# RequestProcessor.java

    /*
     Copyright (c) 2019, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
     *
     * WSO2 Inc. 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.emulator;

    import com.google.gson.JsonObject;
    import com.google.gson.JsonParser;
    import org.apache.log4j.Logger;
    import org.w3c.dom.Document;
    import org.w3c.dom.Node;
    import org.xml.sax.InputSource;

    import javax.xml.parsers.DocumentBuilder;
    import javax.xml.parsers.DocumentBuilderFactory;
    import javax.xml.transform.OutputKeys;
    import javax.xml.transform.Transformer;
    import javax.xml.transform.TransformerFactory;
    import javax.xml.transform.dom.DOMSource;
    import javax.xml.transform.stream.StreamResult;
    import java.io.StringReader;
    import java.io.StringWriter;

    /**
     * Class responsible for removing the unwanted whitespaces in any type of inputs.
     */
    public class RequestProcessor {

        RequestProcessor() {
        }

        private static Logger logger = Logger.getLogger(RequestProcessor.class.getName());

        /**
         * Remove irrelevant whitespaces from the input string.
         *
         * @param inputString string which needs to remove whitespaces
         * @return trim string not include irrelevant whitespaces
         */
        public static String trimStrings(String inputString) {

            //trim the string
            String trimedString = inputString.trim();

            //check whether string is an XML
            if (trimedString.startsWith("<")) {

                //remove CDATA tag from the string
                if (trimedString.startsWith("<![CDATA[")) {
                    trimedString = trimedString.substring(9);
                    int i = trimedString.indexOf("]]>");
                    if (i == -1)
                        throw new IllegalStateException("argument starts with <![CDATA[ but cannot find pairing ]]>");
                    trimedString = trimedString.substring(0, i);
                }

                //convert string to XML DOM
                Document xmlDOM = convertStringToXMLDocument(trimedString);
                trimedString = nodeToString(xmlDOM);
                trimedString = trimedString.replaceAll("xmlns=\"\"", "");

            } else if (trimedString.startsWith("{")) {
                JsonObject inputJSON = new JsonParser()
                        .parse(trimedString).getAsJsonObject();
                trimedString = inputJSON.toString();
            }
            return trimedString.replaceAll("\\s", "");
        }

        private static Document convertStringToXMLDocument(String xmlString) {
            //Parser that produces DOM object trees from XML content
            DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();

            //API to obtain DOM Document instance
            DocumentBuilder builder;
            try {
                //Create DocumentBuilder with default configuration
                builder = factory.newDocumentBuilder();

                //Parse the content to Document object
                return builder.parse(new InputSource(new StringReader(xmlString)));
            } catch (Exception e) {
                logger.error("Error while parsing xmlString to DOM", e);
            }
            return null;
        }

        private static String nodeToString(Node node) {
            StringWriter sw = new StringWriter();
            try {
                Transformer t = TransformerFactory.newInstance().newTransformer();
                t.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
                t.setOutputProperty(OutputKeys.INDENT, "yes");
                t.transform(new DOMSource(node), new StreamResult(sw));
            } catch (Exception e) {
                logger.error("nodeToString Transformer Exception", e);
            }
            return sw.toString();
        }
    }