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/* |
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* Written by Doug Lea and Josh Bloch with assistance from members of JCP |
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* JSR-166 Expert Group and released to the public domain, as explained at |
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* http://creativecommons.org/publicdomain/zero/1.0/ |
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*/ |
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|
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package java.util; |
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|
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/** |
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* A {@link SortedMap} extended with navigation methods returning the |
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* closest matches for given search targets. Methods |
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* {@code lowerEntry}, {@code floorEntry}, {@code ceilingEntry}, |
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* and {@code higherEntry} return {@code Map.Entry} objects |
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* associated with keys respectively less than, less than or equal, |
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* greater than or equal, and greater than a given key, returning |
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* {@code null} if there is no such key. Similarly, methods |
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* {@code lowerKey}, {@code floorKey}, {@code ceilingKey}, and |
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* {@code higherKey} return only the associated keys. All of these |
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* methods are designed for locating, not traversing entries. |
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* |
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* <p>A {@code NavigableMap} may be accessed and traversed in either |
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* ascending or descending key order. The {@code descendingMap} |
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* method returns a view of the map with the senses of all relational |
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* and directional methods inverted. The performance of ascending |
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* operations and views is likely to be faster than that of descending |
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* ones. Methods {@code subMap}, {@code headMap}, |
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* and {@code tailMap} differ from the like-named {@code |
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* SortedMap} methods in accepting additional arguments describing |
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* whether lower and upper bounds are inclusive versus exclusive. |
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* Submaps of any {@code NavigableMap} must implement the {@code |
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* NavigableMap} interface. |
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* |
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* <p>This interface additionally defines methods {@code firstEntry}, |
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* {@code pollFirstEntry}, {@code lastEntry}, and |
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* {@code pollLastEntry} that return and/or remove the least and |
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* greatest mappings, if any exist, else returning {@code null}. |
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* |
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* <p>Implementations of entry-returning methods are expected to |
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* return {@code Map.Entry} pairs representing snapshots of mappings |
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* at the time they were produced, and thus generally do <em>not</em> |
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* support the optional {@code Entry.setValue} method. Note however |
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* that it is possible to change mappings in the associated map using |
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* method {@code put}. |
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* |
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* <p>Methods |
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* {@link #subMap(Object, Object) subMap(K, K)}, |
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* {@link #headMap(Object) headMap(K)}, and |
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* {@link #tailMap(Object) tailMap(K)} |
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* are specified to return {@code SortedMap} to allow existing |
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* implementations of {@code SortedMap} to be compatibly retrofitted to |
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* implement {@code NavigableMap}, but extensions and implementations |
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* of this interface are encouraged to override these methods to return |
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* {@code NavigableMap}. Similarly, |
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* {@link #keySet()} can be overridden to return {@code NavigableSet}. |
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* |
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* <p>This interface is a member of the |
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* <a href="{@docRoot}/../technotes/guides/collections/index.html"> |
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* Java Collections Framework</a>. |
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* |
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* @author Doug Lea |
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* @author Josh Bloch |
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* @param <K> the type of keys maintained by this map |
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* @param <V> the type of mapped values |
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* @since 1.6 |
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*/ |
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public interface NavigableMap<K,V> extends SortedMap<K,V> { |
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/** |
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* Returns a key-value mapping associated with the greatest key |
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* strictly less than the given key, or {@code null} if there is |
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* no such key. |
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* |
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* @param key the key |
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* @return an entry with the greatest key less than {@code key}, |
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* or {@code null} if there is no such key |
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* @throws ClassCastException if the specified key cannot be compared |
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* with the keys currently in the map |
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* @throws NullPointerException if the specified key is null |
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* and this map does not permit null keys |
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*/ |
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Map.Entry<K,V> lowerEntry(K key); |
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|
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/** |
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* Returns the greatest key strictly less than the given key, or |
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* {@code null} if there is no such key. |
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* |
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* @param key the key |
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* @return the greatest key less than {@code key}, |
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* or {@code null} if there is no such key |
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* @throws ClassCastException if the specified key cannot be compared |
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* with the keys currently in the map |
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* @throws NullPointerException if the specified key is null |
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* and this map does not permit null keys |
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*/ |
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K lowerKey(K key); |
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|
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/** |
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* Returns a key-value mapping associated with the greatest key |
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* less than or equal to the given key, or {@code null} if there |
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* is no such key. |
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* |
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* @param key the key |
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* @return an entry with the greatest key less than or equal to |
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* {@code key}, or {@code null} if there is no such key |
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* @throws ClassCastException if the specified key cannot be compared |
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* with the keys currently in the map |
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* @throws NullPointerException if the specified key is null |
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* and this map does not permit null keys |
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*/ |
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Map.Entry<K,V> floorEntry(K key); |
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|
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/** |
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* Returns the greatest key less than or equal to the given key, |
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* or {@code null} if there is no such key. |
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* |
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* @param key the key |
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* @return the greatest key less than or equal to {@code key}, |
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* or {@code null} if there is no such key |
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* @throws ClassCastException if the specified key cannot be compared |
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* with the keys currently in the map |
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* @throws NullPointerException if the specified key is null |
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* and this map does not permit null keys |
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*/ |
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K floorKey(K key); |
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|
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/** |
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* Returns a key-value mapping associated with the least key |
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* greater than or equal to the given key, or {@code null} if |
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* there is no such key. |
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* |
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* @param key the key |
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* @return an entry with the least key greater than or equal to |
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* {@code key}, or {@code null} if there is no such key |
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* @throws ClassCastException if the specified key cannot be compared |
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* with the keys currently in the map |
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* @throws NullPointerException if the specified key is null |
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* and this map does not permit null keys |
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*/ |
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Map.Entry<K,V> ceilingEntry(K key); |
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|
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/** |
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* Returns the least key greater than or equal to the given key, |
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* or {@code null} if there is no such key. |
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* |
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* @param key the key |
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* @return the least key greater than or equal to {@code key}, |
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* or {@code null} if there is no such key |
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* @throws ClassCastException if the specified key cannot be compared |
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* with the keys currently in the map |
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* @throws NullPointerException if the specified key is null |
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* and this map does not permit null keys |
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*/ |
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K ceilingKey(K key); |
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|
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/** |
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* Returns a key-value mapping associated with the least key |
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* strictly greater than the given key, or {@code null} if there |
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* is no such key. |
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* |
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* @param key the key |
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* @return an entry with the least key greater than {@code key}, |
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* or {@code null} if there is no such key |
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* @throws ClassCastException if the specified key cannot be compared |
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* with the keys currently in the map |
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* @throws NullPointerException if the specified key is null |
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* and this map does not permit null keys |
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*/ |
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Map.Entry<K,V> higherEntry(K key); |
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|
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/** |
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* Returns the least key strictly greater than the given key, or |
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* {@code null} if there is no such key. |
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* |
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* @param key the key |
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* @return the least key greater than {@code key}, |
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* or {@code null} if there is no such key |
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* @throws ClassCastException if the specified key cannot be compared |
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* with the keys currently in the map |
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* @throws NullPointerException if the specified key is null |
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* and this map does not permit null keys |
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*/ |
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K higherKey(K key); |
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|
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/** |
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* Returns a key-value mapping associated with the least |
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* key in this map, or {@code null} if the map is empty. |
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* |
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* @return an entry with the least key, |
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* or {@code null} if this map is empty |
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*/ |
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Map.Entry<K,V> firstEntry(); |
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|
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/** |
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* Returns a key-value mapping associated with the greatest |
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* key in this map, or {@code null} if the map is empty. |
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* |
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* @return an entry with the greatest key, |
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* or {@code null} if this map is empty |
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*/ |
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Map.Entry<K,V> lastEntry(); |
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|
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/** |
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* Removes and returns a key-value mapping associated with |
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* the least key in this map, or {@code null} if the map is empty. |
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* |
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* @return the removed first entry of this map, |
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* or {@code null} if this map is empty |
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*/ |
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Map.Entry<K,V> pollFirstEntry(); |
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|
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/** |
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* Removes and returns a key-value mapping associated with |
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* the greatest key in this map, or {@code null} if the map is empty. |
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* |
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* @return the removed last entry of this map, |
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* or {@code null} if this map is empty |
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*/ |
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Map.Entry<K,V> pollLastEntry(); |
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|
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/** |
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* Returns a reverse order view of the mappings contained in this map. |
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* The descending map is backed by this map, so changes to the map are |
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* reflected in the descending map, and vice-versa. If either map is |
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* modified while an iteration over a collection view of either map |
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* is in progress (except through the iterator's own {@code remove} |
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* operation), the results of the iteration are undefined. |
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* |
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* <p>The returned map has an ordering equivalent to |
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* {@link Collections#reverseOrder(Comparator) Collections.reverseOrder}{@code (comparator())}. |
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* The expression {@code m.descendingMap().descendingMap()} returns a |
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* view of {@code m} essentially equivalent to {@code m}. |
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* |
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* @return a reverse order view of this map |
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*/ |
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NavigableMap<K,V> descendingMap(); |
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|
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/** |
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* Returns a {@link NavigableSet} view of the keys contained in this map. |
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* The set's iterator returns the keys in ascending order. |
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* The set is backed by the map, so changes to the map are reflected in |
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* the set, and vice-versa. If the map is modified while an iteration |
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* over the set is in progress (except through the iterator's own {@code |
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* remove} operation), the results of the iteration are undefined. The |
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* set supports element removal, which removes the corresponding mapping |
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* from the map, via the {@code Iterator.remove}, {@code Set.remove}, |
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* {@code removeAll}, {@code retainAll}, and {@code clear} operations. |
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* It does not support the {@code add} or {@code addAll} operations. |
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* |
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* @return a navigable set view of the keys in this map |
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*/ |
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NavigableSet<K> navigableKeySet(); |
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|
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/** |
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* Returns a reverse order {@link NavigableSet} view of the keys contained in this map. |
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* The set's iterator returns the keys in descending order. |
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* The set is backed by the map, so changes to the map are reflected in |
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* the set, and vice-versa. If the map is modified while an iteration |
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* over the set is in progress (except through the iterator's own {@code |
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* remove} operation), the results of the iteration are undefined. The |
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* set supports element removal, which removes the corresponding mapping |
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* from the map, via the {@code Iterator.remove}, {@code Set.remove}, |
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* {@code removeAll}, {@code retainAll}, and {@code clear} operations. |
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* It does not support the {@code add} or {@code addAll} operations. |
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* |
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* @return a reverse order navigable set view of the keys in this map |
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*/ |
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NavigableSet<K> descendingKeySet(); |
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|
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/** |
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* Returns a view of the portion of this map whose keys range from |
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* {@code fromKey} to {@code toKey}. If {@code fromKey} and |
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* {@code toKey} are equal, the returned map is empty unless |
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* {@code fromInclusive} and {@code toInclusive} are both true. The |
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* returned map is backed by this map, so changes in the returned map are |
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* reflected in this map, and vice-versa. The returned map supports all |
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* optional map operations that this map supports. |
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* |
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* <p>The returned map will throw an {@code IllegalArgumentException} |
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* on an attempt to insert a key outside of its range, or to construct a |
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* submap either of whose endpoints lie outside its range. |
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* |
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* @param fromKey low endpoint of the keys in the returned map |
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* @param fromInclusive {@code true} if the low endpoint |
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* is to be included in the returned view |
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* @param toKey high endpoint of the keys in the returned map |
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* @param toInclusive {@code true} if the high endpoint |
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* is to be included in the returned view |
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* @return a view of the portion of this map whose keys range from |
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* {@code fromKey} to {@code toKey} |
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* @throws ClassCastException if {@code fromKey} and {@code toKey} |
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* cannot be compared to one another using this map's comparator |
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* (or, if the map has no comparator, using natural ordering). |
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* Implementations may, but are not required to, throw this |
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* exception if {@code fromKey} or {@code toKey} |
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* cannot be compared to keys currently in the map. |
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* @throws NullPointerException if {@code fromKey} or {@code toKey} |
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* is null and this map does not permit null keys |
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* @throws IllegalArgumentException if {@code fromKey} is greater than |
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* {@code toKey}; or if this map itself has a restricted |
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* range, and {@code fromKey} or {@code toKey} lies |
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* outside the bounds of the range |
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*/ |
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NavigableMap<K,V> subMap(K fromKey, boolean fromInclusive, |
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K toKey, boolean toInclusive); |
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|
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/** |
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* Returns a view of the portion of this map whose keys are less than (or |
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* equal to, if {@code inclusive} is true) {@code toKey}. The returned |
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* map is backed by this map, so changes in the returned map are reflected |
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* in this map, and vice-versa. The returned map supports all optional |
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* map operations that this map supports. |
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* |
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* <p>The returned map will throw an {@code IllegalArgumentException} |
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* on an attempt to insert a key outside its range. |
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* |
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* @param toKey high endpoint of the keys in the returned map |
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* @param inclusive {@code true} if the high endpoint |
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* is to be included in the returned view |
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* @return a view of the portion of this map whose keys are less than |
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* (or equal to, if {@code inclusive} is true) {@code toKey} |
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* @throws ClassCastException if {@code toKey} is not compatible |
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* with this map's comparator (or, if the map has no comparator, |
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* if {@code toKey} does not implement {@link Comparable}). |
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* Implementations may, but are not required to, throw this |
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* exception if {@code toKey} cannot be compared to keys |
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* currently in the map. |
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* @throws NullPointerException if {@code toKey} is null |
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* and this map does not permit null keys |
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* @throws IllegalArgumentException if this map itself has a |
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* restricted range, and {@code toKey} lies outside the |
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* bounds of the range |
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*/ |
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NavigableMap<K,V> headMap(K toKey, boolean inclusive); |
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|
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/** |
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* Returns a view of the portion of this map whose keys are greater than (or |
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* equal to, if {@code inclusive} is true) {@code fromKey}. The returned |
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* map is backed by this map, so changes in the returned map are reflected |
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* in this map, and vice-versa. The returned map supports all optional |
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* map operations that this map supports. |
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* |
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* <p>The returned map will throw an {@code IllegalArgumentException} |
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* on an attempt to insert a key outside its range. |
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* |
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* @param fromKey low endpoint of the keys in the returned map |
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* @param inclusive {@code true} if the low endpoint |
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* is to be included in the returned view |
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* @return a view of the portion of this map whose keys are greater than |
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* (or equal to, if {@code inclusive} is true) {@code fromKey} |
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* @throws ClassCastException if {@code fromKey} is not compatible |
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* with this map's comparator (or, if the map has no comparator, |
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* if {@code fromKey} does not implement {@link Comparable}). |
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* Implementations may, but are not required to, throw this |
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* exception if {@code fromKey} cannot be compared to keys |
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* currently in the map. |
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* @throws NullPointerException if {@code fromKey} is null |
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* and this map does not permit null keys |
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* @throws IllegalArgumentException if this map itself has a |
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* restricted range, and {@code fromKey} lies outside the |
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* bounds of the range |
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*/ |
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NavigableMap<K,V> tailMap(K fromKey, boolean inclusive); |
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|
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/** |
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* {@inheritDoc} |
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* |
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* <p>Equivalent to {@code subMap(fromKey, true, toKey, false)}. |
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* |
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* @throws ClassCastException {@inheritDoc} |
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* @throws NullPointerException {@inheritDoc} |
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* @throws IllegalArgumentException {@inheritDoc} |
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*/ |
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SortedMap<K,V> subMap(K fromKey, K toKey); |
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|
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/** |
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* {@inheritDoc} |
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* |
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* <p>Equivalent to {@code headMap(toKey, false)}. |
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* |
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* @throws ClassCastException {@inheritDoc} |
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* @throws NullPointerException {@inheritDoc} |
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* @throws IllegalArgumentException {@inheritDoc} |
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*/ |
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SortedMap<K,V> headMap(K toKey); |
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|
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/** |
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* {@inheritDoc} |
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* |
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* <p>Equivalent to {@code tailMap(fromKey, true)}. |
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* |
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* @throws ClassCastException {@inheritDoc} |
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* @throws NullPointerException {@inheritDoc} |
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* @throws IllegalArgumentException {@inheritDoc} |
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*/ |
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SortedMap<K,V> tailMap(K fromKey); |
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} |
