AbstractConfigurationAwareModule.java

/*
 * 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 io.airlift.configuration;

import com.google.common.annotations.Beta;
import com.google.inject.Binder;
import com.google.inject.Module;

import static com.google.common.base.Preconditions.checkState;
import static io.airlift.configuration.ConfigBinder.configBinder;
import static java.util.Objects.requireNonNull;

@Beta
public abstract class AbstractConfigurationAwareModule
        implements ConfigurationAwareModule
{
    private ConfigurationFactory configurationFactory;
    private Binder binder;

    @Override
    public synchronized void setConfigurationFactory(ConfigurationFactory configurationFactory)
    {
        this.configurationFactory = requireNonNull(configurationFactory, "configurationFactory is null");
    }

    @Override
    public final synchronized void configure(Binder binder)
    {
        checkState(this.binder == null, "re-entry not allowed");
        this.binder = requireNonNull(binder, "binder is null");
        try {
            setup(binder);
        }
        finally {
            this.binder = null;
        }
    }

    protected synchronized <T> T buildConfigObject(Class<T> configClass)
    {
        configBinder(binder).bindConfig(configClass);
        return configurationFactory.build(configClass);
    }

    protected synchronized <T> T buildConfigObject(Class<T> configClass, String prefix)
    {
        configBinder(binder).bindConfig(configClass, prefix);
        return configurationFactory.build(configClass, prefix);
    }

    protected synchronized void install(Module module)
    {
        if (module instanceof ConfigurationAwareModule) {
            ((ConfigurationAwareModule) module).setConfigurationFactory(configurationFactory);
        }
        binder.install(module);
    }

    protected abstract void setup(Binder binder);
}