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org.eclipse.emf.edit.command
Class CreateChildCommand

java.lang.Object
  org.eclipse.emf.common.command.AbstractCommand
      org.eclipse.emf.common.command.CommandWrapper
          org.eclipse.emf.edit.command.CreateChildCommand

All Implemented Interfaces:

Command, CommandActionDelegate

public class CreateChildCommand

extends CommandWrapper

implements CommandActionDelegate

This command wraps an AddCommand or SetCommand to provide the higher-level operation of "creating" an appropriate child object and adding it to a owner object. In fact, all of the possible child objects are created by the owner's item provider before this command is created, and specified in the newChildDescriptor argument to create() -- they must be, so that the user can specify which he actually wishes to create. As a result, this command essentially just creates and executes the appropriate lower-level EMF command, and delegates matters of appearance (text, icon, result) to the appropriate item provider, so that it may be handled correctly for the given model.

Note that this command makes no assumptions about the relationship between the owner, to which the new child will be added, and the selected object. This allows the command to be reused for sibling creation. As a result, the selection be explicitly specified, so that it can be restored when the command is undone.

Nested Class Summary

static interface

CreateChildCommand.Helper This is the helper interface to which CreateChildCommand functionality is delegated.

Nested classes inherited from class org.eclipse.emf.common.command.AbstractCommand

AbstractCommand.NonDirtying

Field Summary

protected Collection	affectedObjects This is the value to be returned by getAffectedObjects().
protected Object	child This is the child object to be added.
protected EditingDomain	domain This is the editing doman in which this command operates.
protected EStructuralFeature	feature This is the feature of the owner to which the child will be added.
protected CreateChildCommand.Helper	helper This is the helper object, usually the item provider for owner, to which parts of this command's functionality are delegated.
protected int	index This is the index for the new object's position under the feature.
protected static int	NO_INDEX Deprecated. As of EMF 2.0, use CommandParameter.NO_INDEX, whose value is equal to this, instead.
protected EObject	owner This is the object to which the child will be added.
protected Collection	selection This is the collection of objects that were selected when this command was created.

Fields inherited from class org.eclipse.emf.common.command.CommandWrapper

command

Fields inherited from class org.eclipse.emf.common.command.AbstractCommand

description, isExecutable, isPrepared, label

Constructor Summary

CreateChildCommand(EditingDomain domain, EObject owner, EStructuralFeature feature, Object child, Collection selection)
This constructor initializes an instance that adds the specified child object to the feature of the owner object.

CreateChildCommand(EditingDomain domain, EObject owner, EStructuralFeature feature, Object child, Collection selection, CreateChildCommand.Helper helper)
This constructor initializes an instance, as above, but the command delegates functionality to the specified Helper.

CreateChildCommand(EditingDomain domain, EObject owner, EStructuralFeature feature, Object child, int index, Collection selection)
This constructor initializes an instance that adds the specified child object to the owner object, at the specified index of its feature feature, if it is multi-valued.

CreateChildCommand(EditingDomain domain, EObject owner, EStructuralFeature feature, Object child, int index, Collection selection, CreateChildCommand.Helper helper)
This constructor initializes an instance, as above, but the command delegates functionality to the specified Helper.

Method Summary

static Command	create(EditingDomain domain, Object owner, Object newChildDescriptor, Collection selection) This returns a command created by the editing domain to add the child described by newChildDescriptor to the given object.
protected Command	createCommand() This creates the wrapped AddCommand or SetCommand that adds the child object to the model.
void	execute() This executes the wrapped command and sets the affected objects to the collection returned by helper.getCreateChildResult().
Collection	getAffectedObjects() This returns the affected objects.
String	getDescription() This returns the description by delegating to helper.getCreateChildDescription().
Object	getImage() This returns the icon by delegating to helper.getCreateChildImage().
Collection	getResult() This returns the result of this command by delegating to helper.getCreateChildResult().
String	getText() This returns the label by delegating to helper.getCreateChildText().
String	getToolTipText() This returns the tool tip text by delegating to helper.getCreateChildToolTipText().
void	redo() This redoes the wrapped command and sets the affected objects to the collection returned by helper.getCreateChildResult().
String	toString() This gives an abbreviated name using this object's own class name, without package qualification, followed by a space-separated list of field:value pairs.
void	undo() This undoes the wrapped command and sets the affected objects to the original selection.

Methods inherited from class org.eclipse.emf.common.command.CommandWrapper

canUndo, dispose, getCommand, getLabel, prepare

Methods inherited from class org.eclipse.emf.common.command.AbstractCommand

canExecute, chain, setDescription, setLabel

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.eclipse.emf.edit.command.CommandActionDelegate

canExecute

Field Detail

NO_INDEX

protected static final int NO_INDEX

Deprecated. As of EMF 2.0, use CommandParameter.NO_INDEX, whose value is equal to this, instead.

This value is used to indicate that an optional positional index indicator is unspecified.

See Also:

Constant Field Values

domain

protected EditingDomain domain

This is the editing doman in which this command operates.

owner

protected EObject owner

This is the object to which the child will be added.

feature

protected EStructuralFeature feature

This is the feature of the owner to which the child will be added.

child

protected Object child

This is the child object to be added.

index

protected int index

This is the index for the new object's position under the feature.

helper

protected CreateChildCommand.Helper helper

This is the helper object, usually the item provider for owner, to which parts of this command's functionality are delegated.

affectedObjects

protected Collection affectedObjects

This is the value to be returned by getAffectedObjects(). The affected objects are different after an execute or redo from after an undo, so we record them.

selection

protected Collection selection

This is the collection of objects that were selected when this command was created. After an undo, these are considered the affected objects.

Constructor Detail

CreateChildCommand

public CreateChildCommand(EditingDomain domain,
                          EObject owner,
                          EStructuralFeature feature,
                          Object child,
                          Collection selection)

This constructor initializes an instance that adds the specified child object to the feature of the owner object. If any of owner, feature, or child are null, createCommand() will return UnexecutableCommand.INSTANCE and, hence, AbstractCommand.canExecute() will return false. If non-null, selection is the collection of selected objects. An internal default Helper will provide generic implmentations for the delegated command methods.

CreateChildCommand

public CreateChildCommand(EditingDomain domain,
                          EObject owner,
                          EStructuralFeature feature,
                          Object child,
                          Collection selection,
                          CreateChildCommand.Helper helper)

This constructor initializes an instance, as above, but the command delegates functionality to the specified Helper. If helper is null, the internal default helper is used.

CreateChildCommand

public CreateChildCommand(EditingDomain domain,
                          EObject owner,
                          EStructuralFeature feature,
                          Object child,
                          int index,
                          Collection selection)

This constructor initializes an instance that adds the specified child object to the owner object, at the specified index of its feature feature, if it is multi-valued. If any of owner, feature, or child are null, createCommand() will return UnexecutableCommand.INSTANCE and, hence, AbstractCommand.canExecute() will return false. If non-null, selection is the collection of selected objects. The internal default helper is used by the command. If index is CommandParameter.NO_INDEX, this behaves just like the first constructor form.

CreateChildCommand

public CreateChildCommand(EditingDomain domain,
                          EObject owner,
                          EStructuralFeature feature,
                          Object child,
                          int index,
                          Collection selection,
                          CreateChildCommand.Helper helper)

This constructor initializes an instance, as above, but the command delegates functionality to the specified Helper. If helper is null, the internal default helper is used.

Method Detail

create

public static Command create(EditingDomain domain,
                             Object owner,
                             Object newChildDescriptor,
                             Collection selection)

This returns a command created by the editing domain to add the child described by newChildDescriptor to the given object.

createCommand

protected Command createCommand()

This creates the wrapped AddCommand or SetCommand that adds the child object to the model. If the owner, feature, or child is null, or if the feature is single-valued and has already been set to an object, UnexecutableCommand.INSTANCE will be returned.

Overrides:

createCommand in class CommandWrapper

Returns:

the command being proxied.

execute

public void execute()

This executes the wrapped command and sets the affected objects to the collection returned by helper.getCreateChildResult().

Specified by:

execute in interface Command

Overrides:

execute in class CommandWrapper

undo

public void undo()

This undoes the wrapped command and sets the affected objects to the original selection.

Specified by:

undo in interface Command

Overrides:

undo in class CommandWrapper

redo

public void redo()

This redoes the wrapped command and sets the affected objects to the collection returned by helper.getCreateChildResult().

Specified by:

redo in interface Command

Overrides:

redo in class CommandWrapper

getAffectedObjects

public Collection getAffectedObjects()

This returns the affected objects.

Specified by:

getAffectedObjects in interface Command

Overrides:

getAffectedObjects in class CommandWrapper

Returns:

the result.

getResult

public Collection getResult()

This returns the result of this command by delegating to helper.getCreateChildResult().

Specified by:

getResult in interface Command

Overrides:

getResult in class CommandWrapper

Returns:

the result.

getText

public String getText()

This returns the label by delegating to helper.getCreateChildText().

Specified by:

getText in interface CommandActionDelegate

getDescription

public String getDescription()

This returns the description by delegating to helper.getCreateChildDescription().

Specified by:

getDescription in interface CommandActionDelegate

Overrides:

getDescription in class CommandWrapper

Returns:

the description.

getToolTipText

public String getToolTipText()

This returns the tool tip text by delegating to helper.getCreateChildToolTipText().

Specified by:

getToolTipText in interface CommandActionDelegate

getImage

public Object getImage()

This returns the icon by delegating to helper.getCreateChildImage().

Specified by:

getImage in interface CommandActionDelegate

toString

public String toString()

This gives an abbreviated name using this object's own class name, without package qualification, followed by a space-separated list of field:value pairs.

Overrides:

toString in class CommandWrapper