org.nakedobjects.object.collection
Class AbstractNakedCollection

java.lang.Object
  java.util.Observable
      org.nakedobjects.object.AbstractNakedObject
          org.nakedobjects.object.collection.AbstractNakedCollection

All Implemented Interfaces:

java.io.Externalizable, Naked, NakedCollection, NakedObject, java.io.Serializable

Direct Known Subclasses:

ArbitraryCollection, TypedCollection

public abstract class AbstractNakedCollection

extends AbstractNakedObject

implements NakedCollection

This is the new type of collection for Naked Objects. It is designed to work efficiently is a distributed envirmoment by providing a window on a logical collection. This collection is therefore just a cache of a subset of the complete collection. The real collection is maintained by the ObjectStore. Within this cache there is also a viewing window, which the user is expected to be viewing. As the user pages through the cache more items will be retrieved as the bounds of the cache are hit.

See Also:

to set the size of the viewing window., to set the size of the cache. To move through the collection on a page-by-page basis, first(), next(), last(), previous(), Serialized Form

Constructor Summary

AbstractNakedCollection()

Method Summary

void	add(NakedObject object) adds object to the collection and notifies all views that the collection has changed.
void	addAll(NakedCollection collection) Add all elements from the collection.
void	added(NakedObject object)
abstract Permission	canAdd(NakedObject object) Vetos the addition to this collection if the object being added requests it.
abstract Permission	canRemove(NakedObject object) Vetos the removal from this collection if the object being removed requests it.
boolean	contains(NakedObject object) Returns true if the logical collection contains the specified object.
java.util.Enumeration	displayElements() Return cache to be viewed on current page
java.util.Enumeration	elements() Return all elements in this collection
ArbitraryCollection	extract() Return an ArbitraryCollection with the same elements as this collection
void	first() Position cursor at first element
int	getDisplaySize()
int	getMaxCacheSize() returns the maximum number of elements to hold from the logical collection.
boolean	hasNext() If true there is a next page to display, and 'next' and 'last' options are valid
boolean	hasPrevious()
boolean	isEmpty() Returns true if the object contains no data, eg when new
void	last() Position cursor at last
void	next() Position cursor at beginning of next page
int	position()
void	previous() Position cursor at beginning of previous page
void	remove(NakedObject object) removes object from the collection and notifies all views that the collection has changed.
void	removeAll() Removes all objects from the collection.
void	removed(NakedObject object)
void	reset()
AbstractNakedCollection	search(NakedObject pattern) Return a NakedCollection of objects which match the specified pattern from within the current collection
void	setDisplaySize(int displaySize) Set the size of the display or viewing window.
void	setMaxCacheSize(int maxCacheSize) Sets the maximum size of the cache providing the specified size is greater than the display size.
int	size() Return a NakedCollection of objects which match the specified pattern from within the current collection
Title	title() by default returns the collections name and its number of elements

Methods inherited from class org.nakedobjects.object.AbstractNakedObject

about, aboutExplorationActionClass, aboutExplorationActionClone, aboutExplorationActionMakePersistent, canClone, contextualTitle, copyObject, created, createInstance, createInstance, createTransientInstance, deleted, destroy, equals, explorationActionClass, explorationActionClone, explorationActionMakePersistent, getClassHelpText, getClassName, getCollectiveName, getFullClassName, getIconName, getIdString, getNakedClass, getObjectHelpText, getObjectStore, getOid, hashCode, iconImage, init, isFinder, isLookupElement, isPersistent, isResolved, isSameAs, isValid, makeFinder, makePersistent, objectChanged, readExternal, resolve, resolve, setChangedAndNotifyObservers, setOid, setResolved, summary, toString, writeExternal

Methods inherited from class java.util.Observable

addObserver, clearChanged, countObservers, deleteObserver, deleteObservers, hasChanged, notifyObservers, notifyObservers, setChanged

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.nakedobjects.object.NakedCollection

copyObject

Methods inherited from interface org.nakedobjects.object.NakedObject

addObserver, contextualTitle, countObservers, created, deleted, deleteObserver, destroy, getCollectiveName, getIdString, getNakedClass, getObjectStore, getOid, hasChanged, iconImage, isFinder, isLookupElement, isPersistent, isResolved, makeFinder, makePersistent, objectChanged, resolve, setChangedAndNotifyObservers, setOid, setResolved

Methods inherited from interface org.nakedobjects.object.Naked

about, getClassName, getFullClassName, getObjectHelpText, isSameAs, isValid, summary

Constructor Detail

AbstractNakedCollection

public AbstractNakedCollection()

Method Detail

setDisplaySize

public void setDisplaySize(int displaySize)

Set the size of the display or viewing window. If the cache size is less than the display size the max cache size will also be set to specified size.

getDisplaySize

public int getDisplaySize()

Specified by:

getDisplaySize in interface NakedCollection

Returns:

int

isEmpty

public boolean isEmpty()

Description copied from interface: Naked

Returns true if the object contains no data, eg when new

Specified by:

isEmpty in interface Naked

Overrides:

isEmpty in class AbstractNakedObject

setMaxCacheSize

public void setMaxCacheSize(int maxCacheSize)

Sets the maximum size of the cache providing the specified size is greater than the display size.

getMaxCacheSize

public int getMaxCacheSize()

returns the maximum number of elements to hold from the logical collection.

add

public void add(NakedObject object)

Description copied from interface: NakedCollection

adds object to the collection and notifies all views that the collection has changed.

Specified by:

add in interface NakedCollection

added

public void added(NakedObject object)

Specified by:

added in interface NakedCollection

canAdd

public abstract Permission canAdd(NakedObject object)

Description copied from interface: NakedCollection

Vetos the addition to this collection if the object being added requests it. Returns the result of canAddTo() called on the object reference. Also disallows the addition of itself. By default a collection can be added to another collection (but not to itself). Any type of object which wishes to restrict its placement in a collection should override this method.

Specified by:

canAdd in interface NakedCollection

canRemove

public abstract Permission canRemove(NakedObject object)

Description copied from interface: NakedCollection

Vetos the removal from this collection if the object being removed requests it. Returns the result of canRemoveFrom() called on the object reference.

Specified by:

canRemove in interface NakedCollection

contains

public boolean contains(NakedObject object)

Returns true if the logical collection contains the specified object.

Specified by:

contains in interface NakedCollection

displayElements

public java.util.Enumeration displayElements()

Return cache to be viewed on current page

Specified by:

displayElements in interface NakedCollection

elements

public java.util.Enumeration elements()

Return all elements in this collection

Specified by:

elements in interface NakedCollection

extract

public ArbitraryCollection extract()

Return an ArbitraryCollection with the same elements as this collection

first

public void first()

Position cursor at first element

Specified by:

first in interface NakedCollection

hasNext

public boolean hasNext()

If true there is a next page to display, and 'next' and 'last' options are valid

Specified by:

hasNext in interface NakedCollection

hasPrevious

public boolean hasPrevious()

Specified by:

hasPrevious in interface NakedCollection

last

public void last()

Position cursor at last

Specified by:

last in interface NakedCollection

next

public void next()

Position cursor at beginning of next page

Specified by:

next in interface NakedCollection

position

public int position()

Specified by:

position in interface NakedCollection

previous

public void previous()

Position cursor at beginning of previous page

Specified by:

previous in interface NakedCollection

remove

public void remove(NakedObject object)

Description copied from interface: NakedCollection

removes object from the collection and notifies all views that the collection has changed.

Specified by:

remove in interface NakedCollection

removed

public void removed(NakedObject object)

Specified by:

removed in interface NakedCollection

reset

public void reset()

Specified by:

reset in interface NakedCollection

search

public AbstractNakedCollection search(NakedObject pattern)

Return a NakedCollection of objects which match the specified pattern from within the current collection

size

public int size()

Description copied from interface: NakedCollection

Return a NakedCollection of objects which match the specified pattern from within the current collection

Specified by:

size in interface NakedCollection

title

public Title title()

Description copied from interface: NakedCollection

by default returns the collections name and its number of elements

Specified by:

title in interface NakedCollection

Overrides:

title in class AbstractNakedObject

See Also:

AbstractNakedObject.contextualTitle()

addAll

public void addAll(NakedCollection collection)

Add all elements from the collection. If the reference to the collection is null, then does nothing.

Implementation note: this code is not threadsafe and does not synchronize on either itself or the collection passed in.

removeAll

public void removeAll()

Removes all objects from the collection.

Implementation note: this code is not threadsafe; it does not synchronize on itself.

Implemented by invoking remove(NakedObject) on each object