source: java/main/src/main/java/com/framsticks/util/dispatching/BufferedDispatcher.java @ 105

package com.framsticks.util.dispatching;


import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.LogManager;

import com.framsticks.util.FramsticksException;
import com.framsticks.util.lang.Strings;
// import static com.framsticks.util.dispatching.AbstractJoinable.wrap;

public class BufferedDispatcher<C> extends AbstractJoinable implements Dispatcher<C>, JoinableParent {
        private static final Logger log = LogManager.getLogger(BufferedDispatcher.class);

        protected final RunnableQueue<C> queue = new RunnableQueue<>();

        protected Dispatcher<C> targetDispatcher;

        protected boolean buffer = true;
        protected Dispatcher<C> parent;

        /**
         * @param parent
         */
        public BufferedDispatcher(Dispatcher<C> parent) {
                this.parent = parent;
        }

        /**
         * @return the targetDispatcher
         */
        public synchronized Dispatcher<C> getTargetDispatcher() {
                return targetDispatcher;
        }

        /**
         * @param targetDispatcher the targetDispatcher to set
         */
        public synchronized void setTargetDispatcher(Dispatcher<C> targetDispatcher) {
                if (this.targetDispatcher != null) {
                        throw new FramsticksException().msg("dispatcher is already set").arg("dispatcher", this.targetDispatcher).arg("in", this);
                }
                if (targetDispatcher == null) {
                        throw new FramsticksException().msg("trying to set empty target dispatcher").arg("in", this);
                }
                log.debug("setting {} to {}", this, targetDispatcher);
                this.targetDispatcher = targetDispatcher;
                flushQueue();
        }

        public synchronized boolean isActive() {
                if (targetDispatcher == null || buffer) {
                        return false;
                        // throw new FramsticksException().msg("no dispatcher is set for tree yet").arg("tree", this);
                }
                return targetDispatcher.isActive();
        }

        public synchronized void dispatch(final RunAt<? extends C> runnable) {
                if (targetDispatcher != null && !buffer) {
                        targetDispatcher.dispatch(runnable);
                        return;
                }
                queue.push(runnable);
        }

        protected void flushQueue() {
                if (this.buffer || targetDispatcher == null) {
                        return;
                }
                log.debug("flushing {} tasks in {}", queue.size(), this);
                while (!queue.isEmpty()) {
                        targetDispatcher.dispatch(queue.pollFirst());
                }
        }

        public synchronized void setBuffer(final boolean buffer) {
                if (this.buffer == buffer) {
                        return;
                }
                if (buffer) {
                        this.buffer = true;
                        return;
                }
                this.buffer = false;
                flushQueue();
        }

        @Override
        public String toString() {
                return parent + " -> " + Strings.toStringNullProof(targetDispatcher, "<null>");
        }

        public void createThreadIfNeeded() {
                synchronized (this) {
                        if (targetDispatcher != null) {
                                return;
                        }
                }
                this.setTargetDispatcher(new Thread<C>().setName(parent.getName()));
        }

        @Override
        public String getName() {
                return parent + " buffered dispatcher";
        }

        @Override
        protected synchronized void joinableStart() {
                Dispatching.use(targetDispatcher, this);
        }

        @Override
        protected synchronized void joinableInterrupt() {
                Dispatching.drop(targetDispatcher, this);

                finishJoinable();
        }

        @Override
        protected void joinableFinish() {

        }

        @Override
        protected synchronized void joinableJoin() throws InterruptedException {
                Dispatching.join(targetDispatcher);
        }

        @Override
        public void childChangedState(Joinable joinable, JoinableState state) {
                proceedToState(state);
        }
}