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Only the Java Core part of Javolution library, with slight modifications for use in MSFTBX.

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/*
 * Javolution - Java(TM) Solution for Real-Time and Embedded Systems
 * Copyright (C) 2012 - Javolution (http://javolution.org/)
 * All rights reserved.
 * 
 * Permission to use, copy, modify, and distribute this software is
 * freely granted, provided that this notice is preserved.
 */
package javolution.util.function;

import static javolution.lang.Realtime.Limit.LINEAR;

import java.util.Collection;
import java.util.Comparator;
import java.util.Iterator;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;

import javolution.lang.Parallelizable;
import javolution.lang.Realtime;
import javolution.util.FastCollection;

/**
 * 

A set of useful {@link Reducer reducers} of collection elements.

* * @author Jean-Marie Dautelle * @version 6.0, July 21, 2013 * @see FastCollection#reduce(Reducer) */ public class Reducers { // Utility class, no default constructor. private Reducers() {} /** * Returns any non-null element of the specified type. * This reducer stops iterating as soon as an element with the matching * type is found. */ @Parallelizable @Realtime(limit = LINEAR) public static Reducer any(Class type) { return new AnyReducer(type); } private static class AnyReducer implements Reducer { private final Class type; private volatile E found; public AnyReducer(Class type) { this.type = type; } @Override public void accept(Collection param) { Iterator it = param.iterator(); while (it.hasNext() && (found == null)) { E e = it.next(); if (type.isInstance(e)) { found = e; break; } } } @Override public E get() { return found; } } /** * Returns the greatest element of a collection according to the * specified comparator (returns {@code null} if the collection is empty). */ @Parallelizable(mutexFree = true, comment = "Internal use of AtomicReference") @Realtime(limit = LINEAR) public static Reducer max(Comparator comparator) { return new MaxReducer(comparator); } private static class MaxReducer implements Reducer { private final Comparator cmp; private final AtomicReference max = new AtomicReference(null); public MaxReducer(Comparator cmp) { this.cmp = cmp; } @Override public void accept(Collection param) { Iterator it = param.iterator(); while (it.hasNext()) { E e = it.next(); E read = max.get(); while ((read == null) || (cmp.compare(e, read) > 0)) { if (max.compareAndSet(read, e)) break; read = max.get(); } } } @Override public E get() { return max.get(); } } /** * Returns the smallest element of a collection according to the collection * comparator (returns {@code null} if the collection is empty). */ @Parallelizable(mutexFree = true, comment = "Internal use of AtomicReference") @Realtime(limit = LINEAR) public static Reducer min(Comparator comparator) { return new MinReducer(comparator); } private static class MinReducer implements Reducer { private final Comparator cmp; private final AtomicReference min = new AtomicReference(null); public MinReducer(Comparator cmp) { this.cmp = cmp; } @Override public void accept(Collection param) { Iterator it = param.iterator(); while (it.hasNext()) { E e = it.next(); E read = min.get(); while ((read == null) || (cmp.compare(e, read) < 0)) { if (min.compareAndSet(read, e)) break; read = min.get(); } } } @Override public E get() { return min.get(); } } /** * Conditional 'and' operator (returns {@code true} if the collection is * empty). This operator stops iterating as soon as a {@code false} value * is found. */ @Parallelizable @Realtime(limit = LINEAR) public static Reducer and() { return new AndReducer(); } private static class AndReducer implements Reducer { volatile boolean result = true; @Override public void accept(Collection param) { Iterator it = param.iterator(); while (result && it.hasNext()) { if (!it.next()) result = false; } } @Override public Boolean get() { return result; } } /** * Conditional 'or' operator (returns {@code false} if the collection is * empty). This operator stops iterating as soon as a {@code true} value * is found. */ @Parallelizable @Realtime(limit = LINEAR) public static Reducer or() { return new OrReducer(); } private static class OrReducer implements Reducer { volatile boolean result = false; @Override public void accept(Collection param) { Iterator it = param.iterator(); while (!result && it.hasNext()) { if (!it.next()) result = true; } } @Override public Boolean get() { return result; } } /** * Returns the sum of the specified integers value (returns {@code 0} * if the collection is empty). */ @Parallelizable(comment = "Internal use of AtomicInteger") @Realtime(limit = LINEAR) public static Reducer sum() { return new SumReducer(); } private static class SumReducer implements Reducer { private final AtomicInteger sum = new AtomicInteger(0); @Override public void accept(Collection param) { Iterator it = param.iterator(); while (it.hasNext()) { sum.getAndAdd(it.next().intValue()); } } @Override public Integer get() { return sum.get(); } } }




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