org.eclipse.jdt.ui/ui/org/eclipse/jdt/ui/actions/ConvertNestedToTopAction.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.jdt.ui.actions;

import org.eclipse.jface.dialogs.MessageDialog;
import org.eclipse.jface.text.ITextSelection;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.jface.viewers.StructuredSelection;

import org.eclipse.ui.IWorkbenchSite;
import org.eclipse.ui.help.WorkbenchHelp;

import org.eclipse.jdt.core.ICompilationUnit;
import org.eclipse.jdt.core.IJavaElement;
import org.eclipse.jdt.core.IType;
import org.eclipse.jdt.core.JavaModelException;

import org.eclipse.jdt.internal.ui.IJavaHelpContextIds;
import org.eclipse.jdt.internal.ui.JavaPlugin;
import org.eclipse.jdt.internal.ui.actions.ActionUtil;
import org.eclipse.jdt.internal.ui.actions.SelectionConverter;
import org.eclipse.jdt.internal.ui.javaeditor.CompilationUnitEditor;
import org.eclipse.jdt.internal.ui.javaeditor.JavaTextSelection;
import org.eclipse.jdt.internal.ui.preferences.JavaPreferencesSettings;
import org.eclipse.jdt.internal.ui.refactoring.MoveInnerToTopWizard;
import org.eclipse.jdt.internal.ui.refactoring.RefactoringMessages;
import org.eclipse.jdt.internal.ui.refactoring.RefactoringWizard;
import org.eclipse.jdt.internal.ui.refactoring.actions.RefactoringStarter;
import org.eclipse.jdt.internal.ui.util.ExceptionHandler;

import org.eclipse.jdt.internal.corext.Assert;
import org.eclipse.jdt.internal.corext.refactoring.structure.MoveInnerToTopRefactoring;
import org.eclipse.jdt.internal.corext.refactoring.util.JavaElementUtil;
import org.eclipse.jdt.internal.corext.util.JavaModelUtil;

/**
 * Action to convert a nested class to a top level class.
 * 
 * <p>
 * This class may be instantiated; it is not intended to be subclassed.
 * </p>
 * 
 * @since 2.1
 */
public class ConvertNestedToTopAction extends SelectionDispatchAction {

	private CompilationUnitEditor fEditor;

	/**
	 * Note: This constructor is for internal use only. Clients should not call
	 * this constructor.
	 */
	public ConvertNestedToTopAction(CompilationUnitEditor editor) {
		this(editor.getEditorSite());
		fEditor= editor;
		setEnabled(SelectionConverter.canOperateOn(fEditor));
	}

	/**
	 * Creates a new <code>MoveInnerToTopAction</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 ConvertNestedToTopAction(IWorkbenchSite site) {
		super(site);
		setText(RefactoringMessages.getString("ConvertNestedToTopAction.Convert")); //$NON-NLS-1$
		WorkbenchHelp.setHelp(this, IJavaHelpContextIds.MOVE_INNER_TO_TOP_ACTION);
	}

	//---- Structured selection ------------------------------------------------

	/*
	 * @see SelectionDispatchAction#selectionChanged(IStructuredSelection)
	 */
	public void selectionChanged(IStructuredSelection selection) {
		try {
			setEnabled(canEnable(selection));
		} catch (JavaModelException e) {
			// http://bugs.eclipse.org/bugs/show_bug.cgi?id=19253
			if (JavaModelUtil.filterNotPresentException(e))
				JavaPlugin.log(e);
			setEnabled(false);//no ui
		}
	}

	/*
	 * @see SelectionDispatchAction#run(IStructuredSelection)
	 */
	public void run(IStructuredSelection selection) {
		try {
			//we have to call this here - no selection changed event is sent
			// after a refactoring but it may still invalidate enablement
			if (canEnable(selection))
				startRefactoring(getSingleSelectedType(selection));
		} catch (JavaModelException e) {
			ExceptionHandler.handle(e, 
				RefactoringMessages.getString("OpenRefactoringWizardAction.refactoring"), //$NON-NLS-1$ 
				RefactoringMessages.getString("OpenRefactoringWizardAction.exception")); //$NON-NLS-1$
		}
	}

	private static boolean canEnable(IStructuredSelection selection) throws JavaModelException {
		return canRunOn(getSingleSelectedType(selection));
	}

	private static IType getSingleSelectedType(IStructuredSelection selection) throws JavaModelException {
		if (selection.isEmpty() || selection.size() != 1)
			return null;

		Object first= selection.getFirstElement();
		if (first instanceof IType)
			return (IType)first;
		if (first instanceof ICompilationUnit)
			return JavaElementUtil.getMainType((ICompilationUnit)first);
		return null;
	}

	//---- Text Selection -------------------------------------------------------

	/*
	 * @see SelectionDispatchAction#selectionChanged(ITextSelection)
	 */
	public void selectionChanged(ITextSelection selection) {
		setEnabled(true);
	}
	
	/**
	 * Note: This method is for internal use only. Clients should not call this method.
	 */
	public void selectionChanged(JavaTextSelection selection) {
		try {
			setEnabled(canEnable(selection));
		} catch (JavaModelException e) {
			setEnabled(false);
		}
	}
	
	private boolean canEnable(JavaTextSelection selection) throws JavaModelException {
		IType type= getType(selection.resolveEnclosingElement());
		if (type == null)
			return false;
		return MoveInnerToTopRefactoring.isAvailable(type);
	}

	/*
	 * @see SelectionDispatchAction#run(ITextSelection)
	 */
	public void run(ITextSelection selection) {
		try {
			if (!ActionUtil.isProcessable(getShell(), fEditor))
				return;
			IType type= getType(SelectionConverter.resolveEnclosingElement(fEditor, selection));
			if (canRunOn(type)) {
				startRefactoring(type);
			} else {
				String unavailable= RefactoringMessages.getString("ConvertNestedToTopAction.To_activate"); //$NON-NLS-1$
				MessageDialog.openInformation(
					getShell(), 
					RefactoringMessages.getString("OpenRefactoringWizardAction.unavailable"), unavailable); //$NON-NLS-1$
			}
		} catch (JavaModelException e) {
			ExceptionHandler.handle(e, 
				RefactoringMessages.getString("OpenRefactoringWizardAction.refactoring"),//$NON-NLS-1$ 
				RefactoringMessages.getString("OpenRefactoringWizardAction.exception")); //$NON-NLS-1$
		}
	}

	private IType getType(IJavaElement element) {
		if (element == null)
			return null;
		if (! (element instanceof IType))
			element= element.getAncestor(IJavaElement.TYPE);
		return (IType)element;
	}

	//---- helpers ----------------------------------------------------------------------

	private static boolean canRunOn(IType type) throws JavaModelException {
		if (type == null)
			return false;
		return MoveInnerToTopRefactoring.isAvailable(type);
	}

	private static RefactoringWizard createWizard(MoveInnerToTopRefactoring refactoring) {
		return new MoveInnerToTopWizard(refactoring);
	}

	private static MoveInnerToTopRefactoring createRefactoring(IType type) throws JavaModelException {
		return MoveInnerToTopRefactoring.create(type, JavaPreferencesSettings.getCodeGenerationSettings());
	}

	private void startRefactoring(IType type) throws JavaModelException {
		MoveInnerToTopRefactoring refactoring= createRefactoring(type);
		Assert.isNotNull(refactoring);
		// Work around for http://dev.eclipse.org/bugs/show_bug.cgi?id=19104
		if (!ActionUtil.isProcessable(getShell(), refactoring.getInputType()))
			return;
		Object newElementToProcess= new RefactoringStarter().activate(refactoring, createWizard(refactoring), getShell(),
			RefactoringMessages.getString("OpenRefactoringWizardAction.refactoring"), true); //$NON-NLS-1$
		if (newElementToProcess == null)
			return;
		IStructuredSelection mockSelection= new StructuredSelection(newElementToProcess);
		selectionChanged(mockSelection);
		if (isEnabled())
			run(mockSelection);
		else
			MessageDialog.openInformation(getShell(), RefactoringMessages.getString("ConvertNestedToTopAction.Refactoring"), //$NON-NLS-1$ 
				RefactoringMessages.getString("ConvertNestedToTopAction.not_possible"));  //$NON-NLS-1$
	}
}