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Platform for Functional Reactive Programming with Java 8
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package cyclops.control;
import com.oath.cyclops.hkt.Higher;
import com.oath.cyclops.hkt.Higher2;
import com.oath.cyclops.types.functor.Transformable;
import cyclops.function.Function3;
import cyclops.function.Function4;
import cyclops.function.Monoid;
import com.oath.cyclops.hkt.DataWitness.writer;
import cyclops.typeclasses.functor.Functor;
import lombok.AccessLevel;
import lombok.AllArgsConstructor;
import lombok.Getter;
import cyclops.data.tuple.Tuple;
import cyclops.data.tuple.Tuple2;
import java.io.Serializable;
import java.util.Arrays;
import java.util.Iterator;
import java.util.function.BiFunction;
import java.util.function.Function;
@AllArgsConstructor(access= AccessLevel.PRIVATE)
@Getter
public final class Writer implements Transformable, Iterable,Higher2, Serializable {
private static final long serialVersionUID = 1L;
private final Tuple2 value;
private final Monoid monoid;
public Writer map(Function mapper) {
return writer(mapper.apply(value._1()), value._2(), monoid);
}
public R fold(BiFunction,? super Monoid,? extends R> fn){
return fn.apply(value,monoid);
}
public Writer flatMap(Function> fn) {
Writer writer = fn.apply(value._1());
return writer(writer.value._1(), writer.monoid.apply(value._2(), writer.value._2()), writer.monoid);
}
public Writer tell(W write){
return writer(value._1(),monoid.apply(write,value._2()),monoid);
}
public Writer set(R value){
return writer(value,this.value._2(),monoid);
}
/*
* Perform a For Comprehension over a Writer, accepting 3 generating function.
* This results in a four level nested internal iteration over the provided Writers.
*
*
* {@code
*
* import static com.oath.cyclops.reactor.Writers.forEach4;
*
forEach4(Writer.just(1),
a-> Writer.just(a+1),
(a,b) -> Writer.just(a+b),
a (a,b,c) -> Writer.just(a+b+c),
Tuple::tuple)
*
* }
*
*
* @param value1 top level Writer
* @param value2 Nested Writer
* @param value3 Nested Writer
* @param value4 Nested Writer
* @param yieldingFunction Generates a result per combination
* @return Writer with a combined value generated by the yielding function
*/
public Writer forEach4(Function> value2,
BiFunction> value3,
Function3> value4,
Function4 yieldingFunction) {
return this.flatMap(in -> {
Writer a = value2.apply(in);
return a.flatMap(ina -> {
Writer b = value3.apply(in,ina);
return b.flatMap(inb -> {
Writer c = value4.apply(in,ina,inb);
return c.map(in2 -> {
return yieldingFunction.apply(in, ina, inb, in2);
});
});
});
});
}
/**
* Perform a For Comprehension over a Writer, accepting 2 generating function.
* This results in a three level nested internal iteration over the provided Writers.
*
*
* {@code
*
* import static com.oath.cyclops.reactor.Writers.forEach3;
*
forEach3(Writer.just(1),
a-> Writer.just(a+1),
(a,b) -> Writer.just(a+b),
Tuple::tuple)
*
* }
*
*
* @param value2 Nested Writer
* @param value3 Nested Writer
* @param yieldingFunction Generates a result per combination
* @return Writer with a combined value generated by the yielding function
*/
public Writer forEach3(Function> value2,
BiFunction> value3,
Function3 yieldingFunction) {
return this.flatMap(in -> {
Writer a = value2.apply(in);
return a.flatMap(ina -> {
Writer b = value3.apply(in,ina);
return b.map(in2 -> {
return yieldingFunction.apply(in, ina, in2);
});
});
});
}
/**
* Perform a For Comprehension over a Writer, accepting a generating function.
* This results in a two level nested internal iteration over the provided Writers.
*
*
* {@code
*
* import static com.oath.cyclops.reactor.Writers.forEach;
*
forEach(Writer.just(1),
a-> Writer.just(a+1),
Tuple::tuple)
*
* }
*
*
* @param value2 Nested Writer
* @param yieldingFunction Generates a result per combination
* @return Writer with a combined value generated by the yielding function
*/
public Writer forEach2(Function> value2,
BiFunction yieldingFunction) {
return this.flatMap(in -> {
Writer a = value2.apply(in);
return a.map(in2 -> {
return yieldingFunction.apply(in, in2);
});
});
}
public static Writer writer(T value, Monoid combiner) {
return new Writer(Tuple.tuple(value, combiner.zero()), combiner);
}
public static Writer writer(T value, W initial, Monoid combiner) {
return new Writer(Tuple.tuple(value, initial), combiner);
}
public static Writer writer(Tuple2 values, Monoid combiner) {
return new Writer(values, combiner);
}
@Override
public Iterator iterator() {
return Arrays.asList(value._1()).iterator();
}
public static Writer narrowK2(final Higher2 t) {
return (Writer)t;
}
public static Writer narrowK(final Higher,T> t) {
return (Writer)t;
}
public static Higher, T> widen(Writer narrow) {
return narrow;
}
}