oracle.ide.model
Class DefaultFolder

java.lang.Object
  oracle.ide.model.DefaultDisplayable
      oracle.ide.model.DefaultElement
          oracle.ide.model.DefaultFolder

All Implemented Interfaces:

Displayable, Element, Folder

Direct Known Subclasses:

Connections, ObservableFolder, Preferences

public class DefaultFolder
extends DefaultElement
implements Folder

DefaultFolder is a complete, default implementation of the Folder interface. This is a convenient starting point for the implementation of data classes which can be integrated with the IDE framework.

If a subclass of DefaultFolder adheres to the JavaBeans API, it can also interoperate with the IDE's marshalling framework, which is used for persistence. Such a subclass can be persisted automatically (i.e. no custom persistence code needs to be written), so long as the subclass implementation follows the guidelines of the marshalling framework. For details, see the documentation for the oracle.ide.marshal package and its subpackages.

A JavaBean also has the advantage of interoperating with the property inspector. Newer APIs are also being considered which leverage the JavaBeans API, so implementing a DefaultFolder subclass to follow the JavaBeans API will also result in compatibility with future features.

See Also:

DefaultElement, Folder, oracle.ide.marshal, oracle.ide.marshal.xml, Object2Dom

Field Summary

protected java.util.ArrayList

_children The "final" modifier makes it possible to synchronize on the _children object, since its value can never change.

Constructor Summary

DefaultFolder()
Creates a new DefaultFolder instance.

Method Summary

boolean	add(Element element) Part of the Folder interface.
boolean	canAdd(Element element) Part of the Folder interface.
boolean	canRemove(Element element) Part of the Folder interface.
boolean	containsChild(Element child) Returns true if the folder contains the specified child Element; returns false otherwise.
protected void	copyToImpl(DefaultFolder copy) Design pattern for supporting strongly typed copying.
protected boolean	equalsImpl(DefaultFolder defaultFolder) This is a helper method for Object.equals(Object) that can also be used by subclasses that implement Object.equals(Object).
java.util.Iterator	getChildren() Part of the Element interface.
javax.swing.Icon	getIcon() Part of Element interface.
boolean	mayHaveChildren() Part of the Element interface.
boolean	remove(Element element) Part of the Folder interface.
void	removeAll() Removes all children from the folder.
int	size() Returns the current number of children in the folder.

Methods inherited from class oracle.ide.model.DefaultElement

getAttributes, getData

Methods inherited from class oracle.ide.model.DefaultDisplayable

getLongLabel, getShortLabel, getToolTipText, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface oracle.ide.model.Element

getAttributes, getData

Methods inherited from interface oracle.ide.model.Displayable

getLongLabel, getShortLabel, getToolTipText, toString

Field Detail

_children

protected final java.util.ArrayList _children

The "final" modifier makes it possible to synchronize on the _children object, since its value can never change. All subclasses that directly access the _children field are responsible for first synchronizing on the _children object before accessing its contents and and for managing the state of the dirty flag when changes are made.

Constructor Detail

DefaultFolder

public DefaultFolder()

Creates a new DefaultFolder instance.

Subclasses that are designed to operate as a JavaBean must implement a public default constructor.

Method Detail

mayHaveChildren

public boolean mayHaveChildren()

Part of the Element interface. This implementation always returns true.

Specified by:

mayHaveChildren in interface Element

Overrides:

mayHaveChildren in class DefaultElement

Returns:

true if this Element may contain child Elements.

See Also:

Element.mayHaveChildren()

getChildren

public java.util.Iterator getChildren()

Part of the Element interface. This implementation returns an Iterator over the current list of children.

Specified by:

getChildren in interface Element

Overrides:

getChildren in class DefaultElement

Returns:

an Iterator over any child Elements contained by this Element. If there are no children, null is returned.

See Also:

Element.getChildren()

getIcon

public javax.swing.Icon getIcon()

Part of Element interface. The default implementation returns null, which causes a default folder icon to be used.

Specified by:

getIcon in interface Displayable

Overrides:

getIcon in class DefaultDisplayable

Returns:

the Icon to be displayed for the Displayable.

See Also:

Displayable.getIcon()

canAdd

public boolean canAdd(Element element)

Part of the Folder interface. The default implementation returns true if and only if the specified Element is not null.

Specified by:

canAdd in interface Folder

Parameters:

element - the Element that is about to be added to this Folder.

Returns:

true if and only if the specified Element is not null.

See Also:

Folder.canAdd(Element)

add

public boolean add(Element element)

Part of the Folder interface. The specified Element is added to the end of the child list. However, if the Element is null, this method does nothing.

In order for the UI to get updated correctly, an appropriate UpdateMessage will need to be sent to Observers of the DefaultFolder. The policy in the IDE is that the class that changes the state of an object is responsible for firing the UpdateMessages for those changes. UpdageMessages are not fired by the changed object itself.

For a single UpdateMessage corresponding to add(Element), you can fire the UpdateMessage using code like:

UpdateMessage.fireChildAdded(folder, newlyAddedChild);

Specified by:

add in interface Folder

See Also:

Folder.add(oracle.ide.model.Element)

canRemove

public boolean canRemove(Element element)

Part of the Folder interface. The default implementation returns true if and only if the specified Element is not null.

Specified by:

canRemove in interface Folder

Parameters:

element - the Element that is about to be removed from this Folder.

Returns:

true if and only if the specified Element is not null.

See Also:

Folder.canRemove(Element)

remove

public boolean remove(Element element)

Part of the Folder interface. The specified Element is removed from the child list. However, if the Element is null, this method does nothing. If the Element occurs more than once in the child list, then only the first instance is removed.

In order for the UI to get updated correctly, an appropriate UpdateMessage will need to be sent to Observers of the DefaultFolder. The policy in the IDE is that the class that changes the state of an object is responsible for firing the UpdateMessages for those changes. UpdateMessages are not fired by the changed object itself.

For a single UpdateMessage corresponding to remove(Element), you can fire the UpdateMessage using code like:

UpdateMessage.fireChildRemoved(folder, removedChild);

Specified by:

remove in interface Folder

Parameters:

element - The child object to remove.

See Also:

Folder.remove(Element)

containsChild

public boolean containsChild(Element child)

Description copied from interface: Folder

Returns true if the folder contains the specified child Element; returns false otherwise.

Specified by:

containsChild in interface Folder

size

public int size()

Description copied from interface: Folder

Returns the current number of children in the folder.

Specified by:

size in interface Folder

removeAll

public void removeAll()

Description copied from interface: Folder

Removes all children from the folder.

Specified by:

removeAll in interface Folder

equalsImpl

protected final boolean equalsImpl(DefaultFolder defaultFolder)

This is a helper method for Object.equals(Object) that can also be used by subclasses that implement Object.equals(Object). It assumes that the argument is not null.

copyToImpl

protected final void copyToImpl(DefaultFolder copy)

Design pattern for supporting strongly typed copying.

This method is intended to be helper method that subclasses can use, if they implement the Copyable interface. The copy of the children list is a shallow copy. That is, the children themselves are not copied, but the list is copied.