gov.nih.nci.cabig.caaers.utils.XmlValidator.java Source code

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Here is the source code for gov.nih.nci.cabig.caaers.utils.XmlValidator.java

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/*******************************************************************************
 * Copyright SemanticBits, Northwestern University and Akaza Research
 * 
 * Distributed under the OSI-approved BSD 3-Clause License.
 * See http://ncip.github.com/caaers/LICENSE.txt for details.
 ******************************************************************************/
package gov.nih.nci.cabig.caaers.utils;

import gov.nih.nci.cabig.caaers.CaaersSystemException;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.StringReader;

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.dom.DOMSource;
import javax.xml.transform.stream.StreamSource;
import javax.xml.validation.Schema;
import javax.xml.validation.SchemaFactory;
import javax.xml.validation.Validator;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.w3c.dom.Document;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;

/**
 * This class provides a static method to validate an XMLFile against a Schema.
 * 
 * @author Monish Dombla
 *
 */
public class XmlValidator {

    private static Log logger = LogFactory.getLog(XmlValidator.class);

    public static boolean validateAgainstSchema(String xmlContent, String xsdUrl, StringBuffer validationResult) {
        boolean validXml = false;
        try {
            // parse an XML document into a DOM tree
            DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
            documentBuilderFactory.setValidating(false);
            documentBuilderFactory.setNamespaceAware(true);
            DocumentBuilder parser = documentBuilderFactory.newDocumentBuilder();
            Document document = parser.parse(new InputSource(new StringReader(xmlContent)));

            // create a SchemaFactory capable of understanding WXS schemas
            SchemaFactory schemaFactory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
            // load a WXS schema, represented by a Schema instance
            Source schemaFile = new StreamSource(getResources(xsdUrl)[0].getFile());

            Schema schema = schemaFactory.newSchema(schemaFile);
            // create a Validator instance, which can be used to validate an instance document
            Validator validator = schema.newValidator();
            // validate the DOM tree
            validator.validate(new DOMSource(document));
            validXml = true;
        } catch (FileNotFoundException ex) {
            throw new CaaersSystemException("File Not found Exception", ex);
        } catch (IOException ioe) {
            validationResult.append(ioe.getMessage());
            logger.error(ioe.getMessage());
        } catch (SAXParseException spe) {
            validationResult.append("Line : " + spe.getLineNumber() + " - " + spe.getMessage());
            logger.error("Line : " + spe.getLineNumber() + " - " + spe.getMessage());
        } catch (SAXException e) {
            validationResult.append(e.toString());
            logger.error(e.toString());
        } catch (ParserConfigurationException pce) {
            validationResult.append(pce.getMessage());
        }
        return validXml;
    }

    /**
     * This method fetches the specified resource pattern from classpath.
     * In this context used to fetch xsd files.
     * @param pattern
     * @return
     * @throws IOException
     */
    public static Resource[] getResources(String pattern) throws IOException {
        ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        if (logger.isDebugEnabled())
            logger.debug("Looking for resources matching " + pattern);
        Resource[] resources = resolver.getResources(pattern);
        return resources;
    }
}