net.hillsdon.testlink.model.impl.JavaSelection.java Source code

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Here is the source code for net.hillsdon.testlink.model.impl.JavaSelection.java

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/*******************************************************************************
 * Copyright (c) 2008 Matthew Hillsdon.
 * 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:
 *     Matthew Hillsdon <matt@hillsdon.net>
 *******************************************************************************/
package net.hillsdon.testlink.model.impl;

import net.hillsdon.testlink.model.IJavaSelection;

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.actions.SelectionConverter;
import org.eclipse.jdt.internal.ui.javaeditor.JavaEditor;
import org.eclipse.jface.text.ITextSelection;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.ui.IEditorPart;
import org.eclipse.ui.PlatformUI;

@SuppressWarnings("restriction")
public class JavaSelection implements IJavaSelection {

    /**
     * May be null.
     */
    private ISelection _workbenchSelection;

    public void selectionChanged(final ISelection selection) {
        _workbenchSelection = selection;
    }

    /**
     * Using the current workbench selection determine the
     * Java model component that is selected, if any.
     *
     * @return The model component, or null.
     * @throws JavaModelException If an error occurs reading the java model.
     */
    private IJavaElement getSelectedJavaElement() throws JavaModelException {
        // We have an editor
        if (_workbenchSelection instanceof ITextSelection) {
            // Would be nice if there was a better way to do this.  Interestingly
            // the text selections from JavaEditors aren't JavaTextSelections.
            // Seems better to re-use this code rather than copy and paste.
            IEditorPart editor = PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage()
                    .getActiveEditor();
            if (editor instanceof JavaEditor) {
                return SelectionConverter.getElementAtOffset((JavaEditor) editor);
            }
        }
        // Selection in e.g. package explorer
        else if (_workbenchSelection instanceof IStructuredSelection) {
            Object element = ((IStructuredSelection) _workbenchSelection).getFirstElement();
            if (element instanceof IJavaElement) {
                return (IJavaElement) element;
            }
        }
        return null;
    }

    /**
     * Find the type best associated with the java element.
     *
     * @param javaElement A java element.
     * @return A type, or null if we can't figure one out.
     * @throws JavaModelException If we fail to read from the java model.
     */
    public IType getSelectedType() throws JavaModelException {
        final IJavaElement javaElement = getSelectedJavaElement();
        IType type = null;
        if (javaElement != null) {
            type = getOutermostType(javaElement);
            if (type == null) {
                ICompilationUnit cu = (ICompilationUnit) javaElement.getAncestor(IJavaElement.COMPILATION_UNIT);
                if (cu != null) {
                    IType[] types = cu.getTypes();
                    if (types.length > 0) {
                        type = types[0];
                    }
                }
            }
        }
        return type;
    }

    /**
     * We bias towards the outermost type for two reasons:
     *   1) It won't be anonymous
     *   2) If you're going to test it it probably deserves its own file and test class...
     *   
     * @param javaElement Any java element.
     * @return
     */
    private IType getOutermostType(final IJavaElement javaElement) {
        IJavaElement outermost = javaElement;
        while (true) {
            IType better = (IType) outermost.getParent().getAncestor(IJavaElement.TYPE);
            if (better == null || better.equals(outermost)) {
                break;
            }
            outermost = better;
        }
        return outermost instanceof IType ? (IType) outermost : null;
    }

}