MapResolver.java

/*
 * Copyright 2013 Martin Kouba
 *
 * 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.trimou.engine.resolver;

import static org.trimou.engine.priority.Priorities.after;

import java.util.Map;

/**
 * Deals with {@link Map} (the key is expected to be an instance of a
 * {@link String}) and {@link Mapper} instances.
 *
 * @author Martin Kouba
 */
public class MapResolver extends AbstractResolver {

    public static final int MAP_RESOLVER_PRIORITY = after(ThisResolver.THIS_RESOLVER_PRIORITY, 3);

    private final Hint hint;

    public MapResolver() {
        this(MAP_RESOLVER_PRIORITY);
    }

    public MapResolver(int priority) {
        super(priority);
        this.hint = MapResolver.this::resolve;
    }

    @SuppressWarnings("rawtypes")
    @Override
    public Object resolve(Object contextObject, String name,
            ResolutionContext context) {
        if (contextObject == null) {
            return null;
        }
        if (contextObject instanceof Map) {
            Map map = (Map) contextObject;
            return map.get(name);
        }
        if (contextObject instanceof Mapper) {
            Mapper mapper = (Mapper) contextObject;
            return mapper.get(name);
        }
        return null;
    }

    @Override
    public Hint createHint(Object contextObject, String name,
            ResolutionContext context) {
        return hint;
    }

}