Example usage for java.util.stream Collector of

Introduction

In this page you can find the example usage for java.util.stream Collector of.

Prototype

public static <T, R> Collector<T, R, R> of(Supplier<R> supplier, BiConsumer<R, T> accumulator,
        BinaryOperator<R> combiner, Characteristics... characteristics) 

Source Link

Document

Returns a new Collector described by the given supplier , accumulator , and combiner functions.

Usage

From source file:org.briljantframework.data.Collectors.java

public static Collector<Number, ?, Number> min() {
    class MinBox {

        double value = Double.NEGATIVE_INFINITY;
        boolean hasValue = false;

        void update(double v) {
            if (!Is.NA(v)) {
                hasValue = true;//from  www.j av a 2s. c o m
                value = Math.min(v, value);
            }
        }
    }
    return Collector.of(MinBox::new, (a, v) -> a.update(v.doubleValue()), (left, right) -> {
        left.update(right.value);
        return left;
    }, (r) -> r.hasValue ? r.value : Na.DOUBLE);
}

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From source file:org.briljantframework.data.Collectors.java

/**
 * Returns a collector that counts non-NA values
 *
 * @return a collector that counts non-NA values
 *///from w  w w  .  ja  v a  2  s .  c  om
public static Collector<Object, ?, Integer> count() {
    return Collector.of(() -> new int[1], (int[] a, Object b) -> {
        if (!Is.NA(b)) {
            a[0] += 1;
        }
    }, (int[] left, int[] right) -> {
        left[0] += right[0];
        return left;
    }, (int[] a) -> a[0]);
}

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From source file:org.briljantframework.data.Collectors.java

/**
 * Returns a collector that collects objects into a vector while filling NA-values with the
 * supplied value//from  www .j  av a  2s.c  o m
 *
 * @param fill the value to fill NA with
 * @return a collector for filling NA values
 */
public static Collector<Object, ?, Vector> fillNa(Object fill) {
    return Collector.of(TypeInferenceVectorBuilder::new, (builder, t) -> {
        if (Is.NA(t)) {
            builder.add(fill);
        } else {
            builder.add(t);
        }
    }, (left, right) -> {
        left.addAll(right);
        return left;
    }, Vector.Builder::build);
}

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From source file:org.briljantframework.data.vector.Vectors.java

public static <T, V extends Vector.Builder> Collector<T, ?, Vector> collector(Supplier<V> supplier) {
    return Collector.of(supplier, Vector.Builder::add, (left, right) -> {
        left.addAll(right.getView());/*from   ww  w .  j  av  a  2 s.  com*/
        return left;
    }, Vector.Builder::build);
}

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From source file:org.trellisldp.api.TrellisUtils.java

/**
 * Collect a stream of Triples into a Graph.
 *
 * @return a graph/*from   w w w .j av  a  2  s.com*/
 */
public static Collector<Triple, ?, Graph> toGraph() {
    return Collector.of(rdf::createGraph, Graph::add, (left, right) -> {
        right.iterate().forEach(left::add);
        return left;
    }, UNORDERED);
}

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