HttpPayload.java

package dk.kb.yggdrasil;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.util.UUID;

/**
 * Wrapper for the HTTP response payload.
 */
public class HttpPayload {

    /** Response content body steam. (Remember to close) */
    private InputStream contentBody;
    /** Response content body content encoding, null if not returned. */
    private String contentEncoding;
    /** Response content type, null if not returned. */
    private String contentType;
    /** Response content length, null if not returned. */
    private Long contentLength;
    /** The amount of data read into the buffer. */
    private static final int READBUFFERSIZE = 16384; // 16 Kbytes
    /** The directory, where the file should be placed. */
    private final File tmpDir;
    
    /**
     * Construct a payload object with the supplied parameters.
     * @param contentBody <code>InputStream</code> with the content body
     * @param contentEncoding content encoding, null if not returned
     * @param contentType content type, null if not returned
     * @param contentLength content length, null if not returned
     * @param tmpDir The temporary directory, where the files will be stored while downloading.
     */
    public HttpPayload(InputStream contentBody, String contentEncoding, String contentType, Long contentLength,
            File tmpDir) {
        this.contentBody = contentBody;
        this.contentEncoding = contentEncoding;
        this.contentType = contentType;
        this.contentLength = contentLength;
        this.tmpDir = tmpDir;
    }

    /**
     * Close the payload object and release any resources associated with it.
     * @throws IOException an i/o exception if an error occurs while closing stream
     */
    public void close() throws IOException {
        if (contentBody != null) {
            contentBody.close();
            contentBody = null;
        }
    }

    /**
     * Write the payload to a file. A temporary file is created for this purpose. 
     * @return the File containing the payload.
     * @throws IOException If unable to read or write the data.
     */
    public File writeToFile() throws IOException {
        byte[] tmpBuf = new byte[READBUFFERSIZE];
        int read;
        File tmpFile = null;
        RandomAccessFile raf;
        UUID uuid = UUID.randomUUID();
        tmpFile = new File(tmpDir, uuid.toString());
        raf = new RandomAccessFile(tmpFile, "rw");
        InputStream in = contentBody;
        while ((read = in.read(tmpBuf)) != -1 ) {
            raf.write(tmpBuf, 0, read);
        }
        raf.close();
        raf = null;
        in.close();
        return tmpFile;
    }

    /** @return Response content body steam. (Remember to close) */
    public InputStream getContentBody() {
        return contentBody;
    }
    /** @return Response content body content encoding, null if not returned. */
    public String getContentEncoding() {
        return contentEncoding;
    }
    /** @return Response content type, null if not returned. */
    public String getContentType() {
        return contentType;
    }
    /** @return Response content length, null if not returned. */
    public Long getContentLength() {
        return contentLength;
    };

}