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/* |
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* Written by Doug Lea with assistance from members of JCP JSR-166 |
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* 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 jsr166x; |
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|
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import 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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* <tt>lowerEntry</tt>, <tt>floorEntry</tt>, <tt>ceilingEntry</tt>, |
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* and <tt>higherEntry</tt> return <tt>Map.Entry</tt> 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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* <tt>null</tt> if there is no such key. Similarly, methods |
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* <tt>lowerKey</tt>, <tt>floorKey</tt>, <tt>ceilingKey</tt>, and |
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* <tt>higherKey</tt> 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 <tt>NavigableMap</tt> may be viewed and traversed in either |
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* ascending or descending key order. The <tt>Map</tt> methods |
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* <tt>keySet</tt> and <tt>entrySet</tt> return ascending views, and |
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* the additional methods <tt>descendingKeySet</tt> and |
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* <tt>descendingEntrySet</tt> return descending views. The |
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* performance of ascending traversals is likely to be faster than |
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* descending traversals. Notice that it is possible to perform |
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* subrannge traversals in either direction using <tt>SubMap</tt>. |
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* |
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* <p>This interface additionally defines methods <tt>firstEntry</tt>, |
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* <tt>pollFirstEntry</tt>, <tt>lastEntry</tt>, and |
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* <tt>pollLastEntry</tt> that return and/or remove the least and |
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* greatest mappings, if any exist, else returning <tt>null</tt>. |
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* |
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* <p> Implementations of entry-returning methods are expected to |
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* return <tt>Map.Entry</tt> 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 <tt>Entry.setValue</tt> method. Note however |
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* that it is possible to change mappings in the associated map using |
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* method <tt>put</tt>. |
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* |
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* @author Doug Lea |
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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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*/ |
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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 least key |
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* greater than or equal to the given key, or <tt>null</tt> if there is |
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* no such entry. |
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* |
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* @param key the key. |
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* @return an Entry associated with ceiling of given key, or <tt>null</tt> |
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* if there is no such Entry. |
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* @throws ClassCastException if key cannot be compared with the keys |
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* currently in the map. |
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* @throws NullPointerException if key is <tt>null</tt> and this map |
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* does not support <tt>null</tt> keys. |
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*/ |
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public Map.Entry<K,V> ceilingEntry(K key); |
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|
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/** |
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* Returns least key greater than or equal to the given key, or |
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* <tt>null</tt> if there is no such key. |
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* |
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* @param key the key. |
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* @return the ceiling key, or <tt>null</tt> |
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* if there is no such key. |
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* @throws ClassCastException if key cannot be compared with the keys |
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* currently in the map. |
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* @throws NullPointerException if key is <tt>null</tt> and this map |
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* does not support <tt>null</tt> keys. |
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*/ |
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public K ceilingKey(K key); |
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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 strictly less than the given key, or <tt>null</tt> if there is no |
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* such entry. |
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* |
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* @param key the key. |
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* @return an Entry with greatest key less than the given |
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* key, or <tt>null</tt> if there is no such Entry. |
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* @throws ClassCastException if key cannot be compared with the keys |
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* currently in the map. |
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* @throws NullPointerException if key is <tt>null</tt> and this map |
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* does not support <tt>null</tt> keys. |
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*/ |
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public 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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* <tt>null</tt> 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 the given |
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* key, or <tt>null</tt> if there is no such key. |
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* @throws ClassCastException if key cannot be compared with the keys |
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* currently in the map. |
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* @throws NullPointerException if key is <tt>null</tt> and this map |
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* does not support <tt>null</tt> keys. |
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*/ |
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public 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 <tt>null</tt> if there |
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* is no such entry. |
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* |
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* @param key the key. |
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* @return an Entry associated with floor of given key, or <tt>null</tt> |
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* if there is no such Entry. |
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* @throws ClassCastException if key cannot be compared with the keys |
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* currently in the map. |
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* @throws NullPointerException if key is <tt>null</tt> and this map |
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* does not support <tt>null</tt> keys. |
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*/ |
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public Map.Entry<K,V> floorEntry(K key); |
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|
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/** |
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* Returns the greatest key |
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* less than or equal to the given key, or <tt>null</tt> 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 the floor of given key, or <tt>null</tt> if there is no |
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* such key. |
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* @throws ClassCastException if key cannot be compared with the keys |
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* currently in the map. |
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* @throws NullPointerException if key is <tt>null</tt> and this map |
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* does not support <tt>null</tt> keys. |
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*/ |
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public 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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* strictly greater than the given key, or <tt>null</tt> if there |
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* is no such entry. |
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* |
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* @param key the key. |
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* @return an Entry with least key greater than the given key, or |
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* <tt>null</tt> if there is no such Entry. |
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* @throws ClassCastException if key cannot be compared with the keys |
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* currently in the map. |
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* @throws NullPointerException if key is <tt>null</tt> and this map |
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* does not support <tt>null</tt> keys. |
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*/ |
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public 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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* <tt>null</tt> 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 the given key, or |
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* <tt>null</tt> if there is no such key. |
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* @throws ClassCastException if key cannot be compared with the keys |
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* currently in the map. |
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* @throws NullPointerException if key is <tt>null</tt> and this map |
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* does not support <tt>null</tt> keys. |
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*/ |
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public 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 <tt>null</tt> if the map is empty. |
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* |
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* @return an Entry with least key, or <tt>null</tt> |
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* if the map is empty. |
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*/ |
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public 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 <tt>null</tt> if the map is empty. |
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* |
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* @return an Entry with greatest key, or <tt>null</tt> |
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* if the map is empty. |
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*/ |
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public 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 <tt>null</tt> if the map is empty. |
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* |
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* @return the removed first entry of this map, or <tt>null</tt> |
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* if the map is empty. |
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*/ |
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public 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 <tt>null</tt> if the map is empty. |
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* |
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* @return the removed last entry of this map, or <tt>null</tt> |
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* if the map is empty. |
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*/ |
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public Map.Entry<K,V> pollLastEntry(); |
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|
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/** |
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* Returns a set view of the keys contained in this map, in |
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* descending key order. The set is backed by the map, so changes |
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* to the map are reflected in the set, and vice-versa. If the |
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* map is modified while an iteration over the set is in progress |
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* (except through the iterator's own <tt>remove</tt> operation), |
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* the results of the iteration are undefined. The set supports |
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* element removal, which removes the corresponding mapping from |
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* the map, via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>, |
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* <tt>removeAll</tt> <tt>retainAll</tt>, and <tt>clear</tt> |
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* operations. It does not support the add or <tt>addAll</tt> |
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* operations. |
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* |
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* @return a set view of the keys contained in this map. |
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*/ |
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Set<K> descendingKeySet(); |
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|
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/** |
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* Returns a set view of the mappings contained in this map, in |
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* descending key order. Each element in the returned set is a |
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* <tt>Map.Entry</tt>. The set is backed by the map, so changes to |
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* the map are reflected in the set, and vice-versa. If the map |
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* is modified while an iteration over the set is in progress |
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* (except through the iterator's own <tt>remove</tt> operation, |
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* or through the <tt>setValue</tt> operation on a map entry |
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* returned by the iterator) the results of the iteration are |
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* undefined. The set supports element removal, which removes the |
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* corresponding mapping from the map, via the |
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* <tt>Iterator.remove</tt>, <tt>Set.remove</tt>, |
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* <tt>removeAll</tt>, <tt>retainAll</tt> and <tt>clear</tt> |
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* operations. It does not support the <tt>add</tt> or |
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* <tt>addAll</tt> operations. |
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* |
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* @return a set view of the mappings contained in this map. |
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*/ |
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Set<Map.Entry<K, V>> descendingEntrySet(); |
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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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* <tt>fromKey</tt>, inclusive, to <tt>toKey</tt>, exclusive. (If |
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* <tt>fromKey</tt> and <tt>toKey</tt> are equal, the returned sorted map |
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* is empty.) The returned sorted map is backed by this map, so changes |
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* in the returned sorted map are reflected in this map, and vice-versa. |
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* |
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* @param fromKey low endpoint (inclusive) of the subMap. |
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* @param toKey high endpoint (exclusive) of the subMap. |
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* |
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* @return a view of the portion of this map whose keys range from |
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* <tt>fromKey</tt>, inclusive, to <tt>toKey</tt>, exclusive. |
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* |
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* @throws ClassCastException if <tt>fromKey</tt> and |
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* <tt>toKey</tt> cannot be compared to one another using this |
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* map's comparator (or, if the map has no comparator, using |
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* natural ordering). |
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* @throws IllegalArgumentException if <tt>fromKey</tt> is greater |
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* than <tt>toKey</tt>. |
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* @throws NullPointerException if <tt>fromKey</tt> or |
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* <tt>toKey</tt> is <tt>null</tt> and this map does not support |
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* <tt>null</tt> keys. |
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*/ |
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public NavigableMap<K,V> subMap(K fromKey, K toKey); |
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|
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/** |
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* Returns a view of the portion of this map whose keys are strictly less |
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* than <tt>toKey</tt>. The returned sorted map is backed by this map, so |
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* changes in the returned sorted map are reflected in this map, and |
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* vice-versa. |
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* @param toKey high endpoint (exclusive) of the headMap. |
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* @return a view of the portion of this map whose keys are strictly |
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* less than <tt>toKey</tt>. |
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* |
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* @throws ClassCastException if <tt>toKey</tt> is not compatible |
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* with this map's comparator (or, if the map has no comparator, |
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* if <tt>toKey</tt> does not implement <tt>Comparable</tt>). |
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* @throws NullPointerException if <tt>toKey</tt> is <tt>null</tt> |
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* and this map does not support <tt>null</tt> keys. |
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*/ |
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public NavigableMap<K,V> headMap(K toKey); |
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|
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/** |
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* Returns a view of the portion of this map whose keys are |
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* greater than or equal to <tt>fromKey</tt>. The returned sorted |
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* map is backed by this map, so changes in the returned sorted |
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* map are reflected in this map, and vice-versa. |
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* @param fromKey low endpoint (inclusive) of the tailMap. |
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* @return a view of the portion of this map whose keys are greater |
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* than or equal to <tt>fromKey</tt>. |
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* @throws ClassCastException if <tt>fromKey</tt> is not compatible |
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* with this map's comparator (or, if the map has no comparator, |
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* if <tt>fromKey</tt> does not implement <tt>Comparable</tt>). |
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* @throws NullPointerException if <tt>fromKey</tt> is <tt>null</tt> |
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* and this map does not support <tt>null</tt> keys. |
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*/ |
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public NavigableMap<K,V> tailMap(K fromKey); |
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} |
