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/*******************************************************************************
* Copyright (c) 2000, 2012 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.expressions;
import org.osgi.framework.Bundle;
import org.eclipse.core.internal.expressions.PropertyTesterDescriptor;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.Platform;
/**
* Abstract superclass of all property testers. Implementation classes of
* the extension point org.eclipse.core.expresssions.propertyTesters
* must extend PropertyTester.
*
* A property tester implements the property tests enumerated in the property
* tester extension point. For the following property test extension
*
* <propertyTester
* namespace="org.eclipse.jdt.core"
* id="org.eclipse.jdt.core.IPackageFragmentTester"
* properties="isDefaultPackage"
* type="org.eclipse.jdt.core.IPackageFragment"
* class="org.eclipse.demo.MyPackageFragmentTester">
* </propertyTester>
*
* the corresponding implementation class looks like:
*
* public class MyPackageFragmentTester extends PropertyTester {
* public boolean test(Object receiver, String property, Object[] args, Object expectedValue) {
* IPackageFragment fragment= (IPackageFragment)receiver;
* if ("isDefaultPackage".equals(property)) {
* return expectedValue == null
* ? fragment.isDefaultPackage()
* : fragment.isDefaultPackage() == ((Boolean)expectedValue).booleanValue();
* }
* Assert.isTrue(false);
* return false;
* }
* }
*
* The property can then be used in a test expression as follows:
*
* <instanceof value="org.eclipse.core.IPackageFragment"/>
* <test property="org.eclipse.jdt.core.isDefaultPackage"/>
*
*
*
* There is no guarantee that the same instance of a property tester is used
* to handle <test property="..."/> requests. So property testers
* should always be implemented in a stateless fashion.
*
* @since 3.0
*/
public abstract class PropertyTester implements IPropertyTester {
private IConfigurationElement fConfigElement;
private String fNamespace;
private String fProperties;
/**
* Initialize the property tester with the given name space and property.
*
* Note: this method is for internal use only. Clients must not call
* this method.
*
* @param descriptor the descriptor object for this tester
*
* @noreference This method is not intended to be referenced by clients.
*/
public final void internalInitialize(PropertyTesterDescriptor descriptor) {
fProperties= descriptor.getProperties();
fNamespace= descriptor.getNamespace();
fConfigElement= descriptor.getConfigurationElement();
}
/**
* Note: this method is for internal use only. Clients must not call
* this method.
*
* @return the property tester descriptor
*
* @noreference This method is not intended to be referenced by clients.
*/
public final PropertyTesterDescriptor internalCreateDescriptor() {
return new PropertyTesterDescriptor(fConfigElement, fNamespace, fProperties);
}
/**
* {@inheritDoc}
*/
public final boolean handles(String namespace, String property) {
return fNamespace.equals(namespace) && fProperties.indexOf("," + property + ",") != -1; //$NON-NLS-1$//$NON-NLS-2$
}
/**
* {@inheritDoc}
*/
public final boolean isInstantiated() {
return true;
}
/**
* {@inheritDoc}
*/
public boolean isDeclaringPluginActive() {
Bundle bundle= Platform.getBundle(fConfigElement.getContributor().getName());
return bundle.getState() == Bundle.ACTIVE;
}
/**
* {@inheritDoc}
*/
public final IPropertyTester instantiate() {
return this;
}
}