TraitContainer.java

/**
 * Copyright 2011-2017 Asakusa Framework Team.
 *
 * 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 com.asakusafw.dmdl.semantics;

import java.util.LinkedHashMap;
import java.util.Map;

class TraitContainer {

    private final Map<Class<? extends Trait<?>>, Trait<?>> traits = new LinkedHashMap<>();

    <T extends Trait<T>> T get(Class<T> kind) {
        if (kind == null) {
            throw new IllegalArgumentException("kind must not be null"); //$NON-NLS-1$
        }
        return kind.cast(traits.get(kind));
    }

    <T extends Trait<T>> void put(Class<T> kind, T trait) {
        if (kind == null) {
            throw new IllegalArgumentException("kind must not be null"); //$NON-NLS-1$
        }
        if (trait == null) {
            traits.remove(kind);
        } else {
            traits.put(kind, trait);
        }
    }
}