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 java.util.Arrays;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.Set;
  
  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.IJavaScriptElement;
  import org.eclipse.wst.jsdt.core.IMember;
  import org.eclipse.wst.jsdt.core.IType;
  import org.eclipse.wst.jsdt.core.JavaScriptModelException;
  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 push down methods and fields into subclasses.
   * <p>
   * Action is applicable to selections containing elements of type
   * <code>IField</code> and <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 PushDownAction extends SelectionDispatchAction {
  
  	private static IMember[] getSelectedMembers(IStructuredSelection selection) {
  		if (selection.isEmpty())
  			return null;
  		if (selection.size() == 1) {
  			try {
  				final IType type= RefactoringAvailabilityTester.getSingleSelectedType(selection);
  				if (type != null)
  					return new IType[] { type};
  			} catch (JavaScriptModelException exception) {
  				JavaScriptPlugin.log(exception);
  			}
  		}
  		for (Iterator iter= selection.iterator(); iter.hasNext();) {
  			if (!(iter.next() instanceof IMember))
  				return null;
  		}
  		Set memberSet= new HashSet();
  		memberSet.addAll(Arrays.asList(selection.toArray()));
  		return (IMember[]) memberSet.toArray(new IMember[memberSet.size()]);
  	}
  
  	private JavaEditor fEditor;
  
  	/**
  	 * Note: This constructor is for internal use only. Clients should not call
  	 * this constructor.
  	 * 
  	 * @param editor the JavaScript editor
  	 */
  	public PushDownAction(JavaEditor editor) {
  		this(editor.getEditorSite());
  		fEditor= editor;
  		setEnabled(SelectionConverter.canOperateOn(fEditor));
  	}
  
  	/**
  	 * Creates a new <code>PushDownAction</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 PushDownAction(IWorkbenchSite site) {
  		super(site);
  		setText(RefactoringMessages.PushDownAction_Push_Down);
  		PlatformUI.getWorkbench().getHelpSystem().setHelp(this, IJavaHelpContextIds.PUSH_DOWN_ACTION);
  	}
  
  	private IMember getSelectedMemberFromEditor() throws JavaScriptModelException {
  		IJavaScriptElement element= SelectionConverter.resolveEnclosingElement(fEditor, (ITextSelection) fEditor.getSelectionProvider().getSelection());
  		if (element == null || !(element instanceof IMember))
  			return null;
  		return (IMember) element;
  	}
  
  	/**
  	 * {@inheritDoc}
  	 */
  	public void run(IStructuredSelection selection) {
  		try {
  			IMember[] members= getSelectedMembers(selection);
  			if (RefactoringAvailabilityTester.isPushDownAvailable(members) && ActionUtil.isEditable(getShell(), members[0]))
  				RefactoringExecutionStarter.startPushDownRefactoring(members, getShell());
  		} catch (JavaScriptModelException e) {
  			ExceptionHandler.handle(e, RefactoringMessages.OpenRefactoringWizardAction_refactoring, RefactoringMessages.OpenRefactoringWizardAction_exception);
  		}
  	}
  
  	/**
  	 * {@inheritDoc}
  	 */
  	public void run(ITextSelection selection) {
  		try {
  			if (!ActionUtil.isEditable(fEditor))
  				return;
  			IMember member= getSelectedMemberFromEditor();
  			IMember[] array= new IMember[] { member};
  			if (member != null && RefactoringAvailabilityTester.isPushDownAvailable(array)) {
  				RefactoringExecutionStarter.startPushDownRefactoring(array, getShell());
  			} else {
  				MessageDialog.openInformation(getShell(), RefactoringMessages.OpenRefactoringWizardAction_unavailable, RefactoringMessages.PushDownAction_To_activate);
  			}
  		} catch (JavaScriptModelException e) {
  			ExceptionHandler.handle(e, RefactoringMessages.OpenRefactoringWizardAction_refactoring, RefactoringMessages.OpenRefactoringWizardAction_exception);
  		}
  	}
  
  	/**
  	 * {@inheritDoc}
  	 */
  	public void selectionChanged(IStructuredSelection selection) {
  		try {
  			setEnabled(RefactoringAvailabilityTester.isPushDownAvailable(selection));
  		} catch (JavaScriptModelException e) {
  			// http://bugs.eclipse.org/bugs/show_bug.cgi?id=19253
  			if (JavaModelUtil.isExceptionToBeLogged(e))
  				JavaScriptPlugin.log(e);
  			setEnabled(false);// no UI
  		}
  	}
  
  	/**
  	 * {@inheritDoc}
  	 */
  	public void selectionChanged(ITextSelection selection) {
  		setEnabled(true);
  	}
  
  	/**
  	 * Note: This method is for internal use only. Clients should not call this
  	 * method.
  	 * 
  	 * @param selection
  	 */
  	public void selectionChanged(JavaTextSelection selection) {
  		try {
  			setEnabled(RefactoringAvailabilityTester.isPushDownAvailable(selection));
  		} catch (JavaScriptModelException e) {
  			setEnabled(false);
  		}
  	}
  }
  