jnidzwetzki/bitfinex-v2-wss-api-java

/*******************************************************************************
 *
 *    Copyright (C) 2015-2018 Jan Kristof Nidzwetzki
 *  
 *    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
 *  
 *      http://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 com.github.jnidzwetzki.bitfinex.v2.manager;

import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.ExecutorService;
import java.util.function.BiConsumer;

import com.github.jnidzwetzki.bitfinex.v2.BitfinexWebsocketClient;
import com.github.jnidzwetzki.bitfinex.v2.exception.BitfinexClientException;

public class BiConsumerCallbackManager<S, T> extends AbstractManager {

    /**
     * The callbacks
     */
    private final Map<S, List<BiConsumer<S, T>>> callbacks;
    
    public BiConsumerCallbackManager(final ExecutorService executorService, 
            final BitfinexWebsocketClient client) {
        
        super(client, executorService);
        this.callbacks = new ConcurrentHashMap<>();
    }
    
    /**
     * Register a new callback
     * @param symbol
     * @param callback
     * @throws BitfinexClientException
     */
    public void registerCallback(final S symbol, final BiConsumer<S, T> callback) throws BitfinexClientException {
        final List<BiConsumer<S, T>> callbackList 
            = callbacks.computeIfAbsent(symbol, (k) -> new CopyOnWriteArrayList<>());    
        callbackList.add(callback);
    }
    
    /**
     * Remove the a callback
     * @param symbol
     * @param callback
     * @return
     * @throws BitfinexClientException
     */
    public boolean removeCallback(final S symbol, final BiConsumer<S, T> callback) throws BitfinexClientException {
        
        final List<BiConsumer<S, T>> callbackList = callbacks.get(symbol);

        if(callbackList == null) {
            throw new BitfinexClientException("Unknown ticker string: " + symbol);
        }            
        
        return callbackList.remove(callback);    
    }
    
    /**
     * Process a list with event
     * @param symbol
     * @param ticksArray
     */
    public void handleEventsCollection(final S symbol, final Collection<T> elements) {
        
        final List<BiConsumer<S, T>> callbackList = callbacks.get(symbol);
        
        if(callbackList == null) {
            return;
        }
                
        if(callbackList.isEmpty()) {
            return;
        }
        
        // Notify callbacks synchronously, to preserve the order of events
        for (final T element : elements) {
            callbackList.forEach((c) -> {
                c.accept(symbol, element);
            });
        }
    }
    
    /**
     * Handle a new tick
     * @param symbol
     * @param element
     */
    public void handleEvent(final S symbol, final T element) {
        
        final List<BiConsumer<S, T>> callbackList = callbacks.get(symbol);
        
        if(callbackList == null) {
            return;
        }

        if(callbackList.isEmpty()) {
            return;
        }

        callbackList.forEach((c) -> {
            final Runnable runnable = () -> c.accept(symbol, element);
            executorService.submit(runnable);
        });
    }
}