc}

 This default implementation just delegates to the corresponding Map method. 
Deprecated:Please use the corresponding type-specific method instead.
/**
	 * {@inheritDoc}
	 * <p>
	 * This default implementation just delegates to the corresponding {@link Map}
	 * method.
	 * 
	 * @deprecated Please use the corresponding type-specific method instead.
	 */
	@Deprecated
	@Override
	default boolean replace(final Integer key, final Integer oldValue, final Integer newValue) {
		return Map.super.replace(key, oldValue, newValue);
	}
	
{@inheritDoc}

 This default implementation just delegates to the corresponding Map method. 
Deprecated:Please use the corresponding type-specific method instead.
/**
	 * {@inheritDoc}
	 * <p>
	 * This default implementation just delegates to the corresponding {@link Map}
	 * method.
	 * 
	 * @deprecated Please use the corresponding type-specific method instead.
	 */
	@Deprecated
	@Override
	default Integer replace(final Integer key, final Integer value) {
		return Map.super.replace(key, value);
	}
	
{@inheritDoc}

 This default implementation just delegates to the corresponding Map method. 
Deprecated:Please use the corresponding type-specific method instead.
/**
	 * {@inheritDoc}
	 * <p>
	 * This default implementation just delegates to the corresponding {@link Map}
	 * method.
	 * 
	 * @deprecated Please use the corresponding type-specific method instead.
	 */
	@Deprecated
	@Override
	default Integer computeIfAbsent(final Integer key,
			final java.util.function.Function<? super Integer, ? extends Integer> mappingFunction) {
		return Map.super.computeIfAbsent(key, mappingFunction);
	}
	
{@inheritDoc}

 This default implementation just delegates to the corresponding Map method. 
Deprecated:Please use the corresponding type-specific method instead.
/**
	 * {@inheritDoc}
	 * <p>
	 * This default implementation just delegates to the corresponding {@link Map}
	 * method.
	 * 
	 * @deprecated Please use the corresponding type-specific method instead.
	 */
	@Deprecated
	@Override
	default Integer computeIfPresent(final Integer key,
			final java.util.function.BiFunction<? super Integer, ? super Integer, ? extends Integer> remappingFunction) {
		return Map.super.computeIfPresent(key, remappingFunction);
	}
	
{@inheritDoc}

 This default implementation just delegates to the corresponding Map method. 
Deprecated:Please use the corresponding type-specific method instead.
/**
	 * {@inheritDoc}
	 * <p>
	 * This default implementation just delegates to the corresponding {@link Map}
	 * method.
	 * 
	 * @deprecated Please use the corresponding type-specific method instead.
	 */
	@Deprecated
	@Override
	default Integer compute(final Integer key,
			final java.util.function.BiFunction<? super Integer, ? super Integer, ? extends Integer> remappingFunction) {
		return Map.super.compute(key, remappingFunction);
	}
	
{@inheritDoc}

 This default implementation just delegates to the corresponding Map method. 
Deprecated:Please use the corresponding type-specific method instead.
/**
	 * {@inheritDoc}
	 * <p>
	 * This default implementation just delegates to the corresponding {@link Map}
	 * method.
	 * 
	 * @deprecated Please use the corresponding type-specific method instead.
	 */
	@Deprecated
	@Override
	default Integer merge(final Integer key, final Integer value,
			final java.util.function.BiFunction<? super Integer, ? super Integer, ? extends Integer> remappingFunction) {
		return Map.super.merge(key, value, remappingFunction);
	}
	
A type-specific Entry; provides some additional methods that use polymorphism to avoid (un)boxing. 
See Also:
/**
	 * A type-specific {@link java.util.Map.Entry}; provides some additional methods
	 * that use polymorphism to avoid (un)boxing.
	 *
	 * @see java.util.Map.Entry
	 */
	interface Entry extends Map.Entry<Integer, Integer> {
		
Returns the key corresponding to this entry.

See Also:
  • getKey.getKey()
/**
		 * Returns the key corresponding to this entry.
		 * 
		 * @see java.util.Map.Entry#getKey()
		 */
		int getIntKey();
		
{@inheritDoc}

Deprecated:Please use the corresponding type-specific method instead.
/**
		 * {@inheritDoc}
		 * 
		 * @deprecated Please use the corresponding type-specific method instead.
		 */
		@Deprecated
		@Override
		default Integer getKey() {
			return Integer.valueOf(getIntKey());
		}
		
Returns the value corresponding to this entry.

See Also:
  • getValue.getValue()
/**
		 * Returns the value corresponding to this entry.
		 * 
		 * @see java.util.Map.Entry#getValue()
		 */
		int getIntValue();
		
Replaces the value corresponding to this entry with the specified value
(optional operation).

See Also:
  • setValue.setValue(Object)
/**
		 * Replaces the value corresponding to this entry with the specified value
		 * (optional operation).
		 * 
		 * @see java.util.Map.Entry#setValue(Object)
		 */
		int setValue(final int value);
		
{@inheritDoc}

Deprecated:Please use the corresponding type-specific method instead.
/**
		 * {@inheritDoc}
		 * 
		 * @deprecated Please use the corresponding type-specific method instead.
		 */
		@Deprecated
		@Override
		default Integer getValue() {
			return Integer.valueOf(getIntValue());
		}
		
{@inheritDoc}

Deprecated:Please use the corresponding type-specific method instead.
/**
		 * {@inheritDoc}
		 * 
		 * @deprecated Please use the corresponding type-specific method instead.
		 */
		@Deprecated
		@Override
		default Integer setValue(final Integer value) {
			return Integer.valueOf(setValue((value).intValue()));
		}
	}
}