001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.wicket.response.filter;
018
019import org.apache.wicket.util.string.AppendingStringBuffer;
020
021/**
022 * A response filter can be added to the
023 * {@link org.apache.wicket.settings.RequestCycleSettings#addResponseFilter(IResponseFilter)}
024 * object. This will be called from the Buffered Response objects right before they would send it to
025 * the real responses. You have to use the
026 * {@link org.apache.wicket.settings.RequestCycleSettings#setBufferResponse(boolean)}(to true which
027 * is the default) for this filtering to work.
028 * 
029 * @author jcompagner
030 * 
031 * @see org.apache.wicket.settings.RequestCycleSettings#addResponseFilter(IResponseFilter)
032 */
033@FunctionalInterface
034public interface IResponseFilter
035{
036        /**
037         * Filters the response buffer and returns the filtered response that can be used in the next
038         * filter or returned to the real output itself.
039         * 
040         * A filter may alter the response buffer and return the response buffer itself.
041         * 
042         * @param responseBuffer
043         *            The response buffer to be filtered
044         * @return The changed buffer or the response buffer itself (changed or not)
045         */
046        AppendingStringBuffer filter(AppendingStringBuffer responseBuffer);
047}