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package bjc.utils.data;
import java.util.function.BiFunction;
import java.util.function.Function;
/**
* A pair of values, with nothing special about them.
*
* @author ben
*
* @param <LeftType>
* The type of the left value
* @param <RightType>
* The type of the right value
*/
public class Pair<LeftType, RightType> implements IPair<LeftType, RightType> {
// The left value
private LeftType leftValue;
// The right value
private RightType rightValue;
/**
* Create a new pair with both sides set to null
*/
public Pair() {
}
/**
* Create a new pair with both sides set to the specified values
*
* @param left
* The value of the left side
* @param right
* The value of the right side
*/
public Pair(LeftType left, RightType right) {
leftValue = left;
rightValue = right;
}
@Override
public <BoundLeft, BoundRight> IPair<BoundLeft, BoundRight> bind(
BiFunction<LeftType, RightType, IPair<BoundLeft, BoundRight>> binder) {
if(binder == null) throw new NullPointerException("Binder must not be null.");
return binder.apply(leftValue, rightValue);
}
@Override
public <BoundLeft> IPair<BoundLeft, RightType> bindLeft(
Function<LeftType, IPair<BoundLeft, RightType>> leftBinder) {
if(leftBinder == null) throw new NullPointerException("Binder must not be null");
return leftBinder.apply(leftValue);
}
@Override
public <BoundRight> IPair<LeftType, BoundRight> bindRight(
Function<RightType, IPair<LeftType, BoundRight>> rightBinder) {
if(rightBinder == null) throw new NullPointerException("Binder must not be null");
return rightBinder.apply(rightValue);
}
@Override
public <OtherLeft, OtherRight, CombinedLeft, CombinedRight> IPair<CombinedLeft, CombinedRight> combine(
IPair<OtherLeft, OtherRight> otherPair,
BiFunction<LeftType, OtherLeft, CombinedLeft> leftCombiner,
BiFunction<RightType, OtherRight, CombinedRight> rightCombiner) {
return otherPair.bind((otherLeft, otherRight) -> {
return new Pair<>(leftCombiner.apply(leftValue, otherLeft),
rightCombiner.apply(rightValue, otherRight));
});
}
@Override
public <NewLeft> IPair<NewLeft, RightType> mapLeft(Function<LeftType, NewLeft> mapper) {
if(mapper == null) throw new NullPointerException("Mapper must not be null");
return new Pair<>(mapper.apply(leftValue), rightValue);
}
@Override
public <NewRight> IPair<LeftType, NewRight> mapRight(Function<RightType, NewRight> mapper) {
if(mapper == null) throw new NullPointerException("Mapper must not be null");
return new Pair<>(leftValue, mapper.apply(rightValue));
}
@Override
public <MergedType> MergedType merge(BiFunction<LeftType, RightType, MergedType> merger) {
if(merger == null) throw new NullPointerException("Merger must not be null");
return merger.apply(leftValue, rightValue);
}
@Override
public String toString() {
return "pair[l=" + leftValue.toString() + ", r=" + rightValue.toString() + "]";
}
}
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