BatchModifyValidator.java

/* The contents of this file are subject to the license and copyright terms
 * detailed in the license directory at the root of the source tree (also 
 * available online at http://fedora-commons.org/license/).
 */
package fedora.client.batch;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.PrintStream;

import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;

import fedora.server.utilities.StreamUtility;

/**
 * A class for parsing the xml modify directives in the Batch Modify input
 * file.
 * 
 * The parsing is configured to parse directives in the file sequentially.
 * Logs are written for each successful and failed directive that is processed.
 * Recoverable(non-fatal) errors are written to the log file and processing
 * continues. Catastrophic errors will cause parsing to halt and set the count
 * of failed directives to -1 indicating that parsing was halted prior to 
 * the end of the file. In this case the logs will contain all directives 
 * processed up to the point of failure.
 * 
 * @author Ross Wayland
 */
public class BatchModifyValidator
        extends DefaultHandler {

    //private InputStream in;
    private static PrintStream out;

    private boolean isValid = false;

    private static int errorCount = 0;

    /**
     * Constructor allows this class to initiate the parsing.
     * 
     * @param in
     *        An input stream containing the xml to be parsed.
     * @param out
     *        A print stream used for writing log info.
     * @throws Exception
     *         If an error occurs in configuring the SAX parser.
     */
    public BatchModifyValidator(InputStream in, PrintStream out)
            throws Exception {
        //this.in = in;
        BatchModifyValidator.out = out;
        BatchModifyValidator.errorCount = 0;
        XMLReader xmlReader = null;

        // Configure the SAX parser.
        BatchModifyValidatorErrorHandler errorHandler =
                new BatchModifyValidatorErrorHandler(out);
        try {
            SAXParserFactory saxfactory = SAXParserFactory.newInstance();
            saxfactory.setValidating(true);
            SAXParser parser = saxfactory.newSAXParser();
            xmlReader = parser.getXMLReader();
            xmlReader.setContentHandler(this);
            xmlReader
                    .setFeature("http://xml.org/sax/features/namespaces", true);
            xmlReader
                    .setFeature("http://xml.org/sax/features/namespace-prefixes",
                                true);
            xmlReader
                    .setFeature("http://apache.org/xml/features/validation/schema",
                                true);
            xmlReader
                    .setFeature("http://apache.org/xml/features/continue-after-fatal-error",
                                true);
            xmlReader.setErrorHandler(errorHandler);
        } catch (Exception e) {
            System.err.println("ERROR: "
                    + e.getClass().getName()
                    + " - "
                    + (e.getMessage() == null ? "(no detail provided)" : e
                            .getMessage()));
            logError(e, "(no detail provided.)");
            errorCount = BatchModifyValidatorErrorHandler.errorCount;
            if (errorCount == 0) {
                errorCount++;
            }
            isValid = false;
        }

        // Parse the file.
        try {
            xmlReader.parse(new InputSource(in));
            errorCount = BatchModifyValidatorErrorHandler.errorCount;
            if (BatchModifyValidatorErrorHandler.errorCount == 0) {
                isValid = true;
            }
        } catch (Exception e) {
            System.err.println("ERROR: "
                    + e.getClass().getName()
                    + " - "
                    + (e.getMessage() == null ? "(no detail provided)" : e
                            .getMessage()));
            logError(e, "(no detail provided.)");
            errorCount = BatchModifyValidatorErrorHandler.errorCount;
            isValid = false;

        }
    }

    public boolean isValid() {
        return isValid;
    }

    public int getErrorCount() {
        return errorCount;
    }

    private static void logError(Exception e, String msg) {
        out.println("  <parser-error>");
        if (e != null) {
            String message = e.getMessage();
            if (message == null) {
                message = e.getClass().getName();
            }
            out.println("    " + StreamUtility.enc(message));
        } else {
            out.println("    " + StreamUtility.enc(msg));
        }
        out.println("  </parser-error>");
    }

    public static void main(String[] args) {

        try {
            PrintStream log =
                    new PrintStream(new FileOutputStream("c:\\zlogfile.txt"));
            InputStream file =
                    new FileInputStream("c:\\fedora\\mellon\\dist\\client\\demo\\batch-demo\\modify-batch-directives.xml");
            new BatchModifyValidator(file, log);
            file.close();
        } catch (Exception e) {
            System.out.println("ERROR: "
                    + e.getClass().getName()
                    + " - "
                    + (e.getMessage() == null ? "(no detail provided)" : e
                            .getMessage()));
        }
    }

}