org.eclipse.contribution.visualiser.internal.help.VisualiserHelp.java Source code

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Here is the source code for org.eclipse.contribution.visualiser.internal.help.VisualiserHelp.java

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/*******************************************************************************
 * Copyright (c) 2000, 2005 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 Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.contribution.visualiser.internal.help;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.help.HelpSystem;
import org.eclipse.help.IContext;
import org.eclipse.help.IContextProvider;
import org.eclipse.jdt.core.JavaModelException;
import org.eclipse.jdt.internal.ui.actions.SelectionConverter;
import org.eclipse.jdt.internal.ui.util.JavadocHelpContext;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.jface.viewers.StructuredSelection;
import org.eclipse.jface.viewers.StructuredViewer;
import org.eclipse.swt.events.HelpEvent;
import org.eclipse.swt.events.HelpListener;
import org.eclipse.ui.IWorkbenchPart;

// Partly copied from JavaUIHelp
public class VisualiserHelp {

    public static void setHelp(StructuredViewer viewer, String contextId) {
        XRefUIHelpListener listener = new XRefUIHelpListener(viewer, contextId);
        viewer.getControl().addHelpListener(listener);
    }

    /**
     * Creates and returns a help context provider for the given part.
     * 
     * @param part the part for which to create the help context provider
     * @param contextId   the optional context ID used to retrieve static help
     * @return the help context provider 
     */
    public static IContextProvider getHelpContextProvider(IWorkbenchPart part, String contextId) {
        IStructuredSelection selection;
        try {
            selection = SelectionConverter.getStructuredSelection(part);
        } catch (JavaModelException ex) {
            selection = StructuredSelection.EMPTY;
        }
        Object[] elements = selection.toArray();
        return new XRefUIHelpContextProvider(contextId, elements);
    }

    private static class XRefUIHelpListener implements HelpListener {

        private StructuredViewer fViewer;
        private String fContextId;

        public XRefUIHelpListener(StructuredViewer viewer, String contextId) {
            fViewer = viewer;
            fContextId = contextId;
        }

        /*
         * @see HelpListener#helpRequested(HelpEvent)
         * 
         */
        public void helpRequested(HelpEvent e) {
            try {
                Object[] selected = null;
                ISelection selection = fViewer.getSelection();
                if (selection instanceof IStructuredSelection) {
                    selected = ((IStructuredSelection) selection).toArray();
                }
                JavadocHelpContext.displayHelp(fContextId, selected);
            } catch (CoreException x) {
            }
        }
    }

    private static class XRefUIHelpContextProvider implements IContextProvider {
        private String fId;
        private Object[] fSelected;

        public XRefUIHelpContextProvider(String id, Object[] selected) {
            fId = id;
            fSelected = selected;
        }

        public int getContextChangeMask() {
            return SELECTION;
        }

        public IContext getContext(Object target) {
            IContext context = HelpSystem.getContext(fId);
            if (fSelected != null && fSelected.length > 0) {
                try {
                    context = new JavadocHelpContext(context, fSelected);
                } catch (JavaModelException e) {
                }
            }
            return context;
        }

        public String getSearchExpression(Object target) {
            return null;
        }
    }
}