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

/*******************************************************************************
 * Copyright (c) 2000, 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/

package org.eclipse.ui.internal;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.widgets.*;

import org.eclipse.jface.action.IAction;
import org.eclipse.jface.action.IMenuCreator;
import org.eclipse.jface.viewers.ISelection;

import org.eclipse.ui.*;

/**
 * The <code>NavigationHistoryAction</code> moves navigation history 
 * back and forward.
 */
public class NavigationHistoryAction extends PageEventAction implements IWorkbenchWindowPulldownDelegate2, IMenuCreator {
	private boolean forward;
	private Menu historyMenu;
	private int MAX_HISTORY_LENGTH = 9;
	
	/**
	 * Create a new instance of <code>NavigationHistoryAction</code>
	 * 
	 * @param window the workbench window this action applies to
	 * @param forward if this action should move history forward of backward
	 */
	public NavigationHistoryAction(IWorkbenchWindow window,boolean forward) {
		super("",window); //$NON-NLS-1$
		if(forward) {
			setText(WorkbenchMessages.getString("NavigationHistoryAction.forward.text")); //$NON-NLS-1$
			setToolTipText(WorkbenchMessages.getString("NavigationHistoryAction.forward.toolTip")); //$NON-NLS-1$
		} else {
			setText(WorkbenchMessages.getString("NavigationHistoryAction.backward.text")); //$NON-NLS-1$
			setToolTipText(WorkbenchMessages.getString("NavigationHistoryAction.backward.toolTip")); //$NON-NLS-1$
		}
		// WorkbenchHelp.setHelp(this, IHelpContextIds.CLOSE_ALL_PAGES_ACTION);
		setEnabled(false);
		this.forward = forward;
		setMenuCreator(this);
	}
	/* (non-Javadoc)
	 * Method declared on PageEventAction.
	 */		
	public void pageClosed(IWorkbenchPage page) {
		super.pageClosed(page);
		setEnabled(false);
	}
	public void dispose() {
		if (historyMenu != null) {
			for (int i=0; i<historyMenu.getItemCount(); i++) {
				MenuItem menuItem = historyMenu.getItem(i);
				menuItem.setData(null);
			}
			historyMenu.dispose();
			historyMenu = null;
		}
	}
	public Menu getMenu(Menu parent) {
		return null;
	}
	public Menu getMenu(Control parent) {
		dispose();
		historyMenu = new Menu(parent);
		IWorkbenchPage page = getWorkbenchWindow().getActivePage();
		if(page == null)
			return historyMenu;

		final NavigationHistory history = (NavigationHistory)getWorkbenchWindow().getActivePage().getNavigationHistory();
		NavigationHistoryEntry[] entries;
		if (forward) entries = history.getForwardEntries();
		else entries = history.getBackwardEntries();
		int entriesCount[] = new int[entries.length];
		for (int i = 0; i < entriesCount.length; i++)
			entriesCount[i] = 1;
		entries = colapseEntries(entries,entriesCount);
		for (int i=0; i<entries.length; i++) {
			if (i > MAX_HISTORY_LENGTH) break;
			String text = entries[i].getHistoryText();
			if (text != null) {
				MenuItem item = new MenuItem(historyMenu, SWT.NONE);
				item.setData(entries[i]);
				if(entriesCount[i] > 1)
					text = WorkbenchMessages.format("NavigationHistoryAction.locations", new String[] {text,new Integer(entriesCount[i]).toString()}); //$NON-NLS-1$
				item.setText(text);
				item.addSelectionListener(new SelectionAdapter() {
					public void widgetSelected(SelectionEvent e) {
						history.shiftCurrentEntry((NavigationHistoryEntry)e.widget.getData());
					}
				});
			}
		}
		return historyMenu;
	}
	
	private NavigationHistoryEntry[] colapseEntries(NavigationHistoryEntry[] entries,int entriesCount[]) {
		ArrayList allEntries = new ArrayList(Arrays.asList(entries));
		NavigationHistoryEntry priviousEntry = null;
		int i = -1;
		for (Iterator iter = allEntries.iterator(); iter.hasNext();) {
			NavigationHistoryEntry entry = (NavigationHistoryEntry) iter.next();
			if(priviousEntry != null) {
				String text = priviousEntry.getHistoryText();
				if(text != null) {
					if(text.equals(entry.getHistoryText()) && priviousEntry.editorInfo == entry.editorInfo) {
						iter.remove();
						entriesCount[i]++;
						continue;
					}
				}
			}
			priviousEntry = entry;
			i++;
		}
		entries = new NavigationHistoryEntry[allEntries.size()];
		return (NavigationHistoryEntry[])allEntries.toArray(entries);
	}
	
	public void init(IWorkbenchWindow window){
	}
	/* (non-Javadoc)
	 * Method declared on PageEventAction.
	 */	
	public void pageActivated(IWorkbenchPage page) {
		super.pageActivated(page);
		NavigationHistory nh = (NavigationHistory)page.getNavigationHistory();
		if(forward)
			nh.setForwardAction(this);
		else
			nh.setBackwardAction(this);
	}
	/* (non-Javadoc)
	 * Method declared on IAction.
	 */
	public void run() {
		WorkbenchPage page = (WorkbenchPage)getActivePage();
		if (page != null) {
			NavigationHistory nh = (NavigationHistory)page.getNavigationHistory();
			if(forward)
				nh.forward();
			else
				nh.backward();
		}
	}
	public void run(IAction action) {
	}
	public void selectionChanged(IAction action, ISelection selection) {
	}
	public void update() {
		// Set the enabled state of the action and set the tool tip text.  The tool tip
		// text is set to reflect the item that one will move back/forward to.
		WorkbenchPage page = (WorkbenchPage)getActivePage();
		if (page == null) return;
		NavigationHistory history = (NavigationHistory)page.getNavigationHistory();
		NavigationHistoryEntry[] entries;
		if (forward) {
			setEnabled(history.canForward());
			entries = history.getForwardEntries();
			if (entries.length > 0) {
				NavigationHistoryEntry entry = entries[0];
				String text = WorkbenchMessages.format("NavigationHistoryAction.forward.toolTipName", new String[] {entry.getHistoryText()}); //$NON-NLS-1$
				setToolTipText(text);
			} else {
				setToolTipText(WorkbenchMessages.getString("NavigationHistoryAction.forward.toolTip")); //$NON-NLS-1$
			}
		}
		else {
			setEnabled(history.canBackward());
			entries = history.getBackwardEntries();
			if (entries.length > 0) {
				NavigationHistoryEntry entry = entries[0];
				String text = WorkbenchMessages.format("NavigationHistoryAction.backward.toolTipName", new String[] {entry.getHistoryText()}); //$NON-NLS-1$
				setToolTipText(text);
			} else {
				setToolTipText(WorkbenchMessages.getString("NavigationHistoryAction.backward.toolTip")); //$NON-NLS-1$
			}
		}
	}	
}