AutoCloser.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.core.util;
import edu.umd.cs.findbugs.annotations.NonNull;
import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
/**
* Wraps a resource to make it {@link AutoCloseable}.
*
* @param <T>
* the resource type
* @param <E>
* the exception type that may be thrown if an error occurs when
* closing the resource
*/
public class AutoCloser<T, E extends Exception> implements AutoCloseable {
@NonNull
private final T resource;
@NonNull
private final Closer<T, E> closeLambda;
/**
* Adapt the the provided {@code resource} to be {@link AutoCloseable}, using a
* provided closer {@code lambda}.
*
* @param <T>
* the resource's type
* @param <E>
* the exception type that can be thrown when closing
* @param resource
* the object to adapt
* @param lambda
* the lambda to use as a callback on close
* @return the resource wrapped in an {@link AutoCloseable}
*/
@NonNull
public static <T, E extends Exception> AutoCloser<T, E> autoClose(
@NonNull T resource,
@NonNull Closer<T, E> lambda) {
return new AutoCloser<>(resource, lambda);
}
/**
* Adapt the provided {@code resource} to be {@link AutoCloseable}, using a
* provided closer {@code lambda}.
*
* @param resource
* the object to adapt
* @param lambda
* the lambda to use as a callback on close
*/
public AutoCloser(@NonNull T resource, @NonNull Closer<T, E> lambda) {
this.resource = resource;
this.closeLambda = lambda;
}
/**
* Get the wrapped resource.
*
* @return the resource object
*/
@NonNull
public T getResource() {
return resource;
}
@Override
@SuppressFBWarnings("THROWS_METHOD_THROWS_CLAUSE_BASIC_EXCEPTION")
public void close() throws E {
closeLambda.close(getResource());
}
@FunctionalInterface
public interface Closer<T, E extends Exception> {
/**
* This method is called to auto-close the resource.
*
* @param object
* the resource to auto-close
* @throws E
* the exception type that can be thrown when closing
*/
@SuppressFBWarnings("THROWS_METHOD_THROWS_CLAUSE_BASIC_EXCEPTION")
void close(@NonNull T object) throws E;
}
}