SelfContainingCycleContext.java

/**
 *  Copyright 2012-2017 Gunnar Morling (http://www.gunnarmorling.de/)
 *  and/or other contributors as indicated by the @authors tag. See the
 *  copyright.txt file in the distribution for a full listing of all
 *  contributors.
 *
 *  Licensed 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.mapstruct.ap.test.context;

import java.util.IdentityHashMap;
import java.util.Map;

import org.mapstruct.BeforeMapping;
import org.mapstruct.Context;
import org.mapstruct.MappingTarget;
import org.mapstruct.TargetType;

/**
 * A type to be used as {@link Context} parameter to track cycles in graphs.
 *
 * @author Andreas Gudian
 */
public class SelfContainingCycleContext {
    private Map<Object, Object> knownInstances = new IdentityHashMap<Object, Object>();

    @BeforeMapping
    @SuppressWarnings("unchecked")
    public <T> T getMappedInstance(Object source, @TargetType Class<T> targetType) {
        return (T) knownInstances.get( source );
    }

    @BeforeMapping
    public void storeMappedInstance(Object source, @MappingTarget Object target) {
        knownInstances.put( source, target );
    }
}