keywhiz.generators.SecretGeneratorModule.java Source code

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Here is the source code for keywhiz.generators.SecretGeneratorModule.java

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/*
 * Copyright (C) 2015 Square, Inc.
 *
 * 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 keywhiz.generators;

import com.google.common.collect.Sets;
import com.google.inject.AbstractModule;
import com.google.inject.Provider;
import com.google.inject.multibindings.MapBinder;
import java.util.Map;
import javax.inject.Inject;
import keywhiz.service.daos.SecretController;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;

/**
 * Registers configured {@link SecretGenerator}s and {@link SecretGeneratorFactory}s, with their
 * associated names, using guice. A guice multibinding is used so consumers can request injection of
 * <code>Map&lt;String, SecretGenerator&gt;</code> to get all the instantiated SecretGenerators and names.
 */
public class SecretGeneratorModule extends AbstractModule {
    private static final Logger logger = LoggerFactory.getLogger(SecretGeneratorModule.class);

    private final Map<String, SecretGeneratorFactory<?>> secretGeneratorFactories;
    private final Map<String, SecretGenerator<?>> secretGenerators;

    public SecretGeneratorModule(Map<String, SecretGeneratorFactory<?>> secretGeneratorFactories,
            Map<String, SecretGenerator<?>> secretGenerators) {
        checkArgument(Sets.intersection(secretGeneratorFactories.keySet(), secretGenerators.keySet()).isEmpty(),
                "SecretGeneratorFactories and SecretGenerators cannot share names.");
        this.secretGeneratorFactories = secretGeneratorFactories;
        this.secretGenerators = secretGenerators;
    }

    @Override
    protected void configure() {
        MapBinder<String, SecretGenerator> mapBinder = MapBinder.newMapBinder(binder(), String.class,
                SecretGenerator.class);
        // Register the factories
        for (Map.Entry<String, SecretGeneratorFactory<?>> entry : secretGeneratorFactories.entrySet()) {
            logger.info("Binding secret generator provider named {}", entry.getKey());
            mapBinder.addBinding(entry.getKey()).toProvider(new SecretGeneratorProvider(entry.getValue()));
        }

        // Register the instances
        for (Map.Entry<String, SecretGenerator<?>> entry : secretGenerators.entrySet()) {
            logger.info("Binding secret generator named {}", entry.getKey());
            mapBinder.addBinding(entry.getKey()).toInstance(entry.getValue());
        }
    }

    /**
     * Private Provider which creates SecretGenerators from SecretGeneratorFactories. Objects
     * necessary for each factory's <code>create</code> method are injected as fields.
     */
    private static class SecretGeneratorProvider implements Provider<SecretGenerator> {
        @Inject
        private SecretController secretController;
        private final SecretGeneratorFactory factory;

        public SecretGeneratorProvider(SecretGeneratorFactory factory) {
            this.factory = checkNotNull(factory);
        }

        @Override
        public SecretGenerator get() {
            return factory.create(secretController);
        }
    }
}