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.
DefaultElement
, Folder
, oracle.ide.marshal
, oracle.ide.marshal.xml
, Object2Dom
Modifier and Type | Field and Description |
---|---|
protected java.util.ArrayList |
_children
The "
final " modifier makes it possible to synchronize on the _children object, since its value can never change. |
Constructor and Description |
---|
DefaultFolder()
Creates a new
DefaultFolder instance. |
Modifier and Type | Method and Description |
---|---|
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)
|
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.
|
getAttributes, getData
getLongLabel, getShortLabel, getToolTipText, toString
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
getAttributes, getData
getLongLabel, getShortLabel, getToolTipText, toString
protected final java.util.ArrayList _children
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.public DefaultFolder()
DefaultFolder
instance.
Subclasses that are designed to operate as a JavaBean must implement a public default constructor.
public boolean mayHaveChildren()
Element
interface. This implementation always returns true
.mayHaveChildren
in interface Element
mayHaveChildren
in class DefaultElement
true
if this Element
may contain child Element
s.Element.mayHaveChildren()
public java.util.Iterator getChildren()
Element
interface. This implementation returns an Iterator
over the current list of children.getChildren
in interface Element
getChildren
in class DefaultElement
Iterator
over any child Element
s contained by this Element
. If there are no children, null
is returned.Element.getChildren()
public javax.swing.Icon getIcon()
Element
interface. The default implementation returns null
, which causes a default folder icon to be used.getIcon
in interface Displayable
getIcon
in class DefaultDisplayable
Icon
to be displayed for the Displayable
.Displayable.getIcon()
public boolean canAdd(Element element)
Folder
interface. The default implementation returns true
if and only if the specified Element
is not null
.canAdd
in interface Folder
element
- the Element
that is about to be added to this Folder
.true
if and only if the specified Element
is not null
.Folder.canAdd(Element)
public boolean add(Element element)
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 Observer
s of the DefaultFolder
. The policy in the IDE is that the class that changes the state of an object is responsible for firing the UpdateMessage
s for those changes. UpdageMessage
s 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);
add
in interface Folder
Folder.add(oracle.ide.model.Element)
public boolean canRemove(Element element)
Folder
interface. The default implementation returns true
if and only if the specified Element
is not null
.canRemove
in interface Folder
element
- the Element
that is about to be removed from this Folder
.true
if and only if the specified Element
is not null
.Folder.canRemove(Element)
public boolean remove(Element element)
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 Observer
s of the DefaultFolder
. The policy in the IDE is that the class that changes the state of an object is responsible for firing the UpdateMessage
s for those changes. UpdateMessage
s 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);
remove
in interface Folder
element
- The child object to remove.Folder.remove(Element)
public boolean containsChild(Element child)
Folder
containsChild
in interface Folder
public int size()
Folder
public void removeAll()
Folder
protected final boolean equalsImpl(DefaultFolder defaultFolder)
Object.equals(Object)
that can also be used by subclasses that implement Object.equals(Object)
. It assumes that the argument is not null
.protected final void copyToImpl(DefaultFolder copy)
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.