core/src/main/java/org/apache/cxf/transport/common/gzip/GZIPFeature.java

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.cxf.transport.common.gzip;

import java.util.List;

import org.apache.cxf.Bus;
import org.apache.cxf.common.injection.NoJSR250Annotations;
import org.apache.cxf.feature.AbstractFeature;
import org.apache.cxf.interceptor.Interceptor;
import org.apache.cxf.interceptor.InterceptorProvider;
import org.apache.cxf.message.Message;

/**
 * This class is used to control GZIP compression of messages.
 * Attaching this feature to an endpoint will allow the endpoint to handle
 * compressed requests, and will cause outgoing responses to be compressed if
 * the client indicates (via the Accept-Encoding header) that it can handle
 * them.
 * <pre>
 * <![CDATA[
 * <jaxws:endpoint ...>
 *   <jaxws:features>
 *     <bean class="org.apache.cxf.transport.common.gzip.GZIPFeature"/>
 *   </jaxws:features>
 * </jaxws:endpoint>
 * ]]>
 * </pre>
 * Attaching this feature to a client will cause outgoing request messages 
 * to be compressed and incoming compressed responses to be uncompressed. 
 * Accept-Encoding header is sent to let the service know 
 * that your client can accept compressed responses. 
 */
@NoJSR250Annotations
public class GZIPFeature extends AbstractFeature {
    private static final GZIPInInterceptor IN = new GZIPInInterceptor();
    private static final GZIPOutInterceptor OUT = new GZIPOutInterceptor();
    
    /**
     * The compression threshold to pass to the outgoing interceptor.
     */
    int threshold = -1;
    
    /**
     * Force GZIP instead of negotiate
     */
    boolean force;
    
    
    @Override
    protected void initializeProvider(InterceptorProvider provider, Bus bus) {
        provider.getInInterceptors().add(IN);
        if (threshold == -1 && !force) {
            provider.getOutInterceptors().add(OUT);
            provider.getOutFaultInterceptors().add(OUT);
        } else {
            GZIPOutInterceptor out = new GZIPOutInterceptor();
            out.setThreshold(threshold);
            out.setForce(force);
            remove(provider.getOutInterceptors());
            remove(provider.getOutFaultInterceptors());
            provider.getOutInterceptors().add(out);
            provider.getOutFaultInterceptors().add(out);
        }
    }

    private void remove(List<Interceptor<? extends Message>> outInterceptors) {
        int x = outInterceptors.size();
        while (x > 0) {
            --x;
            if (outInterceptors.get(x) instanceof GZIPOutInterceptor) {
                outInterceptors.remove(x);
            }
        }
    }

    public void setThreshold(int threshold) {
        this.threshold = threshold;
    }
    
    public int getThreshold() {
        return threshold;
    }
    
    
    /**
     * Set if GZIP is always used without negotiation 
     * @param b
     */
    public void setForce(boolean b) {
        force = b;
    }
    
    /**
     * Retrieve the value set with {@link #setForce(boolean)}.
     */
    public boolean getForce() {
        return force;
    }  
}