Introduce InvocationArguments type to capture the arguments passed to a method invocation's parameters.

apache-geode-extensions/src/main/java/org/springframework/geode/util/function/InvocationArguments.java

@@ -0,0 +1,84 @@
+/*
+ * Copyright 2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License 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 org.springframework.geode.util.function;
+
+import java.lang.reflect.Method;
+import java.util.Arrays;
+import java.util.Iterator;
+
+/**
+ * {@link Iterable} of {@link Method} invocation {@link Object arguments}.
+ *
+ * @author John Blum
+ * @see java.lang.Iterable
+ * @since 1.3.0
+ */
+public class InvocationArguments implements Iterable<Object> {
+
+	public static InvocationArguments from(Object... arguments) {
+		return new InvocationArguments(arguments);
+	}
+
+	private final Object[] arguments;
+
+	/**
+	 * Constructs a new instance of {@link InvocationArguments} initialized with the given array of
+	 * {@link Object arguments}.
+	 *
+	 * @param arguments array of {@link Object arguments} indicating the values passed to the {@link Method} invocation
+	 * parameters; may be {@literal null}.
+	 */
+	public InvocationArguments(Object[] arguments) {
+		this.arguments = arguments != null ? arguments : new Object[0];
+	}
+
+	protected Object[] getArguments() {
+		return this.arguments;
+	}
+
+	@SuppressWarnings("unchecked")
+	protected <T> T getArgumentAt(int index) {
+		return (T) getArguments()[index];
+	}
+
+	@Override
+	public Iterator<Object> iterator() {
+
+		return new Iterator<Object>() {
+
+			int index = 0;
+
+			@Override
+			public boolean hasNext() {
+				return this.index < InvocationArguments.this.getArguments().length;
+			}
+
+			@Override
+			public Object next() {
+				return InvocationArguments.this.getArguments()[this.index++];
+			}
+		};
+	}
+
+	public int size() {
+		return this.arguments.length;
+	}
+
+	@Override
+	public String toString() {
+		return Arrays.toString(getArguments());
+	}
+}

apache-geode-extensions/src/test/java/org/springframework/geode/util/function/InvocationArgumentsUnitTests.java

@@ -0,0 +1,97 @@
+/*
+ * Copyright 2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License 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 org.springframework.geode.util.function;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.Arrays;
+
+import org.junit.Test;
+
+/**
+ * Unit Tests for {@link InvocationArguments).
+ *
+ * @author John Blum
+ * @see org.junit.Test
+ * @see org.springframework.geode.util.function.InvocationArguments
+ * @since 1.3.0
+ */
+public class InvocationArgumentsUnitTests {
+
+	@Test
+	public void constructsInvocationArgumentsWithArguments() {
+
+		Object[] arguments = { true, 'c', 1, Math.PI, "test" };
+
+		InvocationArguments invocationArguments = new InvocationArguments(arguments);
+
+		assertThat(invocationArguments).isNotNull();
+		assertThat(invocationArguments.size()).isEqualTo(arguments.length);
+		assertThat(Arrays.equals(invocationArguments.getArguments(), arguments)).isTrue();
+		assertThat(invocationArguments.<Boolean>getArgumentAt(0)).isEqualTo(true);
+		assertThat(invocationArguments.<Character>getArgumentAt(1)).isEqualTo('c');
+		assertThat(invocationArguments.<Integer>getArgumentAt(2)).isEqualTo(1);
+		assertThat(invocationArguments.<Double>getArgumentAt(3)).isEqualTo(Math.PI);
+		assertThat(invocationArguments.<String>getArgumentAt(4)).isEqualTo("test");
+	}
+
+	@Test
+	public void fromConstructsNewInvocationArguments() {
+
+		InvocationArguments arguments = InvocationArguments.from("test", 1, false);
+
+		assertThat(arguments).isNotNull();
+		assertThat(arguments).hasSize(3);
+		assertThat(arguments.size()).isEqualTo(3);
+		assertThat(arguments).containsExactly("test", 1, false);
+		assertThat(arguments.<String>getArgumentAt(0)).isEqualTo("test");
+		assertThat(arguments.<Integer>getArgumentAt(1)).isEqualTo(1);
+		assertThat(arguments.<Boolean>getArgumentAt(2)).isEqualTo(false);
+	}
+
+	@Test
+	public void constructInvocationArgumentsWithNull() {
+
+		InvocationArguments arguments = new InvocationArguments(null);
+
+		assertThat(arguments).isNotNull();
+		assertThat(arguments).hasSize(0);
+		assertThat(arguments.getArguments()).isNotNull();
+	}
+
+	@Test
+	public void iteratesArguments() {
+
+		Object[] arguments = { true, 1, "test" };
+
+		InvocationArguments invocationArguments = new InvocationArguments(arguments);
+
+		int index = 0;
+
+		for (Object argument : invocationArguments) {
+			assertThat(argument).isEqualTo(arguments[index++]);
+		}
+	}
+
+	@Test
+	public void toStringIsCorrect() {
+
+		InvocationArguments arguments = InvocationArguments.from("one", "two", "three");
+
+		assertThat(arguments).isNotNull();
+		assertThat(arguments.toString()).isEqualTo("[one, two, three]");
+	}
+}