CppPublisher.java

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// author: Jason Wolfe


package ros.roscpp;

import ros.Publisher;
import ros.RosException;
import ros.communication.Message;

public class CppPublisher<M extends Message> implements Publisher<M> {
        private String topic;
        private M msgTemplate;
        private long cppPublisher;
        
        private CppPublisher() {}
        
        protected static <M extends Message> CppPublisher<M> create(long cppHandle, String topic, M msgTemplate, int queueSize, boolean latch) throws RosException {
                CppPublisher<M> that = new CppPublisher<M>();
                that.topic = topic;
                that.msgTemplate = msgTemplate;
                that.cppPublisher = JNI.advertise(cppHandle, topic, msgTemplate, queueSize, latch);
                if (that.cppPublisher == 0) throw new RosException("Could not advertise topic " + topic);
                return that;
        }
        
        public String getTopic() { return topic; }

        public int getNumSubscribers() {
                return JNI.getNumSubscribers(cppPublisher);
        }

        public void publish(M m) {
                if (cppPublisher == 0) throw new RuntimeException("This publication was already shutdown");
                if (m.getClass() != msgTemplate.getClass()) throw new RuntimeException("This message does not match the advertised type.");
                JNI.publish(cppPublisher, m);
        }

        public boolean isValid() { return (cppPublisher != 0) && JNI.isPublisherValid(cppPublisher);} 

        public void shutdown() {
                JNI.shutdownPublisher(cppPublisher);
                cppPublisher = 0;
        }
}