001// Copyright 2013 The Apache Software Foundation 002// 003// Licensed under the Apache License, Version 2.0 (the "License"); 004// you may not use this file except in compliance with the License. 005// You may obtain a copy of the License at 006// 007// http://www.apache.org/licenses/LICENSE-2.0 008// 009// Unless required by applicable law or agreed to in writing, software 010// distributed under the License is distributed on an "AS IS" BASIS, 011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 012// See the License for the specific language governing permissions and 013// limitations under the License. 014 015package org.apache.tapestry5.internal.services.assets; 016 017import org.apache.tapestry5.services.assets.AssetChecksumGenerator; 018import org.apache.tapestry5.services.assets.CompressionStatus; 019import org.apache.tapestry5.services.assets.StreamableResource; 020 021import java.io.BufferedOutputStream; 022import java.io.ByteArrayOutputStream; 023import java.io.IOException; 024import java.io.OutputStream; 025import java.util.zip.GZIPOutputStream; 026 027/** 028 * GZip compressed representation of a {@link StreamableResource}. 029 * 030 * @since 5.4 031 */ 032public class CompressedStreamableResource extends StreamableResourceImpl 033{ 034 public CompressedStreamableResource(StreamableResource base, AssetChecksumGenerator assetChecksumGenerator) throws IOException 035 { 036 super(base.getDescription(), base.getContentType(), CompressionStatus.COMPRESSED, base.getLastModified(), compressContent(base), assetChecksumGenerator); 037 038 assert base.getCompression() == CompressionStatus.COMPRESSABLE; 039 } 040 041 private static BytestreamCache compressContent(StreamableResource resource) throws IOException 042 { 043 ByteArrayOutputStream compressed = new ByteArrayOutputStream(resource.getSize()); 044 OutputStream compressor = new BufferedOutputStream(new GZIPOutputStream(compressed)); 045 046 resource.streamTo(compressor); 047 048 compressor.close(); 049 050 return new BytestreamCache(compressed); 051 } 052}