BinaryProductHandler.java

package gov.usgs.earthquake.product.io;

import gov.usgs.earthquake.product.ByteContent;
import gov.usgs.earthquake.product.Content;
import gov.usgs.earthquake.product.ProductId;
import gov.usgs.util.StreamUtils;
import gov.usgs.util.CryptoUtils.Version;

import java.io.InputStream;
import java.io.OutputStream;
import java.net.URI;
import java.net.URL;

/**
 * Generator of binary format for product data.
 *
 * Binary representation of data types:
 * <dl>
 * <dt>Integer</dt>
 * <dd>4-bytes</dd>
 * <dt>Long</dt>
 * <dd>8-bytes</dd>
 * <dt>Date</dt>
 * <dd>Long (Date.getTime())</dd>
 * <dt>byte[]</dt>
 * <dd>Integer length, raw bytes</dd>
 * <dt>String</dt>
 * <dd>byte[] (String.getBytes(StandardCharsets.UTF_8))</dd>
 * <dt>URL/URI</dt>
 * <dd>String (URL.toString())</dd>
 * </dl>
 *
 *
 * Product is stored in this order:
 *
 * <ol>
 *
 * <li>Header, exactly 1
 * <ol>
 * <li>"BEGINPRODUCT" (string)</li>
 * <li>ProductId (String)</li>
 * <li>Status (String)</li>
 * <li>TrackerURL (URL)</li>
 * </ol>
 * </li>
 *
 * <li>Properties, 0 to many:
 * <ol>
 * <li>"PROPERTY" (String)</li>
 * <li>name (String)</li>
 * <li>value (String)</li>
 * </ol>
 * </li>
 *
 * <li>Links, 0 to many:
 * <ol>
 * <li>"LINK" (String)</li>
 * <li>relation (String)</li>
 * <li>href (URI)</li>
 * </ol>
 * </li>
 *
 * <li>Contents, 0 to many:
 * <ol>
 * <li>"CONTENT" (String)</li>
 * <li>path (String)</li>
 * <li>contentType (String)</li>
 * <li>lastModified (Date)</li>
 * <li>length (Long)</li>
 * <li>raw bytes</li>
 * </ol>
 * </li>
 *
 * <li>Signature Version, 0 or 1.
 * <em>Note, only sent when version != SIGNATURE_V1 for backward compatibility</em>
 * <ol>
 * <li>"SIGNATUREVERSION" (String)</li>
 * <li>version (String)</li>
 * </ol>
 * </li>
 *
 * <li>Signature, 0 or 1:
 * <ol>
 * <li>"SIGNATURE" (String)</li>
 * <li>signature (String)</li>
 * </ol>
 * </li>
 *
 * <li>Footer, exactly 1:
 * <ol>
 * <li>"ENDPRODUCT" (String)</li>
 * </ol>
 * </li>
 *
 * </ol>
 */
public class BinaryProductHandler implements ProductHandler {

    /** HEADER - BEGINPRODUCT */
    public static final String HEADER = "BEGINPRODUCT";
    /** PROPERTY */
    public static final String PROPERTY = "PROPERTY";
    /** LINK */
    public static final String LINK = "LINK";
    /** CONTENT */
    public static final String CONTENT = "CONTENT";
    /** SIGNATURE VERSION */
    public static final String SIGNATUREVERSION = "SIGNATUREVERSION";
    /** SIGNATURE */
    public static final String SIGNATURE = "SIGNATURE";
    /** ENDPRODUCT */
    public static final String FOOTER = "ENDPRODUCT";

    private OutputStream out;
    private BinaryIO io;

    /**
     * Constructor. Sets up a new BinaryIO
     * @param out an OutputStream
     */
    public BinaryProductHandler(final OutputStream out) {
        this.out = out;
        this.io = new BinaryIO();
    }

    @Override
    public void onBeginProduct(ProductId id, String status, URL trackerURL)
            throws Exception {
        io.writeString(HEADER, out);
        io.writeString(id.toString(), out);
        io.writeString(status, out);
        // allow trackerURL to be null
        if (trackerURL == null) {
            io.writeString("null", out);
        } else {
            io.writeString(trackerURL.toString(), out);
        }
    }

    @Override
    public void onProperty(ProductId id, String name, String value)
            throws Exception {
        io.writeString(PROPERTY, out);
        io.writeString(name, out);
        io.writeString(value, out);
    }

    @Override
    public void onLink(ProductId id, String relation, URI href)
            throws Exception {
        io.writeString(LINK, out);
        io.writeString(relation, out);
        io.writeString(href.toString(), out);
    }

    @Override
    public void onContent(ProductId id, String path, Content content)
            throws Exception {
        if (content.getLength() == null || content.getLength() < 0) {
            // binary io only handles streams with length, convert to content
            // with length
            content = new ByteContent(content);
        }

        io.writeString(CONTENT, out);
        io.writeString(path, out);

        io.writeString(content.getContentType(), out);
        io.writeDate(content.getLastModified(), out);
        InputStream contentInputStream = content.getInputStream();
        try {
            io.writeStream(content.getLength().longValue(), contentInputStream, out);
        } finally {
            StreamUtils.closeStream(contentInputStream);
        }
    }

    @Override
    public void onSignatureVersion(ProductId id, Version version) throws Exception {
        if (version != Version.SIGNATURE_V1) {
            io.writeString(SIGNATUREVERSION, out);
            io.writeString(version.toString(), out);
        }
    }

    @Override
    public void onSignature(ProductId id, String signature) throws Exception {
        // allow signature to be null
        if (signature == null) {
            return;
        }

        io.writeString(SIGNATURE, out);
        io.writeString(signature, out);
    }

    @Override
    public void onEndProduct(ProductId id) throws Exception {
        io.writeString(FOOTER, out);

        out.flush();
        out.close();
    }

    /**
     * Free any resources associated with this source.
     */
    @Override
    public void close() {
        StreamUtils.closeStream(out);
        out = null;
    }

}