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/*******************************************************************************
* Copyright (c) 2007, 2015 IBM Corporation and others.
*
* This program and the accompanying materials
* are made available under the terms of the Eclipse Public License 2.0
* which accompanies this distribution, and is available at
* https://www.eclipse.org/legal/epl-2.0/
*
* SPDX-License-Identifier: EPL-2.0
*
* Contributors:
* IBM Corporation - initial API and implementation
******************************************************************************/
package org.eclipse.ui.internal.services;
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.e4.core.commands.ExpressionContext;
import org.eclipse.e4.core.contexts.IEclipseContext;
import org.eclipse.e4.core.contexts.RunAndTrack;
import org.eclipse.e4.ui.internal.workbench.Activator;
import org.eclipse.jface.util.IPropertyChangeListener;
import org.eclipse.jface.util.PropertyChangeEvent;
import org.eclipse.ui.services.IEvaluationReference;
import org.osgi.service.log.LogService;
/**
* @since 3.3
*
*/
public class EvaluationReference extends RunAndTrack implements IEvaluationReference {
final IEclipseContext context;
final Expression expression;
final IPropertyChangeListener listener;
final String property;
final int sourcePriority;
boolean cache;
boolean participating = true;
boolean postingChanges = true;
boolean hasRun = false;
public EvaluationReference(IEclipseContext context, Expression expression, IPropertyChangeListener listener,
String property) {
this.context = context;
this.expression = expression;
this.listener = listener;
this.property = property;
this.sourcePriority = SourcePriorityNameMapping.computeSourcePriority(expression);
}
@Override
public void clearResult() {
}
@Override
public Expression getExpression() {
return expression;
}
@Override
public int getSourcePriority() {
return sourcePriority;
}
@Override
public boolean evaluate(IEvaluationContext context) {
if (expression == null) {
cache = true;
} else {
try {
cache = expression.evaluate(context) != EvaluationResult.FALSE;
} catch (CoreException e) {
Activator.log(LogService.LOG_ERROR, "Failed to evaluate: " + expression, e); //$NON-NLS-1$
return false;
}
}
return cache;
}
@Override
public void setResult(boolean result) {
cache = result;
}
@Override
public boolean changed(IEclipseContext context) {
if (!participating) {
return false;
}
evaluate();
return participating;
}
public void evaluate() {
boolean value = cache;
evaluate(new ExpressionContext(context));
if (!postingChanges) {
return;
}
if (!hasRun) {
getListener().propertyChange(new PropertyChangeEvent(this, getProperty(), null, Boolean.valueOf(cache)));
} else if (!participating) {
getListener().propertyChange(new PropertyChangeEvent(this, getProperty(), Boolean.valueOf(value), null));
}
if (value != cache) {
getListener().propertyChange(
new PropertyChangeEvent(this, getProperty(), Boolean.valueOf(value), Boolean.valueOf(cache)));
}
hasRun = true;
}
@Override
public IPropertyChangeListener getListener() {
return listener;
}
@Override
public String getProperty() {
return property;
}
public void setPostingChanges(boolean b) {
postingChanges = b;
}
public boolean isPostingChanges() {
return postingChanges;
}
}
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