+++ /dev/null
-/*
- * Copyright (c) 2014, 2017 Cisco Systems, Inc. and others. All rights reserved.
- *
- * This program and the accompanying materials are made available under the
- * terms of the Eclipse Public License v1.0 which accompanies this distribution,
- * and is available at http://www.eclipse.org/legal/epl-v10.html
- */
-
-package org.opendaylight.controller.config.spi;
-
-import org.opendaylight.controller.config.api.DependencyResolver;
-import org.opendaylight.controller.config.api.ModuleIdentifier;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-/**
- * Base implementation of Module. This implementation contains base logic for
- * Module reconfiguration with associated fields.
- *
- * @param <M>
- * Type of module implementation. Enables easier implementation for
- * the <code>isSame()</code> method
- */
-public abstract class AbstractModule<M extends AbstractModule<M>>
- implements org.opendaylight.controller.config.spi.Module {
-
- private static final Logger LOG = LoggerFactory.getLogger(AbstractModule.class);
-
- protected final DependencyResolver dependencyResolver;
- protected final ModuleIdentifier identifier;
-
- private AutoCloseable oldInstance;
- private M oldModule;
- private AutoCloseable instance;
- private boolean canReuseInstance = true;
-
- /**
- * Called when module is configured.
- *
- * @param identifier
- * id of current instance.
- * @param dependencyResolver
- * resolver used in dependency injection and validation.
- */
- public AbstractModule(final ModuleIdentifier identifier, final DependencyResolver dependencyResolver) {
- this(identifier, dependencyResolver, null, null);
- }
-
- /**
- * Called when module is reconfigured.
- *
- * @param identifier
- * id of current instance.
- * @param dependencyResolver
- * resolver used in dependency injection and validation.
- * @param oldModule
- * old instance of module that is being reconfigred(replaced) by
- * current instance. The old instance can be examined for reuse.
- * @param oldInstance
- * old instance wrapped by the old module. This is the resource that
- * is actually being reused if possible or closed otherwise.
- */
- public AbstractModule(final ModuleIdentifier identifier, final DependencyResolver dependencyResolver,
- final M oldModule, final AutoCloseable oldInstance) {
- this.identifier = identifier;
- this.dependencyResolver = dependencyResolver;
- this.oldModule = oldModule;
- this.oldInstance = oldInstance;
- }
-
- @Override
- public ModuleIdentifier getIdentifier() {
- return identifier;
- }
-
- public final void setCanReuseInstance(final boolean canReuseInstance) {
- this.canReuseInstance = canReuseInstance;
- }
-
- /**
- * General algorithm for spawning/closing and reusing wrapped instances.
- *
- * @return current instance of wrapped resource either by reusing the old one
- * (if present) or constructing a brand new.
- */
- @Override
- @SuppressWarnings("IllegalCatch")
- public final AutoCloseable getInstance() {
- if (instance == null) {
- if (oldInstance != null && canReuseInstance && canReuseInstance(oldModule)) {
- resolveDependencies();
- instance = reuseInstance(oldInstance);
- } else {
- if (oldInstance != null) {
- try {
- oldInstance.close();
- } catch (final Exception exception) {
- LOG.error("An error occurred while closing old instance {} for module {}", oldInstance,
- getIdentifier(), exception);
- }
- }
- resolveDependencies();
- instance = createInstance();
- if (instance == null) {
- throw new IllegalStateException(
- "Error in createInstance - null is not allowed as return value. Module: "
- + getIdentifier());
- }
- }
-
- // Prevent serial memory leak: clear these references as we will not use them
- // again.
- oldInstance = null;
- oldModule = null;
- }
-
- return instance;
- }
-
- /**
- * Create instance.
- *
- * @return Brand new instance of wrapped class in case no previous instance is
- * present or reconfiguration is impossible.
- */
- protected abstract AutoCloseable createInstance();
-
- @Override
- public final boolean canReuse(final Module prevModule) {
- // Just cast into a specific instance
- // TODO unify this method with canReuseInstance (required Module interface to be
- // generic which requires quite a lot of changes)
- return canReuseInstance && getClass().isInstance(prevModule) ? canReuseInstance((M) prevModule) : false;
- }
-
- /**
- * Users are welcome to override this method to provide custom logic for
- * advanced reusability detection.
- *
- * @param prevModule
- * old instance of a Module
- * @return true if the old instance is reusable false if a new one should be
- * spawned
- */
- protected abstract boolean canReuseInstance(M prevModule);
-
- /**
- * By default the oldInstance is returned since this method is by default called
- * only if the oldModule had the same configuration and dependencies configured.
- * Users are welcome to override this method to provide custom logic for
- * advanced reusability.
- *
- * @param prevInstance
- * old instance of a class wrapped by the module
- * @return reused instance
- */
- protected AutoCloseable reuseInstance(final AutoCloseable prevInstance) {
- // implement if instance reuse should be supported. Override canReuseInstance to
- // change the criteria.
- return prevInstance;
- }
-
- /**
- * Inject all the dependencies using dependency resolver instance.
- */
- protected abstract void resolveDependencies();
-}
Code Review / controller.git / blobdiff