StubConfigurationValidator.java

package com.epam.wilma.service.configuration.stub.helper.common;
/*==========================================================================
 Copyright 2013-2017 EPAM Systems

 This file is part of Wilma.

 Wilma is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 Wilma is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with Wilma.  If not, see <http://www.gnu.org/licenses/>.
 ===========================================================================*/

import org.w3c.dom.Document;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

import javax.xml.XMLConstants;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Source;
import javax.xml.transform.stream.StreamSource;
import javax.xml.validation.Schema;
import javax.xml.validation.SchemaFactory;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;

/**
 * This validator class is used to check the generated config is valid or not.
 *
 * @author tkohegyi
 */
public class StubConfigurationValidator {

    /**
     * Validates the specified string as stub configuration XML against the XSD.
     *
     * @param candidateConfiguration is the candidate
     * @throws StubConfigurationException when the (structure) validation fails
     */
    public void validate(String candidateConfiguration) throws StubConfigurationException {
        try {
            ClassLoader classloader = Thread.currentThread().getContextClassLoader();
            InputStream is = classloader.getResourceAsStream("StubConfig.xsd");
            Source schemaFile = new StreamSource(is);
            SchemaFactory factory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
            Schema schema = factory.newSchema(schemaFile);
            DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
            dbFactory.setNamespaceAware(true);
            dbFactory.setSchema(schema);
            DocumentBuilder documentBuilder = dbFactory.newDocumentBuilder();
            Document document = documentBuilder.parse(new InputSource(new ByteArrayInputStream(candidateConfiguration.getBytes("utf-8"))));
            document.getDocumentElement().normalize();
            //if we are here then the xml is valid
        } catch (SAXException | ParserConfigurationException | IOException e) {
            // instance document is invalid!
            throw new StubConfigurationException("Stub Configuration structure is invalid.", e);
        }
    }
}