/*******************************************************************************
* Copyright (c) 2005, 2006 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.expressions;
import org.eclipse.core.expressions.EvaluationResult;
import org.eclipse.core.expressions.Expression;
import org.eclipse.core.expressions.ExpressionInfo;
import org.eclipse.core.expressions.IEvaluationContext;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.ui.ISources;
import org.eclipse.ui.IWorkbenchWindow;
import org.eclipse.ui.SelectionEnabler;
/**
* <p>
* An expression wrapper for the legacy {@link SelectionEnabler}. This emulates
* an {@link Expression} using an instance of <code>SelectionEnabler</code>.
* </p>
* <p>
* This class is not intended for use outside of the
* <code>org.eclipse.ui.workbench</code> plug-in.
* </p>
*
* @since 3.2
*/
public final class LegacySelectionEnablerWrapper extends
WorkbenchWindowExpression {
/**
* The seed for the hash code for all schemes.
*/
private static final int HASH_INITIAL = LegacySelectionEnablerWrapper.class
.getName().hashCode();
/**
* The enabler for this expression; never <code>null</code>.
*/
private final SelectionEnabler enabler;
/**
* Constructs a new instance of <code>SelectionEnablerExpression</code>.
*
* @param enabler
* The enabler; must not be <code>null</code>.
* @param window
* The workbench window which must be active for this expression
* to evaluate to <code>true</code>; may be <code>null</code>
* if the window should be disregarded.
*/
public LegacySelectionEnablerWrapper(final SelectionEnabler enabler,
final IWorkbenchWindow window) {
super(window);
if (enabler == null) {
throw new NullPointerException("There is no enabler"); //$NON-NLS-1$
}
this.enabler = enabler;
}
public final void collectExpressionInfo(final ExpressionInfo info) {
super.collectExpressionInfo(info);
info.markDefaultVariableAccessed();
}
protected final int computeHashCode() {
int hashCode = HASH_INITIAL * HASH_FACTOR + hashCode(getWindow());
hashCode = hashCode * HASH_FACTOR + hashCode(enabler);
return hashCode;
}
public final boolean equals(final Object object) {
if (object instanceof LegacySelectionEnablerWrapper) {
final LegacySelectionEnablerWrapper that = (LegacySelectionEnablerWrapper) object;
return equals(this.enabler, that.enabler)
&& equals(this.getWindow(), that.getWindow());
}
return false;
}
public final EvaluationResult evaluate(final IEvaluationContext context)
throws CoreException {
final EvaluationResult result = super.evaluate(context);
if (result == EvaluationResult.FALSE) {
return result;
}
final Object defaultVariable = context
.getVariable(ISources.ACTIVE_CURRENT_SELECTION_NAME);
if (defaultVariable instanceof ISelection) {
final ISelection selection = (ISelection) defaultVariable;
if (enabler.isEnabledForSelection(selection)) {
return EvaluationResult.TRUE;
}
}
return EvaluationResult.FALSE;
}
public final String toString() {
final StringBuffer buffer = new StringBuffer();
buffer.append("LegacySelectionEnablerWrapper("); //$NON-NLS-1$
buffer.append(enabler);
buffer.append(',');
buffer.append(getWindow());
buffer.append(')');
return buffer.toString();
}
}