EncounterProvider.java

/**
 * 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.camel.guice.support;

import com.google.inject.Key;
import com.google.inject.Provider;
import com.google.inject.spi.TypeEncounter;

/**
 * Like a {@link com.google.inject.Provider} but which is also given an
 * {@link TypeEncounter}
 * 
 * @version
 */
public abstract class EncounterProvider<T> {
    public abstract Provider<? extends T> get(TypeEncounter<?> encounter);

    /**
     * Returns a new encounter provider for the given key
     */
    public static <T> EncounterProvider<T> encounterProvider(
            final Key<? extends T> key) {
        return new EncounterProvider<T>() {
            public Provider<? extends T> get(TypeEncounter<?> encounter) {
                return encounter.getProvider(key);
            }
        };
    }

    /**
     * Returns a new encounter provider for the given type
     */
    public static <T> EncounterProvider<T> encounterProvider(
            final Class<? extends T> type) {
        return new EncounterProvider<T>() {
            public Provider<? extends T> get(TypeEncounter<?> encounter) {
                return encounter.getProvider(type);
            }
        };
    }

    /**
     * Returns a new encounter provider for the given instance
     */
    public static <T> EncounterProvider<T> encounterProvider(final T instance) {
        return new EncounterProvider<T>() {
            public Provider<? extends T> get(TypeEncounter<?> encounter) {
                return new Provider<T>() {
                    public T get() {
                        return instance;
                    }
                };
            }
        };
    }

}