org.reactfx.AccumulatingStream Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of reactfx Show documentation

Reactive event streams for JavaFX

The newest version!

package org.reactfx;

import java.util.function.BiFunction;
import java.util.function.Function;

/**
 * See {@link EventStream#accumulate(BiFunction, Function)}
 */
class AccumulatingStream extends EventStreamBase {
    private final EventStream input;
    private final Function initialTransformation;
    private final BiFunction reduction;

    private boolean hasEvent = false;
    private U event = null;

    public AccumulatingStream(
            EventStream input,
            Function initial,
            BiFunction reduction) {

        this.input = input;
        this.initialTransformation = initial;
        this.reduction = reduction;
    }

    @Override
    protected final Subscription observeInputs() {
        return input.subscribe(i -> {
            event = hasEvent
                    ? reduction.apply(event, i)
                    : initialTransformation.apply(i);
            hasEvent = true;
            emit(event);
        });
    }
}