Trimmer.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.unittest;
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 remove the unwanted whitespaces in any type of inputs.
*/
class Trimmer {
Trimmer() {
}
private static Logger log = Logger.getLogger(Trimmer.class.getName());
/**
* Remove irrelevant whitespaces from the input string.
*
* @param inputString string which needs to remove whitespaces
* @return trim string not include irrelevant whitespaces
*/
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) {
log.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) {
log.error("nodeToString Transformer Exception", e);
}
return sw.toString();
}
}