com.sun.squawk.debugger.sda
Class WeakIntHashtable

java.lang.Object
  com.sun.squawk.util.IntHashtable
      com.sun.squawk.debugger.sda.WeakIntHashtable

public final class WeakIntHashtable
extends IntHashtable

This class extends an IntHashtable in two important ways: 1. It wraps all inserted values in a WeakReference. 2. It compares all (wrapped) values using reference equality as opposed to Object.equals(java.lang.Object).

Field Summary

Fields inherited from class com.sun.squawk.util.IntHashtable

count, table, threshold

Constructor Summary

WeakIntHashtable()
Constructs a new, empty hashtable with a default capacity and load factor.

Method Summary

void	compact() Removes all the entries whose wrapped objects have been collected or cleared.
boolean	contains(Object value) Tests if some key maps into the specified value in this hashtable.
Object	get(int key) Returns the value to which key is mapped in this hashtable.
Integer	getKey(Object value) Gets the key for a given value in this table.
Object	put(int key, Object value) Maps the specified key to the specified value in this hashtable.

Methods inherited from class com.sun.squawk.util.IntHashtable

clear, containsKey, elements, isEmpty, keys, rehash, remove, size, toString, visit

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

WeakIntHashtable

public WeakIntHashtable()

Constructs a new, empty hashtable with a default capacity and load factor.

Method Detail

contains

public boolean contains(Object value)

Tests if some key maps into the specified value in this hashtable. This operation is more expensive than the containsKey method.

This implementation uses reference equality when comparing values.

Overrides:

contains in class IntHashtable

Parameters:

value - a value to search for.

Returns:

true if some key maps to the value argument in this hashtable; false otherwise.

See Also:

Hashtable.containsKey(java.lang.Object)

put

public Object put(int key,
                  Object value)
           throws IllegalArgumentException

Maps the specified key to the specified value in this hashtable. Neither the key nor the value can be null.

If value is an instanceof WeakReference, then it is directly inserted in the table otherwise value is wrapped in a WeakReference before being inserted. However, value retrieved by calling the get method will always be the value within the WeakReference.

Overrides:

put in class IntHashtable

Parameters:

key - the key

value - the value

Returns:

the previous value mapped by key

Throws:

IllegalArgumentException - if value instanceof WeakReference and the referent is a WeakReference itself

See Also:

Object.equals(java.lang.Object), Hashtable.get(java.lang.Object)

compact

public void compact()

Removes all the entries whose wrapped objects have been collected or cleared.

get

public Object get(int key)

Returns the value to which key is mapped in this hashtable. This will return null if key does not map to a value or the value has been garbage collected.

Overrides:

get in class IntHashtable

Parameters:

key - the key to search for

Returns:

the value corresponding to key or null

See Also:

Hashtable.put(java.lang.Object, java.lang.Object)

getKey

public Integer getKey(Object value)

Gets the key for a given value in this table. Values in the tables are compared against value using reference equality as opposed to Object.equals(java.lang.Object).

Parameters:

value - the value for which the key is requested

Returns:

the key for value or null if value is not in this table