org.hibernate.search.engine.environment.bean.BeanHolder Maven / Gradle / Ivy
/*
* SPDX-License-Identifier: Apache-2.0
* Copyright Red Hat Inc. and Hibernate Authors
*/
package org.hibernate.search.engine.environment.bean;
import java.util.Arrays;
import java.util.List;
/**
* An object holding a bean instance, and allowing to release it.
*
* @param The type of the bean instance.
*/
public interface BeanHolder extends AutoCloseable {
/**
* @return The bean instance. Guaranteed to always return the exact same object,
* i.e. {@code beanHolder.get() == beanHolder.get()} is always true.
*/
T get();
/**
* Release any resource currently held by the {@link BeanHolder}.
*
* After this method has been called, the result of calling {@link #get()} on the same instance is undefined.
*
* Warning: this method only releases resources that were allocated
* by the creator of the bean instance, and of which the bean instance itself may not be aware.
* If the bean instance itself (the one returned by {@link #get()}) exposes any {@code close()}
* or other release method, they should be called before the {@link BeanHolder} is released.
*
* @throws RuntimeException If an error occurs while releasing resources.
*/
@Override
void close();
/**
* @param dependencies Dependencies that should be closed eventually.
* @return A bean holder that wraps the current bean holder, and ensures the dependencies are also
* closed when its {@link #close()} method is called.
*/
default BeanHolder withDependencyAutoClosing(BeanHolder... dependencies) {
return new DependencyClosingBeanHolder<>( this, Arrays.asList( dependencies ) );
}
/**
* @param instance The bean instance.
* @param The type of the bean instance.
* @return A {@link BeanHolder} whose {@link #get()} method returns the given instance,
* and whose {@link #close()} method does not do anything.
*/
static BeanHolder of(T instance) {
return new SimpleBeanHolder<>( instance );
}
/**
* @param instance The bean instance.
* @param The type of the bean instance.
* @return A {@link BeanHolder} whose {@link #get()} method returns the given instance,
* and whose {@link #close()} method calls {@link AutoCloseable#close()} on the given instance.
*/
static BeanHolder ofCloseable(T instance) {
return new AutoCloseableBeanHolder<>( instance );
}
/**
* @param beanHolders The bean holders.
* @param The type of the bean instances.
* @return A {@link BeanHolder} whose {@link #get()} method returns a list containing
* the instance of each given bean holder, in order,
* and whose {@link #close()} method closes every given bean holder.
*/
static BeanHolder> of(List> beanHolders) {
return new CompositeBeanHolder<>( beanHolders );
}
}