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The module for FunctionalJ Core.
There is a newer version: 1.0.17
// ============================================================================
// Copyright (c) 2017-2019 Nawapunth Manusitthipol (NawaMan - http://nawaman.net).
// ----------------------------------------------------------------------------
// MIT License
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
// ============================================================================
package functionalj.promise;

import static java.util.Objects.requireNonNull;

import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.Supplier;

import functionalj.function.Func1;
import functionalj.function.FuncUnit1;
import functionalj.result.Result;
import lombok.val;

public class Loop extends Retry {
    
    private final Integer                      count;
    private final Func1, Boolean> breakCondition;
    
    public Loop(int count) {
        super(Retry.RETRY_FOREVER, Retry.NO_WAIT);
        this.count          = count;
        this.breakCondition = null;
    }
    public Loop(Func1, Boolean> breakCondition) {
        super(Retry.RETRY_FOREVER, Retry.NO_WAIT);
        this.count          = null;
        this.breakCondition = requireNonNull(breakCondition);
    }
    
    @Override
    DeferAction create(DeferActionBuilder builder) {
        val interruptOnCancel = builder.interruptOnCancel();
        val supplier          = builder.supplier();
        val onStart           = builder.onStart();
        val runner            = builder.runner();
        
        DeferAction finalAction = DeferAction.createNew();
        
        val config = new DeferActionConfig()
                .interruptOnCancel(interruptOnCancel)
                .onStart(onStart)
                .runner(runner);
        
        val shouldStop      = shouldStop();
        val actionBuilder   = config.createBuilder(supplier);
        val subscriptionRef = new AtomicReference>();
        val onComplete      = new OnComplete<>(actionBuilder, shouldStop, finalAction, subscriptionRef::get);
        
        val action       = actionBuilder.build();
        val subscription = action.getPromise().onComplete(onComplete);
        subscriptionRef.set(subscription);
        action.start();
        
        return finalAction;
    }
    private Func1, Boolean> shouldStop() {
        if (breakCondition != null)
            return breakCondition;
        
        val counter = new AtomicInteger(count.intValue());
        val stopPredicate = (Func1, Boolean>)(result)->{
            return counter.decrementAndGet() <= 0;
        };
        return stopPredicate;
    }
    
    static class OnComplete implements FuncUnit1> {
        
        private final DeferActionBuilder           actionBuilder;
        private final Func1, Boolean>       shouldStop;
        private final DeferAction                  finalAction;
        private final Supplier> subscriptionRef;
        
        public OnComplete(
                DeferActionBuilder           actionBuilder,
                Func1, Boolean>       shouldStop,
                DeferAction                  finalAction,
                Supplier> subscriptionRef) {
            this.actionBuilder = actionBuilder;
            this.shouldStop = shouldStop;
            this.finalAction = finalAction;
            this.subscriptionRef = subscriptionRef;
        }
        
        @Override
        public void acceptUnsafe(Result result) throws Exception {
            val shouldBreak = shouldStop.apply(result);
            if (shouldBreak) {
                val value = result.value();
                finalAction.complete(value);
            } else {
                subscriptionRef.get().unsubscribe();
                
                actionBuilder
                .build()
                .onComplete(this)
                .start();
            }
        }
        
    }
    
}