*  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

*

*  $Id$

*/

* @author wolf

*

*/

 

  /**

   * @param context

   */

  public Replace(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 inSeq = select.eval(contextSequence);

    if (inSeq.isEmpty())

      {return Sequence.EMPTY_SEQUENCE;}

       

    //START trap Replace failure

        /* If we try and Replace 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 replace 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 Replace failure

   

    Sequence contentSeq = value.eval(contextSequence);

    if (contentSeq.isEmpty())

      {throw new XPathException(this, Messages.getMessage(Error.UPDATE_EMPTY_CONTENT));}

    context.pushInScopeNamespaces();

        contentSeq = deepCopy(contentSeq);

       

        //start a transaction

        final Txn transaction = getTransaction();

        try {

            final StoredNode ql[] = selectAndLock(transaction, inSeq);

            final IndexListener listener = new IndexListener(ql);

            final NotificationService notifier = context.getBroker().getBrokerPool().getNotificationService();

            Item temp;

            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 PermissionDeniedException("User '" + context.getSubject().getName() + "' does not have permission to write to the document '" + doc.getDocumentURI() + "'!");

                }

                doc.getMetadata().setIndexListener(listener);

               

                //update the document

                parent = (ElementImpl) node.getParentStoredNode();

                if (parent == null)

                    {throw new XPathException(this, "The root element of a document can not be replaced with 'update replace'. " +

                            "Please consider removing the document or use 'update value' to just replace the children of the root.");}

                switch (node.getNodeType()) {

                    case Node.ELEMENT_NODE:

                        temp = contentSeq.itemAt(0);

            if (!Type.subTypeOf(temp.getType(), Type.NODE))

              {throw new XPathException(this,

                  Messages.getMessage(Error.UPDATE_REPLACE_ELEM_TYPE,

                      Type.getTypeName(temp.getType())));}

                        parent.replaceChild(transaction, ((NodeValue)temp).getNode(), node);

                        break;

                    case Node.TEXT_NODE:

                        text = new TextImpl(contentSeq.getStringValue());

                        text.setOwnerDocument(doc);

                        parent.updateChild(transaction, node, text);

                        break;

                    case Node.ATTRIBUTE_NODE:

                        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 EXistException("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 replace").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 replace ");   

    result.append(select.toString());

    result.append(" with ");

    result.append(value.toString());

    return result.toString();

  } 

}