content: /*******************************************************************************
   * Copyright (c) 2000, 2008 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.wst.jsdt.ui.actions;
  
  import org.eclipse.core.runtime.CoreException;
  import org.eclipse.jface.dialogs.MessageDialog;
  import org.eclipse.jface.text.ITextSelection;
  import org.eclipse.jface.viewers.IStructuredSelection;
  import org.eclipse.ui.IWorkbenchSite;
  import org.eclipse.ui.PlatformUI;
  import org.eclipse.wst.jsdt.core.Flags;
  import org.eclipse.wst.jsdt.core.IFunction;
  import org.eclipse.wst.jsdt.core.IJavaScriptElement;
  import org.eclipse.wst.jsdt.core.IType;
  import org.eclipse.wst.jsdt.core.JavaScriptModelException;
  import org.eclipse.wst.jsdt.internal.corext.util.Messages;
  import org.eclipse.wst.jsdt.internal.corext.util.MethodOverrideTester;
  import org.eclipse.wst.jsdt.internal.corext.util.SuperTypeHierarchyCache;
  import org.eclipse.wst.jsdt.internal.ui.IJavaHelpContextIds;
  import org.eclipse.wst.jsdt.internal.ui.JavaScriptPlugin;
  import org.eclipse.wst.jsdt.internal.ui.actions.ActionMessages;
  import org.eclipse.wst.jsdt.internal.ui.actions.ActionUtil;
  import org.eclipse.wst.jsdt.internal.ui.actions.SelectionConverter;
  import org.eclipse.wst.jsdt.internal.ui.javaeditor.JavaEditor;
  import org.eclipse.wst.jsdt.internal.ui.util.ExceptionHandler;
  import org.eclipse.wst.jsdt.ui.JavaScriptUI;
  
  /**
   * The action opens a JavaScript editor on the selected method's super implementation.
   * <p>
   * The action is applicable to selections containing elements of type <code>
   * IFunction</code>.
   * 
   * <p>
   * This class may be instantiated; it is not intended to be subclassed.
   * </p>
   * 
   *
   * Provisional API: This class/interface is part of an interim API that is still under development and expected to
   * change significantly before reaching stability. It is being made available at this early stage to solicit feedback
   * from pioneering adopters on the understanding that any code that uses this API will almost certainly be broken
   * (repeatedly) as the API evolves.
   */
  public class OpenSuperImplementationAction extends SelectionDispatchAction {
  
  	private JavaEditor fEditor;
  
  	/**
  	 * Creates a new <code>OpenSuperImplementationAction</code>. The action requires
  	 * that the selection provided by the site's selection provider is of type <code>
  	 * org.eclipse.jface.viewers.IStructuredSelection</code>.
  	 * 
  	 * @param site the site providing context information for this action
  	 */
  	public OpenSuperImplementationAction(IWorkbenchSite site) {
  		super(site);
  		setText(ActionMessages.OpenSuperImplementationAction_label); 
  		setDescription(ActionMessages.OpenSuperImplementationAction_description); 
  		setToolTipText(ActionMessages.OpenSuperImplementationAction_tooltip); 
  		PlatformUI.getWorkbench().getHelpSystem().setHelp(this, IJavaHelpContextIds.OPEN_SUPER_IMPLEMENTATION_ACTION);
  	}
  	
      
  
  	
  	/**
  	 * Note: This constructor is for internal use only. Clients should not call this constructor.
  	 * @param editor the JavaScript editor
  	 */
  	public OpenSuperImplementationAction(JavaEditor editor) {
  		this(editor.getEditorSite());
  		fEditor= editor;
  		setEnabled(SelectionConverter.canOperateOn(fEditor));
  	}
  	
  	/* (non-Javadoc)
  	 * Method declared on SelectionDispatchAction.
  	 */
  	public void selectionChanged(ITextSelection selection) {
  	}
  
  	/* (non-Javadoc)
  	 * Method declared on SelectionDispatchAction.
  	 */
  	public void selectionChanged(IStructuredSelection selection) {
  		IFunction method= getMethod(selection);
  		
  		setEnabled(method != null && checkMethod(method));
  	}
  	
  	/* (non-Javadoc)
  	 * Method declared on SelectionDispatchAction.
  	 */
  	public void run(ITextSelection selection) {
  		if (!ActionUtil.isProcessable(fEditor))
  			return;
  		IJavaScriptElement element= elementAtOffset();
  		if (element == null || !(element instanceof IFunction)) {
  			MessageDialog.openInformation(getShell(), getDialogTitle(), ActionMessages.OpenSuperImplementationAction_not_applicable); 
  			return;
  		}
  		run((IFunction) element);
  	}
  	
  	/* (non-Javadoc)
  	 * Method declared on SelectionDispatchAction.
  	 */
  	public void run(IStructuredSelection selection) {
  		run(getMethod(selection));
  	}
  	
  	/*
  	 * No Javadoc since the method isn't meant to be public but is
  	 * since the beginning
  	 */
  	public void run(IFunction method) {
  		if (method == null)
  			return;		
  		if (!ActionUtil.isProcessable(getShell(), method))
  			return;
  		
  		if (!checkMethod(method)) {
  			MessageDialog.openInformation(getShell(), getDialogTitle(), 
  				Messages.format(ActionMessages.OpenSuperImplementationAction_no_super_implementation, method.getElementName())); 
  			return;
  		}		
  
  		try {
  			IFunction impl= findSuperImplementation(method);
  			if (impl != null) {
  				JavaScriptUI.openInEditor(impl, true, true);
  			}
  		} catch (CoreException e) {
  			ExceptionHandler.handle(e, getDialogTitle(), ActionMessages.OpenSuperImplementationAction_error_message);
  		}
  	}
  	
  	private IFunction findSuperImplementation(IFunction method) throws JavaScriptModelException {
  		MethodOverrideTester tester= SuperTypeHierarchyCache.getMethodOverrideTester(method.getDeclaringType());
  		return tester.findOverriddenMethod(method, false);
  	}
  	
  	
  	private IFunction getMethod(IStructuredSelection selection) {
  		if (selection.size() != 1)
  			return null;
  		Object element= selection.getFirstElement();
  		if (element instanceof IFunction) {
  			return (IFunction) element;
  		}
  		return null;
  	}
  	
  	private boolean checkMethod(IFunction method) {
  		try {
  			int flags= method.getFlags();
  			if (!Flags.isStatic(flags) && !Flags.isPrivate(flags)) {
  				IType declaringType= method.getDeclaringType();
  				if (declaringType==null)
  					return false;
  				if (SuperTypeHierarchyCache.hasInCache(declaringType)) {
  					if (findSuperImplementation(method) == null) {
  						return false;
  					}
  				}
  				return true;
  			}
  		} catch (JavaScriptModelException e) {
  			if (!e.isDoesNotExist()) {
  				JavaScriptPlugin.log(e);
  			}
  		}
  		return false;
  	}
  	
  	private IJavaScriptElement elementAtOffset() {
  		try {
  			return SelectionConverter.getElementAtOffset(fEditor);
  		} catch(JavaScriptModelException e) {
  		}
  		return null;
  	}
  	
  	private static String getDialogTitle() {
  		return ActionMessages.OpenSuperImplementationAction_error_title; 
  	}		
  }
  