# TextProcessingEvaluatorSerializer.java

    /*
     *  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.synapse.commons.evaluators.config;

    import org.apache.synapse.commons.evaluators.source.*;
    import org.apache.synapse.commons.evaluators.EvaluatorConstants;
    import org.apache.synapse.commons.evaluators.EvaluatorException;
    import org.apache.axiom.om.OMElement;

    public abstract class TextProcessingEvaluatorSerializer extends AbstractEvaluatorSerializer {

        protected void serializeSourceTextRetriever(SourceTextRetriever textRetriever,
                                                    OMElement element) throws EvaluatorException {

            if (textRetriever instanceof HeaderTextRetriever) {
                element.addAttribute(fac.createOMAttribute(EvaluatorConstants.TYPE, nullNS,
                        EvaluatorConstants.HEADER));
                addSourceAttribute(textRetriever.getSource(), element);

            } else if (textRetriever instanceof ParameterTextRetriever) {
                element.addAttribute(fac.createOMAttribute(EvaluatorConstants.TYPE, nullNS,
                        EvaluatorConstants.PARAM));
                addSourceAttribute(textRetriever.getSource(), element);

            } else if (textRetriever instanceof PropertyTextRetriever) {
                element.addAttribute(fac.createOMAttribute(EvaluatorConstants.TYPE, nullNS,
                        EvaluatorConstants.PROPERTY));
                addSourceAttribute(textRetriever.getSource(), element);

            } else if (textRetriever instanceof SOAPEnvelopeTextRetriever) {
                element.addAttribute(fac.createOMAttribute(EvaluatorConstants.TYPE, nullNS,
                        EvaluatorConstants.SOAP));
                addSourceAttribute(textRetriever.getSource(), element);

            } else {
                element.addAttribute(fac.createOMAttribute(EvaluatorConstants.TYPE, nullNS,
                        EvaluatorConstants.URL));
                if (textRetriever.getSource() != null) {
                    element.addAttribute(fac.createOMAttribute(EvaluatorConstants.SOURCE,
                            nullNS, textRetriever.getSource()));
                }
            }
        }

        private void addSourceAttribute(String source, OMElement element)
                throws EvaluatorException {

            if (source != null) {
                element.addAttribute(fac.createOMAttribute(EvaluatorConstants.SOURCE, nullNS,
                        source));
            } else {
                String msg = "If type is not URL a source value should be specified for " +
                                "the evaluator";
                log.error(msg);
                throw new EvaluatorException(msg);
            }
        }

    }