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/* |
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* %W% %E% |
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* |
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* Copyright 2005 Sun Microsystems, Inc. All rights reserved. |
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* Copyright 2006 Sun Microsystems, Inc. All rights reserved. |
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* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. |
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*/ |
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* map being implemented admits a more efficient implementation. |
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* |
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* <p>This class is a member of the |
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< |
* <a href="{@docRoot}/../guide/collections/index.html"> |
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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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* @param <K> the type of keys maintained by this map |
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* @throws IllegalArgumentException {@inheritDoc} |
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*/ |
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public void putAll(Map<? extends K, ? extends V> m) { |
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Iterator<? extends Entry<? extends K, ? extends V>> i = m.entrySet().iterator(); |
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while (i.hasNext()) { |
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Entry<? extends K, ? extends V> e = i.next(); |
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put(e.getKey(), e.getValue()); |
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} |
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for (Map.Entry<? extends K, ? extends V> e : m.entrySet()) |
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put(e.getKey(), e.getValue()); |
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} |
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/** |
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// Comparison and hashing |
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/** |
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* {@inheritDoc} |
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* Compares the specified object with this map for equality. Returns |
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* <tt>true</tt> if the given object is also a map and the two maps |
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* represent the same mappings. More formally, two maps <tt>m1</tt> and |
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* <tt>m2</tt> represent the same mappings if |
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* <tt>m1.entrySet().equals(m2.entrySet())</tt>. This ensures that the |
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* <tt>equals</tt> method works properly across different implementations |
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* of the <tt>Map</tt> interface. |
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* |
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* <p>This implementation first checks if the specified object is this map; |
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* if so it returns <tt>true</tt>. Then, it checks if the specified |
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* contains each mapping that this map contains. If the specified map |
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* fails to contain such a mapping, <tt>false</tt> is returned. If the |
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* iteration completes, <tt>true</tt> is returned. |
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* |
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* @param o object to be compared for equality with this map |
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* @return <tt>true</tt> if the specified object is equal to this map |
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*/ |
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public boolean equals(Object o) { |
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if (o == this) |
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if (!(o instanceof Map)) |
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return false; |
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Map<K,V> t = (Map<K,V>) o; |
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if (t.size() != size()) |
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Map<K,V> m = (Map<K,V>) o; |
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if (m.size() != size()) |
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return false; |
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|
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try { |
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K key = e.getKey(); |
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V value = e.getValue(); |
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if (value == null) { |
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if (!(t.get(key)==null && t.containsKey(key))) |
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if (!(m.get(key)==null && m.containsKey(key))) |
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return false; |
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} else { |
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if (!value.equals(t.get(key))) |
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if (!value.equals(m.get(key))) |
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return false; |
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} |
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} |
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} |
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|
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/** |
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* {@inheritDoc} |
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* Returns the hash code value for this map. The hash code of a map is |
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* defined to be the sum of the hash codes of each entry in the map's |
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* <tt>entrySet()</tt> view. This ensures that <tt>m1.equals(m2)</tt> |
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* implies that <tt>m1.hashCode()==m2.hashCode()</tt> for any two maps |
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* <tt>m1</tt> and <tt>m2</tt>, as required by the general contract of |
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* {@link Object#hashCode}. |
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* |
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* <p>This implementation iterates over <tt>entrySet()</tt>, calling |
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* <tt>hashCode()</tt> on each element (entry) in the set, and |
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* adding up the results. |
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* {@link Map.Entry#hashCode hashCode()} on each element (entry) in the |
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* set, and adding up the results. |
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* |
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* @return the hash code value for this map |
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* @see Map.Entry#hashCode() |
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– |
* @see Object#hashCode() |
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* @see Object#equals(Object) |
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* @see Set#equals(Object) |
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*/ |
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* <tt>", "</tt> (comma and space). Each key-value mapping is rendered as |
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* the key followed by an equals sign (<tt>"="</tt>) followed by the |
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* associated value. Keys and values are converted to strings as by |
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* <tt>String.valueOf(Object)</tt>.<p> |
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* |
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* This implementation creates an empty string buffer, appends a left |
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* brace, and iterates over the map's <tt>entrySet</tt> view, appending |
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* the string representation of each <tt>map.entry</tt> in turn. After |
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* appending each entry except the last, the string <tt>", "</tt> is |
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* appended. Finally a right brace is appended. A string is obtained |
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* from the stringbuffer, and returned. |
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* {@link String#valueOf(Object)}. |
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* |
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* @return a String representation of this map |
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* @return a string representation of this map |
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*/ |
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public String toString() { |
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– |
StringBuilder sb = new StringBuilder(); |
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– |
sb.append("{"); |
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– |
|
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Iterator<Entry<K,V>> i = entrySet().iterator(); |
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boolean hasNext = i.hasNext(); |
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while (hasNext) { |
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if (! i.hasNext()) |
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return "{}"; |
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|
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StringBuilder sb = new StringBuilder(); |
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sb.append('{'); |
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for (;;) { |
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Entry<K,V> e = i.next(); |
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K key = e.getKey(); |
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V value = e.getValue(); |
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if (key == this) |
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sb.append("(this Map)"); |
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else |
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sb.append(key); |
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sb.append("="); |
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if (value == this) |
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sb.append("(this Map)"); |
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else |
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< |
sb.append(value); |
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hasNext = i.hasNext(); |
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if (hasNext) |
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sb.append(", "); |
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} |
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|
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sb.append("}"); |
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return sb.toString(); |
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V value = e.getValue(); |
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sb.append(key == this ? "(this Map)" : key); |
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sb.append('='); |
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sb.append(value == this ? "(this Map)" : value); |
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if (! i.hasNext()) |
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return sb.append('}').toString(); |
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sb.append(", "); |
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> |
} |
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} |
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|
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/** |
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* Test for equality, checking for nulls. |
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*/ |
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private static boolean eq(Object o1, Object o2) { |
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return (o1 == null ? o2 == null : o1.equals(o2)); |
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> |
return o1 == null ? o2 == null : o1.equals(o2); |
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} |
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|
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// Implementation Note: SimpleEntry and SimpleImmutableEntry |
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* facilitates the process of building custom map |
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* implementations. For example, it may be convenient to return |
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* arrays of <tt>SimpleEntry</tt> instances in method |
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* <tt>Map.entrySet().toArray</tt> |
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> |
* <tt>Map.entrySet().toArray</tt>. |
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> |
* |
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> |
* @since 1.6 |
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*/ |
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< |
public static class SimpleEntry<K,V> implements Entry<K,V> { |
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> |
public static class SimpleEntry<K,V> |
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implements Entry<K,V>, java.io.Serializable |
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{ |
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> |
private static final long serialVersionUID = -8499721149061103585L; |
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> |
|
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private final K key; |
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private V value; |
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|
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return oldValue; |
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} |
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|
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/** |
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* Compares the specified object with this entry for equality. |
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* Returns {@code true} if the given object is also a map entry and |
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* the two entries represent the same mapping. More formally, two |
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* entries {@code e1} and {@code e2} represent the same mapping |
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* if<pre> |
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* (e1.getKey()==null ? |
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* e2.getKey()==null : |
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* e1.getKey().equals(e2.getKey())) |
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* && |
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* (e1.getValue()==null ? |
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* e2.getValue()==null : |
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* e1.getValue().equals(e2.getValue()))</pre> |
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* This ensures that the {@code equals} method works properly across |
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* different implementations of the {@code Map.Entry} interface. |
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+ |
* |
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+ |
* @param o object to be compared for equality with this map entry |
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* @return {@code true} if the specified object is equal to this map |
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* entry |
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* @see #hashCode |
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*/ |
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public boolean equals(Object o) { |
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if (!(o instanceof Map.Entry)) |
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return false; |
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return eq(key, e.getKey()) && eq(value, e.getValue()); |
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} |
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|
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+ |
/** |
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* Returns the hash code value for this map entry. The hash code |
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* of a map entry {@code e} is defined to be: <pre> |
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* (e.getKey()==null ? 0 : e.getKey().hashCode()) ^ |
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* (e.getValue()==null ? 0 : e.getValue().hashCode())</pre> |
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+ |
* This ensures that {@code e1.equals(e2)} implies that |
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+ |
* {@code e1.hashCode()==e2.hashCode()} for any two Entries |
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+ |
* {@code e1} and {@code e2}, as required by the general |
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+ |
* contract of {@link Object#hashCode}. |
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* |
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* @return the hash code value for this map entry |
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* @see #equals |
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*/ |
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public int hashCode() { |
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< |
return ((key == null) ? 0 : key.hashCode()) ^ |
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< |
((value == null) ? 0 : value.hashCode()); |
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> |
return (key == null ? 0 : key.hashCode()) ^ |
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> |
(value == null ? 0 : value.hashCode()); |
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} |
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|
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/** |
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} |
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|
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/** |
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< |
* An Entry maintaining an immutable key and value, This class |
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> |
* An Entry maintaining an immutable key and value. This class |
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* does not support method <tt>setValue</tt>. This class may be |
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* convenient in methods that return thread-safe snapshots of |
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* key-value mappings. |
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+ |
* |
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* @since 1.6 |
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*/ |
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< |
public static class SimpleImmutableEntry<K,V> implements Entry<K,V> { |
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> |
public static class SimpleImmutableEntry<K,V> |
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> |
implements Entry<K,V>, java.io.Serializable |
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> |
{ |
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> |
private static final long serialVersionUID = 7138329143949025153L; |
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> |
|
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private final K key; |
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private final V value; |
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|
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throw new UnsupportedOperationException(); |
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} |
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|
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+ |
/** |
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* Compares the specified object with this entry for equality. |
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* Returns {@code true} if the given object is also a map entry and |
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* the two entries represent the same mapping. More formally, two |
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* entries {@code e1} and {@code e2} represent the same mapping |
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* if<pre> |
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+ |
* (e1.getKey()==null ? |
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+ |
* e2.getKey()==null : |
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* e1.getKey().equals(e2.getKey())) |
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* && |
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+ |
* (e1.getValue()==null ? |
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+ |
* e2.getValue()==null : |
| 741 |
+ |
* e1.getValue().equals(e2.getValue()))</pre> |
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+ |
* This ensures that the {@code equals} method works properly across |
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+ |
* different implementations of the {@code Map.Entry} interface. |
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+ |
* |
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+ |
* @param o object to be compared for equality with this map entry |
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* @return {@code true} if the specified object is equal to this map |
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* entry |
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* @see #hashCode |
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*/ |
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public boolean equals(Object o) { |
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if (!(o instanceof Map.Entry)) |
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return false; |
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return eq(key, e.getKey()) && eq(value, e.getValue()); |
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} |
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|
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+ |
/** |
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+ |
* Returns the hash code value for this map entry. The hash code |
| 759 |
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* of a map entry {@code e} is defined to be: <pre> |
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+ |
* (e.getKey()==null ? 0 : e.getKey().hashCode()) ^ |
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+ |
* (e.getValue()==null ? 0 : e.getValue().hashCode())</pre> |
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+ |
* This ensures that {@code e1.equals(e2)} implies that |
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+ |
* {@code e1.hashCode()==e2.hashCode()} for any two Entries |
| 764 |
+ |
* {@code e1} and {@code e2}, as required by the general |
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+ |
* contract of {@link Object#hashCode}. |
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* |
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* @return the hash code value for this map entry |
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+ |
* @see #equals |
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*/ |
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public int hashCode() { |
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< |
return ((key == null) ? 0 : key.hashCode()) ^ |
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< |
((value == null) ? 0 : value.hashCode()); |
| 771 |
> |
return (key == null ? 0 : key.hashCode()) ^ |
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> |
(value == null ? 0 : value.hashCode()); |
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} |
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|
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/** |
