| 388 |
|
// Comparison and hashing |
| 389 |
|
|
| 390 |
|
/** |
| 391 |
< |
* {@inheritDoc} |
| 391 |
> |
* Compares the specified object with this map for equality. Returns |
| 392 |
> |
* <tt>true</tt> if the given object is also a map and the two maps |
| 393 |
> |
* represent the same mappings. More formally, two maps <tt>m1</tt> and |
| 394 |
> |
* <tt>m2</tt> represent the same mappings if |
| 395 |
> |
* <tt>m1.entrySet().equals(m2.entrySet())</tt>. This ensures that the |
| 396 |
> |
* <tt>equals</tt> method works properly across different implementations |
| 397 |
> |
* of the <tt>Map</tt> interface. |
| 398 |
|
* |
| 399 |
|
* <p>This implementation first checks if the specified object is this map; |
| 400 |
|
* if so it returns <tt>true</tt>. Then, it checks if the specified |
| 404 |
|
* contains each mapping that this map contains. If the specified map |
| 405 |
|
* fails to contain such a mapping, <tt>false</tt> is returned. If the |
| 406 |
|
* iteration completes, <tt>true</tt> is returned. |
| 407 |
+ |
* |
| 408 |
+ |
* @param o object to be compared for equality with this map |
| 409 |
+ |
* @return <tt>true</tt> if the specified object is equal to this map |
| 410 |
|
*/ |
| 411 |
|
public boolean equals(Object o) { |
| 412 |
|
if (o == this) |
| 442 |
|
} |
| 443 |
|
|
| 444 |
|
/** |
| 445 |
< |
* {@inheritDoc} |
| 445 |
> |
* Returns the hash code value for this map. The hash code of a map is |
| 446 |
> |
* defined to be the sum of the hash codes of each entry in the map's |
| 447 |
> |
* <tt>entrySet()</tt> view. This ensures that <tt>m1.equals(m2)</tt> |
| 448 |
> |
* implies that <tt>m1.hashCode()==m2.hashCode()</tt> for any two maps |
| 449 |
> |
* <tt>m1</tt> and <tt>m2</tt>, as required by the general contract of |
| 450 |
> |
* {@link Object#hashCode}. |
| 451 |
|
* |
| 452 |
|
* <p>This implementation iterates over <tt>entrySet()</tt>, calling |
| 453 |
< |
* <tt>hashCode()</tt> on each element (entry) in the set, and |
| 454 |
< |
* adding up the results. |
| 453 |
> |
* {@link Map.Entry#hashCode hashCode()} on each element (entry) in the |
| 454 |
> |
* set, and adding up the results. |
| 455 |
|
* |
| 456 |
+ |
* @return the hash code value for this map |
| 457 |
|
* @see Map.Entry#hashCode() |
| 443 |
– |
* @see Object#hashCode() |
| 458 |
|
* @see Object#equals(Object) |
| 459 |
|
* @see Set#equals(Object) |
| 460 |
|
*/ |
| 531 |
|
* Test for equality, checking for nulls. |
| 532 |
|
*/ |
| 533 |
|
private static boolean eq(Object o1, Object o2) { |
| 534 |
< |
return (o1 == null ? o2 == null : o1.equals(o2)); |
| 534 |
> |
return o1 == null ? o2 == null : o1.equals(o2); |
| 535 |
|
} |
| 536 |
|
|
| 537 |
|
// Implementation Note: SimpleEntry and SimpleImmutableEntry |
| 548 |
|
* facilitates the process of building custom map |
| 549 |
|
* implementations. For example, it may be convenient to return |
| 550 |
|
* arrays of <tt>SimpleEntry</tt> instances in method |
| 551 |
< |
* <tt>Map.entrySet().toArray</tt> |
| 551 |
> |
* <tt>Map.entrySet().toArray</tt>. |
| 552 |
> |
* |
| 553 |
> |
* @since 1.6 |
| 554 |
|
*/ |
| 555 |
< |
public static class SimpleEntry<K,V> implements Entry<K,V> { |
| 555 |
> |
public static class SimpleEntry<K,V> |
| 556 |
> |
implements Entry<K,V>, java.io.Serializable |
| 557 |
> |
{ |
| 558 |
> |
private static final long serialVersionUID = -8499721149061103585L; |
| 559 |
> |
|
| 560 |
|
private final K key; |
| 561 |
|
private V value; |
| 562 |
|
|
| 622 |
|
} |
| 623 |
|
|
| 624 |
|
public int hashCode() { |
| 625 |
< |
return ((key == null) ? 0 : key.hashCode()) ^ |
| 626 |
< |
((value == null) ? 0 : value.hashCode()); |
| 625 |
> |
return (key == null ? 0 : key.hashCode()) ^ |
| 626 |
> |
(value == null ? 0 : value.hashCode()); |
| 627 |
|
} |
| 628 |
|
|
| 629 |
|
/** |
| 641 |
|
} |
| 642 |
|
|
| 643 |
|
/** |
| 644 |
< |
* An Entry maintaining an immutable key and value, This class |
| 644 |
> |
* An Entry maintaining an immutable key and value. This class |
| 645 |
|
* does not support method <tt>setValue</tt>. This class may be |
| 646 |
|
* convenient in methods that return thread-safe snapshots of |
| 647 |
|
* key-value mappings. |
| 648 |
+ |
* |
| 649 |
+ |
* @since 1.6 |
| 650 |
|
*/ |
| 651 |
< |
public static class SimpleImmutableEntry<K,V> implements Entry<K,V> { |
| 651 |
> |
public static class SimpleImmutableEntry<K,V> |
| 652 |
> |
implements Entry<K,V>, java.io.Serializable |
| 653 |
> |
{ |
| 654 |
> |
private static final long serialVersionUID = 7138329143949025153L; |
| 655 |
> |
|
| 656 |
|
private final K key; |
| 657 |
|
private final V value; |
| 658 |
|
|
| 719 |
|
} |
| 720 |
|
|
| 721 |
|
public int hashCode() { |
| 722 |
< |
return ((key == null) ? 0 : key.hashCode()) ^ |
| 723 |
< |
((value == null) ? 0 : value.hashCode()); |
| 722 |
> |
return (key == null ? 0 : key.hashCode()) ^ |
| 723 |
> |
(value == null ? 0 : value.hashCode()); |
| 724 |
|
} |
| 725 |
|
|
| 726 |
|
/** |
