Package org.exist.xquery.update

Source Code of org.exist.xquery.update.Update

/*
*  eXist Open Source Native XML Database
*  Copyright (C) 2001-2010 The eXist Project
*  http://exist-db.org
*
*  This program is free software; you can redistribute it and/or
*  modify it under the terms of the GNU Lesser General Public License
*  as published by the Free Software Foundation; either version 2
*  of the License, or (at your option) any later version.
*
*  This program is distributed in the hope that it will be useful,
*  but WITHOUT ANY WARRANTY; without even the implied warranty of
*  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
*  GNU Lesser General Public License for more details.
*
*  You should have received a copy of the GNU Lesser General Public
*  License along with this library; if not, write to the Free Software
*  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*
*  $Id$
*/
package org.exist.xquery.update;

import org.apache.log4j.Logger;
import org.exist.EXistException;
import org.exist.collections.triggers.TriggerException;
import org.exist.dom.AttrImpl;
import org.exist.dom.DocumentImpl;
import org.exist.dom.ElementImpl;
import org.exist.dom.NodeListImpl;
import org.exist.dom.StoredNode;
import org.exist.dom.TextImpl;
import org.exist.security.Permission;
import org.exist.security.PermissionDeniedException;
import org.exist.storage.NotificationService;
import org.exist.storage.UpdateListener;
import org.exist.storage.txn.Txn;
import org.exist.util.LockException;
import org.exist.xquery.Dependency;
import org.exist.xquery.Expression;
import org.exist.xquery.Profiler;
import org.exist.xquery.XPathException;
import org.exist.xquery.XPathUtil;
import org.exist.xquery.XQueryContext;
import org.exist.xquery.util.Error;
import org.exist.xquery.util.ExpressionDumper;
import org.exist.xquery.util.Messages;
import org.exist.xquery.value.Item;
import org.exist.xquery.value.NodeValue;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.SequenceIterator;
import org.exist.xquery.value.StringValue;
import org.exist.xquery.value.Type;
import org.exist.xquery.value.ValueSequence;
import org.w3c.dom.Node;

/**
* @author wolf
*
*/
public class Update extends Modification {

  private final static Logger LOG = Logger.getLogger(Update.class);
 
  public Update(XQueryContext context, Expression select, Expression value) {
    super(context, select, value);
  }

  /* (non-Javadoc)
   * @see org.exist.xquery.AbstractExpression#eval(org.exist.xquery.value.Sequence, org.exist.xquery.value.Item)
   */
  public Sequence eval(Sequence contextSequence, Item contextItem) throws XPathException {
        if (context.getProfiler().isEnabled()) {
            context.getProfiler().start(this);      
            context.getProfiler().message(this, Profiler.DEPENDENCIES, "DEPENDENCIES", Dependency.getDependenciesName(this.getDependencies()));
            if (contextSequence != null)
                {context.getProfiler().message(this, Profiler.START_SEQUENCES, "CONTEXT SEQUENCE", contextSequence);}
            if (contextItem != null)
                {context.getProfiler().message(this, Profiler.START_SEQUENCES, "CONTEXT ITEM", contextItem.toSequence());}
        }
       
    if (contextItem != null)
      {contextSequence = contextItem.toSequence();}
       
        final Sequence contentSeq = value.eval(contextSequence);
        if (contentSeq.isEmpty())
            {throw new XPathException(this, Messages.getMessage(Error.UPDATE_EMPTY_CONTENT));}
       
        final Sequence inSeq = select.eval(contextSequence);
       
        //START trap Update failure
        /* If we try and Update a node at an invalid location,
         * trap the error in a context variable,
         * this is then accessible from xquery via. the context extension module - deliriumsky
         * TODO: This trapping could be expanded further - basically where XPathException is thrown from thiss class
         * TODO: Maybe we could provide more detailed messages in the trap, e.g. couldnt update node `xyz` into `abc` becuase... this would be nicer for the end user of the xquery application
         */
        if (!Type.subTypeOf(inSeq.getItemType(), Type.NODE))
        {
          //Indicate the failure to perform this update by adding it to the sequence in the context variable XQueryContext.XQUERY_CONTEXTVAR_XQUERY_UPDATE_ERROR
          ValueSequence prevUpdateErrors = null;
         
          final XPathException xpe = new XPathException(this, Messages.getMessage(Error.UPDATE_SELECT_TYPE));
          final Object ctxVarObj = context.getXQueryContextVar(XQueryContext.XQUERY_CONTEXTVAR_XQUERY_UPDATE_ERROR);
          if(ctxVarObj == null)
          {
            prevUpdateErrors = new ValueSequence();
          }
          else
          {
            prevUpdateErrors = (ValueSequence)XPathUtil.javaObjectToXPath(ctxVarObj, context);
          }
          prevUpdateErrors.add(new StringValue(xpe.getMessage()));
      context.setXQueryContextVar(XQueryContext.XQUERY_CONTEXTVAR_XQUERY_UPDATE_ERROR, prevUpdateErrors);
     
          if(!inSeq.isEmpty())
            {throw xpe;//TODO: should we trap this instead of throwing an exception - deliriumsky?
        }
        //END trap Update failure
       
        if (!inSeq.isEmpty()) {         
          context.pushInScopeNamespaces();
            //start a transaction
            final Txn transaction = getTransaction();
        try {
          final NotificationService notifier = context.getBroker().getBrokerPool().getNotificationService();

                final StoredNode ql[] = selectAndLock(transaction, inSeq);
                final IndexListener listener = new IndexListener(ql);
                TextImpl text;
                AttrImpl attribute;
                ElementImpl parent;
                for (int i = 0; i < ql.length; i++) {
                    final StoredNode node = ql[i];
                    final DocumentImpl doc = (DocumentImpl)node.getOwnerDocument();
                    if (!doc.getPermissions().validate(context.getUser(),
                            Permission.WRITE)){
                            throw new XPathException(this, "User '" + context.getSubject().getName() + "' does not have permission to write to the document '" + doc.getDocumentURI() + "'!");
                    }
                    doc.getMetadata().setIndexListener(listener);
                                       
                    //update the document
                    switch (node.getNodeType())
                    {
                        case Node.ELEMENT_NODE:
                final NodeListImpl content = new NodeListImpl();
                for (final SequenceIterator j = contentSeq.iterate(); j.hasNext(); ) {
                  final Item next = j.nextItem();
                  if (Type.subTypeOf(next.getType(), Type.NODE))
                    {content.add(((NodeValue)next).getNode());}
                  else {
                    text = new TextImpl(next.getStringValue());
                    content.add(text);
                  }
                }
                            ((ElementImpl) node).update(transaction, content);
                            break;
                        case Node.TEXT_NODE:
                            parent = (ElementImpl) node.getParentNode();
                          text = new TextImpl(contentSeq.getStringValue());
                            text.setOwnerDocument(doc);
                            parent.updateChild(transaction, node, text);
                            break;
                        case Node.ATTRIBUTE_NODE:
                            parent = (ElementImpl) node.getParentNode();
                            if (parent == null) {
                                LOG.warn("parent node not found for "
                                        + node.getNodeId());
                                break;
                            }
                            final AttrImpl attr = (AttrImpl) node;
                            attribute = new AttrImpl(attr.getQName(), contentSeq.getStringValue(), context.getBroker().getBrokerPool().getSymbols());
                            attribute.setOwnerDocument(doc);
                            parent.updateChild(transaction, node, attribute);
                            break;
                        default:
                            throw new XPathException(this, "unsupported node-type");
                    }
                    doc.getMetadata().clearIndexListener();
                    doc.getMetadata().setLastModified(System.currentTimeMillis());
                    modifiedDocuments.add(doc);
                    context.getBroker().storeXMLResource(transaction, doc);
                    notifier.notifyUpdate(doc, UpdateListener.UPDATE);
                }
                finishTriggers(transaction);
                //commit the transaction
                commitTransaction(transaction);
            } catch (final LockException e) {
                abortTransaction(transaction);
                throw new XPathException(this, e.getMessage(), e);
        } catch (final PermissionDeniedException e) {
                abortTransaction(transaction);
                throw new XPathException(this, e.getMessage(), e);
        } catch (final EXistException e) {
                abortTransaction(transaction);
                throw new XPathException(this, e.getMessage(), e);
        } catch (final TriggerException e) {
                abortTransaction(transaction);
                throw new XPathException(this, e.getMessage(), e);
      } finally {
                unlockDocuments();
                closeTransaction(transaction);
                context.popInScopeNamespaces();
            }
        }

        if (context.getProfiler().isEnabled())
            {context.getProfiler().end(this, "", Sequence.EMPTY_SEQUENCE);}
       
        return Sequence.EMPTY_SEQUENCE;
  }

  /* (non-Javadoc)
   * @see org.exist.xquery.Expression#dump(org.exist.xquery.util.ExpressionDumper)
   */
  public void dump(ExpressionDumper dumper) {
    dumper.display("update value").nl();
    dumper.startIndent();
    select.dump(dumper);
    dumper.nl().endIndent().display("with").nl().startIndent();
    value.dump(dumper);
    dumper.nl().endIndent();
  }
 
  public String toString() {
    final StringBuilder result = new StringBuilder();
    result.append("update value" );   
    result.append(select.toString());
    result.append(" with ");
    result.append(value.toString());
    return result.toString();
 
}
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