ContentListener.java

package gov.usgs.earthquake.distribution;

import java.io.File;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Iterator;
import java.util.Map;
import java.util.logging.Logger;

import gov.usgs.earthquake.product.Content;
import gov.usgs.earthquake.product.Product;
import gov.usgs.earthquake.product.ProductId;
import gov.usgs.util.Config;
import gov.usgs.util.StreamUtils;

/**
 * A listener that listens for a specific content path.
 *
 * This is intended for users who wish to output specific pieces of product
 * content, such as "quakeml.xml", for products that otherwise meet their
 * configured NotificationListener criteria.
 */
public class ContentListener extends DefaultNotificationListener {

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

    /** configuration property for includePaths - output directory. */
    public static final String OUTPUT_DIRECTORY_PROPERTY = "outputDirectory";
    /** property for temporary directory */
    public static final String TEMP_DIRECTORY_PROPERTY = "tempDirectory";
    /** property for output format */
    public static final String OUTPUT_FORMAT_PROPERTY = "outputFormat";

    /** property for default output format */
    public static final String DEFAULT_OUTPUT_FORMAT = "SOURCE_TYPE_CODE_UPDATETIME_PATH";

    /** Directory where content is output. */
    private File outputDirectory = null;

    /**
     * Temporary directory where content is written before moving to
     * outputDirectory, defaults to system temp directory when null.
     */
    private File tempDirectory = null;

    /** Output format for files inside outputDirectory. */
    private String outputFormat = DEFAULT_OUTPUT_FORMAT;

    /** empty constructor for ContentListener */
    public ContentListener() {
    }

    @Override
    public void configure(final Config config) throws Exception {
        super.configure(config);

        if (getIncludePaths().size() == 0) {
            throw new ConfigurationException("[" + getName()
                    + "] ContentListener requires 'includePaths' be non-empty");
        }

        outputDirectory = new File(
                config.getProperty(OUTPUT_DIRECTORY_PROPERTY));
        LOGGER.config("[" + getName() + "] output directory = "
                + outputDirectory);

        String tempDirectoryString = config
                .getProperty(TEMP_DIRECTORY_PROPERTY);
        if (tempDirectoryString != null) {
            tempDirectory = new File(tempDirectoryString);
        }
        LOGGER.config("[" + getName() + "] temp directory = " + tempDirectory);

        outputFormat = config.getProperty(OUTPUT_FORMAT_PROPERTY,
                DEFAULT_OUTPUT_FORMAT);
        LOGGER.config("[" + getName() + "] output format = " + outputFormat);
    }

    @Override
    public void onProduct(final Product product) throws Exception {
        Map<String, Content> contents = product.getContents();
        Iterator<String> iter = getIncludePaths().iterator();
        while (iter.hasNext()) {
            String path = iter.next();
            Content content = contents.get(path);
            if (content != null) {
                // product has content at this path
                writeContent(product.getId(), path, content);
            }
        }
    }

    /**
     * Generate an output path based on product id and content path.
     *
     * @param id
     *            the product id.
     * @param path
     *            the content path.
     * @return relative path to write content within output directory.
     */
    protected String getOutputPath(final ProductId id, final String path) {
        return outputFormat
                .replace("SOURCE", id.getSource())
                .replace("TYPE", id.getType())
                .replace("CODE", id.getCode())
                .replace("UPDATETIME",
                        Long.toString(id.getUpdateTime().getTime()))
                .replace("PATH", path);
    }

    /**
     * Output a product content that was in includePaths.
     *
     * @param id
     *            the product id.
     * @param path
     *            the content path.
     * @param content
     *            the content.
     * @throws Exception
     *             when unable to output the content.
     */
    protected void writeContent(final ProductId id, final String path,
            final Content content) throws Exception {
        String outputPath = getOutputPath(id, path);
        if (tempDirectory != null && !tempDirectory.exists()) {
            // make sure parent directories exist
            tempDirectory.mkdirs();
        }
        File tempFile = File.createTempFile(outputPath, null, tempDirectory);

        File outputFile = new File(outputDirectory, outputPath);
        File outputFileParent = outputFile.getParentFile();
        if (!outputFileParent.exists()) {
            // make sure parent directories exist
            outputFileParent.mkdirs();
        }

        // write, then move into place
        InputStream in = null;
        OutputStream out = null;
        try {
            if (!tempFile.getParentFile().exists()) {
                tempFile.getParentFile().mkdirs();
            }
            if (!outputFile.getParentFile().exists()) {
                outputFile.getParentFile().mkdirs();
            }
            in = content.getInputStream();
            out = StreamUtils.getOutputStream(tempFile);
            // write to temp file
            StreamUtils.transferStream(in, out);
            // move to output file
            tempFile.renameTo(outputFile);
        } finally {
            StreamUtils.closeStream(in);
            StreamUtils.closeStream(out);
            // clean up temp file if it wasn't renamed
            if (tempFile.exists()) {
                tempFile.delete();
            }
        }
    }

    /**
     * @return the outputDirectory
     */
    public File getOutputDirectory() {
        return outputDirectory;
    }

    /**
     * @param outputDirectory
     *            the outputDirectory to set
     */
    public void setOutputDirectory(File outputDirectory) {
        this.outputDirectory = outputDirectory;
    }

    /**
     * @return the tempDirectory
     */
    public File getTempDirectory() {
        return tempDirectory;
    }

    /**
     * @param tempDirectory
     *            the tempDirectory to set
     */
    public void setTempDirectory(File tempDirectory) {
        this.tempDirectory = tempDirectory;
    }

    /**
     * @return the outputFormat
     */
    public String getOutputFormat() {
        return outputFormat;
    }

    /**
     * @param outputFormat
     *            the outputFormat to set
     */
    public void setOutputFormat(String outputFormat) {
        this.outputFormat = outputFormat;
    }

}