com.netxforge.screens.editing.base.actions.handlers.CommandActionHandler.java Source code

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Here is the source code for com.netxforge.screens.editing.base.actions.handlers.CommandActionHandler.java

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/**
 * <copyright> 
 *
 * Copyright (c) 2002-2006 IBM Corporation and others.
 * All rights reserved.   This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors: 
 *   IBM - Initial API and implementation
 *
 * </copyright>
 *
 * $Id: CommandActionHandler.java,v 1.6 2008/05/07 19:08:40 emerks Exp $
 */
package com.netxforge.screens.editing.base.actions.handlers;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

import org.eclipse.emf.common.command.Command;
import org.eclipse.emf.common.command.UnexecutableCommand;
import org.eclipse.emf.edit.domain.EditingDomain;
import org.eclipse.jface.viewers.IStructuredSelection;

import com.netxforge.screens.editing.base.actions.BaseSelectionListenerAction;

/*
 * This base action class implements an action by creating a command and delegating to it;
 * it's main use is as a base class for action handlers.
 */
public class CommandActionHandler extends BaseSelectionListenerAction {
    /**
     * This keeps track of the editing domain of the action.
     */
    protected EditingDomain domain;

    /**
     * This keeps track of the command delegate that is created by
     * {@link #createCommand}.
     */
    protected Command command;

    /**
     * This constructs and instance in this editing domain.
     */
    public CommandActionHandler(EditingDomain domain) {
        // The label is not used.
        //
        super("");

        this.domain = domain;
    }

    /**
     * This constructs and instance in this editing domain.
     */
    public CommandActionHandler(EditingDomain domain, String label) {
        super(label);

        this.domain = domain;
    }

    /**
     * This returns the action's domain.
     */
    public EditingDomain getEditingDomain() {
        return domain;
    }

    /**
     * This sets the action's domain.
     */
    public void setEditingDomain(EditingDomain domain) {
        this.domain = domain;
    }

    /**
     * This simply execute the command.
     */
    @Override
    public void run() {
        domain.getCommandStack().execute(command);
    }

    /**
     * When the selection changes, this will call {@link #createCommand} with
     * the appropriate collection of selected objects.
     */
    @Override
    public boolean updateSelection(IStructuredSelection selection) {
        List<?> list = selection.toList();
        Collection<Object> collection = new ArrayList<Object>(list);
        command = createCommand(collection);

        return command.canExecute();
    }

    /**
     * This default implementation simply returns
     * {@link org.eclipse.emf.common.command.UnexecutableCommand#INSTANCE}.
     */
    public Command createCommand(Collection<?> selection) {
        return UnexecutableCommand.INSTANCE;
    }
}