Java XML String Transform identity(String xml)

Description

Executes an identity transform.

License

Apache License

Parameter

Parameter	Description
xml	the xml

Exception

Parameter	Description
TransformerException	if an exception occurs

Declaration

public static String identity(String xml) throws TransformerException 

Method Source Code

//package com.java2s;
/* See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * Esri 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.//w  w w .j ava2 s.co  m
 */

import java.io.StringReader;
import java.io.StringWriter;
import java.io.UnsupportedEncodingException;
import javax.xml.XMLConstants;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.stream.StreamResult;
import javax.xml.transform.stream.StreamSource;

public class Main {
    /** DEFAULT_ENCODING = "UTF-8" */
    public static final String DEFAULT_ENCODING = "UTF-8";
    /** DEFAULT_HEADER = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>" */
    public static final String DEFAULT_HEADER = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>";

    /**
     * Executes an identity transform.
     * @param xml the xml
     * @throws TransformerException if an exception occurs
     */
    public static String identity(String xml) throws TransformerException {
        xml = removeBOM(xml);
        if (xml != null)
            xml = xml.trim();
        if ((xml == null) || (xml.length() == 0)) {
            throw new TransformerException("Empty XML.");
        }
        StringWriter result = new StringWriter();
        transform(new StreamSource(new StringReader(xml)), new StreamResult(result), false);
        return checkResult(result, false);
    }

    /**
     * Removes a windows byte order mark if present.
     * @param s the string to check
     * @return the string absent the byte order mark
     */
    public static String removeBOM(String s) {
        if (s != null) {
            byte[] bom = new byte[3];
            bom[0] = (byte) 0xEF;
            bom[1] = (byte) 0xBB;
            bom[2] = (byte) 0xBF;
            try {
                String sbom = new String(bom, "UTF-8");
                s = s.trim();
                if (s.startsWith(sbom)) {
                    s = s.substring(1).trim();
                }
            } catch (UnsupportedEncodingException e) {
            }
        }
        return s;
    }

    /**
     * Executes a transformation.
     * <br>The output encoding is set to UTF-8
     * @param source the transformation source
     * @param result the transformation result
     * @param indent if true, the output indent key is set to "yes"
     * @throws TransformerException if an exception occurs
     */
    public static void transform(javax.xml.transform.Source source, javax.xml.transform.Result result,
            boolean indent) throws TransformerException {
        TransformerFactory factory = TransformerFactory.newInstance();
        factory.setAttribute(XMLConstants.ACCESS_EXTERNAL_DTD, "");
        factory.setFeature("http://javax.xml.XMLConstants/feature/secure-processing", true);
        //factory.setFeature("http://apache.org/xml/features/disallow-doctype-decl",true); 
        Transformer transformer = factory.newTransformer();
        transformer.setOutputProperty(OutputKeys.ENCODING, DEFAULT_ENCODING);
        transformer.setOutputProperty(OutputKeys.METHOD, "xml");
        if (indent) {
            transformer.setOutputProperty(OutputKeys.INDENT, "yes");
            transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "2");
        }
        transformer.transform(source, result);
    }

    /**
     * Check a result.
     * @param result the result
     * @return the string (trimmed, null if empty)
     */
    public static String checkResult(StringWriter result, boolean checkIndent) {
        String s = result.toString();
        if (s != null) {
            s = s.trim();
            if (checkIndent) {
                if (s.startsWith(DEFAULT_HEADER + "<")) {
                    s = s.replace(DEFAULT_HEADER, DEFAULT_HEADER + "\r\n");
                }
            }
            if (s.length() == 0)
                s = null;
        }
        ;
        return s;
    }
}

Related

1. getString(Node node, boolean indent)
2. getStringFromStreamSource(StreamSource src)
3. getTemplates(String name)
4. getValidator(String path)
5. getXmlStringFromSource(Source payload)
6. indentXML(String fileContent)
7. loadSourceFromURL(String systemID)
8. mergeXml(String... xmlSources)
9. normXML(String s)