/*******************************************************************************
* Copyright (c) 2006, 2015 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.ui.internal.navigator.sorters;
import org.eclipse.core.expressions.EvaluationResult;
import org.eclipse.core.expressions.Expression;
import org.eclipse.core.expressions.IEvaluationContext;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.SafeRunner;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.jface.viewers.ViewerComparator;
import org.eclipse.jface.viewers.ViewerSorter;
import org.eclipse.ui.internal.navigator.CustomAndExpression;
import org.eclipse.ui.internal.navigator.NavigatorPlugin;
import org.eclipse.ui.internal.navigator.NavigatorSafeRunnable;
import org.eclipse.ui.internal.navigator.extensions.INavigatorContentExtPtConstants;
/**
*
* Describes a <b>commonSorter</b> element under a
* <b>org.eclipse.ui.navigator.navigatorContent</b> extension.
*
* @since 3.2
*/
public class CommonSorterDescriptor implements INavigatorContentExtPtConstants {
private IConfigurationElement element;
private Expression parentExpression;
private String id;
protected CommonSorterDescriptor(IConfigurationElement anElement) {
element = anElement;
init();
}
private void init() {
id = element.getAttribute(ATT_ID);
if (id == null) {
id = ""; //$NON-NLS-1$
}
IConfigurationElement[] children = element
.getChildren(TAG_PARENT_EXPRESSION);
if (children.length == 1) {
parentExpression = new CustomAndExpression(children[0]);
}
}
/**
*
* @return An identifier used to determine whether the sorter is visible.
* May not be unique.
*/
public String getId() {
return id;
}
/**
*
* @param aParent
* An element from the viewer
* @return True if and only if this CommonSorter can sort the children of
* the given parent.
*/
public boolean isEnabledForParent(Object aParent) {
if(aParent == null) {
return false;
}
if (parentExpression != null) {
IEvaluationContext context = NavigatorPlugin.getEvalContext(aParent);
return NavigatorPlugin.safeEvaluate(parentExpression, context) == EvaluationResult.TRUE;
}
return true;
}
/**
*
* @return An instance of the ViewerSorter defined by the extension. Callers
* of this method are responsible for managing the instantiated
* filter.
*/
public ViewerSorter createSorter() {
final ViewerSorter[] sorter = new ViewerSorter[1];
SafeRunner.run(new NavigatorSafeRunnable(element) {
@Override
public void run() throws Exception {
sorter[0] = createSorterInstance();
}
});
if (sorter[0] != null)
return sorter[0];
return SkeletonViewerSorter.INSTANCE;
}
private ViewerSorter createSorterInstance() throws CoreException {
Object contributed = element.createExecutableExtension(ATT_CLASS);
if (contributed instanceof ViewerSorter) {
return (ViewerSorter) contributed;
}
if (contributed instanceof ViewerComparator) {
return new WrappedViewerComparator((ViewerComparator) contributed);
}
throw new ClassCastException("Class contributed by " + element.getNamespaceIdentifier() + //$NON-NLS-1$
" to " + INavigatorContentExtPtConstants.TAG_NAVIGATOR_CONTENT + //$NON-NLS-1$
"/" + INavigatorContentExtPtConstants.TAG_COMMON_SORTER //$NON-NLS-1$
+ " is not an instance of " + ViewerComparator.class.getName() + ": " + contributed.getClass().getName() //$NON-NLS-1$ //$NON-NLS-2$
);
}
/**
* Public for tests only.
*/
public static class WrappedViewerComparator extends ViewerSorter {
private final ViewerComparator comparator;
public WrappedViewerComparator(ViewerComparator comparator) {
this.comparator = comparator;
}
@Override
public int category(Object element) {
return comparator.category(element);
}
@Override
public int compare(Viewer viewer, Object e1, Object e2) {
return comparator.compare(viewer, e1, e2);
}
@Override
public boolean isSorterProperty(Object element, String property) {
return comparator.isSorterProperty(element, property);
}
/**
* Public for tests only.
*
* @return Returns the original comparator instance wrapped by this
* instance.
*/
public ViewerComparator getWrappedComparator() {
return comparator;
}
}
@Override
public String toString() {
return "CommonSorterDescriptor[" + getId() + "]"; //$NON-NLS-1$//$NON-NLS-2$
}
}