ThreadScope.java

/*
 * Copyright (c) 2014 David Sowerby
 *
 * 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 uk.q3c.krail.core.guice.threadscope;

import com.google.inject.Key;
import com.google.inject.Provider;
import com.google.inject.Scope;
import uk.q3c.krail.core.guice.threadscope.ThreadCache.Cache;

public class ThreadScope implements Scope {
    private final ThreadCache thread;

    ThreadScope(ThreadCache thread) {
        this.thread = thread;
    }

    /**
     * @see com.google.inject.Scope#scope(com.google.inject.Key, com.google.inject.Provider)
     */
    @Override
    public <T> Provider<T> scope(final Key<T> key, final Provider<T> creator) {
        return new Provider<T>() {
            @Override
            public T get() {
                Cache cache = thread.getCache();
                T value = cache.get(key);
                if (value == null) {
                    value = creator.get();
                    cache.add(key, value);
                }
                return value;
            }
        };
    }
}