content: /*******************************************************************************
   * Copyright (c) 2000, 2009 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.text.ITextSelection;
  import org.eclipse.jface.viewers.IStructuredSelection;
  import org.eclipse.ui.IWorkbenchSite;
  import org.eclipse.ui.PlatformUI;
  import org.eclipse.wst.jsdt.core.IField;
  import org.eclipse.wst.jsdt.core.IFunction;
  import org.eclipse.wst.jsdt.core.IMember;
  import org.eclipse.wst.jsdt.core.ISourceRange;
  import org.eclipse.wst.jsdt.core.JavaScriptModelException;
  import org.eclipse.wst.jsdt.core.Signature;
  import org.eclipse.wst.jsdt.core.dom.PrimitiveType;
  import org.eclipse.wst.jsdt.internal.corext.refactoring.RefactoringAvailabilityTester;
  import org.eclipse.wst.jsdt.internal.corext.refactoring.RefactoringExecutionStarter;
  import org.eclipse.wst.jsdt.internal.corext.util.JavaModelUtil;
  import org.eclipse.wst.jsdt.internal.ui.IJavaHelpContextIds;
  import org.eclipse.wst.jsdt.internal.ui.JavaScriptPlugin;
  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.javaeditor.JavaTextSelection;
  import org.eclipse.wst.jsdt.internal.ui.refactoring.RefactoringMessages;
  import org.eclipse.wst.jsdt.internal.ui.util.ExceptionHandler;
  
  /**
   * Action to generalize the type of a local or field declaration or the
   * return type of a method declaration.
   * 
   * <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 ChangeTypeAction extends SelectionDispatchAction {
  	
  	private JavaEditor fEditor;
  
  	/**
  	 * Note: This constructor is for internal use only. Clients should not call
  	 * this constructor.
  	 * @param editor the JavaScript editor
  	 */
  	public ChangeTypeAction(JavaEditor editor) {
  		this(editor.getEditorSite());
  		fEditor= editor;
  		setEnabled(SelectionConverter.getInputAsCompilationUnit(fEditor) != null);
  	}
  
  	/**
  	 * Creates a new <code>ChangeTypeAction</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 ChangeTypeAction(IWorkbenchSite site) {
  		super(site);
  		setText(RefactoringMessages.ChangeTypeAction_label); 
  		setToolTipText(RefactoringMessages.ChangeTypeAction_tooltipText); 
  		setDescription(RefactoringMessages.ChangeTypeAction_description); 
  		PlatformUI.getWorkbench().getHelpSystem().setHelp(this, IJavaHelpContextIds.CHANGE_TYPE_ACTION);
  	}
  	
  	//---- structured selection ---------------------------------------------
  
  	public void selectionChanged(IStructuredSelection selection) {
  		try {
  			setEnabled(RefactoringAvailabilityTester.isGeneralizeTypeAvailable(selection));
  		} catch (JavaScriptModelException e) {
  			if (JavaModelUtil.isExceptionToBeLogged(e))
  				JavaScriptPlugin.log(e);
  			setEnabled(false);
  		}
  	}
  
  	public void run(IStructuredSelection selection) {
  		try {
  			IMember member= getMember(selection);
  			if (member == null || !ActionUtil.isEditable(getShell(), member))
  				return;
  			ISourceRange range= member.getNameRange();
  			RefactoringExecutionStarter.startChangeTypeRefactoring(member.getJavaScriptUnit(), getShell(), range.getOffset(), range.getLength());
  		} catch (CoreException e) {
  			ExceptionHandler.handle(e, RefactoringMessages.ChangeTypeAction_dialog_title, RefactoringMessages.ChangeTypeAction_exception); 
  		}
  	}
  
  	private static IMember getMember(IStructuredSelection selection) throws JavaScriptModelException {
  		if (selection.size() != 1)
  			return null;
  		
  		Object element= selection.getFirstElement();
  		if (!(element instanceof IMember))
  			return null;
  		
  		if (element instanceof IFunction) {
  			IFunction method= (IFunction)element;
  			String returnType= method.getReturnType();
  			if (PrimitiveType.toCode(Signature.toString(returnType)) != null)
  				return null;
  			return method;
  		} else if (element instanceof IField) {
  			return (IField)element;
  		}
  		return null;
  	}
  
  	//---- text selection ------------------------------------------------------------
  	
  	/*
  	 * (non-Javadoc) Method declared on SelectionDispatchAction
  	 */
  	public void selectionChanged(ITextSelection selection) {
  		setEnabled(true);
  	}
  
  	/**
  	 * Note: This method is for internal use only. Clients should not call this method.
  	 * @param selection the JavaScript text selection
  	 */
  	public void selectionChanged(JavaTextSelection selection) {
  		try {
  			setEnabled(RefactoringAvailabilityTester.isGeneralizeTypeAvailable(selection));
  		} catch (JavaScriptModelException e) {
  			setEnabled(false);
  		}
  	}
  
  	/*
  	 * (non-Javadoc) Method declared on SelectionDispatchAction
  	 */
  	public void run(ITextSelection selection) {
  		if (!ActionUtil.isEditable(fEditor))
  			return;
  		try {
  			RefactoringExecutionStarter.startChangeTypeRefactoring(SelectionConverter.getInputAsCompilationUnit(fEditor), getShell(), selection.getOffset(), selection.getLength());
  		} catch (CoreException e) {
  			ExceptionHandler.handle(e, RefactoringMessages.ChangeTypeAction_dialog_title, RefactoringMessages.ChangeTypeAction_exception); 
  		}
  	}
  }
  