/*******************************************************************************
* Copyright (c) 2000, 2007 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.core.internal.expressions;
import org.w3c.dom.Element;
import org.eclipse.core.runtime.Assert;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IAdapterManager;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.Platform;
import org.eclipse.core.expressions.EvaluationResult;
import org.eclipse.core.expressions.ExpressionInfo;
import org.eclipse.core.expressions.IEvaluationContext;
public class AdaptExpression extends CompositeExpression {
private static final String ATT_TYPE= "type"; //$NON-NLS-1$
/**
* The seed for the hash code for all adapt expressions.
*/
private static final int HASH_INITIAL= AdaptExpression.class.getName().hashCode();
private String fTypeName;
public AdaptExpression(IConfigurationElement configElement) throws CoreException {
fTypeName= configElement.getAttribute(ATT_TYPE);
Expressions.checkAttribute(ATT_TYPE, fTypeName);
}
public AdaptExpression(Element element) throws CoreException {
fTypeName= element.getAttribute(ATT_TYPE);
Expressions.checkAttribute(ATT_TYPE, fTypeName.length() > 0 ? fTypeName : null);
}
public AdaptExpression(String typeName) {
Assert.isNotNull(typeName);
fTypeName= typeName;
}
public boolean equals(final Object object) {
if (!(object instanceof AdaptExpression))
return false;
final AdaptExpression that= (AdaptExpression)object;
return this.fTypeName.equals(that.fTypeName)
&& equals(this.fExpressions, that.fExpressions);
}
protected int computeHashCode() {
return HASH_INITIAL * HASH_FACTOR + hashCode(fExpressions)
* HASH_FACTOR + fTypeName.hashCode();
}
/* (non-Javadoc)
* @see Expression#evaluate(IVariablePool)
*/
public EvaluationResult evaluate(IEvaluationContext context) throws CoreException {
if (fTypeName == null)
return EvaluationResult.FALSE;
Object var= context.getDefaultVariable();
Object adapted= null;
IAdapterManager manager= Platform.getAdapterManager();
if (Expressions.isInstanceOf(var, fTypeName)) {
adapted= var;
} else {
if (!manager.hasAdapter(var, fTypeName))
return EvaluationResult.FALSE;
adapted= manager.getAdapter(var, fTypeName);
}
// the adapted result is null but hasAdapter returned true check
// if the adapter is loaded.
if (adapted == null) {
if (manager.queryAdapter(var, fTypeName) == IAdapterManager.NOT_LOADED) {
return EvaluationResult.NOT_LOADED;
} else {
return EvaluationResult.FALSE;
}
}
return evaluateAnd(new DefaultVariable(context, adapted));
}
public void collectExpressionInfo(ExpressionInfo info) {
// Although the default variable is passed to the children of this
// expression as an instance of the adapted type it is OK to only
// mark a default variable access.
info.markDefaultVariableAccessed();
super.collectExpressionInfo(info);
}
}