org.apache.wicket.request.mapper.CompoundRequestMapper Maven / Gradle / Ivy
/*
* 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.mapper;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;
import org.apache.wicket.request.IRequestHandler;
import org.apache.wicket.request.IRequestMapper;
import org.apache.wicket.request.Request;
import org.apache.wicket.request.Url;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Thread safe compound {@link IRequestMapper}. The mappers are searched depending on their
* compatibility score and the orders they were registered. If two or more {@link IRequestMapper}s
* have the same compatibility score, the last registered mapper has highest priority.
*
* @author igor.vaynberg
* @author Matej Knopp
*/
public class CompoundRequestMapper implements ICompoundRequestMapper
{
private static final Logger LOG = LoggerFactory.getLogger(CompoundRequestMapper.class);
static class MapperWithScore implements Comparable
{
private final IRequestMapper mapper;
private final int compatibilityScore;
public MapperWithScore(final IRequestMapper mapper, final int compatibilityScore)
{
this.mapper = mapper;
this.compatibilityScore = compatibilityScore;
}
@Override
public int compareTo(final MapperWithScore o)
{
return (compatibilityScore < o.compatibilityScore ? 1
: (compatibilityScore > o.compatibilityScore ? -1 : 0));
}
public IRequestMapper getMapper()
{
return mapper;
}
@Override
public boolean equals(Object o)
{
if (this == o)
return true;
if (!(o instanceof MapperWithScore))
return false;
MapperWithScore that = (MapperWithScore)o;
if (compatibilityScore != that.compatibilityScore)
return false;
return mapper.equals(that.mapper);
}
@Override
public int hashCode()
{
int result = mapper.hashCode();
result = 31 * result + compatibilityScore;
return result;
}
@Override
public String toString()
{
return "Mapper: " + mapper.getClass().getName() + "; Score: " + compatibilityScore;
}
}
private final List mappers = new CopyOnWriteArrayList<>();
@Override
public CompoundRequestMapper add(final IRequestMapper mapper)
{
mappers.add(0, mapper);
return this;
}
@Override
public CompoundRequestMapper remove(final IRequestMapper mapper)
{
mappers.remove(mapper);
return this;
}
/**
* Searches the registered {@link IRequestMapper}s to find one that can map the {@link Request}.
* Each registered {@link IRequestMapper} is asked to provide its compatibility score. Then the
* mappers are asked to map the request in order depending on the provided compatibility
* score.
*
* The mapper with highest compatibility score which can map the request is returned.
*
* @param request
* @return RequestHandler for the request or null if no mapper for the request is
* found.
*/
@Override
public IRequestHandler mapRequest(final Request request)
{
List list = new ArrayList<>(mappers.size());
for (IRequestMapper mapper : mappers)
{
int score = mapper.getCompatibilityScore(request);
list.add(new MapperWithScore(mapper, score));
}
Collections.sort(list);
if (LOG.isDebugEnabled())
{
logMappers(list, request.getUrl().toString());
}
for (MapperWithScore mapperWithScore : list)
{
IRequestMapper mapper = mapperWithScore.getMapper();
IRequestHandler handler = mapper.mapRequest(request);
if (handler != null)
{
return handler;
}
}
return null;
}
/**
* Logs all mappers with a positive compatibility score
*
* @param mappersWithScores
* the list of all mappers
* @param url
* the url to match by these mappers
*/
private void logMappers(final List mappersWithScores, final String url)
{
final List compatibleMappers = new ArrayList<>();
for (MapperWithScore mapperWithScore : mappersWithScores)
{
if (mapperWithScore.compatibilityScore > 0)
{
compatibleMappers.add(mapperWithScore);
}
}
if (compatibleMappers.size() == 0)
{
LOG.debug("No compatible mapper found for URL '{}'", url);
}
else if (compatibleMappers.size() == 1)
{
LOG.debug("One compatible mapper found for URL '{}' -> '{}'", url, compatibleMappers.get(0));
}
else
{
LOG.debug("Multiple compatible mappers found for URL '{}'", url);
for (MapperWithScore compatibleMapper : compatibleMappers)
{
LOG.debug(" * {}", compatibleMapper);
}
}
}
/**
* Searches the registered {@link IRequestMapper}s to find one that can map the
* {@link IRequestHandler}. Each registered {@link IRequestMapper} is asked to map the
* {@link IRequestHandler} until a mapper which can map the {@link IRequestHandler} is found or
* no more mappers are left.
*
* The mappers are searched in reverse order as they have been registered. More recently
* registered mappers have bigger priority.
*
* @param handler
* @return Url for the handler or null if no mapper for the handler is found.
*/
@Override
public Url mapHandler(final IRequestHandler handler)
{
for (IRequestMapper mapper : mappers)
{
Url url = mapper.mapHandler(handler);
if (url != null)
{
return url;
}
}
return null;
}
/**
* The scope of the compound mapper is the highest score of the registered mappers.
*
* {@inheritDoc}
*/
@Override
public int getCompatibilityScore(final Request request)
{
int score = Integer.MIN_VALUE;
for (IRequestMapper mapper : mappers)
{
score = Math.max(score, mapper.getCompatibilityScore(request));
}
return score;
}
@Override
public Iterator iterator()
{
return mappers.iterator();
}
}