/*
 * Copyright 2002-2020 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.jca.work;

import java.util.concurrent.Callable;
import java.util.concurrent.Future;
import java.util.concurrent.FutureTask;
import javax.naming.NamingException;
import javax.resource.spi.BootstrapContext;
import javax.resource.spi.work.ExecutionContext;
import javax.resource.spi.work.Work;
import javax.resource.spi.work.WorkException;
import javax.resource.spi.work.WorkListener;
import javax.resource.spi.work.WorkManager;
import javax.resource.spi.work.WorkRejectedException;

import org.springframework.beans.factory.InitializingBean;
import org.springframework.core.task.AsyncListenableTaskExecutor;
import org.springframework.core.task.TaskDecorator;
import org.springframework.core.task.TaskRejectedException;
import org.springframework.core.task.TaskTimeoutException;
import org.springframework.jca.context.BootstrapContextAware;
import org.springframework.jndi.JndiLocatorSupport;
import org.springframework.scheduling.SchedulingException;
import org.springframework.scheduling.SchedulingTaskExecutor;
import org.springframework.util.Assert;
import org.springframework.util.concurrent.ListenableFuture;
import org.springframework.util.concurrent.ListenableFutureTask;

/**
 * {@link org.springframework.core.task.TaskExecutor} implementation
 * that delegates to a JCA 1.5 WorkManager, implementing the
 * {@link javax.resource.spi.work.WorkManager} interface.
 *
 * <p>This is mainly intended for use within a JCA ResourceAdapter implementation,
 * but may also be used in a standalone environment, delegating to a locally
 * embedded WorkManager implementation (such as Geronimo's).
 *
 * <p>Also implements the JCA 1.5 WorkManager interface itself, delegating all
 * calls to the target WorkManager. Hence, a caller can choose whether it wants
 * to talk to this executor through the Spring TaskExecutor interface or the
 * JCA 1.5 WorkManager interface.
 *
 * <p>This adapter is also capable of obtaining a JCA WorkManager from JNDI.
 * This is for example appropriate on the Geronimo application server, where
 * WorkManager GBeans (e.g. Geronimo's default "DefaultWorkManager" GBean)
 * can be linked into the J2EE environment through "gbean-ref" entries
 * in the {@code geronimo-web.xml} deployment descriptor.
 *
 * <p><b>On JBoss and GlassFish, obtaining the default JCA WorkManager
 * requires special lookup steps.</b> See the
 * {@link org.springframework.jca.work.jboss.JBossWorkManagerTaskExecutor}
 * {@link org.springframework.jca.work.glassfish.GlassFishWorkManagerTaskExecutor}
 * classes which are the direct equivalent of this generic JCA adapter class.
 *
 * @author Juergen Hoeller
 * @since 2.0.3
 * @see #setWorkManager
 * @see javax.resource.spi.work.WorkManager#scheduleWork
 */
public class WorkManagerTaskExecutor extends JndiLocatorSupport
                implements AsyncListenableTaskExecutor, SchedulingTaskExecutor, WorkManager, BootstrapContextAware, InitializingBean {

        private WorkManager workManager;

        private String workManagerName;

        private boolean blockUntilStarted = false;

        private boolean blockUntilCompleted = false;

        private WorkListener workListener;

        private TaskDecorator taskDecorator;


        /**
         * Create a new WorkManagerTaskExecutor, expecting bean-style configuration.
         * @see #setWorkManager
         */
        public WorkManagerTaskExecutor() {
        }

        /**
         * Create a new WorkManagerTaskExecutor for the given WorkManager.
         * @param workManager the JCA WorkManager to delegate to
         */
        public WorkManagerTaskExecutor(WorkManager workManager) {
                setWorkManager(workManager);
        }


        /**
         * Specify the JCA WorkManager instance to delegate to.
         */
        public void setWorkManager(WorkManager workManager) {
                Assert.notNull(workManager, "WorkManager must not be null");
                this.workManager = workManager;
        }

        /**
         * Set the JNDI name of the JCA WorkManager.
         * <p>This can either be a fully qualified JNDI name,
         * or the JNDI name relative to the current environment
         * naming context if "resourceRef" is set to "true".
         * @see #setWorkManager
         * @see #setResourceRef
         */
        public void setWorkManagerName(String workManagerName) {
                this.workManagerName = workManagerName;
        }

        /**
         * Specify the JCA BootstrapContext that contains the
         * WorkManager to delegate to.
         */
        @Override
        public void setBootstrapContext(BootstrapContext bootstrapContext) {
                Assert.notNull(bootstrapContext, "BootstrapContext must not be null");
                this.workManager = bootstrapContext.getWorkManager();
        }

        /**
         * Set whether to let {@link #execute} block until the work
         * has been actually started.
         * <p>Uses the JCA {@code startWork} operation underneath,
         * instead of the default {@code scheduleWork}.
         * @see javax.resource.spi.work.WorkManager#startWork
         * @see javax.resource.spi.work.WorkManager#scheduleWork
         */
        public void setBlockUntilStarted(boolean blockUntilStarted) {
                this.blockUntilStarted = blockUntilStarted;
        }

        /**
         * Set whether to let {@link #execute} block until the work
         * has been completed.
         * <p>Uses the JCA {@code doWork} operation underneath,
         * instead of the default {@code scheduleWork}.
         * @see javax.resource.spi.work.WorkManager#doWork
         * @see javax.resource.spi.work.WorkManager#scheduleWork
         */
        public void setBlockUntilCompleted(boolean blockUntilCompleted) {
                this.blockUntilCompleted = blockUntilCompleted;
        }

        /**
         * Specify a JCA 1.5 WorkListener to apply, if any.
         * <p>This shared WorkListener instance will be passed on to the
         * WorkManager by all {@link #execute} calls on this TaskExecutor.
         */
        public void setWorkListener(WorkListener workListener) {
                this.workListener = workListener;
        }

        /**
         * Specify a custom {@link TaskDecorator} to be applied to any {@link Runnable}
         * about to be executed.
         * <p>Note that such a decorator is not necessarily being applied to the
         * user-supplied {@code Runnable}/{@code Callable} but rather to the actual
         * execution callback (which may be a wrapper around the user-supplied task).
         * <p>The primary use case is to set some execution context around the task's
         * invocation, or to provide some monitoring/statistics for task execution.
         * <p><b>NOTE:</b> Exception handling in {@code TaskDecorator} implementations
         * is limited to plain {@code Runnable} execution via {@code execute} calls.
         * In case of {@code #submit} calls, the exposed {@code Runnable} will be a
         * {@code FutureTask} which does not propagate any exceptions; you might
         * have to cast it and call {@code Future#get} to evaluate exceptions.
         * @since 4.3
         */
        public void setTaskDecorator(TaskDecorator taskDecorator) {
                this.taskDecorator = taskDecorator;
        }

        @Override
        public void afterPropertiesSet() throws NamingException {
                if (this.workManager == null) {
                        if (this.workManagerName != null) {
                                this.workManager = lookup(this.workManagerName, WorkManager.class);
                        }
                        else {
                                this.workManager = getDefaultWorkManager();
                        }
                }
        }

        /**
         * Obtain a default WorkManager to delegate to.
         * Called if no explicit WorkManager or WorkManager JNDI name has been specified.
         * <p>The default implementation returns a {@link SimpleTaskWorkManager}.
         * Can be overridden in subclasses.
         */
        protected WorkManager getDefaultWorkManager() {
                return new SimpleTaskWorkManager();
        }


        //-------------------------------------------------------------------------
        // Implementation of the Spring SchedulingTaskExecutor interface
        //-------------------------------------------------------------------------

        @Override
        public void execute(Runnable task) {
                execute(task, TIMEOUT_INDEFINITE);
        }

        @Override
        public void execute(Runnable task, long startTimeout) {
                Assert.state(this.workManager != null, "No WorkManager specified");
                Work work = new DelegatingWork(this.taskDecorator != null ? this.taskDecorator.decorate(task) : task);
                try {
                        if (this.blockUntilCompleted) {
                                if (startTimeout != TIMEOUT_INDEFINITE || this.workListener != null) {
                                        this.workManager.doWork(work, startTimeout, null, this.workListener);
                                }
                                else {
                                        this.workManager.doWork(work);
                                }
                        }
                        else if (this.blockUntilStarted) {
                                if (startTimeout != TIMEOUT_INDEFINITE || this.workListener != null) {
                                        this.workManager.startWork(work, startTimeout, null, this.workListener);
                                }
                                else {
                                        this.workManager.startWork(work);
                                }
                        }
                        else {
                                if (startTimeout != TIMEOUT_INDEFINITE || this.workListener != null) {
                                        this.workManager.scheduleWork(work, startTimeout, null, this.workListener);
                                }
                                else {
                                        this.workManager.scheduleWork(work);
                                }
                        }
                }
                catch (WorkRejectedException ex) {
                        if (WorkException.START_TIMED_OUT.equals(ex.getErrorCode())) {
                                throw new TaskTimeoutException("JCA WorkManager rejected task because of timeout: " + task, ex);
                        }
                        else {
                                throw new TaskRejectedException("JCA WorkManager rejected task: " + task, ex);
                        }
                }
                catch (WorkException ex) {
                        throw new SchedulingException("Could not schedule task on JCA WorkManager", ex);
                }
        }

        @Override
        public Future<?> submit(Runnable task) {
                FutureTask<Object> future = new FutureTask<Object>(task, null);
                execute(future, TIMEOUT_INDEFINITE);
                return future;
        }

        @Override
        public <T> Future<T> submit(Callable<T> task) {
                FutureTask<T> future = new FutureTask<T>(task);
                execute(future, TIMEOUT_INDEFINITE);
                return future;
        }

        @Override
        public ListenableFuture<?> submitListenable(Runnable task) {
                ListenableFutureTask<Object> future = new ListenableFutureTask<Object>(task, null);
                execute(future, TIMEOUT_INDEFINITE);
                return future;
        }

        @Override
        public <T> ListenableFuture<T> submitListenable(Callable<T> task) {
                ListenableFutureTask<T> future = new ListenableFutureTask<T>(task);
                execute(future, TIMEOUT_INDEFINITE);
                return future;
        }

        /**
         * This task executor prefers short-lived work units.
         */
        @Override
        public boolean prefersShortLivedTasks() {
                return true;
        }


        //-------------------------------------------------------------------------
        // Implementation of the JCA WorkManager interface
        //-------------------------------------------------------------------------

        @Override
        public void doWork(Work work) throws WorkException {
                this.workManager.doWork(work);
        }

        @Override
        public void doWork(Work work, long delay, ExecutionContext executionContext, WorkListener workListener)
                        throws WorkException {

                this.workManager.doWork(work, delay, executionContext, workListener);
        }

        @Override
        public long startWork(Work work) throws WorkException {
                return this.workManager.startWork(work);
        }

        @Override
        public long startWork(Work work, long delay, ExecutionContext executionContext, WorkListener workListener)
                        throws WorkException {

                return this.workManager.startWork(work, delay, executionContext, workListener);
        }

        @Override
        public void scheduleWork(Work work) throws WorkException {
                this.workManager.scheduleWork(work);
        }

        @Override
        public void scheduleWork(Work work, long delay, ExecutionContext executionContext, WorkListener workListener)
                        throws WorkException {

                this.workManager.scheduleWork(work, delay, executionContext, workListener);
        }

}