/*******************************************************************************

 * Copyright (c) 2006 Oracle. 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:

 *     Oracle - initial API and implementation

 ******************************************************************************/

package org.eclipse.jdt.internal.ui.javaeditor;

import org.eclipse.jface.viewers.ISelection;

import org.eclipse.jface.viewers.IStructuredSelection;

import org.eclipse.jface.viewers.StructuredSelection;

import org.eclipse.jface.text.ITextSelection;

import org.eclipse.ui.IEditorPart;

import org.eclipse.ui.IWorkbenchPage;

import org.eclipse.ui.views.properties.tabbed.ISelectionConverter;

import org.eclipse.jdt.core.IJavaElement;

import org.eclipse.jdt.core.ISourceRange;

import org.eclipse.jdt.core.ISourceReference;

import org.eclipse.jdt.core.JavaModelException;

import org.eclipse.jdt.internal.ui.JavaPlugin;

import org.eclipse.jdt.internal.ui.actions.SelectionConverter;

/**

 * An  implementation of the tabbed properties ISelectionConverter for the JavaEditor. 

 * It takes an ISelection which from the JavaEditor will be an ITextSelection and converts

 * it into an IStructuredSelection containing an IJavaElement.

 * 

 * @since 3.3

 */

public class JavaEditorSelectionConverter implements ISelectionConverter {

	public IStructuredSelection structuredSelection(ISelection selection) {

		if (selection instanceof IStructuredSelection)

			return (IStructuredSelection) selection;

		if (!(selection instanceof ITextSelection))

			return StructuredSelection.EMPTY;

		ITextSelection textSelection= (ITextSelection)selection;

		IJavaElement javaElement= getJavaElementAt((textSelection));

		if (javaElement == null)

			return StructuredSelection.EMPTY;

		if (javaElement instanceof ISourceReference) {

			//make sure only one JavaElement is in the selection.  Compare its length

			//to the length of the selection.

			try {

				ISourceRange range= ((ISourceReference) javaElement).getSourceRange();

				if (range != null && textSelection.getLength() > range.getLength())

					return StructuredSelection.EMPTY;

			}

			catch (JavaModelException e) {

				JavaPlugin.log(e);

				return StructuredSelection.EMPTY;

			}

		}

		return new StructuredSelection(javaElement);

	}

	private IJavaElement getJavaElementAt(ITextSelection textSelection) {

		IEditorPart editor= getActiveEditor();

		if (editor instanceof JavaEditor) {

			IJavaElement je= ((JavaEditor)editor).getInputJavaElement();

			try {

				return SelectionConverter.getElementAtOffset(je, textSelection);

			} catch (JavaModelException e) {

				JavaPlugin.log(e);

				// Fall through

			}

		}

		return null;

	}

	private IEditorPart getActiveEditor() {

		IWorkbenchPage activePage= JavaPlugin.getActivePage();

		if (activePage == null)

			return null;

		return activePage.getActiveEditor();

	}

}