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Java > Open Source Codes > org > eclipse > ui > internal > navigator > filters > CoreExpressionFilter


1 /*******************************************************************************
2  * Copyright (c) 2006 IBM Corporation and others.
3  * All rights reserved. This program and the accompanying materials
4  * are made available under the terms of the Eclipse Public License v1.0
5  * which accompanies this distribution, and is available at
6  * http://www.eclipse.org/legal/epl-v10.html
7  *
8  * Contributors:
9  * IBM Corporation - initial API and implementation
10  ******************************************************************************/
11
12 package org.eclipse.ui.internal.navigator.filters;
13
14 import org.eclipse.core.expressions.EvaluationContext;
15 import org.eclipse.core.expressions.EvaluationResult;
16 import org.eclipse.core.expressions.Expression;
17 import org.eclipse.core.runtime.CoreException;
18 import org.eclipse.jface.viewers.Viewer;
19 import org.eclipse.jface.viewers.ViewerFilter;
20 import org.eclipse.ui.internal.navigator.NavigatorPlugin;
21
22 /**
23  * @since 3.2
24  *
25  */
26 public class CoreExpressionFilter extends ViewerFilter {
27
28     private Expression filterExpression;
29
30     /**
31      * Creates a filter which hides all elements that match the given
32      * expression.
33      *
34      * @param aFilterExpression
35      * An expression to hide elements in the viewer.
36      */
37     public CoreExpressionFilter(Expression aFilterExpression) {
38         filterExpression = aFilterExpression;
39     }
40
41     /*
42      * (non-Javadoc)
43      *
44      * @see org.eclipse.jface.viewers.ViewerFilter#select(org.eclipse.jface.viewers.Viewer,
45      * java.lang.Object, java.lang.Object)
46      */
47     public boolean select(Viewer viewer, Object JavaDoc parentElement, Object JavaDoc element) {
48
49         try {
50             return (filterExpression.evaluate(new EvaluationContext(null,
51                     element)) != EvaluationResult.TRUE);
52         } catch (CoreException e) {
53             NavigatorPlugin.logError(0, e.getMessage(), e);
54         }
55         return true;
56     }
57
58 }
59
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