ImmutableMap.java
package org.opentrafficsim.core.immutablecollections;
import java.io.Serializable;
import java.util.ConcurrentModificationException;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import java.util.function.BiConsumer;
/**
* A Map interface without the methods that can change it. The constructor of the ImmutableMap needs to be given an initial Map.
* <p>
* Copyright (c) 2013-2016 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved. <br>
* BSD-style license. See <a href="http://opentrafficsim.org/docs/license.html">OpenTrafficSim License</a>.
* </p>
* $LastChangedDate: 2015-07-24 02:58:59 +0200 (Fri, 24 Jul 2015) $, @version $Revision: 1147 $, by $Author: averbraeck $,
* initial version May 7, 2016 <br>
* @author <a href="http://www.tbm.tudelft.nl/averbraeck">Alexander Verbraeck</a>
* @author <a href="http://www.tudelft.nl/pknoppers">Peter Knoppers</a>
* @author <a href="http://www.transport.citg.tudelft.nl">Wouter Schakel</a>
* @param <K> the key type of content of this Map
* @param <V> the value type of content of this Map
*/
public interface ImmutableMap<K, V> extends Serializable
{
/**
* Returns the number of elements in this immutable collection. If this immutable collection contains more than
* <tt>Integer.MAX_VALUE</tt> elements, returns <tt>Integer.MAX_VALUE</tt>.
* @return the number of elements in this immutable collection
*/
int size();
/**
* Returns <tt>true</tt> if this immutable collection contains no elements.
* @return <tt>true</tt> if this immutable collection contains no elements
*/
boolean isEmpty();
/**
* Returns <tt>true</tt> if this map contains a mapping for the specified key. More formally, returns <tt>true</tt> if and
* only if this map contains a mapping for a key <tt>k</tt> such that <tt>(key==null ? k==null : key.equals(k))</tt>. (There
* can be at most one such mapping.)
* @param key key whose presence in this map is to be tested
* @return <tt>true</tt> if this map contains a mapping for the specified key
* @throws ClassCastException if the key is of an inappropriate type for this map
* @throws NullPointerException if the specified key is null and this map does not permit null keys
*/
boolean containsKey(Object key);
/**
* Returns <tt>true</tt> if this map maps one or more keys to the specified value. More formally, returns <tt>true</tt> if
* and only if this map contains at least one mapping to a value <tt>v</tt> such that
* <tt>(value==null ? v==null : value.equals(v))</tt>. This operation will probably require time linear in the map size for
* most implementations of the <tt>Map</tt> interface.
* @param value value whose presence in this map is to be tested
* @return <tt>true</tt> if this map maps one or more keys to the specified value
* @throws ClassCastException if the value is of an inappropriate type for this map
* @throws NullPointerException if the specified value is null and this map does not permit null values
*/
boolean containsValue(Object value);
/**
* Returns the value to which the specified key is mapped, or {@code null} if this map contains no mapping for the key.
* <p>
* More formally, if this map contains a mapping from a key {@code k} to a value {@code v} such that
* {@code (key==null ? k==null : key.equals(k))}, then this method returns {@code v}; otherwise it returns {@code null}.
* (There can be at most one such mapping.)
* <p>
* If this map permits null values, then a return value of {@code null} does not <i>necessarily</i> indicate that the map
* contains no mapping for the key; it's also possible that the map explicitly maps the key to {@code null}. The
* {@link #containsKey containsKey} operation may be used to distinguish these two cases.
* @param key the key whose associated value is to be returned
* @return the value to which the specified key is mapped, or {@code null} if this map contains no mapping for the key
* @throws ClassCastException if the key is of an inappropriate type for this map
* @throws NullPointerException if the specified key is null and this map does not permit null keys
*/
V get(Object key);
/**
* Returns a {@link Set} view of the keys contained in this map.
* @return an immutable set of the keys contained in this map
*/
ImmutableSet<K> keySet();
/**
* Returns a {@link ImmutableCollection} view of the values contained in this map.
* @return an immutable collection view of the values contained in this map
*/
ImmutableCollection<V> values();
/**
* Returns the value to which the specified key is mapped, or {@code defaultValue} if this map contains no mapping for the
* key. The default implementation makes no guarantees about synchronization or atomicity properties of this method. Any
* implementation providing atomicity guarantees must override this method and document its concurrency properties.
* @param key the key whose associated value is to be returned
* @param defaultValue the default mapping of the key
* @return the value to which the specified key is mapped, or {@code defaultValue} if this map contains no mapping for the
* key
* @throws ClassCastException if the key is of an inappropriate type for this map
* @throws NullPointerException if the specified key is null and this map does not permit null keys
*/
default V getOrDefault(Object key, V defaultValue)
{
V v = get(key);
return ((v != null) || containsKey(key)) ? v : defaultValue;
}
/**
* Performs the given action for each entry in this map until all entries have been processed or the action throws an
* exception. Unless otherwise specified by the implementing class, actions are performed in the order of entry set
* iteration (if an iteration order is specified.) Exceptions thrown by the action are relayed to the caller. The default
* implementation makes no guarantees about synchronization or atomicity properties of this method. Any implementation
* providing atomicity guarantees must override this method and document its concurrency properties.
* @param action The action to be performed for each entry
* @throws NullPointerException if the specified action is null
* @throws ConcurrentModificationException if an entry is found to be removed during iteration
*/
default void forEach(BiConsumer<? super K, ? super V> action)
{
Objects.requireNonNull(action);
for (Map.Entry<K, V> entry : toMap().entrySet())
{
K k;
V v;
try
{
k = entry.getKey();
v = entry.getValue();
}
catch (IllegalStateException ise)
{
// this usually means the entry is no longer in the map.
throw new ConcurrentModificationException(ise);
}
action.accept(k, v);
}
}
/**
* Returns a modifiable copy of this immutable list.
* @return a modifiable copy of this immutable list.
*/
Map<K, V> toMap();
/**
* Force to redefine equals for the implementations of immutable collection classes.
* @param obj the object to compare this collection with
* @return whether the objects are equal
*/
boolean equals(final Object obj);
/**
* Force to redefine hashCode for the implementations of immutable collection classes.
* @return the calculated hashCode
*/
int hashCode();
}