Add TriConsumer

smithy-utils/src/main/java/software/amazon/smithy/utils/TriConsumer.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License").
+ * You may not use this file except in compliance with the License.
+ * A copy of the License is located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file is distributed
+ * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ */
+
+package software.amazon.smithy.utils;
+
+import java.util.Objects;
+import java.util.function.BiConsumer;
+
+/**
+ * Similar to {@link BiConsumer}, but accepts three arguments.
+ *
+ * @param <T> The first argument type.
+ * @param <U> The second argument type.
+ * @param <V> The third argument type.
+ */
+@FunctionalInterface
+public interface TriConsumer<T, U, V> {
+    /**
+     * Performs the operation on the given inputs.
+     *
+     * @param t is the first argument
+     * @param u is the second argument
+     * @param v is the third argument
+     */
+    void accept(T t, U u, V v);
+
+    /**
+     * Returns a composed {@link TriConsumer} that performs, in sequence, this
+     * operation followed by the {@code after} operation.
+     *
+     * @param after the operation to perform after this operation
+     * @return a composed {@link TriConsumer}
+     * @throws NullPointerException if {@code after} is null
+     */
+    default TriConsumer<T, U, V> andThen(TriConsumer<? super T, ? super U, ? super V> after) {
+        Objects.requireNonNull(after);
+
+        return (x, y, z) -> {
+            accept(x, y, z);
+            after.accept(x, y, z);
+        };
+    }
+}

smithy-utils/src/test/java/software/amazon/smithy/utils/TriConsumerTest.java

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+/*
+ * Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License").
+ * You may not use this file except in compliance with the License.
+ * A copy of the License is located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file is distributed
+ * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ */
+
+package software.amazon.smithy.utils;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.equalTo;
+
+import java.util.Locale;
+import org.junit.jupiter.api.Test;
+
+public class TriConsumerTest {
+    @Test
+    public void composes() {
+        StringBuilder result = new StringBuilder();
+
+        TriConsumer<String, String, String> first = (a, b, c) -> {
+            result.append(a).append(b).append(c);
+        };
+
+        TriConsumer<String, String, String> second = (d, e, f) -> {
+            result.append(d.toUpperCase(Locale.ENGLISH))
+                    .append(e.toUpperCase(Locale.ENGLISH))
+                    .append(f.toUpperCase(Locale.ENGLISH));
+        };
+
+        TriConsumer<String, String, String> composed = first.andThen(second);
+
+        composed.accept("a", "b", "c");
+
+        assertThat(result.toString(), equalTo("abcABC"));
+    }
+}