AbstractEnablableFrameworkAction.java

/*******************************************************************************
 * Copyright (c) 1998, 2015 Oracle and/or its affiliates. All rights reserved.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
 * which accompanies this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *     Oracle - initial API and implementation from Oracle TopLink
******************************************************************************/
package org.eclipse.persistence.tools.workbench.framework.action;

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;

import org.eclipse.persistence.tools.workbench.framework.app.AbstractApplicationNode;
import org.eclipse.persistence.tools.workbench.framework.app.ApplicationNode;
import org.eclipse.persistence.tools.workbench.framework.context.WorkbenchContext;



/**
 * Subclass this action if you would like to update the enabled state of
 * your action based on specified model properties.
 */
public abstract class AbstractEnablableFrameworkAction extends AbstractFrameworkAction {

    protected ApplicationNode[] selectedNodes;

    private PropertyChangeListener enabledStateListener;

    /** the model properties that drive the action's enabled property */
    protected static final String[] DEFAULT_ENABLED_PROPERTY_NAMES = {};

    protected AbstractEnablableFrameworkAction(WorkbenchContext context) {
        super(context);
    }

    /**
     * Short-circuit out if the action does not apply to even one of the selected Nodes.
     * Subclasses may override this method if they would like to do something different.
     * In the typical situation a subclass should only need to define
     * shouldBeEnabled(ApplicationNode)
     */
    protected void updateEnabledState()
    {
        for (int index = 0; index < this.selectedNodes.length; index++)
        {
            if (!shouldBeEnabled(this.selectedNodes[index])) {
                setEnabled(false);
                return;
            }
        }

        setEnabled(true);
    }

    /**
     * return whether the given node is in a state where this action could be
     * performed
     */
    protected abstract boolean shouldBeEnabled(ApplicationNode selectedNode);

    public void setUp() {
        super.setUp();
        this.selectedNodes = selectedNodes();
        engageListeners();
        updateEnabledState();
    }

    public void tearDown() {
        disengageListeners();
        this.selectedNodes = null;
        super.tearDown();
    }

    protected void engageListeners() {
        for (int i = 0; i < this.selectedNodes.length; i++) {
            this.engageListeners((AbstractApplicationNode) this.selectedNodes[i]);
        }
    }

    protected void engageListeners(AbstractApplicationNode node) {
        this.engageValueEnabled(node);
    }

    protected void disengageListeners() {
        for (int i = 0; i < this.selectedNodes.length; i++) {
            this.disengageListeners((AbstractApplicationNode) this.selectedNodes[i]);
        }
    }

    protected void disengageListeners(AbstractApplicationNode node) {
        this.disengageValueEnabled(node);
    }

    protected void engageValueEnabled(AbstractApplicationNode node) {
        this.engageValue(node, this.enabledPropertyNames(), this.getEnabledStateListener());
    }

    protected void engageValue(AbstractApplicationNode node, String[] propertyNames, PropertyChangeListener listener) {
        this.engage(node, propertyNames, listener);
    }

    protected void engage(AbstractApplicationNode node, String[] propertyNames, PropertyChangeListener listener) {
        for (int i = propertyNames.length; i-- > 0; ) {
            this.engage(node, propertyNames[i], listener);
        }
    }

    protected void engage(AbstractApplicationNode node, String propertyName, PropertyChangeListener listener) {
        node.addValuePropertyChangeListener(propertyName, listener);
    }

    protected void disengageValueEnabled(AbstractApplicationNode node) {
        this.disengageValue(node, this.enabledPropertyNames(), this.getEnabledStateListener());
    }

    protected void disengageValue(AbstractApplicationNode node, String[] propertyNames, PropertyChangeListener listener) {
        this.disengage(node, propertyNames, listener);
    }

    protected void disengage(AbstractApplicationNode node, String[] propertyNames, PropertyChangeListener listener) {
        for (int i = propertyNames.length; i-- > 0; ) {
            this.disengage(node, propertyNames[i], listener);
        }
    }

    protected void disengage(AbstractApplicationNode node, String propertyName, PropertyChangeListener listener) {
        node.removeValuePropertyChangeListener(propertyName, listener);
    }

    protected PropertyChangeListener getEnabledStateListener() {
        if (this.enabledStateListener == null) {
            this.enabledStateListener = this.buildEnabledStateListener();
        }
        return this.enabledStateListener;
    }

    protected PropertyChangeListener buildEnabledStateListener() {
        return new PropertyChangeListener() {
            public void propertyChange(PropertyChangeEvent evt) {
                AbstractEnablableFrameworkAction.this.updateEnabledState();
            }
        };
    }

    /**
     * Return the names of the value's properties that affect
     * the action's enabled state.
     */
    protected String[] enabledPropertyNames() {
        return DEFAULT_ENABLED_PROPERTY_NAMES;
    }

}