com.opengamma.web.analytics.json.Compressor.java Source code

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Here is the source code for com.opengamma.web.analytics.json.Compressor.java

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/**
 * Copyright (C) 2012 - present by OpenGamma Inc. and the OpenGamma group of companies
 *
 * Please see distribution for license.
 */
package com.opengamma.web.analytics.json;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;

import javax.ws.rs.Consumes;
import javax.ws.rs.FormParam;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;

import org.apache.commons.codec.binary.Base64InputStream;
import org.apache.commons.codec.binary.Base64OutputStream;
import org.json.JSONObject;

import com.google.common.collect.ImmutableMap;

/**
 * REST endpoint for compressing and decompressing the state of the web UI using GZIP and encoding it using base64.
 */
@Path("compressor")
public class Compressor {

    /**
     * Compresses the "content" parameter using GZIP, encodes it to base64 and returns it wrapped in a JSON object
     * with the key "data".
     * @param content The content that needs to be compressed
     * @return Response containing JSON with the compressed content keyed with "data"
     * @throws IOException If compression fails
     */
    @POST
    @Path("compress")
    @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
    public Response compress(@FormParam("content") String content) throws IOException {
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        compressStream(new ByteArrayInputStream(content.getBytes()), outputStream);
        ImmutableMap<String, String> data = ImmutableMap.of("data", outputStream.toString());
        return Response.status(Response.Status.OK).entity(new JSONObject(data).toString()).build();
    }

    /**
     * Decodes the "content" parameter from base64, decompresses it using GZIP and returns it wrapped in a JSON object
     * with the key "data".
     * @param content The content that needs to be decompressed
     * @return Response containing JSON with the decompressed content keyed with "data"
     * @throws IOException If decompression fails
     */
    @POST
    @Path("decompress")
    @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
    public Response decompress(@FormParam("content") String content) throws IOException {
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        decompressStream(new ByteArrayInputStream(content.getBytes()), outputStream);
        String data = "{\"data\":" + outputStream.toString() + "}";
        return Response.status(Response.Status.OK).entity(data).build();
    }

    /* package */ static void compressStream(InputStream inputStream, OutputStream outputStream)
            throws IOException {
        InputStream iStream = new BufferedInputStream(inputStream);
        GZIPOutputStream oStream = new GZIPOutputStream(
                new Base64OutputStream(new BufferedOutputStream(outputStream), true, -1, null), 2048);
        byte[] buffer = new byte[2048];
        int bytesRead;
        while ((bytesRead = iStream.read(buffer)) != -1) {
            oStream.write(buffer, 0, bytesRead);
        }
        oStream.close(); // this is necessary for the gzip and base64 streams
    }

    /* package */ static void decompressStream(InputStream inputStream, OutputStream outputStream)
            throws IOException {
        @SuppressWarnings("resource")
        InputStream iStream = new GZIPInputStream(
                new Base64InputStream(new BufferedInputStream(inputStream), false, -1, null));
        OutputStream oStream = new BufferedOutputStream(outputStream);
        byte[] buffer = new byte[2048];
        int bytesRead;
        while ((bytesRead = iStream.read(buffer)) != -1) {
            oStream.write(buffer, 0, bytesRead);
        }
        oStream.flush();
    }

}