org.eclipse.emf.edit.command

Class SetCommand

java.lang.Object

org.eclipse.emf.common.command.AbstractCommand

org.eclipse.emf.edit.command.AbstractOverrideableCommand

org.eclipse.emf.edit.command.SetCommand

All Implemented Interfaces:

Command, OverrideableCommand

public class SetCommand
extends AbstractOverrideableCommand

The set command logically acts upon an owner object to set a particular feature to a specified value or to unset a feature. The static create methods delegate command creation to EditingDomain.createCommand, which may or may not result in the actual creation of an instance of this class.

The implementation of this class is low-level and EMF specific; it allows a value to be set to a single-valued feature of an owner, i.e., it is equivalent of the call

   ((EObject)object).eSet((EStructuralFeature)feature, value);
 

or to

   ((EObject)object).eUnset((EStructuralFeature)feature);
 

if the value is UNSET_VALUE.

Setting a feature that is a bidirectional reference with a multiplicity-many reverse or with a multiplicity-1 reverse that is already set (on value), is not undoable. In this case, the SetCommand static create function will not return an instance of this class, but instead will return a compound command (e.g., a RemoveCommand followed by an AddCommand for the other end of the relation) which could not be undone.

The exception to the above is when an empty list is being set to empty or unset. Such commands are undoable and represent the only way to toggle whether the feature is set.

When setting a containment (or container) feature, we always assume that the object that will be contained is not already in a container, but take no action in this class to ensure this is the case.

A set command is an OverrideableCommand.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	SetCommand.PessimisticStrictCompoundCommand

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

AbstractCommand.NonDirtying

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	canUndo This specified whether or not this command can be undone.
protected static java.lang.String	DESCRIPTION This caches the description.
protected static EcorePackage	ecorePackage
protected EStructuralFeature	feature This is the feature of the owner object upon the command will act.
protected int	index This is the position at which the object will be set.
protected static java.lang.String	LABEL This caches the label.
protected java.lang.Object	oldValue This is the old value of the feature which must be restored during undo.
protected EObject	owner This is the owner object upon which the command will act.
protected EList<java.lang.Object>	ownerList If non-null, this is the list in which the command will set a value.
protected Command	removeCommand This is any remove commands needed to clear this many valued list or to update the opposite properly.
static java.lang.Object	UNSET_VALUE Specify this as the value in order to unset a feature.
protected java.lang.Object	value This is the value to be set.

Fields inherited from class org.eclipse.emf.edit.command.AbstractOverrideableCommand

domain, overrideCommand

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

description, isExecutable, isPrepared, label

Constructor Summary

Constructors

Constructor and Description
SetCommand(EditingDomain domain, EObject owner, EStructuralFeature feature, java.lang.Object value) This constructs a primitive command to set the owner's feature to the specified value.
SetCommand(EditingDomain domain, EObject owner, EStructuralFeature feature, java.lang.Object value, int index) This constructs a primitive command to set the owner's feature to the specified value at the given index.

Method Summary

Methods

Modifier and Type	Method and Description
static Command	create(EditingDomain domain, java.lang.Object owner, java.lang.Object feature, java.lang.Object value) This creates a command to set the owner's feature to the specified value.
static Command	create(EditingDomain domain, java.lang.Object owner, java.lang.Object feature, java.lang.Object value, int index) This creates a command to set the owner's feature to the specified value at the specified index.
boolean	doCanUndo() This is overrideable command's implementation of canUndo.
void	doExecute() This is overrideable command's implementation of execute.
java.util.Collection<?>	doGetAffectedObjects() This is overrideable command's implementation of getAffectedObjects.
java.util.Collection<?>	doGetResult() This is overrideable command's implementation of getResult.
void	doRedo() This is overrideable command's implementation of redo.
void	doUndo() This is overrideable command's implementation of undo.
EStructuralFeature	getFeature() This returns the feature of the owner object upon the command will act.
int	getIndex() This returns the position at which the objects will be added.
java.lang.Object	getOldValue() This returns the old value of the feature which must be restored during undo.
EObject	getOwner() This returns the owner object upon which the command will act.
EList<java.lang.Object>	getOwnerList() If the command will set a single value in a list, this returns the list in which it will set; null otherwise.
java.lang.Object	getValue() This returns the value to be set.
protected boolean	prepare() Called at most once in AbstractCommand.canExecute() to give the command an opportunity to ready itself for execution.
java.lang.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.

Methods inherited from class org.eclipse.emf.edit.command.AbstractOverrideableCommand

canExecute, canUndo, dispose, doCanExecute, doDispose, doGetChildrenToCopy, doGetDescription, doGetLabel, execute, getAffectedObjects, getChildrenToCopy, getDescription, getDomain, getLabel, getOverride, getOwnerList, getResult, redo, setOverride, undo, updateEMap

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

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.common.command.Command

chain

Field Detail

UNSET_VALUE

public static final java.lang.Object UNSET_VALUE

Specify this as the value in order to unset a feature. Note that this value can be specified for a multiplicity-1 feature or for a multiplicity-many feature with no index given. Unsetting a single value within a list is not possible.

LABEL

protected static final java.lang.String LABEL

This caches the label.

DESCRIPTION

protected static final java.lang.String DESCRIPTION

This caches the description.

owner

protected EObject owner

This is the owner object upon which the command will act.

feature

protected EStructuralFeature feature

This is the feature of the owner object upon the command will act.

ownerList

protected EList<java.lang.Object> ownerList

If non-null, this is the list in which the command will set a value. If null, feature is single-valued or no index was specified.

value

protected java.lang.Object value

This is the value to be set.

oldValue

protected java.lang.Object oldValue

This is the old value of the feature which must be restored during undo.

index

protected int index

This is the position at which the object will be set.

canUndo

protected boolean canUndo

This specified whether or not this command can be undone.

removeCommand

protected Command removeCommand

This is any remove commands needed to clear this many valued list or to update the opposite properly.

ecorePackage

protected static final EcorePackage ecorePackage

Constructor Detail

SetCommand

public SetCommand(EditingDomain domain,
          EObject owner,
          EStructuralFeature feature,
          java.lang.Object value)

This constructs a primitive command to set the owner's feature to the specified value.

SetCommand

public SetCommand(EditingDomain domain,
          EObject owner,
          EStructuralFeature feature,
          java.lang.Object value,
          int index)

This constructs a primitive command to set the owner's feature to the specified value at the given index.

Method Detail

create

public static Command create(EditingDomain domain,
             java.lang.Object owner,
             java.lang.Object feature,
             java.lang.Object value)

This creates a command to set the owner's feature to the specified value.

create

public static Command create(EditingDomain domain,
             java.lang.Object owner,
             java.lang.Object feature,
             java.lang.Object value,
             int index)

This creates a command to set the owner's feature to the specified value at the specified index.

getOwner

public EObject getOwner()

This returns the owner object upon which the command will act.

getFeature

public EStructuralFeature getFeature()

This returns the feature of the owner object upon the command will act.

getOwnerList

public EList<java.lang.Object> getOwnerList()

If the command will set a single value in a list, this returns the list in which it will set; null otherwise.

getIndex

public int getIndex()

This returns the position at which the objects will be added.

getValue

public java.lang.Object getValue()

This returns the value to be set.

getOldValue

public java.lang.Object getOldValue()

This returns the old value of the feature which must be restored during undo.

prepare

protected boolean prepare()

Description copied from class: AbstractCommand

Called at most once in AbstractCommand.canExecute() to give the command an opportunity to ready itself for execution. The returned value is stored in AbstractCommand.canExecute(). In other words, you can override this method to initialize and to yield a cached value for the all subsequent calls to canExecute.

Overrides:

prepare in class AbstractCommand

Returns:

whether the command is executable.

doExecute

public void doExecute()

Description copied from interface: OverrideableCommand

This is overrideable command's implementation of execute.

Specified by:

doExecute in interface OverrideableCommand

Specified by:

doExecute in class AbstractOverrideableCommand

doCanUndo

public boolean doCanUndo()

Description copied from interface: OverrideableCommand

This is overrideable command's implementation of canUndo.

Specified by:

doCanUndo in interface OverrideableCommand

Overrides:

doCanUndo in class AbstractOverrideableCommand

doUndo

public void doUndo()

Description copied from interface: OverrideableCommand

This is overrideable command's implementation of undo.

Specified by:

doUndo in interface OverrideableCommand

Specified by:

doUndo in class AbstractOverrideableCommand

doRedo

public void doRedo()

Description copied from interface: OverrideableCommand

This is overrideable command's implementation of redo.

Specified by:

doRedo in interface OverrideableCommand

Specified by:

doRedo in class AbstractOverrideableCommand

doGetResult

public java.util.Collection<?> doGetResult()

Description copied from interface: OverrideableCommand

This is overrideable command's implementation of getResult.

Specified by:

doGetResult in interface OverrideableCommand

Overrides:

doGetResult in class AbstractOverrideableCommand

doGetAffectedObjects

public java.util.Collection<?> doGetAffectedObjects()

Description copied from interface: OverrideableCommand

This is overrideable command's implementation of getAffectedObjects.

Specified by:

doGetAffectedObjects in interface OverrideableCommand

Overrides:

doGetAffectedObjects in class AbstractOverrideableCommand

toString

public java.lang.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 AbstractOverrideableCommand

Returns:

string representation.