/*
 * Copyright 2002-2017 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.jms.config;

import javax.jms.MessageListener;

import org.springframework.jms.listener.AbstractMessageListenerContainer;
import org.springframework.jms.listener.MessageListenerContainer;
import org.springframework.jms.listener.endpoint.JmsActivationSpecConfig;
import org.springframework.jms.listener.endpoint.JmsMessageEndpointManager;

/**
 * Base model for a JMS listener endpoint
 *
 * @author Stephane Nicoll
 * @author Juergen Hoeller
 * @since 4.1
 * @see MethodJmsListenerEndpoint
 * @see SimpleJmsListenerEndpoint
 */
public abstract class AbstractJmsListenerEndpoint implements JmsListenerEndpoint {

        private String id;

        private String destination;

        private String subscription;

        private String selector;

        private String concurrency;


        public void setId(String id) {
                this.id = id;
        }

        @Override
        public String getId() {
                return this.id;
        }

        /**
         * Set the name of the destination for this endpoint.
         */
        public void setDestination(String destination) {
                this.destination = destination;
        }

        /**
         * Return the name of the destination for this endpoint.
         */
        public String getDestination() {
                return this.destination;
        }

        /**
         * Set the name for the durable subscription.
         */
        public void setSubscription(String subscription) {
                this.subscription = subscription;
        }

        /**
         * Return the name for the durable subscription, if any.
         */
        public String getSubscription() {
                return this.subscription;
        }

        /**
         * Set the JMS message selector expression.
         * <p>See the JMS specification for a detailed definition of selector expressions.
         */
        public void setSelector(String selector) {
                this.selector = selector;
        }

        /**
         * Return the JMS message selector expression, if any.
         */
        public String getSelector() {
                return this.selector;
        }

        /**
         * Set a concurrency for the listener, if any.
         * <p>The concurrency limits can be a "lower-upper" String, e.g. "5-10", or a simple
         * upper limit String, e.g. "10" (the lower limit will be 1 in this case).
         * <p>The underlying container may or may not support all features. For instance, it
         * may not be able to scale: in that case only the upper value is used.
         */
        public void setConcurrency(String concurrency) {
                this.concurrency = concurrency;
        }

        /**
         * Return the concurrency for the listener, if any.
         */
        public String getConcurrency() {
                return this.concurrency;
        }


        @Override
        public void setupListenerContainer(MessageListenerContainer listenerContainer) {
                if (listenerContainer instanceof AbstractMessageListenerContainer) {
                        setupJmsListenerContainer((AbstractMessageListenerContainer) listenerContainer);
                }
                else {
                        new JcaEndpointConfigurer().configureEndpoint(listenerContainer);
                }
        }

        private void setupJmsListenerContainer(AbstractMessageListenerContainer listenerContainer) {
                if (getDestination() != null) {
                        listenerContainer.setDestinationName(getDestination());
                }
                if (getSubscription() != null) {
                        listenerContainer.setSubscriptionName(getSubscription());
                }
                if (getSelector() != null) {
                        listenerContainer.setMessageSelector(getSelector());
                }
                if (getConcurrency() != null) {
                        listenerContainer.setConcurrency(getConcurrency());
                }
                setupMessageListener(listenerContainer);
        }

        /**
         * Create a {@link MessageListener} that is able to serve this endpoint for the
         * specified container.
         */
        protected abstract MessageListener createMessageListener(MessageListenerContainer container);

        private void setupMessageListener(MessageListenerContainer container) {
                MessageListener messageListener = createMessageListener(container);
                if (messageListener == null) {
                        throw new IllegalStateException("Endpoint [" + this + "] must provide a non-null message listener");
                }
                container.setupMessageListener(messageListener);
        }

        /**
         * Return a description for this endpoint.
         * <p>Available to subclasses, for inclusion in their {@code toString()} result.
         */
        protected StringBuilder getEndpointDescription() {
                StringBuilder result = new StringBuilder();
                return result.append(getClass().getSimpleName()).append("[").append(this.id).append("] destination=").
                                append(this.destination).append("' | subscription='").append(this.subscription).
                                append(" | selector='").append(this.selector).append("'");
        }

        @Override
        public String toString() {
                return getEndpointDescription().toString();
        }


        /**
         * Inner class to avoid a hard dependency on the JCA API.
         */
        private class JcaEndpointConfigurer {

                public void configureEndpoint(Object listenerContainer) {
                        if (listenerContainer instanceof JmsMessageEndpointManager) {
                                setupJcaMessageContainer((JmsMessageEndpointManager) listenerContainer);
                        }
                        else {
                                throw new IllegalArgumentException("Could not configure endpoint with the specified container '" +
                                                listenerContainer + "' Only JMS (" + AbstractMessageListenerContainer.class.getName() +
                                                " subclass) or JCA (" + JmsMessageEndpointManager.class.getName() + ") are supported.");
                        }
                }

                private void setupJcaMessageContainer(JmsMessageEndpointManager container) {
                        JmsActivationSpecConfig activationSpecConfig = container.getActivationSpecConfig();
                        if (activationSpecConfig == null) {
                                activationSpecConfig = new JmsActivationSpecConfig();
                                container.setActivationSpecConfig(activationSpecConfig);
                        }
                        if (getDestination() != null) {
                                activationSpecConfig.setDestinationName(getDestination());
                        }
                        if (getSubscription() != null) {
                                activationSpecConfig.setSubscriptionName(getSubscription());
                        }
                        if (getSelector() != null) {
                                activationSpecConfig.setMessageSelector(getSelector());
                        }
                        if (getConcurrency() != null) {
                                activationSpecConfig.setConcurrency(getConcurrency());
                        }
                        setupMessageListener(container);
                }
        }

}