org.apache.xmlbeans.impl.xquery.saxon.XBeansXQuery Maven / Gradle / Ivy

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The Apache Commons Codec package contains simple encoder and decoders for various formats such as Base64 and Hexadecimal. In addition to these widely used encoders and decoders, the codec package also maintains a collection of phonetic encoding utilities.
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/*   Copyright 2004 The Apache Software Foundation
 *
 *   Licensed under the Apache License, Version 2.0 (the "License");
 *   you may not use this file except in compliance with the License.
 *   You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *   Unless required by applicable law or agreed to in writing, software
 *   distributed under the License is distributed on an "AS IS" BASIS,
 *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *   See the License for the specific language governing permissions and
 *  limitations under the License.
 */

package org.apache.xmlbeans.impl.xquery.saxon;

import java.util.List;
import java.util.Map;
import java.util.Iterator;
import java.util.ListIterator;

import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.TransformerException;

import org.apache.xmlbeans.XmlOptions;
import org.w3c.dom.Node;

import net.sf.saxon.Configuration;
import net.sf.saxon.dom.NodeOverNodeInfo;
import net.sf.saxon.om.NodeInfo;
import net.sf.saxon.query.DynamicQueryContext;
import net.sf.saxon.query.StaticQueryContext;
import net.sf.saxon.query.XQueryExpression;

import org.apache.xmlbeans.XmlRuntimeException;
import org.apache.xmlbeans.XmlTokenSource;
import org.apache.xmlbeans.impl.store.QueryDelegate;

public class XBeansXQuery
        implements QueryDelegate.QueryInterface
{
    private XQueryExpression xquery;
    private String contextVar;
    private Configuration config;

    /**
     * Construct given an XQuery expression string.
     * @param query The XQuery expression
     * @param contextVar The name of the context variable
     * @param boundary The offset of the end of the prolog
     */
    public XBeansXQuery(String query, String contextVar, Integer boundary, XmlOptions xmlOptions)
    {
        config = new Configuration();
        config.setDOMLevel(2);
        config.setTreeModel(net.sf.saxon.event.Builder.STANDARD_TREE);
        StaticQueryContext sc = new StaticQueryContext(config);
        @SuppressWarnings("unchecked")
        Map nsMap = (Map)xmlOptions.get(XmlOptions.LOAD_ADDITIONAL_NAMESPACES);
        if (nsMap != null) {
            for (Map.Entry me : nsMap.entrySet()) {
                sc.declareNamespace(me.getKey(), me.getValue());
            }
        }

        this.contextVar = contextVar;
        //Saxon requires external variables at the end of the prolog...
        query = (boundary == 0) ?
                "declare variable $" +
                contextVar + " external;" + query :
                query.substring(0, boundary) +
                "declare variable $" +
                contextVar + " external;" +
                query.substring(boundary);
        try
        {
            xquery = sc.compileQuery(query);
        }
        catch (TransformerException e)
        {
            throw new XmlRuntimeException(e);
        }
    }

    public List execQuery(Object node, Map variableBindings)
    {
        try
        {
            Node contextNode = (Node)node;
            NodeInfo contextItem = 
                config.buildDocument(new DOMSource(contextNode));
                //config.unravel(new DOMSource(contextNode));
            DynamicQueryContext dc = new DynamicQueryContext(config);
            dc.setContextItem(contextItem);
            dc.setParameter(contextVar, contextItem);
            // Set the other variables
            if (variableBindings != null)
            {
                for (Iterator it = variableBindings.entrySet().iterator();
                    it.hasNext(); )
                {
                    Map.Entry entry = (Map.Entry)it.next();
                    String key = (String)entry.getKey();
                    Object value = entry.getValue();
                    if (value instanceof XmlTokenSource)
                    {
                        Node paramObject = ((XmlTokenSource)value).getDomNode();
                        dc.setParameter(key, paramObject);
                    }
                    else if (value instanceof String)
                        dc.setParameter(key, value);
                }
            }

            List saxonNodes = xquery.evaluate(dc);
            for (ListIterator it = saxonNodes.listIterator(); it.hasNext(); )
            {
                Object o = it.next();
                if(o instanceof NodeInfo)
                {
                    Node n = NodeOverNodeInfo.wrap((NodeInfo)o);
                    it.set(n);
                }
            }
            return saxonNodes;
        }
        catch (TransformerException e)
        {
            throw new RuntimeException("Error binding " + contextVar, e);
        }
    }
}