    001    // Copyright 2011 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
    015    package org.apache.tapestry5.internal.services.assets;
    016
    017    import org.apache.tapestry5.services.assets.CompressionStatus;
    018    import org.apache.tapestry5.services.assets.StreamableResource;
    019    import org.apache.tapestry5.services.assets.StreamableResourceProcessing;
    020    import org.apache.tapestry5.services.assets.StreamableResourceSource;
    021
    022    /**
    023     * Specialization of {@link SRSCachingInterceptor} that only attempts to cache
    024     * compressed resources.
    025     */
    026    public class SRSCompressedCachingInterceptor extends SRSCachingInterceptor
    027    {
    028        public SRSCompressedCachingInterceptor(StreamableResourceSource delegate)
    029        {
    030            super(delegate);
    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    }