1 /*******************************************************************************
2  * Copyright (c) 2000, 2008 IBM Corporation and others.
3  *
4  * This program and the accompanying materials
5  * are made available under the terms of the Eclipse Public License 2.0
6  * which accompanies this distribution, and is available at
7  * https://www.eclipse.org/legal/epl-2.0/
8  *
9  * SPDX-License-Identifier: EPL-2.0
10  *
11  * Contributors:
12  *     IBM Corporation - initial API and implementation
13  *******************************************************************************/
14 package org.eclipse.core.internal.expressions;
15 
16 import org.eclipse.core.expressions.IEvaluationContext;
17 
18 import org.eclipse.core.runtime.Assert;
19 import org.eclipse.core.runtime.CoreException;
20 
21 /**
22  * An evaluation context that can be used to add a new default variable
23  * to a hierarchy of evaluation contexts.
24  *
25  * @since 3.0
26  */
27 public final class DefaultVariable implements IEvaluationContext {
28 
29 	private Object fDefaultVariable;
30 	private IEvaluationContext fParent;
31 	private IEvaluationContext fManagedPool;
32 
33 	/**
34 	 * Constructs a new variable pool for a single default variable.
35 	 *
36 	 * @param parent the parent context for the default variable. Must not
37 	 *  be <code>null</code>.
38 	 * @param defaultVariable the default variable
39 	 */
DefaultVariable(IEvaluationContext parent, Object defaultVariable)40 	public DefaultVariable(IEvaluationContext parent, Object defaultVariable) {
41 		Assert.isNotNull(parent);
42 		Assert.isNotNull(defaultVariable);
43 		fParent= parent;
44 		while (parent instanceof DefaultVariable) {
45 			parent= parent.getParent();
46 		}
47 		fManagedPool= parent;
48 		fDefaultVariable= defaultVariable;
49 	}
50 
51 	@Override
getParent()52 	public IEvaluationContext getParent() {
53 		return fParent;
54 	}
55 
56 	@Override
getRoot()57 	public IEvaluationContext getRoot() {
58 		return fParent.getRoot();
59 	}
60 
61 	@Override
getDefaultVariable()62 	public Object getDefaultVariable() {
63 		return fDefaultVariable;
64 	}
65 
66 	@Override
setAllowPluginActivation(boolean value)67 	public void setAllowPluginActivation(boolean value) {
68 		fParent.setAllowPluginActivation(value);
69 	}
70 
71 	@Override
getAllowPluginActivation()72 	public boolean getAllowPluginActivation() {
73 		return fParent.getAllowPluginActivation();
74 	}
75 
76 	@Override
addVariable(String name, Object value)77 	public void addVariable(String name, Object value) {
78 		fManagedPool.addVariable(name, value);
79 	}
80 
81 	@Override
removeVariable(String name)82 	public Object removeVariable(String name) {
83 		return fManagedPool.removeVariable(name);
84 	}
85 
86 	@Override
getVariable(String name)87 	public Object getVariable(String name) {
88 		return fManagedPool.getVariable(name);
89 	}
90 
91 	@Override
resolveVariable(String name, Object[] args)92 	public Object resolveVariable(String name, Object[] args) throws CoreException {
93 		return fManagedPool.resolveVariable(name, args);
94 	}
95 }
96