001// Copyright 2011, 2012 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.CompressionStatus;
018import org.apache.tapestry5.services.assets.StreamableResource;
019import org.apache.tapestry5.services.assets.StreamableResourceProcessing;
020import org.apache.tapestry5.services.assets.StreamableResourceSource;
021
022/**
023 * Specialization of {@link SRSCachingInterceptor} that only attempts to cache
024 * compressed resources.
025 */
026public class SRSCompressedCachingInterceptor extends SRSCachingInterceptor
027{
028    public SRSCompressedCachingInterceptor(StreamableResourceSource delegate, ResourceChangeTracker tracker)
029    {
030        super(delegate, tracker);
031    }
032
033    /**
034     * Return true only if the resource is compressed.
035     */
036    @Override
037    protected boolean isCacheable(StreamableResource resource)
038    {
039        return resource.getCompression() == CompressionStatus.COMPRESSED;
040    }
041
042    /**
043     * Returns true just when the processing enables compression.
044     */
045    @Override
046    protected boolean enableCache(StreamableResourceProcessing processing)
047    {
048        return processing == StreamableResourceProcessing.COMPRESSION_ENABLED;
049    }
050}