bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/ObjectPluginAction.java

/*******************************************************************************
 * Copyright (c) 2000, 2015 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.ui.internal;

import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.ISafeRunnable;
import org.eclipse.core.runtime.SafeRunner;
import org.eclipse.jface.viewers.StructuredSelection;
import org.eclipse.ui.IActionDelegate;
import org.eclipse.ui.IEditorPart;
import org.eclipse.ui.IObjectActionDelegate;
import org.eclipse.ui.IPartListener2;
import org.eclipse.ui.IWorkbenchPage;
import org.eclipse.ui.IWorkbenchPart;
import org.eclipse.ui.IWorkbenchPartReference;
import org.eclipse.ui.part.MultiPageEditorPart;

/**
 * An object action extension in a popup menu.
 * <p>
 * For backward compatibility, the delegate object can implement either
 * <code>IActionDelegate</code> or <code>IObjectActionDelegate</code>.
 * </p>
 */
public class ObjectPluginAction extends PluginAction implements IPartListener2 {
	/**
	 * The configuration element attribute for the identifier of the action
	 * which this action is intended to override (i.e., replace).
	 */
	public static final String ATT_OVERRIDE_ACTION_ID = "overrideActionId";//$NON-NLS-1$

    private String overrideActionId;

    private IWorkbenchPart activePart;

	@Override
	public void partActivated(IWorkbenchPartReference partRef) {
	}

	@Override
	public void partBroughtToTop(IWorkbenchPartReference partRef) {
	}

	@Override
	public void partClosed(IWorkbenchPartReference partRef) {
		IWorkbenchPart part = partRef.getPart(false);
		// FIX 543745
		if (part instanceof MultiPageEditorPart && activePart instanceof IEditorPart) {
			MultiPageEditorPart mulitPageEditorPart = (MultiPageEditorPart) part;
			IEditorPart[] editorsForActivePart = mulitPageEditorPart
					.findEditors(((IEditorPart) activePart).getEditorInput());
			if (editorsForActivePart != null && editorsForActivePart.length > 0) {
				clearActivePart();
				return;
			}
		}
		if (activePart != null && part == activePart) {
			clearActivePart();
		}
	}

	private void clearActivePart() {
		selectionChanged(StructuredSelection.EMPTY);
		stopPartListening();
		disposeDelegate();
		activePart = null;
	}

	@Override
	public void partDeactivated(IWorkbenchPartReference partRef) {
	}

	@Override
	public void partHidden(IWorkbenchPartReference partRef) {
	}

	@Override
	public void partInputChanged(IWorkbenchPartReference partRef) {
	}

	@Override
	public void partOpened(IWorkbenchPartReference partRef) {
	}

	@Override
	public void partVisible(IWorkbenchPartReference partRef) {
	}

    /**
	 * Constructs a new ObjectPluginAction.
	 *
	 * @param actionElement
	 *            The configuration element used to construct this action; must
	 *            not be <code>null</code>.
	 * @param id
	 *            The identifier for this action; must not be <code>null</code>.
	 * @param style
	 *            The style bits
	 */
    public ObjectPluginAction(IConfigurationElement actionElement, String id,
            int style) {
        super(actionElement, id, style);
        overrideActionId = actionElement.getAttribute(ATT_OVERRIDE_ACTION_ID);
    }

    @Override
	protected void initDelegate() {
        super.initDelegate();
		final IActionDelegate actionDelegate = getDelegate();
		if (actionDelegate instanceof IObjectActionDelegate
				&& activePart != null) {
			final IObjectActionDelegate objectActionDelegate = (IObjectActionDelegate) actionDelegate;
			final ISafeRunnable runnable = new ISafeRunnable() {
				@Override
				public void run() throws Exception {
					objectActionDelegate.setActivePart(ObjectPluginAction.this,
							activePart);
				}

				@Override
				public void handleException(Throwable exception) {
					// Do nothing.
				}
			};
			SafeRunner.run(runnable);
		}
	}

    /**
	 * Sets the active part for the delegate.
	 * <p>
	 * This method will be called every time the action appears in a popup menu.
	 * The targetPart may change with each invocation.
	 * </p>
	 *
	 * @param targetPart
	 *            the new part target
	 */
    public void setActivePart(IWorkbenchPart targetPart) {
    	if (activePart != targetPart) {
			if (activePart != null) {
				stopPartListening();
			}
			if (targetPart != null) {
				targetPart.getSite().getPage().addPartListener(this);
			}
		}
        activePart = targetPart;
        IActionDelegate delegate = getDelegate();
        if (delegate instanceof IObjectActionDelegate && activePart != null) {
			final IObjectActionDelegate objectActionDelegate = (IObjectActionDelegate) delegate;
			final ISafeRunnable runnable = new ISafeRunnable() {
				@Override
				public void run() throws Exception {
					objectActionDelegate.setActivePart(ObjectPluginAction.this,
							activePart);
				}

				@Override
				public void handleException(Throwable exception) {
					// Do nothing.
				}
			};
			SafeRunner.run(runnable);
		}
	}

    /**
     * Returns the action identifier this action overrides.
     *
     * @return the action identifier to override or <code>null</code>
     */
    @Override
	public String getOverrideActionId() {
        return overrideActionId;
    }

    @Override
	public void dispose() {
    	if (activePart!=null) {
			stopPartListening();
    		activePart = null;
    	}
    	super.dispose();
    }

	private void stopPartListening() {
		if (activePart != null) {
			IWorkbenchPage page = activePart.getSite().getPage();
			if (page != null) {
				page.removePartListener(this);
			}
		}
	}
}