org.jgroups.util.ResponseCollector Maven / Gradle / Ivy

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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).
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package org.jgroups.util;

import org.jgroups.Address;
import org.jgroups.annotations.GuardedBy;

import java.util.*;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import java.util.stream.Collectors;

/** Similar to AckCollector, but collects responses from cluster members, not just acks. Null is not a valid key.
 * @author Bela Ban
 */
public class ResponseCollector {
    @GuardedBy("lock")
    private final Map responses;
    private final Lock           lock=new ReentrantLock(false);
    private final CondVar        cond=new CondVar(lock);


    /**
     *
     * @param members List of members from which we expect responses
     */
    public ResponseCollector(Collection members) {
        responses=members != null? new HashMap<>(members.size()) : new HashMap<>();
        reset(members);
    }

    public ResponseCollector(Address ... members) {
        responses=members != null? new HashMap<>(members.length) : new HashMap<>();
        reset(members);
    }

    public ResponseCollector() {
        responses=new HashMap<>();
    }

    public boolean add(Address member, T data) {
        if(member == null)
            return false;
        lock.lock();
        try {
            if(responses.containsKey(member)) {
                responses.put(member, data);
                cond.signal(true);
                return true;
            }
            return false;
        }
        finally {
            lock.unlock();
        }
    }

    public void remove(Address member) {
        if(member == null)
            return;
        lock.lock();
        try {
            if(responses.remove(member) != null)
                cond.signal(true);
        }
        finally {
            lock.unlock();
        }
    }

    public void remove(List members) {
        if(members == null || members.isEmpty())
            return;
        lock.lock();
        try {
            members.forEach(responses::remove);
            cond.signal(true);
        }
        finally {
            lock.unlock();
        }
    }

    public boolean retainAll(List members) {
        if(members == null || members.isEmpty())
            return false;
        lock.lock();
        try {
            if(responses.keySet().retainAll(members)) {
                cond.signal(true);
                return true;
            }
            return false;
        }
        finally {
            lock.unlock();
        }
    }

    public void suspect(Address member) {
        remove(member);
    }


    public boolean hasAllResponses() {
        lock.lock();
        try {
            return responses.isEmpty() || responses.entrySet().stream().allMatch(entry -> entry.getValue() != null);
        }
        finally {
            lock.unlock();
        }
    }

    public int numberOfValidResponses() {
        int retval=0;
        lock.lock();
        try {
            for(Map.Entry entry: responses.entrySet()) {
                if(entry.getValue() != null)
                    retval++;
            }
            return retval;
        }
        finally {
            lock.unlock();
        }
    }

    /** Returns a list of members which didn't send a valid response */
    public List getMissing() {
        return responses.entrySet().stream().filter(entry -> entry.getValue() == null).map(Map.Entry::getKey).collect(Collectors.toList());
    }

    public List getValidResults() {
        return responses.entrySet().stream().filter(entry -> entry.getValue() != null).map(Map.Entry::getKey).collect(Collectors.toList());
    }


    public Map getResults() {
        return responses;
    }

    public int size() {
        lock.lock();
        try {
            return responses.size();
        }
        finally {
            lock.unlock();
        }
    }


    /**
     * Waits until all responses have been received, or until a timeout has elapsed.
     * @param timeout Number of milliseconds to wait max. This value needs to be greater than 0, or else
     * it will be adjusted to 2000
     * @return boolean True if all responses have been received within timeout ms, else false (e.g. if interrupted)
     */
    public boolean waitForAllResponses(long timeout) {
        if(timeout <= 0)
            timeout=2000L;
        return cond.waitFor(this::hasAllResponses, timeout, TimeUnit.MILLISECONDS);
    }

    public void reset() {
        reset((Collection)null);
    }

    public void reset(Collection members) {
        lock.lock();
        try {
            responses.clear();
            if(members != null) {
                for(Address mbr: members)
                    responses.put(mbr, null);
            }
            cond.signal(true);
        }
        finally {
            lock.unlock();
        }
    }

    public void reset(Address ... members) {
        lock.lock();
        try {
            responses.clear();
            if(members != null) {
                for(Address mbr: members)
                    responses.put(mbr, null);
            }
            cond.signal(true);
        }
        finally {
            lock.unlock();
        }
    }



    public String toString() {
        return String.format("%s, complete=%s", responses, hasAllResponses());
    }


}