oracle.dss.util
Class ArrayMap<K,V>

java.lang.Object
  java.util.AbstractMap<K,V>
      oracle.dss.util.ArrayMap<K,V>

All Implemented Interfaces:

java.lang.Cloneable, java.util.Map<K,V>

public class ArrayMap<K,V>
extends java.util.AbstractMap<K,V>
implements java.lang.Cloneable

A Map implementation that stores its contents in a single array. This approach is significantly faster for small sets of data than the use of a HashMap or Hashtable, though potentially much slower for very large sets.

ArrayMap is optimized for many-reads-few-write. In particular, it reallocates its array on any insertion or deletion.

ArrayMap also includes a series of static methods for managing the Object array. These may be used in place of instantiating an ArrayMap for clients that don't need a Map implementation. Clients using these methods must be careful to store the returned Object array on any mutator method. They also must provide their own synchronization, if needed. When using these static methods, clients can opt to search for objects by identity (via getByIdentity()) instead of equality, while the static get() method will try identity before equality. This latter approach is extremely fast but still safe for retrieval of Strings that have all been interned, especially if misses are infrequent (since misses do require a scan using Object.equals()). It's worth remembering that String constants are always interned, as required by the language specification.

Nested Class Summary

Nested classes/interfaces inherited from class java.util.AbstractMap

java.util.AbstractMap.SimpleEntry<K,V>, java.util.AbstractMap.SimpleImmutableEntry<K,V>

Nested classes/interfaces inherited from interface java.util.Map

java.util.Map.Entry<K,V>

Constructor Summary

ArrayMap()
Creates an empty ArrayMap, preallocating nothing.

ArrayMap(int size)
Creates an ArrayMap, preallocating for a certain size.

ArrayMap(int size, int increment)
Creates an ArrayMap, preallocating for a certain size.

Method Summary

void	clear() Removes all elements from the ArrayMap.
java.lang.Object	clone() Clones the map.
boolean	containsKey(java.lang.Object key)
boolean	containsValue(java.lang.Object value)
java.util.Set<java.util.Map.Entry<K,V>>	entrySet()
V	get(java.lang.Object key)
static java.lang.Object	get(java.lang.Object[] array, java.lang.Object key) Gets the object stored with the given key.
static java.lang.Object	getByEquality(java.lang.Object[] array, java.lang.Object key) Gets the object stored with the given key, using only object equality.
V	getByIdentity(java.lang.Object key)
static java.lang.Object	getByIdentity(java.lang.Object[] array, java.lang.Object key) Gets the object stored with the given key, using only object identity.
K	getKey(int index) Returns the key at a specific index in the map.
static java.util.Enumeration<java.lang.Object>	getKeys(java.lang.Object[] array) Returns an Iterator of keys in the array.
V	getValue(int index) Returns the value at a specific index in the map.
static java.util.Enumeration<java.lang.Object>	getValues(java.lang.Object[] array) Returns an Iterator of values in the array.
java.util.Enumeration<K>	keys() Returns an enumeration of the keys in this map.
V	put(K key, V value)
static java.lang.Object[]	put(java.lang.Object[] array, java.lang.Object key, java.lang.Object value) Adds the key/value pair to the array, returning a new array if necessary.
V	remove(java.lang.Object key)
static java.lang.Object[]	remove(java.lang.Object[] array, java.lang.Object key) Removes the value for the key from the array, returning a new array if necessary.
static java.lang.Object[]	remove(java.lang.Object[] array, java.lang.Object key, boolean reallocate) Removes the value for the key from the array, returning a new array if necessary.
int	size()

Methods inherited from class java.util.AbstractMap

equals, hashCode, isEmpty, keySet, putAll, toString, values

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

ArrayMap

public ArrayMap()

Creates an empty ArrayMap, preallocating nothing.

ArrayMap

public ArrayMap(int size)

Creates an ArrayMap, preallocating for a certain size.

Parameters:

size - the number of elements to pre-allocate for

ArrayMap

public ArrayMap(int size,
                int increment)

Creates an ArrayMap, preallocating for a certain size.

Parameters:

size - the number of elements to pre-allocate for

increment - the number of additional elements to allocate for when overruning

Method Detail

getKey

public K getKey(int index)

Returns the key at a specific index in the map.

getValue

public V getValue(int index)

Returns the value at a specific index in the map.

get

public static java.lang.Object get(java.lang.Object[] array,
                                   java.lang.Object key)

Gets the object stored with the given key. Scans first by object identity, then by object equality.

getByIdentity

public static java.lang.Object getByIdentity(java.lang.Object[] array,
                                             java.lang.Object key)

Gets the object stored with the given key, using only object identity.

getByEquality

public static java.lang.Object getByEquality(java.lang.Object[] array,
                                             java.lang.Object key)

Gets the object stored with the given key, using only object equality.

put

public static java.lang.Object[] put(java.lang.Object[] array,
                                     java.lang.Object key,
                                     java.lang.Object value)

Adds the key/value pair to the array, returning a new array if necessary.

remove

public static java.lang.Object[] remove(java.lang.Object[] array,
                                        java.lang.Object key)

Removes the value for the key from the array, returning a new array if necessary.

remove

public static java.lang.Object[] remove(java.lang.Object[] array,
                                        java.lang.Object key,
                                        boolean reallocate)

Removes the value for the key from the array, returning a new array if necessary.

size

public int size()

Specified by:

size in interface java.util.Map<K,V>

Overrides:

size in class java.util.AbstractMap<K,V>

containsValue

public boolean containsValue(java.lang.Object value)

Specified by:

containsValue in interface java.util.Map<K,V>

Overrides:

containsValue in class java.util.AbstractMap<K,V>

containsKey

public boolean containsKey(java.lang.Object key)

Specified by:

containsKey in interface java.util.Map<K,V>

Overrides:

containsKey in class java.util.AbstractMap<K,V>

keys

public java.util.Enumeration<K> keys()

Returns an enumeration of the keys in this map. the Iterator methods on the returned object to fetch the elements sequentially.

getKeys

public static java.util.Enumeration<java.lang.Object> getKeys(java.lang.Object[] array)

Returns an Iterator of keys in the array.

getValues

public static java.util.Enumeration<java.lang.Object> getValues(java.lang.Object[] array)

Returns an Iterator of values in the array.

clone

public java.lang.Object clone()

Clones the map.

Overrides:

clone in class java.util.AbstractMap<K,V>

entrySet

public java.util.Set<java.util.Map.Entry<K,V>> entrySet()

Specified by:

entrySet in interface java.util.Map<K,V>

Specified by:

entrySet in class java.util.AbstractMap<K,V>

get

public V get(java.lang.Object key)

Specified by:

get in interface java.util.Map<K,V>

Overrides:

get in class java.util.AbstractMap<K,V>

getByIdentity

public V getByIdentity(java.lang.Object key)

put

public V put(K key,
             V value)

Specified by:

put in interface java.util.Map<K,V>

Overrides:

put in class java.util.AbstractMap<K,V>

remove

public V remove(java.lang.Object key)

Specified by:

remove in interface java.util.Map<K,V>

Overrides:

remove in class java.util.AbstractMap<K,V>

clear

public void clear()

Removes all elements from the ArrayMap.

Specified by:

clear in interface java.util.Map<K,V>

Overrides:

clear in class java.util.AbstractMap<K,V>