com.compoze.collab.util
Class ArrayMap

java.lang.Object
  java.util.AbstractMap
      com.compoze.collab.util.ArrayMap

All Implemented Interfaces

Serializable, Map

public class ArrayMap
extends AbstractMap
implements Serializable

Implements a Map that's backed by an array. This implementation provides all of the optional Map operations and permits null values but does not permit the null key.

This implementation is not thread safe, so use of it from multiple threads without external synchronization will result in undefined behavior.

This Map implementation may provide improved performance over HashMap when used for fewer than 5 mappings. It also consumes less of the Java heap than HashMap. You should test this class with the keys and values that you're using to truly evaluate the performance of both heap and CPU in your real-world scenario, and use it only when the benefit is clear.

See Also

Serialized Form

Constructor Summary

ArrayMap()
Constructs an empty ArrayMap with the default initial capacity (5).

ArrayMap(int iInitialCapacity)
Constructs an empty ArrayMap with the specified initial capacity.

ArrayMap(Map map)
Constructs an empty ArrayMap with the same mappings as the specified Map.

Method Summary

void	clear() Removes all mappings from this map.
boolean	containsKey(Object key) Returns true if this map contains a mapping for the specified key.
boolean	containsValue(Object value) Returns true if this map contains at least one value that is the same as the specified value.
Set	entrySet() Returns a set view of the mappings contained in this map.
Object	get(Object key) Returns the value to which this map maps the specified key.
boolean	isEmpty() Determines if the map is empty.
Set	keySet() Returns a set view of the keys contained in this map.
static void	main(String[] args) Exerciser.
Object	put(Object key, Object value) Associates the specified value with the specified key in this map.
void	putUnique(Object key, Object value) Associates the specified value with the specified key in this map, assuming that the specified key is known to be unique.
Object	remove(Object key) Removes the mapping for this key from this map if it is present.
int	size() Gets the number of mappings in the map.
Collection	values() Returns a collection view of the values contained in this map.

Methods inherited from class java.util.AbstractMap

clone, equals, hashCode, putAll, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

ArrayMap

public ArrayMap()

Constructs an empty ArrayMap with the default initial capacity (5).

ArrayMap

public ArrayMap(int iInitialCapacity)

Constructs an empty ArrayMap with the specified initial capacity.

Parameters

iInitialCapacity - the initial capacity

ArrayMap

public ArrayMap(Map map)

Constructs an empty ArrayMap with the same mappings as the specified Map.

Parameters

map - the Map whose mappings are to be placed in this Map (must not be null)

Method Detail

clear

public void clear()

Removes all mappings from this map.

Specified by:

clear in interface Map

Overrides:

clear in class AbstractMap

See Also

Map.clear()

containsKey

public boolean containsKey(Object key)

Returns true if this map contains a mapping for the specified key.

Specified by:

containsKey in interface Map

Overrides:

containsKey in class AbstractMap

Returns

true if there is a mapping, false otherwise (must not be null)

See Also

Map.containsKey(Object)

containsValue

public boolean containsValue(Object value)

Returns true if this map contains at least one value that is the same as the specified value.

Specified by:

containsValue in interface Map

Overrides:

containsValue in class AbstractMap

Returns

true if it contains the value, false otherwise (may be null)

See Also

Map.containsValue(Object)

entrySet

public Set entrySet()

Returns a set view of the mappings contained in this map.

Specified by:

entrySet in interface Map

Specified by:

entrySet in class AbstractMap

Returns

the Set (each element in the set is a Map.Entry)

See Also

Map.entrySet()

get

public Object get(Object key)

Returns the value to which this map maps the specified key.

Specified by:

get in interface Map

Overrides:

get in class AbstractMap

Parameters

the - key (must not be null)

Returns

the value to which this map maps the specified key

See Also

Map.get(Object)

isEmpty

public boolean isEmpty()

Determines if the map is empty.

Specified by:

isEmpty in interface Map

Overrides:

isEmpty in class AbstractMap

Returns

true if the map is empty, false otherwise

See Also

Map.isEmpty()

keySet

public Set keySet()

Returns a set view of the keys contained in this map.

Specified by:

keySet in interface Map

Overrides:

keySet in class AbstractMap

Returns

the key set

See Also

Map.keySet()

put

public Object put(Object key,
                  Object value)

Associates the specified value with the specified key in this map.

Specified by:

put in interface Map

Overrides:

put in class AbstractMap

Parameters

key - the key (must not be null)

value - the value (may be null)

Returns

any existing value that was replaced, or null if the value was not already in the Map

See Also

Map.put(Object, Object)

putUnique

public void putUnique(Object key,
                      Object value)

Associates the specified value with the specified key in this map, assuming that the specified key is known to be unique. This method may offer a performance benefit since it does not need to check all keys for uniqueness. If the key is not unique then all other Map operations will be undefined after this method is called.

Parameters

key - the key (must not be null)

value - the value (may be null)

See Also

Map.put(Object, Object)

remove

public Object remove(Object key)

Removes the mapping for this key from this map if it is present.

Specified by:

remove in interface Map

Overrides:

remove in class AbstractMap

Parameters

key - the key of the mapping to remove (must not be null)

Returns

the existing value, or null if there was no value

See Also

Map.remove(Object)

size

public int size()

Gets the number of mappings in the map.

Specified by:

size in interface Map

Overrides:

size in class AbstractMap

Returns

the number of mappings (0 if there are no mappings)

See Also

Map.size()

values

public Collection values()

Returns a collection view of the values contained in this map.

Specified by:

values in interface Map

Overrides:

values in class AbstractMap

Returns

the collection

main

public static void main(String[] args)

Exerciser.