/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.ode.bpel.runtime;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.ode.bpel.common.FaultException;
import org.apache.ode.bpel.evt.PartnerLinkModificationEvent;
import org.apache.ode.bpel.evt.ScopeEvent;
import org.apache.ode.bpel.evt.VariableModificationEvent;
import org.apache.ode.bpel.explang.EvaluationContext;
import org.apache.ode.bpel.explang.EvaluationException;
import org.apache.ode.bpel.obj.OAssign;
import org.apache.ode.bpel.obj.OAssign.DirectRef;
import org.apache.ode.bpel.obj.OAssign.LValueExpression;
import org.apache.ode.bpel.obj.OAssign.PropertyRef;
import org.apache.ode.bpel.obj.OAssign.VariableRef;
import org.apache.ode.bpel.obj.OElementVarType;
import org.apache.ode.bpel.obj.OExpression;
import org.apache.ode.bpel.obj.OLink;
import org.apache.ode.bpel.obj.OMessageVarType;
import org.apache.ode.bpel.obj.OMessageVarType.Part;
import org.apache.ode.bpel.obj.OProcess.OProperty;
import org.apache.ode.bpel.obj.OScope;
import org.apache.ode.bpel.obj.OScope.Variable;
import org.apache.ode.bpel.runtime.channels.FaultData;
import org.apache.ode.utils.DOMUtils;
import org.apache.ode.utils.Namespaces;
import org.apache.ode.utils.msg.MessageBundle;
import org.apache.ode.bpel.evar.ExternalVariableModuleException;
import org.w3c.dom.Attr;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.Text;
import org.xml.sax.SAXException;

import javax.xml.namespace.QName;

import java.io.IOException;
import java.net.URI;
import java.util.Calendar;
import java.util.Date;
import java.util.List;
import java.util.Map;

/**
 * Assign activity run-time template.
 */
class ASSIGN extends ACTIVITY {
    private static final long serialVersionUID = 1L;

    private static final Logger __log = LoggerFactory.getLogger(ASSIGN.class);

    private static final ASSIGNMessages __msgs = MessageBundle
            .getMessages(ASSIGNMessages.class);

    public ASSIGN(ActivityInfo self, ScopeFrame scopeFrame, LinkFrame linkFrame) {
        super(self, scopeFrame, linkFrame);
    }

    public void run() {
        OAssign oassign = getOAsssign();

        FaultData faultData = null;

        for (OAssign.Copy aCopy : oassign.getCopy()) {
            try {
                copy(aCopy);
            } catch (FaultException fault) {
                if (aCopy.isIgnoreMissingFromData()) {
                    if (fault.getQName().equals(getOAsssign().getOwner().getConstants().getQnSelectionFailure()) &&
                            (fault.getCause() != null && "ignoreMissingFromData".equals(fault.getCause().getMessage()))) {
                    continue;
                    }
                }
                if (aCopy.isIgnoreUninitializedFromVariable()) {
                    if (fault.getQName().equals(getOAsssign().getOwner().getConstants().getQnUninitializedVariable()) &&
                            (fault.getCause() == null || !"throwUninitializedToVariable".equals(fault.getCause().getMessage()))) {
                    continue;
                    }
                }
                faultData = createFault(fault.getQName(), aCopy, fault
                        .getMessage());
                break;
            } catch (ExternalVariableModuleException e) {
                __log.error("Exception while initializing external variable", e);
                _self.parent.failure(e.toString(), null);
                return;
            }
        }

        if (faultData != null) {
            __log.info("Assignment Fault: " + faultData.getFaultName()
                    + ",lineNo=" + faultData.getFaultLineNo()
                    + ",faultExplanation=" + faultData.getExplanation());
            _self.parent.completed(faultData, CompensationHandler.emptySet());
        } else {
            _self.parent.completed(null, CompensationHandler.emptySet());
        }
    }

    protected Logger log() {
        return __log;
    }

    private OAssign getOAsssign() {
        return (OAssign) _self.o;
    }

    private Node evalLValue(OAssign.LValue to) throws FaultException, ExternalVariableModuleException {
        final BpelRuntimeContext napi = getBpelRuntimeContext();
        Node lval = null;
        if (!(to instanceof OAssign.PartnerLinkRef)) {
            VariableInstance lvar;
            try {
                lvar = _scopeFrame.resolve(to.getVariable());
            } catch (RuntimeException e) {
                __log.error("iid: " + getBpelRuntimeContext().getPid() + " error evaluating lvalue");
                throw new FaultException(getOAsssign().getOwner().getConstants().getQnSelectionFailure(), e.getMessage());
            }
            if (lvar == null) {
                String msg = __msgs.msgEvalException(to.toString(), "Could not resolve variable in current scope");
                if (__log.isDebugEnabled()) __log.debug(to + ": " + msg);
                throw new FaultException(getOAsssign().getOwner().getConstants().getQnSelectionFailure(), msg);
            }
            if (!napi.isVariableInitialized(lvar)) {
                Document doc = DOMUtils.newDocument();
                Node val = to.getVariable().getType().newInstance(doc);
                if (val.getNodeType() == Node.TEXT_NODE) {
                    Element tempwrapper = doc.createElementNS(null, "temporary-simple-type-wrapper");
                    doc.appendChild(tempwrapper);
                    tempwrapper.appendChild(val);
                    val = tempwrapper;
                } else doc.appendChild(val);
                // Only external variables need to be initialized, others are new and going to be overwtitten
                if (lvar.declaration.getExtVar() != null) lval = initializeVariable(lvar, val);
                else lval = val;
            } else
                lval = fetchVariableData(lvar, true);
        }
        return lval;
    }

    /**
     * Get the r-value. There are several possibilities:
     * <ul>
     * <li>a message is selected - an element representing the whole message is
     * returned.</li>
     * <li>a (element) message part is selected - the element is returned.
     * </li>
     * <li>a (typed) message part is select - a wrapper element is returned.
     * </li>
     * <li>an attribute is selected - an attribute node is returned. </li>
     * <li>a text node/string expression is selected - a text node is returned.
     * </li>
     * </ul>
     *
     * @param from
     *
     * @return Either {@link Element}, {@link org.w3c.dom.Text}, or
     *         {@link org.w3c.dom.Attr} node representing the r-value.
     *
     * @throws FaultException
     *             DOCUMENTME
     * @throws UnsupportedOperationException
     *             DOCUMENTME
     * @throws IllegalStateException
     *             DOCUMENTME
     */
    private Node evalRValue(OAssign.RValue from) throws FaultException, ExternalVariableModuleException {
        if (__log.isDebugEnabled())
            __log.debug("Evaluating FROM expression \"" + from + "\".");

        Node retVal;
        if (from instanceof DirectRef) {
            OAssign.DirectRef dref = (OAssign.DirectRef) from;
            sendVariableReadEvent(_scopeFrame.resolve(dref.getVariable()));
            Node data = fetchVariableData(
                    _scopeFrame.resolve(dref.getVariable()), false);
            retVal = DOMUtils.findChildByName((Element)data, dref.getElName());
        } else if (from instanceof OAssign.VariableRef) {
            OAssign.VariableRef varRef = (OAssign.VariableRef) from;
            sendVariableReadEvent(_scopeFrame.resolve(varRef.getVariable()));
            Node data = fetchVariableData(_scopeFrame.resolve(varRef.getVariable()), false);
            retVal = evalQuery(data, varRef.getPart() != null ? varRef.getPart() : varRef.getHeaderPart(), varRef.getLocation(), getEvaluationContext());
        } else if (from instanceof OAssign.PropertyRef) {
            OAssign.PropertyRef propRef = (OAssign.PropertyRef) from;
            sendVariableReadEvent(_scopeFrame.resolve(propRef.getVariable()));
            Node data = fetchVariableData(_scopeFrame.resolve(propRef.getVariable()), false);
            retVal = evalQuery(data, propRef.getPropertyAlias().getPart(),
                    propRef.getPropertyAlias().getLocation(), getEvaluationContext());
        } else if (from instanceof OAssign.PartnerLinkRef) {
            OAssign.PartnerLinkRef pLinkRef = (OAssign.PartnerLinkRef) from;
            PartnerLinkInstance pLink = _scopeFrame.resolve(pLinkRef.getPartnerLink());
            Node tempVal =pLinkRef.isIsMyEndpointReference() ?
                    getBpelRuntimeContext().fetchMyRoleEndpointReferenceData(pLink)
                    : getBpelRuntimeContext().fetchPartnerRoleEndpointReferenceData(pLink);
            if (__log.isDebugEnabled())
                __log.debug("RValue is a partner link, corresponding endpoint "
                        + tempVal.getClass().getName() + " has value " + DOMUtils.domToString(tempVal));
            retVal = tempVal;
        } else if (from instanceof OAssign.Expression) {
            List<Node> l;
            OExpression expr = ((OAssign.Expression) from).getExpression();
            try {
                l = getBpelRuntimeContext().getExpLangRuntime().evaluate(expr, getEvaluationContext());
                if (l.size() == 0 || l.get(0) == null || !(l.get(0) instanceof Element)) {
                    if (__log.isTraceEnabled()) {
                        __log.trace("evalRValue: OAssign.Expression: eval reult not Element or node=null");
                    }
                } else {
                    Element element = (Element)l.get(0);
                    for (Map.Entry<String, String> entry : DOMUtils.getMyNSContext(element).toMap().entrySet()) {
                        String key = entry.getKey();
                        String value = entry.getValue();
                        if (entry.getKey() == null || entry.getKey().length() == 0) {
                            element.setAttributeNS(DOMUtils.NS_URI_XMLNS, "xmlns", value);
                        } else {
                            element.setAttributeNS(DOMUtils.NS_URI_XMLNS, "xmlns:" + key, value);
                        }
                    }
                }
            } catch (EvaluationException e) {
                String msg = __msgs.msgEvalException(from.toString(), e.getMessage());
                if (__log.isDebugEnabled()) __log.debug(from + ": " + msg);
                if (e.getCause() instanceof FaultException) throw (FaultException)e.getCause();
                throw new FaultException(getOAsssign().getOwner().getConstants().getQnSelectionFailure(), msg);
            }
            if (l.size() == 0) {
                String msg = __msgs.msgRValueNoNodesSelected(expr.toString());
                if (__log.isDebugEnabled()) __log.debug(from + ": " + msg);
                throw new FaultException(getOAsssign().getOwner().getConstants().getQnSelectionFailure(), msg, new Throwable("ignoreMissingFromData"));
            } else if (l.size() > 1) {
                String msg = __msgs.msgRValueMultipleNodesSelected(expr.toString());
                if (__log.isDebugEnabled()) __log.debug(from + ": " + msg);
                throw new FaultException(getOAsssign().getOwner().getConstants().getQnSelectionFailure(), msg);
            }
            retVal = (Node) l.get(0);
        } else if (from instanceof OAssign.Literal) {
            String literal = ((OAssign.Literal) from).getXmlLiteral();
            Element literalRoot;
            try {
                literalRoot = DOMUtils.stringToDOM(literal);
            } catch (Exception e) {
                throw new RuntimeException("XML literal parsing failed " + literal, e);
            }
            assert literalRoot.getLocalName().equals("literal");
            // We'd like a single text node...

            literalRoot.normalize();
            retVal = literalRoot.getFirstChild();

            // Adjust for whitespace before an element.
            if (retVal != null && retVal.getNodeType() == Node.TEXT_NODE
                    && retVal.getTextContent().trim().length() == 0
                    && retVal.getNextSibling() != null) {
                retVal = retVal.getNextSibling();
            }

            if (retVal == null) {
                // Special case, no children --> empty TII
                retVal = literalRoot.getOwnerDocument().createTextNode("");
            } else if (retVal.getNodeType() == Node.ELEMENT_NODE) {
                // Make sure there is no more elements.
                Node x = retVal.getNextSibling();
                while (x != null) {
                    if (x.getNodeType() == Node.ELEMENT_NODE) {
                        String msg = __msgs.msgLiteralContainsMultipleEIIs();
                        if (__log.isDebugEnabled())
                            __log.debug(from + ": " + msg);
                        throw new FaultException(
                                getOAsssign().getOwner().getConstants().getQnSelectionFailure(),
                                msg);

                    }
                    x = x.getNextSibling();
                }
            } else if (retVal.getNodeType() == Node.TEXT_NODE) {
                // Make sure there are no elements following this text node.
                Node x = retVal.getNextSibling();
                while (x != null) {
                    if (x.getNodeType() == Node.ELEMENT_NODE) {
                        String msg = __msgs.msgLiteralContainsMixedContent();
                        if (__log.isDebugEnabled())
                            __log.debug(from + ": " + msg);
                        throw new FaultException(
                                getOAsssign().getOwner().getConstants().getQnSelectionFailure(),
                                msg);

                    }
                    x = x.getNextSibling();
                }

            }

            if (retVal == null) {
                String msg = __msgs.msgLiteralMustContainTIIorEII();
                if (__log.isDebugEnabled())
                    __log.debug(from + ": " + msg);
                throw new FaultException(
                        getOAsssign().getOwner().getConstants().getQnSelectionFailure(),
                        msg);
            }
        } else {
            String msg = __msgs
                    .msgInternalError("Unknown RVALUE type: " + from);
            if (__log.isErrorEnabled())
                __log.error(from + ": " + msg);
            throw new FaultException(
                    getOAsssign().getOwner().getConstants().getQnSelectionFailure(), msg);
        }

        // Now verify we got something.
        if (retVal == null) {
            String msg = __msgs.msgEmptyRValue();
            if (__log.isDebugEnabled())
                __log.debug(from + ": " + msg);
            throw new FaultException(
                    getOAsssign().getOwner().getConstants().getQnSelectionFailure(), msg);
        }

        // Now check that we got the right thing.
        switch (retVal.getNodeType()) {
            case Node.TEXT_NODE:
            case Node.ATTRIBUTE_NODE:
            case Node.ELEMENT_NODE:
            case Node.CDATA_SECTION_NODE:
                break;
            default:
                String msg = __msgs.msgInvalidRValue();
                if (__log.isDebugEnabled())
                    __log.debug(from + ": " + msg);

                throw new FaultException(
                        getOAsssign().getOwner().getConstants().getQnSelectionFailure(), msg);

        }

        return retVal;
    }

    private void copy(OAssign.Copy ocopy) throws FaultException, ExternalVariableModuleException {

        if (__log.isDebugEnabled())
            __log.debug("Assign.copy(" + ocopy + ")");

        ScopeEvent se;

        // Check for message to message - copy, we can do this efficiently in
        // the database.
        if ((ocopy.getTo() instanceof VariableRef && ((VariableRef) ocopy.getTo())
                .isMessageRef())
                || (ocopy.getFrom() instanceof VariableRef && ((VariableRef) ocopy.getFrom())
                .isMessageRef())) {

            if ((ocopy.getTo() instanceof VariableRef && ((VariableRef) ocopy.getTo())
                    .isMessageRef())
                    && ocopy.getFrom() instanceof VariableRef
                    && ((VariableRef) ocopy.getFrom()).isMessageRef()) {

                final VariableInstance lval = _scopeFrame.resolve(ocopy.getTo()
                        .getVariable());
                final VariableInstance rval = _scopeFrame
                        .resolve(((VariableRef) ocopy.getFrom()).getVariable());
                Element lvalue = (Element) fetchVariableData(rval, false);
                initializeVariable(lval, lvalue);
                se = new VariableModificationEvent(lval.declaration.getName());
                ((VariableModificationEvent)se).setNewValue(lvalue);
            } else {
                // This really should have been caught by the compiler.
                __log.error("Message/Non-Message Assignment, should be caught by compiler:"
                                + ocopy);
                throw new FaultException(
                        ocopy.getOwner().getConstants().getQnSelectionFailure(),
                        "Message/Non-Message Assignment:  " + ocopy);
            }
        } else {
            // Conventional Assignment logic.
            Node rvalue = evalRValue(ocopy.getFrom());
            Node lvalue = evalLValue(ocopy.getTo());
            if (__log.isDebugEnabled()) {
                __log.debug("lvalue after eval " + lvalue);
                if (lvalue != null) __log.debug("content " + DOMUtils.domToString(lvalue));
            }

            // Get a pointer within the lvalue.
            Node lvaluePtr = lvalue;
            boolean headerAssign = false;
            if (ocopy.getTo() instanceof OAssign.DirectRef) {
                DirectRef dref = ((DirectRef) ocopy.getTo());
                Element el = DOMUtils.findChildByName((Element)lvalue, dref.getElName());
                if (el == null) {
                    el = (Element) ((Element)lvalue).appendChild(lvalue.getOwnerDocument()
                            .createElementNS(dref.getElName().getNamespaceURI(), dref.getElName().getLocalPart()));
                }
                lvaluePtr = el;
            } else if (ocopy.getTo() instanceof OAssign.VariableRef) {
                VariableRef varRef = ((VariableRef) ocopy.getTo());
                if (varRef.getHeaderPart() != null) headerAssign = true;
                lvaluePtr = evalQuery(lvalue, varRef.getPart() != null ? varRef.getPart() : varRef.getHeaderPart(), varRef.getLocation(),
                        new EvaluationContextProxy(varRef.getVariable(), lvalue));
            } else if (ocopy.getTo() instanceof OAssign.PropertyRef) {
                PropertyRef propRef = ((PropertyRef) ocopy.getTo());
                lvaluePtr = evalQuery(lvalue, propRef.getPropertyAlias().getPart(),
                        propRef.getPropertyAlias().getLocation(),
                        new EvaluationContextProxy(propRef.getVariable(),
                                lvalue));
            } else if (ocopy.getTo() instanceof OAssign.LValueExpression) {
                LValueExpression lexpr = (LValueExpression) ocopy.getTo();
                lexpr.setInsertMissingToData(ocopy.isInsertMissingToData());
                lvaluePtr = evalQuery(lvalue, null, lexpr.getExpression(),
                        new EvaluationContextProxy(lexpr.getVariable(), lvalue));
                if (__log.isDebugEnabled())
                    __log.debug("lvaluePtr expr res " + lvaluePtr);
            }

            // For partner link assignmenent, the whole content is assigned.
            if (ocopy.getTo() instanceof OAssign.PartnerLinkRef) {
                OAssign.PartnerLinkRef pLinkRef = ((OAssign.PartnerLinkRef) ocopy.getTo());
                PartnerLinkInstance plval = _scopeFrame
                        .resolve(pLinkRef.getPartnerLink());
                replaceEndpointRefence(plval, rvalue);
                se = new PartnerLinkModificationEvent(((OAssign.PartnerLinkRef) ocopy.getTo()).getPartnerLink().getName());
            } else {
                // Sneakily converting the EPR if it's not the format expected by the lvalue
                if (ocopy.getFrom() instanceof OAssign.PartnerLinkRef) {
                    rvalue = getBpelRuntimeContext().convertEndpointReference((Element)rvalue, lvaluePtr);
                    if (rvalue.getNodeType() == Node.DOCUMENT_NODE)
                        rvalue = ((Document)rvalue).getDocumentElement();
                }

                 Node parentNode = lvaluePtr.getParentNode();
                if (headerAssign && parentNode != null && "message".equals(parentNode.getNodeName()) && rvalue.getNodeType()==Node.ELEMENT_NODE ) {
                    lvalue = copyInto((Element)lvalue, (Element) lvaluePtr, (Element) rvalue);
                } else if (rvalue.getNodeType() == Node.ELEMENT_NODE && lvaluePtr.getNodeType() == Node.ELEMENT_NODE) {
                    lvalue = replaceElement((Element)lvalue, (Element) lvaluePtr, (Element) rvalue,
                            ocopy.isKeepSrcElementName());
                } else {
                    lvalue = replaceContent(lvalue, lvaluePtr, rvalue.getTextContent());
                }
                final VariableInstance lval = _scopeFrame.resolve(ocopy.getTo().getVariable());
                if (__log.isDebugEnabled())
                    __log.debug("ASSIGN Writing variable '" + lval.declaration.getName() +
                                "' value '" + DOMUtils.domToString(lvalue) +"'");
                commitChanges(lval, lvalue);
                se = new VariableModificationEvent(lval.declaration.getName());
                ((VariableModificationEvent)se).setNewValue(lvalue);
            }
        }

        if (ocopy.getDebugInfo() != null)
            se.setLineNo(ocopy.getDebugInfo().getStartLine());
        sendEvent(se);
    }

    @Override
    Node fetchVariableData(VariableInstance variable, boolean forWriting)
            throws FaultException {
        try {
            return super.fetchVariableData(variable, forWriting);
        } catch (FaultException fe) {
            if (forWriting) {
                fe = new FaultException(fe.getQName(), fe.getMessage(), new Throwable("throwUninitializedToVariable"));
            }
            throw fe;
        }
    }

    private void replaceEndpointRefence(PartnerLinkInstance plval, Node rvalue) throws FaultException {
      if (rvalue.getNodeType() == Node.ATTRIBUTE_NODE){
          rvalue = rvalue.getOwnerDocument().createTextNode(((Attr) rvalue).getValue());
      }
        // Eventually wrapping with service-ref element if we've been directly assigned some
        // value that isn't wrapped.
        if (rvalue.getNodeType() == Node.TEXT_NODE ||
                (rvalue.getNodeType() == Node.ELEMENT_NODE && !rvalue.getLocalName().equals("service-ref"))) {
            Document doc = DOMUtils.newDocument();
            Element serviceRef = doc.createElementNS(Namespaces.WSBPEL2_0_FINAL_SERVREF, "service-ref");
            doc.appendChild(serviceRef);
            serviceRef.appendChild(doc.importNode(rvalue, true));
            rvalue = serviceRef;
        }

        getBpelRuntimeContext().writeEndpointReference(plval, (Element)rvalue);
    }

    private Element replaceElement(Element lval, Element ptr, Element src,
                                boolean keepSrcElement) {
        Document doc = ptr.getOwnerDocument();
        Node parent = ptr.getParentNode();
        if (keepSrcElement) {
            Element replacement = (Element)doc.importNode(src, true);
            parent.replaceChild(replacement, ptr);
            return (lval == ptr) ? replacement :  lval;
        }

        Element replacement = doc.createElementNS(ptr.getNamespaceURI(), ptr.getTagName());
        NodeList nl = src.getChildNodes();
        for (int i = 0; i < nl.getLength(); ++i)
            replacement.appendChild(doc.importNode(nl.item(i), true));
        copyAttributes(doc, ptr, replacement);
        copyAttributes(doc, src, replacement);
        parent.replaceChild(replacement, ptr);
        DOMUtils.copyNSContext(ptr, replacement);

        return (lval == ptr) ? replacement :  lval;
    }

    private void copyAttributes(Document doc, Element original,
            Element replacement) {
        NamedNodeMap attrs = original.getAttributes();
        for (int i = 0; i < attrs.getLength(); ++i) {
            Attr attr = (Attr)attrs.item(i);
            replacement.setAttributeNodeNS((Attr)doc.importNode(attr, true));
        }
    }

    private Element copyInto(Element lval, Element ptr, Element src) {
        ptr.appendChild(ptr.getOwnerDocument().importNode(src, true));
        return lval;
    }

    /**
     * isInsert flag desginates this as an 'element' type insertion, which
     * requires insert the actual element value, rather than it's children
     *
     * @return
     * @throws FaultException
     */
    private Node replaceContent(Node lvalue, Node lvaluePtr, String rvalue)
            throws FaultException {
        Document d = lvaluePtr.getOwnerDocument();

        if (__log.isDebugEnabled()) {
            __log.debug("lvaluePtr type " + lvaluePtr.getNodeType());
            __log.debug("lvaluePtr " + DOMUtils.domToString(lvaluePtr));
            __log.debug("lvalue " + lvalue);
            __log.debug("rvalue " + rvalue);
        }

        switch (lvaluePtr.getNodeType()) {
            case Node.ELEMENT_NODE:

                // Remove all the children.
                while (lvaluePtr.hasChildNodes())
                    lvaluePtr.removeChild(lvaluePtr.getFirstChild());

                // Append a new text node.
                lvaluePtr.appendChild(d.createTextNode(rvalue));

                // If lvalue is a text, removing all lvaluePtr children had just removed it
                // so we need to rebuild it as a child of lvaluePtr
                if (lvalue instanceof Text)
                    lvalue = lvaluePtr.getFirstChild();
                break;

            case Node.TEXT_NODE:

                Node newval = d.createTextNode(rvalue);
                // Replace ourselves .
                lvaluePtr.getParentNode().replaceChild(newval, lvaluePtr);

                // A little kludge, let our caller know that the root element has changed.
                // (used for assignment to a simple typed variable)
                if (lvalue.getNodeType() == Node.ELEMENT_NODE) {
                    // No children, adding an empty text children to point to
                    if (lvalue.getFirstChild() == null) {
                        Text txt = lvalue.getOwnerDocument().createTextNode("");
                        lvalue.appendChild(txt);
                    }
                    if (lvalue.getFirstChild().getNodeType() == Node.TEXT_NODE)
                        lvalue = lvalue.getFirstChild();
                }
                if (lvalue.getNodeType() == Node.TEXT_NODE && ((Text) lvalue).getWholeText().equals(
                        ((Text) lvaluePtr).getWholeText()))
                    lvalue = lvaluePtr = newval;
                break;

            case Node.ATTRIBUTE_NODE:

                ((Attr) lvaluePtr).setValue(rvalue);
                break;

            default:
                // This could occur if the expression language selects something
                // like
                // a PI or a CDATA.
                String msg = __msgs.msgInvalidLValue();
                if (__log.isDebugEnabled())
                    __log.debug(lvaluePtr + ": " + msg);
                throw new FaultException(
                        getOAsssign().getOwner().getConstants().getQnSelectionFailure(), msg);
        }

        return lvalue;
    }

    private Node evalQuery(Node data, OMessageVarType.Part part,
                           OExpression expression, EvaluationContext ec) throws FaultException {
        assert data != null;

        if (part != null) {
            QName partName = new QName(null, part.getName());
            Node qualLVal = DOMUtils.findChildByName((Element) data, partName);
            if (part.getType() instanceof OElementVarType) {
                QName elName = ((OElementVarType) part.getType()).getElementType();
                qualLVal = DOMUtils.findChildByName((Element) qualLVal, elName);
            } else if (part.getType() == null) {
                // Special case of header parts never referenced in the WSDL def
                if (qualLVal != null && qualLVal.getNodeType() == Node.ELEMENT_NODE
                        && ((Element)qualLVal).getAttribute("headerPart") != null
                        && DOMUtils.getTextContent(qualLVal) == null)
                    qualLVal = DOMUtils.getFirstChildElement((Element) qualLVal);
                // The needed part isn't there, dynamically creating it
                if (qualLVal == null) {
                    qualLVal = data.getOwnerDocument().createElementNS(null, part.getName());
                    ((Element)qualLVal).setAttribute("headerPart", "true");
                    data.appendChild(qualLVal);
                }
            }
            data = qualLVal;
        }

        if (expression != null) {
            // Neat little trick....
            try {
                data = ec.evaluateQuery(data, expression);
            } catch (EvaluationException e) {
                String msg = __msgs.msgEvalException(expression.toString(), e.getMessage());
                if (__log.isDebugEnabled()) __log.debug(expression + ": " + msg);
                if (e.getCause() instanceof FaultException) throw (FaultException)e.getCause();
                throw new FaultException(getOAsssign().getOwner().getConstants().getQnSubLanguageExecutionFault(), msg);
            }
        }

        return data;
    }

    private class EvaluationContextProxy implements EvaluationContext {

        private Variable _var;

        private Node _varNode;

        private Node _rootNode;

        private EvaluationContext _ctx;


        private EvaluationContextProxy(Variable var, Node varNode) {
            _var = var;
            _varNode = varNode;
            _ctx = getEvaluationContext();
        }

        public Node readVariable(OScope.Variable variable, OMessageVarType.Part part) throws FaultException {
            if (variable.getName().equals(_var.getName())) {
                if (part == null) return _varNode;
                return _ctx.getPartData((Element)_varNode, part);

            } else
                return _ctx.readVariable(variable, part);

        }       /**
     * @see org.apache.ode.bpel.explang.EvaluationContext#readMessageProperty(org.apache.ode.bpel.obj.OScope.Variable,
     *      org.apache.ode.bpel.obj.OProcess.OProperty)
     */
    public String readMessageProperty(Variable variable, OProperty property)
            throws FaultException {
        return _ctx.readMessageProperty(variable, property);
    }

        /**
         * @see org.apache.ode.bpel.explang.EvaluationContext#isLinkActive(org.apache.ode.bpel.obj.OLink)
         */
        public boolean isLinkActive(OLink olink) throws FaultException {
            return _ctx.isLinkActive(olink);
        }

        /**
         * @see org.apache.ode.bpel.explang.EvaluationContext#getRootNode()
         */
        public Node getRootNode() {
            return _rootNode;
        }

        /**
         * @see org.apache.ode.bpel.explang.EvaluationContext#evaluateQuery(org.w3c.dom.Node,
         *      org.apache.ode.bpel.obj.OExpression)
         */
        public Node evaluateQuery(Node root, OExpression expr)
                throws FaultException {
            _rootNode = root;
            try {
                return getBpelRuntimeContext().getExpLangRuntime()
                        .evaluateNode(expr, this);
            } catch (org.apache.ode.bpel.explang.EvaluationException e) {
                throw new FaultException(expr.getOwner().getConstants().getQnSubLanguageExecutionFault(), e);
            }
        }

        public Node getPartData(Element message, Part part) throws FaultException {
            return _ctx.getPartData(message,part);
        }

        public Long getProcessId() {
            return _ctx.getProcessId();
        }

        public boolean narrowTypes() {
            return false;
        }

        public URI getBaseResourceURI() {
            return _ctx.getBaseResourceURI();
        }

        public Node getPropertyValue(QName propertyName) {
            return _ctx.getPropertyValue(propertyName);
        }

        public QName getProcessQName() {
            return _ctx.getProcessQName();
        }

        public Date getCurrentEventDateTime() {
            return Calendar.getInstance().getTime();
        }
    }

}