Add utility to retrieve functions

Treiblesschorle · ctrueden · commit 8d7f1009cf5a · 2019-04-18T12:02:26.000-05:00
diff --git a/src/main/java/org/scijava/ops/util/Functions.java b/src/main/java/org/scijava/ops/util/Functions.java
@@ -0,0 +1,40 @@
+package org.scijava.ops.util;
+
+import java.lang.reflect.Type;
+import java.util.function.BiFunction;
+import java.util.function.Function;
+
+import org.scijava.ops.Op;
+import org.scijava.ops.base.OpService;
+import org.scijava.ops.types.Nil;
+
+/**
+ * Utility providing adaptation between {@link Op} types.
+ */
+public class Functions {
+
+	private Functions() {
+		// NB: Prevent instantiation of utility class.
+	}
+
+	public static <I, O> Function<I, O> unary(final OpService ops, final Class<? extends Op> opClass,
+			final Class<I> inputType, final Class<O> outputType) {
+		return ops.findOp( //
+				new Nil<Function<I, O>>() {
+				}, //
+				new Type[] { opClass }, //
+				new Type[] { inputType }, //
+				outputType);
+	}
+
+	public static <I1, I2, O> BiFunction<I1, I2, O> binary(final OpService ops, final Class<? extends Op> opClass,
+			final Class<I1> input1Type, final Class<I2> input2Type, final Class<O> outputType) {
+		return ops.findOp( //
+				new Nil<BiFunction<I1, I2, O>>() {
+				}, //
+				new Type[] { opClass }, //
+				new Type[] { input1Type, input2Type }, //
+				outputType);
+	}
+
+}
diff --git a/src/test/java/org/scijava/ops/FunctionsTest.java b/src/test/java/org/scijava/ops/FunctionsTest.java
@@ -0,0 +1,62 @@
+/*
+ * #%L
+ * SciJava Operations: a framework for reusable algorithms.
+ * %%
+ * Copyright (C) 2018 SciJava developers.
+ * %%
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ * #L%
+ */
+
+package org.scijava.ops;
+
+import java.util.function.BiFunction;
+import java.util.function.Function;
+
+import org.junit.Test;
+import org.scijava.ops.math.Add.MathAddOp;
+import org.scijava.ops.math.Power.MathPowerOp;
+import org.scijava.ops.math.Sqrt.MathSqrtOp;
+import org.scijava.ops.util.Functions;
+
+public class FunctionsTest extends AbstractTestEnvironment {
+
+	@Test
+	public void testUnaryFunctions() {
+		Function<Double, Double> sqrtFunction = Functions.unary(ops, MathSqrtOp.class, Double.class, Double.class);
+		double answer = sqrtFunction.apply(16.0);
+		assert 4.0 == answer;
+	}
+
+	@Test
+	public void testBinaryFunctions() {
+		BiFunction<Double, Double, Double> addFunction = Functions.binary(ops, MathAddOp.class, Double.class,
+				Double.class, Double.class);
+		double answer = addFunction.apply(16.0, 14.0);
+		assert 30.0 == answer;
+		
+		BiFunction<Double, Double, Double> powerFunction = Functions.binary(ops, MathPowerOp.class, Double.class,
+				Double.class, Double.class);
+		answer = powerFunction.apply(2.0, 10.0);
+		assert 1024.0 == answer;
+	}
+}
