com.cerner.beadledom.configuration.ConfigurationSourcesModuleBuilder Maven / Gradle / Ivy
package com.cerner.beadledom.configuration;
import com.google.inject.AbstractModule;
import com.google.inject.Module;
import com.google.inject.multibindings.Multibinder;
import java.util.ArrayList;
import java.util.List;
/**
* A Builder class that builds a Guice module for binding multiple {@link ConfigurationSource}s.
*
* The Guice module that is built by this builder configures
*
* - A {@link Multibinder} for {@link ConfigurationSource}
*
*
* This builder can be used in multiple modules to bind multiple {@link ConfigurationSource}.
* Consumer must use the {@link ConfigurationSourcesModuleBuilder#addSource(ConfigurationSource)}
* builder method to build the list of configuration Sources.
*
*
The {@link ConfigurationSourcesModuleBuilder#build} method creates a new anonymous
* {@link Module} that configures a {@link Multibinder} for the provided {@link ConfigurationSource}
*
*
Usage:
*
* public class MyModule extends AbstractModule {
* {@literal @}Override
* protected void configure() {
* install(ConfigurationSourcesModuleBuilder.newBuilder()
* .addSource(source1)
* .addSource(source2)
* .addSource(source3)
* .build());
* }
* }
*
*
* It is the responsibility of the consumer to build the configuration sources with appropriate
* priority (natural ordering). The priority or natural ordering of the {@link ConfigurationSource}s
* is what is considered when loading the configurations from the corresponding sources instead of
* the order in which they are configured using this Builder.
*
* @author Sundeep Paruvu
* @see com.cerner.beadledom.configuration.BeadledomConfigurationModule
* @since 2.1
*/
public final class ConfigurationSourcesModuleBuilder {
private List configurationSources;
private ConfigurationSourcesModuleBuilder() {
this.configurationSources = new ArrayList();
}
/**
* Static Convenience method create an instance of {@link ConfigurationSourcesModuleBuilder}.
*/
public static ConfigurationSourcesModuleBuilder newBuilder() {
return new ConfigurationSourcesModuleBuilder();
}
/**
* Adds the given {@code configurationSource} to the list.
*
* @param configurationSource configuration source from which Configuration will be built.
* @return the current instance of the {@link ConfigurationSourcesModuleBuilder}.
*/
public ConfigurationSourcesModuleBuilder addSource(ConfigurationSource configurationSource) {
if (configurationSource == null) {
throw new NullPointerException("configurationSource: null");
}
configurationSources.add(configurationSource);
return this;
}
/**
* Builds the {@link ConfigurationSourcesModuleBuilder} with the list of
* {@link ConfigurationSource}s built using the {@link ConfigurationSourcesModuleBuilder
* #addSource(ConfigurationSource)} builder method.
*
* @return a Guice module that configures a Multibinder for ConfigurationSources
*/
public Module build() {
return new AbstractModule() {
@Override
protected void configure() {
Multibinder multiBinder =
Multibinder.newSetBinder(binder(), ConfigurationSource.class);
for (ConfigurationSource configurationSource : configurationSources) {
multiBinder.addBinding().toInstance(configurationSource);
}
}
};
}
}