org.eclipse.jdt.debug.ui/ui/org/eclipse/jdt/internal/debug/ui/actions/ActionDelegateHelper.java

package org.eclipse.jdt.internal.debug.ui.actions;

/**********************************************************************
Copyright (c) 2002 IBM Corp.  All rights reserved.
This file is 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
**********************************************************************/

import org.eclipse.jdt.core.IClassFile;
import org.eclipse.jdt.core.ICompilationUnit;
import org.eclipse.jdt.core.IJavaElement;
import org.eclipse.jdt.core.IJavaProject;
import org.eclipse.jdt.core.IMember;
import org.eclipse.jdt.core.JavaModelException;
import org.eclipse.jdt.internal.debug.ui.JDIDebugUIPlugin;
import org.eclipse.jdt.internal.debug.ui.snippeteditor.JavaSnippetEditor;
import org.eclipse.jdt.ui.IWorkingCopyManager;
import org.eclipse.jdt.ui.JavaUI;
import org.eclipse.jface.text.ITextSelection;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.ISelectionProvider;
import org.eclipse.ui.IEditorInput;
import org.eclipse.ui.IEditorPart;
import org.eclipse.ui.IPartListener;
import org.eclipse.ui.IWindowListener;
import org.eclipse.ui.IWorkbenchPage;
import org.eclipse.ui.IWorkbenchPart;
import org.eclipse.ui.IWorkbenchWindow;
import org.eclipse.ui.texteditor.ITextEditor;

public class ActionDelegateHelper implements IPartListener, IWindowListener {

	private static ActionDelegateHelper fgDefault;
	private IMember fMember= null;
	private ITextEditor fTextEditor= null;
	private ISelection fCurrentSelection= null;
	private IWorkbenchWindow fCurrentWindow= null;
	
	public static ActionDelegateHelper getDefault() {
		if (fgDefault == null) {
			fgDefault= new ActionDelegateHelper();
		} 
		return fgDefault;
	}
	
	private ActionDelegateHelper() {
		fCurrentWindow= JDIDebugUIPlugin.getActiveWorkbenchWindow();
		if (fCurrentWindow != null) {
			fCurrentWindow.getWorkbench().addWindowListener(this);
			fCurrentWindow.getPartService().addPartListener(this);
			IWorkbenchPage page= fCurrentWindow.getActivePage();
			if (page != null) {
				IEditorPart part= page.getActiveEditor();
				checkToSetTextEditor(part);
			}
		}
	}
	
	/**
	 * @see IPartListener#partActivated(IWorkbenchPart)
	 */
	public void partActivated(IWorkbenchPart part) {
		checkToSetTextEditor(part);
	}

	/**
	 * @see IPartListener#partBroughtToTop(IWorkbenchPart)
	 */
	public void partBroughtToTop(IWorkbenchPart part) {
	}

	/**
	 * @see IPartListener#partClosed(IWorkbenchPart)
	 */
	public void partClosed(IWorkbenchPart part) {
		if (part == getTextEditor()) {
			cleanup();
		}
	}

	/**
	 * @see IPartListener#partDeactivated(IWorkbenchPart)
	 */
	public void partDeactivated(IWorkbenchPart part) {		
	}

	/**
	 * @see IPartListener#partOpened(IWorkbenchPart)
	 */
	public void partOpened(IWorkbenchPart part) {
	}

	protected IMember getMember() {
		return fMember;
	}

	protected void setMember(IMember member) {
		fMember = member;
	}
	
	protected void checkToSetTextEditor(IWorkbenchPart part) {
		if (part instanceof ITextEditor) {
			if (part instanceof JavaSnippetEditor) {
				cleanup();
			} else {
				setTextEditor((ITextEditor)part);
			}	
		} 
	}
	
	public IMember getCurrentMember(ISelection currentSelection) {
		if (currentSelection == getCurrentSelection()) {
			return getMember();
		}
		setCurrentSelection(currentSelection);
		ITextEditor editor= getTextEditor();
		if (editor == null) {
			return null;
		}
		IEditorInput editorInput= editor.getEditorInput();
		ISelectionProvider sp= editor.getSelectionProvider();
		if (sp == null) {
			return null;
		}
		ITextSelection selection= (ITextSelection)sp.getSelection();
		IMember m= null;
		try {
			IClassFile classFile= (IClassFile)editorInput.getAdapter(IClassFile.class);
			if (classFile != null) {
				IJavaElement e= classFile.getElementAt(selection.getOffset());
				if (e instanceof IMember) {
					m= (IMember)e;
				}
			} else {
				IWorkingCopyManager manager= JavaUI.getWorkingCopyManager();
				ICompilationUnit unit= manager.getWorkingCopy(editorInput);
				if (unit != null) {
					synchronized (unit) {
						unit.reconcile();
					}
					IJavaElement e = unit.getElementAt(selection.getOffset());
					if (e instanceof IMember) {
						m= (IMember)e;
					}
				}
			}

			if (m != null) {
				IJavaProject project= m.getJavaProject();
				if (!m.exists() || (project == null || !project.isOnClasspath(m))) {
					m= null;
				}
			}
		} catch (JavaModelException jme) {
			JDIDebugUIPlugin.log(jme);
		}
		
		setMember(m);
		return m;
	}
	
	protected ITextEditor getTextEditor() {
		return fTextEditor;
	}

	protected void setTextEditor(ITextEditor textEditor) {
		fTextEditor = textEditor;
	}
	
	protected ISelection getCurrentSelection() {
		return fCurrentSelection;
	}

	protected void setCurrentSelection(ISelection currentSelection) {
		fCurrentSelection = currentSelection;
	}
	
	/**
	 * @see IWindowListener#windowActivated(IWorkbenchWindow)
	 */
	public void windowActivated(IWorkbenchWindow window) {
		if (fCurrentWindow != null) {
			fCurrentWindow.getPartService().removePartListener(this);
			cleanup();
		}
		fCurrentWindow= window;
		fCurrentWindow.getPartService().addPartListener(this);
		IWorkbenchPage page= window.getActivePage();
		if (page != null) {
			checkToSetTextEditor(page.getActiveEditor());
		}
	}

	/**
	 * @see IWindowListener#windowClosed(IWorkbenchWindow)
	 */
	public void windowClosed(IWorkbenchWindow window) {
		if (fCurrentWindow == window) {
			fCurrentWindow= null;
			cleanup();
		}
	}

	/**
	 * @see IWindowListener#windowDeactivated(IWorkbenchWindow)
	 */
	public void windowDeactivated(IWorkbenchWindow window) {
	}

	/**
	 * @see IWindowListener#windowOpened(IWorkbenchWindow)
	 */
	public void windowOpened(IWorkbenchWindow window) {
	}
	
	protected void cleanup() {
		setTextEditor(null);
		setCurrentSelection(null);
		setMember(null);
	}
}