1   /*   Copyright 2004 The Apache Software Foundation
    2    *
    3    *   Licensed under the Apache License, Version 2.0 (the "License");
    4    *   you may not use this file except in compliance with the License.
    5    *   You may obtain a copy of the License at
    6    *
    7    *       http://www.apache.org/licenses/LICENSE-2.0
    8    *
    9    *   Unless required by applicable law or agreed to in writing, software
   10    *   distributed under the License is distributed on an "AS IS" BASIS,
   11    *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   12    *   See the License for the specific language governing permissions and
   13    *  limitations under the License.
   14    */
   15   
   16   package org.apache.xmlbeans.impl.xquery.saxon;
   17   
   18   import java.util.List;
   19   import java.util.Map;
   20   import java.util.Iterator;
   21   import java.util.ListIterator;
   22   
   23   import javax.xml.transform.dom.DOMSource;
   24   import javax.xml.transform.TransformerException;
   25   
   26   import org.w3c.dom.Node;
   27   
   28   import net.sf.saxon.Configuration;
   29   import net.sf.saxon.dom.NodeOverNodeInfo;
   30   import net.sf.saxon.om.NodeInfo;
   31   import net.sf.saxon.query.DynamicQueryContext;
   32   import net.sf.saxon.query.StaticQueryContext;
   33   import net.sf.saxon.query.XQueryExpression;
   34   
   35   import org.apache.xmlbeans.XmlRuntimeException;
   36   import org.apache.xmlbeans.XmlTokenSource;
   37   import org.apache.xmlbeans.impl.store.QueryDelegate;
   38   
   39   public class XBeansXQuery
   40           implements QueryDelegate.QueryInterface
   41   {
   42       private XQueryExpression xquery;
   43       private String contextVar;
   44       private Configuration config;
   45   
   46       /**
   47        * Construct given an XQuery expression string.
   48        * @param query The XQuery expression
   49        * @param contextVar The name of the context variable
   50        * @param boundary The offset of the end of the prolog
   51        */
   52       public XBeansXQuery(String query, String contextVar, Integer boundary)
   53       {
   54           config = new Configuration();
   55           config.setDOMLevel(2);
   56           config.setTreeModel(net.sf.saxon.event.Builder.STANDARD_TREE);
   57           StaticQueryContext sc = new StaticQueryContext(config);
   58           this.contextVar = contextVar;
   59           int bdry = boundary.intValue();
   60           //Saxon requires external variables at the end of the prolog...
   61           query = (bdry == 0) ?
   62                   "declare variable $" +
   63                   contextVar + " external;" + query :
   64                   query.substring(0, bdry) +
   65                   "declare variable $" +
   66                   contextVar + " external;" +
   67                   query.substring(bdry);
   68           try
   69           {
   70               xquery = sc.compileQuery(query);
   71           }
   72           catch (TransformerException e)
   73           {
   74               throw new XmlRuntimeException(e);
   75           }
   76       }
   77   
   78       public List execQuery(Object node, Map variableBindings)
   79       {
   80           try
   81           {
   82               Node contextNode = (Node)node;
   83               NodeInfo contextItem = 
   84                   config.buildDocument(new DOMSource(contextNode));
   85                   //config.unravel(new DOMSource(contextNode));
   86               DynamicQueryContext dc = new DynamicQueryContext(config);
   87               dc.setContextItem(contextItem);
   88               dc.setParameter(contextVar, contextItem);
   89               // Set the other variables
   90               if (variableBindings != null)
   91               {
   92                   for (Iterator it = variableBindings.entrySet().iterator();
   93                       it.hasNext(); )
   94                   {
   95                       Map.Entry entry = (Map.Entry)it.next();
   96                       String key = (String)entry.getKey();
   97                       Object value = entry.getValue();
   98                       if (value instanceof XmlTokenSource)
   99                       {
  100                           Node paramObject = ((XmlTokenSource)value).getDomNode();
  101                           dc.setParameter(key, paramObject);
  102                       }
  103                       else if (value instanceof String)
  104                           dc.setParameter(key, value);
  105                   }
  106               }
  107   
  108               List saxonNodes = xquery.evaluate(dc);
  109               for (ListIterator it = saxonNodes.listIterator(); it.hasNext(); )
  110               {
  111                   Object o = it.next();
  112                   if(o instanceof NodeInfo)
  113                   {
  114                       Node n = NodeOverNodeInfo.wrap((NodeInfo)o);
  115                       it.set(n);
  116                   }
  117               }
  118               return saxonNodes;
  119           }
  120           catch (TransformerException e)
  121           {
  122               throw new RuntimeException("Error binding " + contextVar, e);
  123           }
  124       }
  125   }