org.apache.druid.guice.ListProvider.java Source code

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Here is the source code for org.apache.druid.guice.ListProvider.java

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/*
 * 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.druid.guice;

import com.google.common.collect.Lists;
import com.google.inject.Inject;
import com.google.inject.Injector;
import com.google.inject.Key;
import com.google.inject.Provider;

import java.util.List;

/**
 */
public class ListProvider<T> implements Provider<List<T>> {
    private final List<Key<? extends T>> itemsToLoad = Lists.newArrayList();
    private Injector injector;

    public ListProvider<T> add(Class<? extends T> clazz) {
        return add(Key.get(clazz));
    }

    public ListProvider<T> add(Key<? extends T> key) {
        itemsToLoad.add(key);
        return this;
    }

    @Inject
    private void configure(Injector injector) {
        this.injector = injector;
    }

    @Override
    public List<T> get() {
        List<T> retVal = Lists.newArrayListWithExpectedSize(itemsToLoad.size());
        for (Key<? extends T> key : itemsToLoad) {
            retVal.add(injector.getInstance(key));
        }
        return retVal;
    }
}