CommandService.java
/*
* Portions of this software was developed by employees of the National Institute
* of Standards and Technology (NIST), an agency of the Federal Government and is
* being made available as a public service. Pursuant to title 17 United States
* Code Section 105, works of NIST employees are not subject to copyright
* protection in the United States. This software may be subject to foreign
* copyright. Permission in the United States and in foreign countries, to the
* extent that NIST may hold copyright, to use, copy, modify, create derivative
* works, and distribute this software and its documentation without fee is hereby
* granted on a non-exclusive basis, provided that this notice and disclaimer
* of warranty appears in all copies.
*
* THE SOFTWARE IS PROVIDED 'AS IS' WITHOUT ANY WARRANTY OF ANY KIND, EITHER
* EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, ANY WARRANTY
* THAT THE SOFTWARE WILL CONFORM TO SPECIFICATIONS, ANY IMPLIED WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND FREEDOM FROM
* INFRINGEMENT, AND ANY WARRANTY THAT THE DOCUMENTATION WILL CONFORM TO THE
* SOFTWARE, OR ANY WARRANTY THAT THE SOFTWARE WILL BE ERROR FREE. IN NO EVENT
* SHALL NIST BE LIABLE FOR ANY DAMAGES, INCLUDING, BUT NOT LIMITED TO, DIRECT,
* INDIRECT, SPECIAL OR CONSEQUENTIAL DAMAGES, ARISING OUT OF, RESULTING FROM,
* OR IN ANY WAY CONNECTED WITH THIS SOFTWARE, WHETHER OR NOT BASED UPON WARRANTY,
* CONTRACT, TORT, OR OTHERWISE, WHETHER OR NOT INJURY WAS SUSTAINED BY PERSONS OR
* PROPERTY OR OTHERWISE, AND WHETHER OR NOT LOSS WAS SUSTAINED FROM, OR AROSE OUT
* OF THE RESULTS OF, OR USE OF, THE SOFTWARE OR SERVICES PROVIDED HEREUNDER.
*/
package gov.nist.secauto.metaschema.cli.processor.command;
import java.util.List;
import java.util.ServiceLoader;
import java.util.ServiceLoader.Provider;
import java.util.stream.Collectors;
import edu.umd.cs.findbugs.annotations.NonNull;
import nl.talsmasoftware.lazy4j.Lazy;
public final class CommandService {
private static final Lazy<CommandService> INSTANCE = Lazy.lazy(() -> new CommandService());
@NonNull
private final ServiceLoader<ICommand> loader;
/**
* Get the singleton instance of the function service.
*
* @return the service instance
*/
public static CommandService getInstance() {
return INSTANCE.get();
}
public CommandService() {
ServiceLoader<ICommand> loader = ServiceLoader.load(ICommand.class);
assert loader != null;
this.loader = loader;
}
/**
* Get the function service loader instance.
*
* @return the service loader instance.
*/
@NonNull
private ServiceLoader<ICommand> getLoader() {
return loader;
}
@SuppressWarnings("null")
@NonNull
public List<ICommand> getCommands() {
return getLoader().stream()
.map(Provider<ICommand>::get)
.collect(Collectors.toUnmodifiableList());
}
}