com.bazoud.elasticsearch.river.git.guava.FunctionFlow Maven / Gradle / Ivy

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package com.bazoud.elasticsearch.river.git.guava;

import java.util.ArrayList;
import java.util.List;

import org.elasticsearch.common.logging.ESLogger;
import org.elasticsearch.common.logging.Loggers;

import com.google.common.base.Function;
import com.google.common.base.Stopwatch;
import com.google.common.collect.ImmutableList;

import static java.util.concurrent.TimeUnit.MILLISECONDS;

/**
 * @author Olivier Bazoud
 */
public class FunctionFlow {
    private static ESLogger logger = Loggers.getLogger(FunctionFlow.class);

    private ImmutableList> functions;

    public FunctionFlow(FunctionFlowBuilder functionFlowBuilder) {
        functions = ImmutableList.copyOf(functionFlowBuilder.functions);
    }

    public void apply(C context) {
        logger.info("Applying {} functions...", functions.size());
        Stopwatch stopwatch = new Stopwatch();
        for (Function function : functions) {
            logger.info("Starting {} ...", function.getClass().getName());
            stopwatch.reset().start();
            context = function.apply(context);
            stopwatch.stop();
            logger.info("{} done. Tooks {} ms.", function.getClass().getName(), stopwatch.elapsed(MILLISECONDS));
        }
        logger.info("Apply done.");
    }

    public static  FunctionFlowBuilder flow() {
        return new FunctionFlowBuilder();
    }

    public static class FunctionFlowBuilder {
        private List> functions = new ArrayList>();

        public FunctionFlow build() {
            return new FunctionFlow(this);
        }

        public FunctionFlowBuilder add(Function function) {
            functions.add(function);
            return this;
        }
    }

}