oracle.toplink.essentials.indirection

Class IndirectMap

java.lang.Object

java.util.Dictionary<K,V>

java.util.Hashtable

oracle.toplink.essentials.indirection.IndirectMap

All Implemented Interfaces:

Serializable, Cloneable, Map, IndirectContainer

public class IndirectMap
extends Hashtable
implements IndirectContainer

IndirectMap allows a domain class to take advantage of TopLink indirection without having to declare its instance variable as a ValueHolderInterface.

To use an IndirectMap:

• Declare the appropriate instance variable with type Hashtable (jdk1.1) or Map (jdk1.2).
• Send the message #useTransparentMap(String) to the appropriate CollectionMapping.

TopLink will place an IndirectMap in the instance variable when the containing domain object is read from the datatabase. With the first message sent to the IndirectMap, the contents are fetched from the database and normal Hashtable/Map behavior is resumed.

Since:

TOPLink/Java 2.5

Author:

Big Country

See Also:

CollectionMapping, IndirectList, Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected Hashtable	delegate Reduce type casting
protected int	initialCapacity Store initial size for lazy init.
protected float	loadFactor Store load factor for lazy init.
protected ValueHolderInterface	valueHolder Delegate indirection behavior to a value holder

Constructor Summary

Constructors

Constructor and Description
IndirectMap() PUBLIC: Construct a new, empty IndirectMap with a default capacity and load factor.
IndirectMap(int initialCapacity) PUBLIC: Construct a new, empty IndirectMap with the specified initial capacity and default load factor.
IndirectMap(int initialCapacity, float loadFactor) PUBLIC: Construct a new, empty IndirectMap with the specified initial capacity and load factor.
IndirectMap(Map m) PUBLIC: Construct a new IndirectMap with the same mappings as the given Map.

Method Summary

Modifier and Type	Method and Description
protected Hashtable	buildDelegate() Return the freshly-built delegate.
void	clear()
Object	clone()
boolean	contains(Object value)
boolean	containsKey(Object key)
boolean	containsValue(Object value)
Enumeration	elements()
Set	entrySet()
boolean	equals(Object o)
Object	get(Object key)
protected Hashtable	getDelegate() Check whether the contents have been read from the database.
String	getTopLinkAttributeName() Return the mapping attribute name, used to raise change events.
ValueHolderInterface	getValueHolder() PUBLIC: Return the valueHolder.
int	hashCode()
protected void	initialize(int initialCapacity, float loadFactor) Initialize the instance.
protected void	initialize(Map m) Initialize the instance.
boolean	isEmpty()
boolean	isInstantiated() PUBLIC: Return whether the contents have been read from the database.
Enumeration	keys()
Set	keySet()
Object	put(Object key, Object value)
void	putAll(Map t)
protected void	raiseAddChangeEvent(Object key, Object value) Raise the add change event and relationship maintainence.
protected void	raiseRemoveChangeEvent(Object key, Object value) Raise the remove change event.
protected void	rehash()
Object	remove(Object key)
void	setTopLinkAttributeName(String attributeName) Set the mapping attribute name, used to raise change events.
void	setValueHolder(ValueHolderInterface valueHolder) PUBLIC: Set the value holder.
int	size()
String	toString() PUBLIC: Use the Hashtable.toString(); but wrap it with braces to indicate there is a bit of indirection.
Collection	values()

Methods inherited from class java.util.Hashtable

compute, computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, putIfAbsent, remove, replace, replace, replaceAll

Methods inherited from class java.lang.Object

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

Field Detail

delegate

protected Hashtable delegate

Reduce type casting

valueHolder

protected ValueHolderInterface valueHolder

Delegate indirection behavior to a value holder

initialCapacity

protected int initialCapacity

Store initial size for lazy init.

loadFactor

protected float loadFactor

Store load factor for lazy init.

Constructor Detail

IndirectMap

public IndirectMap()

PUBLIC: Construct a new, empty IndirectMap with a default capacity and load factor.

IndirectMap

public IndirectMap(int initialCapacity)

PUBLIC: Construct a new, empty IndirectMap with the specified initial capacity and default load factor.

Parameters:

initialCapacity - the initial capacity of the hashtable

IndirectMap

public IndirectMap(int initialCapacity,
                   float loadFactor)

PUBLIC: Construct a new, empty IndirectMap with the specified initial capacity and load factor.

Parameters:

initialCapacity - the initial capacity of the hashtable

loadFactor - a number between 0.0 and 1.0

Throws:

IllegalArgumentException - if the initial capacity is less than or equal to zero, or if the load factor is less than or equal to zero

IndirectMap

public IndirectMap(Map m)

PUBLIC: Construct a new IndirectMap with the same mappings as the given Map. The IndirectMap is created with a capacity of twice the number of entries in the given Map or 11 (whichever is greater), and a default load factor, which is 0.75.

Parameters:

m - a map containing the mappings to use

Method Detail

buildDelegate

protected Hashtable buildDelegate()

Return the freshly-built delegate.

clear

public void clear()

Specified by:

clear in interface Map

Overrides:

clear in class Hashtable

See Also:

Hashtable.clear()

clone

public Object clone()

Overrides:

clone in class Hashtable

See Also:

This will result in a database query if necessary.

contains

public boolean contains(Object value)

Overrides:

contains in class Hashtable

See Also:

Hashtable.contains(java.lang.Object)

containsKey

public boolean containsKey(Object key)

Specified by:

containsKey in interface Map

Overrides:

containsKey in class Hashtable

See Also:

Hashtable.containsKey(java.lang.Object)

containsValue

public boolean containsValue(Object value)

Specified by:

containsValue in interface Map

Overrides:

containsValue in class Hashtable

See Also:

Hashtable.containsValue(java.lang.Object)

elements

public Enumeration elements()

Overrides:

elements in class Hashtable

See Also:

Hashtable.elements()

entrySet

public Set entrySet()

Specified by:

entrySet in interface Map

Overrides:

entrySet in class Hashtable

See Also:

Hashtable.entrySet()

equals

public boolean equals(Object o)

Specified by:

equals in interface Map

Overrides:

equals in class Hashtable

See Also:

Hashtable.equals(java.lang.Object)

get

public Object get(Object key)

Specified by:

get in interface Map

Overrides:

get in class Hashtable

See Also:

Hashtable.get(java.lang.Object)

getDelegate

protected Hashtable getDelegate()

Check whether the contents have been read from the database. If they have not, read them and set the delegate.

getTopLinkAttributeName

public String getTopLinkAttributeName()

Return the mapping attribute name, used to raise change events.

getValueHolder

public ValueHolderInterface getValueHolder()

PUBLIC: Return the valueHolder.

Specified by:

getValueHolder in interface IndirectContainer

Returns:

oracle.toplink.essentials.indirection.ValueHolderInterface A representation of the valueholder * which this container uses

hashCode

public int hashCode()

Specified by:

hashCode in interface Map

Overrides:

hashCode in class Hashtable

See Also:

Hashtable.hashCode()

initialize

protected void initialize(int initialCapacity,
                          float loadFactor)

Initialize the instance.

initialize

protected void initialize(Map m)

Initialize the instance.

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface Map

Overrides:

isEmpty in class Hashtable

See Also:

Hashtable.isEmpty()

isInstantiated

public boolean isInstantiated()

PUBLIC: Return whether the contents have been read from the database.

Specified by:

isInstantiated in interface IndirectContainer

keys

public Enumeration keys()

Overrides:

keys in class Hashtable

See Also:

Hashtable.keys()

keySet

public Set keySet()

Specified by:

keySet in interface Map

Overrides:

keySet in class Hashtable

See Also:

Hashtable.keySet()

put

public Object put(Object key,
                  Object value)

Specified by:

put in interface Map

Overrides:

put in class Hashtable

See Also:

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

putAll

public void putAll(Map t)

Specified by:

putAll in interface Map

Overrides:

putAll in class Hashtable

See Also:

Hashtable.putAll(java.util.Map)

rehash

protected void rehash()

Overrides:

rehash in class Hashtable

See Also:

Hashtable.rehash()

raiseAddChangeEvent

protected void raiseAddChangeEvent(Object key,
                                   Object value)

Raise the add change event and relationship maintainence.

raiseRemoveChangeEvent

protected void raiseRemoveChangeEvent(Object key,
                                      Object value)

Raise the remove change event.

remove

public Object remove(Object key)

Specified by:

remove in interface Map

Overrides:

remove in class Hashtable

See Also:

Hashtable.remove(java.lang.Object)

setTopLinkAttributeName

public void setTopLinkAttributeName(String attributeName)

Set the mapping attribute name, used to raise change events. This is required if the change listener is set.

setValueHolder

public void setValueHolder(ValueHolderInterface valueHolder)

PUBLIC: Set the value holder.

Specified by:

setValueHolder in interface IndirectContainer

size

public int size()

Specified by:

size in interface Map

Overrides:

size in class Hashtable

See Also:

Hashtable.size()

toString

public String toString()

PUBLIC: Use the Hashtable.toString(); but wrap it with braces to indicate there is a bit of indirection. Don't allow this method to trigger a database read.

Overrides:

toString in class Hashtable

See Also:

Hashtable.toString()

values

public Collection values()

Specified by:

values in interface Map

Overrides:

values in class Hashtable

See Also:

Hashtable.values()