io.leishvl.core.xml.XmlHelper.java Source code

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Here is the source code for io.leishvl.core.xml.XmlHelper.java

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/*
 * Copyright 2014-2015 EUBrazilCC (EU?Brazil Cloud Connect)
 *
 * Licensed 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.
 *
 * This product combines work with different licenses. See the "NOTICE" text
 * file for details on the various modules and licenses.
 *
 * The "NOTICE" text file is part of the distribution. Any derivative works
 * that you distribute must include a readable copy of the "NOTICE" text file.
 */

package io.leishvl.core.xml;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static java.nio.charset.StandardCharsets.UTF_8;
import static javax.xml.transform.OutputKeys.ENCODING;
import static javax.xml.transform.OutputKeys.INDENT;
import static javax.xml.transform.OutputKeys.OMIT_XML_DECLARATION;
import static org.apache.commons.lang3.StringUtils.isNoneBlank;
import static org.slf4j.LoggerFactory.getLogger;

import java.io.ByteArrayInputStream;
import java.io.StringWriter;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.slf4j.Logger;
import org.w3c.dom.Document;

/**
 * Utilities to handle XML documents and fragments.
 * @author Erik Torres <ertorser@upv.es>
 */
public final class XmlHelper {

    private static final Logger LOGGER = getLogger(XmlHelper.class);

    /**
     * Obtains a String representation of a XML document, omitting the XML declaration.
     * @param document the document to be transformed into String.
     * @return a String representation of the specified XML document.
     */
    public static String documentToStringOmitXmlDeclaration(final Document document) {
        checkNotNull(document, "Uninitialized document");
        String docStr;
        try {
            final TransformerFactory tf = TransformerFactory.newInstance();
            final Transformer transformer = tf.newTransformer();
            transformer.setOutputProperty(ENCODING, UTF_8.name());
            transformer.setOutputProperty(OMIT_XML_DECLARATION, "yes");
            final StringWriter writer = new StringWriter();
            transformer.transform(new DOMSource(document), new StreamResult(writer));
            docStr = writer.toString();
        } catch (Exception e) {
            docStr = null;
            LOGGER.warn("Failed to convert DOM document to String", e);
        }
        return docStr;
    }

    public static String prettyPrint(final String payload) {
        checkArgument(isNoneBlank(payload), "Uninitialized XML payload");
        String docStr;
        try {
            final DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
            dbf.setValidating(false);
            final DocumentBuilder db = dbf.newDocumentBuilder();
            final Document document = db.parse(new ByteArrayInputStream(payload.getBytes()));
            docStr = prettyPrint(document);
        } catch (Exception e) {
            docStr = null;
            LOGGER.warn("Failed to convert DOM document to String", e);
        }
        return docStr;
    }

    public static String prettyPrint(final Document document) {
        checkNotNull(document, "Uninitialized document");
        String docStr;
        try {
            final TransformerFactory tf = TransformerFactory.newInstance();
            final Transformer transformer = tf.newTransformer();
            transformer.setOutputProperty(ENCODING, UTF_8.name());
            transformer.setOutputProperty(OMIT_XML_DECLARATION, "yes");
            transformer.setOutputProperty(INDENT, "yes");
            final StringWriter writer = new StringWriter();
            transformer.transform(new DOMSource(document), new StreamResult(writer));
            docStr = writer.toString();
        } catch (Exception e) {
            docStr = null;
            LOGGER.warn("Failed to convert DOM document to String", e);
        }
        return docStr;
    }

}