From fff6dc5d43539af05ae2679640240b8545b36947 Mon Sep 17 00:00:00 2001
From: bculkin2442 <bjculkin@mix.wvu.edu>
Date: Tue, 10 May 2016 21:58:08 -0400
Subject: Added interface to JDK collector API

---
 .../bjc/utils/funcutils/CompoundCollector.java     | 97 ++++++++++++++++++++++
 1 file changed, 97 insertions(+)
 create mode 100644 BJC-Utils2/src/main/java/bjc/utils/funcutils/CompoundCollector.java

(limited to 'BJC-Utils2/src/main/java/bjc/utils/funcutils/CompoundCollector.java')

diff --git a/BJC-Utils2/src/main/java/bjc/utils/funcutils/CompoundCollector.java b/BJC-Utils2/src/main/java/bjc/utils/funcutils/CompoundCollector.java
new file mode 100644
index 0000000..715a6e5
--- /dev/null
+++ b/BJC-Utils2/src/main/java/bjc/utils/funcutils/CompoundCollector.java
@@ -0,0 +1,97 @@
+package bjc.utils.funcutils;
+
+import java.util.Set;
+import java.util.function.BiConsumer;
+import java.util.function.BinaryOperator;
+import java.util.function.Function;
+import java.util.function.Supplier;
+import java.util.stream.Collector;
+import java.util.stream.Collector.Characteristics;
+
+import bjc.utils.data.IHolder;
+import bjc.utils.data.IPair;
+import bjc.utils.data.Identity;
+import bjc.utils.data.Pair;
+
+final class CompoundCollector<InitialType, AuxType1, AuxType2, FinalType1, FinalType2>
+		implements
+		Collector<InitialType, IHolder<IPair<AuxType1, AuxType2>>, IPair<FinalType1, FinalType2>> {
+	private Set<java.util.stream.Collector.Characteristics>	characteristicSet;
+
+	private Collector<InitialType, AuxType1, FinalType1>	firstCollector;
+	private Collector<InitialType, AuxType2, FinalType2>	secondCollector;
+
+	public CompoundCollector(
+			Collector<InitialType, AuxType1, FinalType1> firstCollector,
+			Collector<InitialType, AuxType2, FinalType2> secondCollector) {
+		this.firstCollector = firstCollector;
+		this.secondCollector = secondCollector;
+
+		characteristicSet = firstCollector.characteristics();
+		characteristicSet.addAll(secondCollector.characteristics());
+	}
+
+	@Override
+	public Supplier<IHolder<IPair<AuxType1, AuxType2>>> supplier() {
+		return () -> new Identity<>(
+				new Pair<>(firstCollector.supplier().get(),
+						secondCollector.supplier().get()));
+	}
+
+	@Override
+	public BiConsumer<IHolder<IPair<AuxType1, AuxType2>>, InitialType>
+			accumulator() {
+		BiConsumer<AuxType1, InitialType> firstAccumulator =
+				firstCollector.accumulator();
+		BiConsumer<AuxType2, InitialType> secondAccumulator =
+				secondCollector.accumulator();
+
+		return (state, value) -> {
+			state.doWith((statePair) -> {
+				statePair.doWith((leftState, rightState) -> {
+					firstAccumulator.accept(leftState, value);
+					secondAccumulator.accept(rightState, value);
+				});
+			});
+		};
+	}
+
+	@Override
+	public BinaryOperator<IHolder<IPair<AuxType1, AuxType2>>>
+			combiner() {
+		BinaryOperator<AuxType1> firstCombiner =
+				firstCollector.combiner();
+		BinaryOperator<AuxType2> secondCombiner =
+				secondCollector.combiner();
+
+		return (leftState, rightState) -> {
+			return leftState.unwrap((leftPair) -> {
+				return rightState.transform((rightPair) -> {
+					return leftPair.combine(rightPair, firstCombiner,
+							secondCombiner);
+				});
+			});
+		};
+	}
+
+	@Override
+	public Function<IHolder<IPair<AuxType1, AuxType2>>, IPair<FinalType1, FinalType2>>
+			finisher() {
+		return (state) -> {
+			return state.unwrap((pair) -> {
+				return pair.bind((leftVal, rightVal) -> {
+					return new Pair<>(
+							firstCollector.finisher().apply(leftVal),
+							secondCollector.finisher()
+									.apply(rightVal));
+				});
+			});
+		};
+	}
+
+	@Override
+	public Set<java.util.stream.Collector.Characteristics>
+			characteristics() {
+		return characteristicSet;
+	}
+}
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