Merge branch '5.3.x'

# Conflicts:
#	spring-core/src/test/java/org/springframework/util/SocketUtilsTests.java

Author: sbrannen

spring-test/src/main/java/org/springframework/test/util/TestSocketUtils.java

@@ -0,0 +1,139 @@
+/*
+ * Copyright 2002-2022 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.test.util;
+
+import java.net.InetAddress;
+import java.net.ServerSocket;
+import java.util.Random;
+
+import javax.net.ServerSocketFactory;
+
+import org.springframework.util.Assert;
+
+/**
+ * Simple utility for finding available TCP ports on {@code localhost} for use in
+ * integration testing scenarios.
+ *
+ * <p>This is a limited form of {@link org.springframework.util.SocketUtils} which
+ * has been deprecated since Spring Framework 5.3.16 and removed in Spring
+ * Framework 6.0.
+ *
+ * <p>{@code TestSocketUtils} can be used in integration tests which start an
+ * external server on an available random port. However, these utilities make no
+ * guarantee about the subsequent availability of a given port and are therefore
+ * unreliable. Instead of using {@code TestSocketUtils} to find an available local
+ * port for a server, it is recommended that you rely on a server's ability to
+ * start on a random <em>ephemeral</em> port that it selects or is assigned by the
+ * operating system. To interact with that server, you should query the server
+ * for the port it is currently using.
+ *
+ * @author Sam Brannen
+ * @author Ben Hale
+ * @author Arjen Poutsma
+ * @author Gunnar Hillert
+ * @author Gary Russell
+ * @author Chris Bono
+ * @since 5.3.24
+ */
+public class TestSocketUtils {
+
+	/**
+	 * The minimum value for port ranges used when finding an available TCP port.
+	 */
+	static final int PORT_RANGE_MIN = 1024;
+
+	/**
+	 * The maximum value for port ranges used when finding an available TCP port.
+	 */
+	static final int PORT_RANGE_MAX = 65535;
+
+	private static final int PORT_RANGE_PLUS_ONE = PORT_RANGE_MAX - PORT_RANGE_MIN + 1;
+
+	private static final int MAX_ATTEMPTS = 1_000;
+
+	private static final Random random = new Random(System.nanoTime());
+
+	private static final TestSocketUtils INSTANCE = new TestSocketUtils();
+
+
+	/**
+	 * Although {@code TestSocketUtils} consists solely of static utility methods,
+	 * this constructor is intentionally {@code public}.
+	 * <h4>Rationale</h4>
+	 * <p>Static methods from this class may be invoked from within XML
+	 * configuration files using the Spring Expression Language (SpEL) and the
+	 * following syntax.
+	 * <pre><code>
+	 * &lt;bean id="myBean" ... p:port="#{T(org.springframework.test.util.TestSocketUtils).findAvailableTcpPort()}" /&gt;</code>
+	 * </pre>
+	 * <p>If this constructor were {@code private}, you would be required to supply
+	 * the fully qualified class name to SpEL's {@code T()} function for each usage.
+	 * Thus, the fact that this constructor is {@code public} allows you to reduce
+	 * boilerplate configuration with SpEL as can be seen in the following example.
+	 * <pre><code>
+	 * &lt;bean id="socketUtils" class="org.springframework.test.util.TestSocketUtils" /&gt;
+	 * &lt;bean id="myBean" ... p:port="#{socketUtils.findAvailableTcpPort()}" /&gt;</code>
+	 * </pre>
+	 */
+	public TestSocketUtils() {
+	}
+
+	/**
+	 * Find an available TCP port randomly selected from the range [1024, 65535].
+	 * @return an available TCP port number
+	 * @throws IllegalStateException if no available port could be found
+	 */
+	public static int findAvailableTcpPort() {
+		return INSTANCE.findAvailableTcpPortInternal();
+	}
+
+
+	/**
+	 * Internal implementation of {@link #findAvailableTcpPort()}.
+	 * <p>Package-private solely for testing purposes.
+	 */
+	int findAvailableTcpPortInternal() {
+		int candidatePort;
+		int searchCounter = 0;
+		do {
+			Assert.state(++searchCounter <= MAX_ATTEMPTS, () -> String.format(
+					"Could not find an available TCP port in the range [%d, %d] after %d attempts",
+					PORT_RANGE_MIN, PORT_RANGE_MAX, MAX_ATTEMPTS));
+			candidatePort = PORT_RANGE_MIN + random.nextInt(PORT_RANGE_PLUS_ONE);
+		}
+		while (!isPortAvailable(candidatePort));
+
+		return candidatePort;
+	}
+
+	/**
+	 * Determine if the specified TCP port is currently available on {@code localhost}.
+	 * <p>Package-private solely for testing purposes.
+	 */
+	boolean isPortAvailable(int port) {
+		try {
+			ServerSocket serverSocket = ServerSocketFactory.getDefault()
+					.createServerSocket(port, 1, InetAddress.getByName("localhost"));
+			serverSocket.close();
+			return true;
+		}
+		catch (Exception ex) {
+			return false;
+		}
+	}
+
+}

spring-test/src/test/java/org/springframework/test/util/TestSocketUtilsTests.java

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+/*
+ * Copyright 2002-2022 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.test.util;
+
+import org.junit.jupiter.api.RepeatedTest;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
+
+/**
+ * Unit tests for {@link  TestSocketUtils}.
+ *
+ * @author Sam Brannen
+ * @author Gary Russell
+ * @since 5.3.24
+ */
+class TestSocketUtilsTests {
+
+	@Test
+	void canBeInstantiated() {
+		// Just making sure somebody doesn't try to make SocketUtils abstract,
+		// since that would be a breaking change due to the intentional public
+		// constructor.
+		new TestSocketUtils();
+	}
+
+	@RepeatedTest(10)
+	void findAvailableTcpPort() {
+		assertThat(TestSocketUtils.findAvailableTcpPort())
+			.isBetween(TestSocketUtils.PORT_RANGE_MIN, TestSocketUtils.PORT_RANGE_MAX);
+	}
+
+	@Test
+	void findAvailableTcpPortWhenNoAvailablePortFoundInMaxAttempts() {
+		TestSocketUtils socketUtils = new TestSocketUtils() {
+			@Override
+			boolean isPortAvailable(int port) {
+				return false;
+			}
+		};
+		assertThatIllegalStateException()
+			.isThrownBy(socketUtils::findAvailableTcpPortInternal)
+			.withMessage("Could not find an available TCP port in the range [1024, 65535] after 1000 attempts");
+	}
+
+}