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/*
 * 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.wicket.request;


/**
 * Encodes {@link IRequestHandler}(s) into {@link Url}(s) and decodes {@link Request}(s) to
 * {@link IRequestHandler}(s). For {@link IRequestHandler}s and {@link Request}s the implementation
 * doesn't know the {@link #mapHandler(IRequestHandler)} and {@link #mapRequest(Request)} methods
 * must return null.
 * 
 * @author Matej Knopp
 */
public interface IRequestMapper
{
	/**
	 * Returns {@link IRequestHandler} for the request or null if the encoder does not
	 * recognize the URL.
	 * 
	 * @param request
	 *            provides access to request data (i.e. Url and Parameters)
	 * 
	 * @return RequestHandler instance or null
	 */
	IRequestHandler mapRequest(Request request);

	/**
	 * Returns the score representing how compatible this request mapper is to processing the given
	 * request. When a request comes in all mappers are scored and are tried in order from highest
	 * score to lowest.
	 * 
	 * A good criteria for calculating the score is the number of matched url segments. For example
	 * when there are two encoders for mounted page, one mapped to /foo another to
	 * /foo/bar and the incoming request URL is /foo/bar/baz, the encoder
	 * mapped to /foo/bar will handle the request first as it has matching segments
	 * count of 2 while the first one has only matching segments count of 1.
	 * 

	 * Note that the method can return value greater then zero even if the encoder can not decode
	 * the request.
	 * 
	 * @param request
	 * @return count of matching segments
	 */
	int getCompatibilityScore(Request request);

	/**
	 * Returns the {@link Url} for given {@link IRequestHandler} or null if the encoder
	 * does not recognize the request handler.
	 * 
	 * @param requestHandler
	 * @return Url instance or null.
	 */
	Url mapHandler(IRequestHandler requestHandler);
}