org.jpox.sco
Class Map

java.lang.Object
  java.util.AbstractMap
      org.jpox.sco.Map

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, java.util.Map, SCO, SCOContainer, SCOMap, Queryable

public class Map
extends java.util.AbstractMap
implements java.util.Map, SCOMap, java.lang.Cloneable, Queryable, java.io.Serializable

A mutable second-class Map object. Uses a "delegate" as a local store for the Map. Uses a "backing store" (SetStore) to represent the datastore. The "delegate" is updated with the "backing store" information at necessary intervals.

Modes of Operation

The user can operate the map in 2 modes. The cached mode will use an internal cache of the elements (in the "delegate") reading them at the first opportunity and then using the cache thereafter. The non-cached mode will just go direct to the "backing store" each call.

Mutators

When the backing store is present any updates are passed direct to the datastore as well as to the "delegate". If the "backing store" isn't present the changes are made to the "delegate" only.

Accessors

When any accessor method is invoked, it typically checks whether the map has been loaded from its backing store and does this as necessary. Some methods (size(), containsKey()) just check if everything is loaded and use the delegate if possible, otherwise going direct to the datastore.

Version:

$Revision: 1.81 $

See Also:

Serialized Form

Nested Class Summary

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

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

Field Summary

protected MapStore	backingStore The "backing store"
protected java.util.Map	delegate The internal "delegate".
protected boolean	isCacheLoaded Status flag whether the map is loaded into the cache.
protected static Localiser	LOCALISER
protected boolean	useCache Whether to use "delegate" caching.

Constructor Summary

Map(StateManager ownerSM, java.lang.String fieldName)
Constructor, using the StateManager of the "owner" and the field name.

Method Summary

protected void	addQueuedOperation(QueuedOperation op) Convenience method to add a queued operation to the operations we perform at commit.
void	attachCopy(java.lang.Object value) Method to return an attached copy of the passed (detached) value.
void	clear() Method to clear the Map.
java.lang.Object	clone() Creates and returns a copy of this object.
boolean	containsKey(java.lang.Object key) Utility to check if a key is contained in the Map.
boolean	containsValue(java.lang.Object value) Utility to check if a value is contained in the Map.
java.lang.Object	detachCopy(FetchPlanState state) Method to return a detached copy of the container.
java.util.Set	entrySet() Accessor for the set of entries in the Map.
boolean	equals(java.lang.Object o) Method to check the equality of this map, and another.
void	flush() Method to flush the changes to the datastore when operating in queued mode.
java.lang.Object	get(java.lang.Object key) Accessor for the value stored against a key.
java.lang.String	getFieldName() Accessor for the field name.
java.lang.Object	getOwner() Accessor for the owner.
java.lang.Object	getValue() Accessor for the unwrapped value that we are wrapping.
int	hashCode() Method to generate a hashcode for this Map.
void	initialise() Method to initialise the SCO for use.
void	initialise(java.lang.Object o, boolean forInsert, boolean forUpdate) Method to initialise the SCO from an existing value.
boolean	isEmpty() Method to return if the Map is empty.
java.util.Set	keySet() Accessor for the set of keys in the Map.
void	load() Method to effect the load of the data in the SCO.
protected void	loadFromStore() Method to load all elements from the "backing store" where appropriate.
void	makeDirty() Utility to mark the object as dirty
QueryExpression	newQueryStatement() Method to generate a QueryStatement for the SCO.
QueryExpression	newQueryStatement(java.lang.Class candidateClass, DatastoreIdentifier candidateAlias) Method to return a QueryStatement, using the specified candidate class.
ResultObjectFactory	newResultObjectFactory(QueryExpression stmt, boolean ignoreCache, java.lang.Class resultClass, boolean useFetchPlan) Method to return a new result object factory for processing of Query statements.
java.lang.Object	put(java.lang.Object key, java.lang.Object value) Method to add a value to the Map.
void	putAll(java.util.Map m) Method to add a Map of values to this map.
java.lang.Object	remove(java.lang.Object key) Method to remove a value from the Map.
int	size() Method to return the size of the Map.
java.lang.String	toString() Method to return a string form of this Map.
void	unsetOwner() Method to unset the owner and field information.
void	updateEmbeddedKey(java.lang.Object key, int fieldNumber, java.lang.Object newValue) Method to update an embedded key in this map.
void	updateEmbeddedValue(java.lang.Object value, int fieldNumber, java.lang.Object newValue) Method to update an embedded value in this map.
java.util.Collection	values() Accessor for the set of values in the Map.
protected java.lang.Object	writeReplace() The writeReplace method is called when ObjectOutputStream is preparing to write the object to the stream.

Methods inherited from class java.lang.Object

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

Field Detail

LOCALISER

protected static final Localiser LOCALISER

backingStore

protected MapStore backingStore

The "backing store"

delegate

protected java.util.Map delegate

The internal "delegate".

useCache

protected boolean useCache

Whether to use "delegate" caching.

isCacheLoaded

protected boolean isCacheLoaded

Status flag whether the map is loaded into the cache.

Constructor Detail

Map

public Map(StateManager ownerSM,
           java.lang.String fieldName)

Constructor, using the StateManager of the "owner" and the field name.

Parameters:

ownerSM - The owner StateManager

fieldName - The name of the field of the SCO.

Method Detail

initialise

public void initialise(java.lang.Object o,
                       boolean forInsert,
                       boolean forUpdate)

Method to initialise the SCO from an existing value.

Specified by:

initialise in interface SCO

Parameters:

o - The object to set from

forInsert - Whether the object needs inserting in the datastore with this value

forUpdate - Whether to update the datastore with this value

initialise

public void initialise()

Method to initialise the SCO for use.

Specified by:

initialise in interface SCO

getValue

public java.lang.Object getValue()

Accessor for the unwrapped value that we are wrapping.

Specified by:

getValue in interface SCO

Returns:

The unwrapped value

load

public void load()

Method to effect the load of the data in the SCO. Used when the SCO supports lazy-loading to tell it to load all now.

Specified by:

load in interface SCOContainer

loadFromStore

protected void loadFromStore()

Method to load all elements from the "backing store" where appropriate.

flush

public void flush()

Method to flush the changes to the datastore when operating in queued mode. Does nothing in "direct" mode.

Specified by:

flush in interface SCOContainer

addQueuedOperation

protected void addQueuedOperation(QueuedOperation op)

Convenience method to add a queued operation to the operations we perform at commit.

Parameters:

op - The operation

updateEmbeddedKey

public void updateEmbeddedKey(java.lang.Object key,
                              int fieldNumber,
                              java.lang.Object newValue)

Method to update an embedded key in this map.

Specified by:

updateEmbeddedKey in interface SCOMap

Parameters:

key - The key

fieldNumber - Number of field in the key

newValue - New value for this field

updateEmbeddedValue

public void updateEmbeddedValue(java.lang.Object value,
                                int fieldNumber,
                                java.lang.Object newValue)

Method to update an embedded value in this map.

Specified by:

updateEmbeddedValue in interface SCOMap

Parameters:

value - The value

fieldNumber - Number of field in the value

newValue - New value for this field

getFieldName

public java.lang.String getFieldName()

Accessor for the field name.

Specified by:

getFieldName in interface SCO

Returns:

The field name.

getOwner

public java.lang.Object getOwner()

Accessor for the owner.

Specified by:

getOwner in interface SCO

Returns:

The owner.

unsetOwner

public void unsetOwner()

Method to unset the owner and field information.

Specified by:

unsetOwner in interface SCO

makeDirty

public void makeDirty()

Utility to mark the object as dirty

detachCopy

public java.lang.Object detachCopy(FetchPlanState state)

Method to return a detached copy of the container. Recurse sthrough the keys/values so that they are likewise detached.

Specified by:

detachCopy in interface SCO

Parameters:

state - State for detachment process

Returns:

The detached container

attachCopy

public void attachCopy(java.lang.Object value)

Method to return an attached copy of the passed (detached) value. The returned attached copy is a SCO wrapper. Goes through the existing keys/values in the store for this owner field and removes ones no longer present, and adds new keys/values. All keys/values in the (detached) value are attached.

Specified by:

attachCopy in interface SCO

Parameters:

value - The new (map) value

newQueryStatement

public QueryExpression newQueryStatement()

Method to generate a QueryStatement for the SCO.

Specified by:

newQueryStatement in interface Queryable

Returns:

The QueryStatement

newQueryStatement

public QueryExpression newQueryStatement(java.lang.Class candidateClass,
                                         DatastoreIdentifier candidateAlias)

Method to return a QueryStatement, using the specified candidate class.

Specified by:

newQueryStatement in interface Queryable

Parameters:

candidateClass - the candidate class

candidateAlias - Alias for the candidate

Returns:

The QueryStatement

newResultObjectFactory

public ResultObjectFactory newResultObjectFactory(QueryExpression stmt,
                                                  boolean ignoreCache,
                                                  java.lang.Class resultClass,
                                                  boolean useFetchPlan)

Method to return a new result object factory for processing of Query statements.

Specified by:

newResultObjectFactory in interface Queryable

Parameters:

stmt - The Query Statement.

ignoreCache - Whether to ignore the cache.

resultClass - Whether to create objects of a particular class

useFetchPlan - whether to use the fetch plan to retrieve fields in the same query

Returns:

The result object factory.

clone

public java.lang.Object clone()

Creates and returns a copy of this object.

Mutable second-class Objects are required to provide a public clone method in order to allow for copying PersistenceCapable objects. In contrast to Object.clone(), this method must not throw a CloneNotSupportedException.

Specified by:

clone in interface SCO

Overrides:

clone in class java.util.AbstractMap

Returns:

Clone of the object

containsKey

public boolean containsKey(java.lang.Object key)

Utility to check if a key is contained in the Map.

Specified by:

containsKey in interface java.util.Map

Overrides:

containsKey in class java.util.AbstractMap

Parameters:

key - The key to check

Returns:

Whether it is contained

containsValue

public boolean containsValue(java.lang.Object value)

Utility to check if a value is contained in the Map.

Specified by:

containsValue in interface java.util.Map

Overrides:

containsValue in class java.util.AbstractMap

Parameters:

value - The value to check

Returns:

Whether it is contained

entrySet

public java.util.Set entrySet()

Accessor for the set of entries in the Map.

Specified by:

entrySet in interface java.util.Map

Specified by:

entrySet in class java.util.AbstractMap

Returns:

Set of entries

equals

public boolean equals(java.lang.Object o)

Method to check the equality of this map, and another.

Specified by:

equals in interface java.util.Map

Overrides:

equals in class java.util.AbstractMap

Parameters:

o - The map to compare against.

Returns:

Whether they are equal.

get

public java.lang.Object get(java.lang.Object key)

Accessor for the value stored against a key.

Specified by:

get in interface java.util.Map

Overrides:

get in class java.util.AbstractMap

Parameters:

key - The key

Returns:

The value.

hashCode

public int hashCode()

Method to generate a hashcode for this Map.

Specified by:

hashCode in interface java.util.Map

Overrides:

hashCode in class java.util.AbstractMap

Returns:

The hashcode.

isEmpty

public boolean isEmpty()

Method to return if the Map is empty.

Specified by:

isEmpty in interface java.util.Map

Specified by:

isEmpty in interface Queryable

Overrides:

isEmpty in class java.util.AbstractMap

Returns:

Whether it is empty.

keySet

public java.util.Set keySet()

Accessor for the set of keys in the Map.

Specified by:

keySet in interface java.util.Map

Overrides:

keySet in class java.util.AbstractMap

Returns:

Set of keys.

size

public int size()

Method to return the size of the Map.

Specified by:

size in interface java.util.Map

Overrides:

size in class java.util.AbstractMap

Returns:

The size

values

public java.util.Collection values()

Accessor for the set of values in the Map.

Specified by:

values in interface java.util.Map

Overrides:

values in class java.util.AbstractMap

Returns:

Set of values.

toString

public java.lang.String toString()

Method to return a string form of this Map.

Overrides:

toString in class java.util.AbstractMap

Returns:

String form of this Map.

clear

public void clear()

Method to clear the Map.

Specified by:

clear in interface java.util.Map

Overrides:

clear in class java.util.AbstractMap

put

public java.lang.Object put(java.lang.Object key,
                            java.lang.Object value)

Method to add a value to the Map.

Specified by:

put in interface java.util.Map

Overrides:

put in class java.util.AbstractMap

Parameters:

key - The key for the value.

value - The value

Returns:

The previous value against this key (if any).

putAll

public void putAll(java.util.Map m)

Method to add a Map of values to this map.

Specified by:

putAll in interface java.util.Map

Overrides:

putAll in class java.util.AbstractMap

Parameters:

m - The Map to add

remove

public java.lang.Object remove(java.lang.Object key)

Method to remove a value from the Map.

Specified by:

remove in interface java.util.Map

Overrides:

remove in class java.util.AbstractMap

Parameters:

key - The key for the value.

Returns:

The value removed.

writeReplace

protected java.lang.Object writeReplace()
                                 throws java.io.ObjectStreamException

The writeReplace method is called when ObjectOutputStream is preparing to write the object to the stream. The ObjectOutputStream checks whether the class defines the writeReplace method. If the method is defined, the writeReplace method is called to allow the object to designate its replacement in the stream. The object returned should be either of the same type as the object passed in or an object that when read and resolved will result in an object of a type that is compatible with all references to the object.

Returns:

the replaced object

Throws:

java.io.ObjectStreamException