org.eclipse.e4.emf.internal.xpath.JXPathContextImpl.java Source code

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Here is the source code for org.eclipse.e4.emf.internal.xpath.JXPathContextImpl.java

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/*******************************************************************************
 * Copyright (c) 2010, 2015 BestSolution.at 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:
 *     Tom Schindl <tom.schindl@bestsolution.at> - adjustment to EObject
 ******************************************************************************/
package org.eclipse.e4.emf.internal.xpath;

import java.util.Collection;
import java.util.Iterator;
import java.util.List;

import org.apache.commons.jxpath.ClassFunctions;
import org.apache.commons.jxpath.JXPathContext;
import org.apache.commons.jxpath.NodeSet;
import org.apache.commons.jxpath.Pointer;
import org.eclipse.e4.emf.xpath.XPathContext;
import org.eclipse.emf.ecore.EObject;

/**
 * Context which uses JXPath to evaluate XPath expressions
 */
public final class JXPathContextImpl implements XPathContext {

    private JXPathContext context;

    public static class EMFFunctions {
        public static String eClassName(Object o) {
            if (o instanceof Collection<?>) {
                if (!((Collection<?>) o).isEmpty()) {
                    return eClassName(((Collection<?>) o).iterator().next());
                }
            } else if (o instanceof EObject) {
                return ((EObject) o).eClass().getName();
            } else if (o instanceof NodeSet) {
                List<?> l = ((NodeSet) o).getValues();
                if (l.size() > 0 && l.get(0) instanceof EObject) {
                    return eClassName(l.get(0));
                }
            } else if (o instanceof Pointer) {
                if (((Pointer) o).getValue() instanceof EObject) {
                    return eClassName(((Pointer) o).getValue());
                }
            }

            return null;
        }
    }

    /**
     * Create a new context
     *
     * @param contextBean
     *            the context bean (=root of the xpath expression)
     */
    JXPathContextImpl(Object contextBean) {
        this.context = JXPathContext.newContext(contextBean);
        this.context.setFunctions(new ClassFunctions(EMFFunctions.class, "ecore"));
    }

    /**
     * Create a new child context
     *
     * @param parentContext
     *            the parent
     * @param contextBean
     *            the context bean (=root of the xpath expression)
     */
    JXPathContextImpl(XPathContext parentContext, Object contextBean) {
        JXPathContext jContext = ((JXPathContextImpl) parentContext).getJXPathContext();
        this.context = JXPathContext.newContext(jContext, contextBean);
    }

    @Override
    public Object getValue(String xpath) {
        return context.getValue(xpath);
    }

    @Override
    public Object getValue(String xpath, Class<?> requiredType) {
        return context.getValue(xpath, requiredType);
    }

    @Override
    public <Type> Iterator<Type> iterate(String xpath) {
        return context.iterate(xpath);
    }

    private JXPathContext getJXPathContext() {
        return context;
    }

}