SocketUtils considers port range including maxPort

Issue: SPR-14211

spring-core/src/main/java/org/springframework/util/SocketUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -192,14 +192,14 @@ public class SocketUtils {
 	}
 
 
-	private static enum SocketType {
+	private enum SocketType {
 
 		TCP {
 			@Override
 			protected boolean isPortAvailable(int port) {
 				try {
-					ServerSocket serverSocket = ServerSocketFactory.getDefault().createServerSocket(port, 1,
-						InetAddress.getByName("localhost"));
+					ServerSocket serverSocket = ServerSocketFactory.getDefault().createServerSocket(
+							port, 1, InetAddress.getByName("localhost"));
 					serverSocket.close();
 					return true;
 				}
@@ -238,7 +238,7 @@ public class SocketUtils {
 		 */
 		private int findRandomPort(int minPort, int maxPort) {
 			int portRange = maxPort - minPort;
-			return minPort + random.nextInt(portRange);
+			return minPort + random.nextInt(portRange + 1);
 		}
 
 		/**
@@ -251,7 +251,7 @@ public class SocketUtils {
 		 */
 		int findAvailablePort(int minPort, int maxPort) {
 			Assert.isTrue(minPort > 0, "'minPort' must be greater than 0");
-			Assert.isTrue(maxPort > minPort, "'maxPort' must be greater than 'minPort'");
+			Assert.isTrue(maxPort >= minPort, "'maxPort' must be greater than or equals 'minPort'");
 			Assert.isTrue(maxPort <= PORT_RANGE_MAX, "'maxPort' must be less than or equal to " + PORT_RANGE_MAX);
 
 			int portRange = maxPort - minPort;
@@ -260,8 +260,8 @@ public class SocketUtils {
 			do {
 				if (++searchCounter > portRange) {
 					throw new IllegalStateException(String.format(
-						"Could not find an available %s port in the range [%d, %d] after %d attempts", name(), minPort,
-						maxPort, searchCounter));
+							"Could not find an available %s port in the range [%d, %d] after %d attempts",
+							name(), minPort, maxPort, searchCounter));
 				}
 				candidatePort = findRandomPort(minPort, maxPort);
 			}
@@ -285,18 +285,18 @@ public class SocketUtils {
 			Assert.isTrue(maxPort <= PORT_RANGE_MAX, "'maxPort' must be less than or equal to " + PORT_RANGE_MAX);
 			Assert.isTrue(numRequested > 0, "'numRequested' must be greater than 0");
 			Assert.isTrue((maxPort - minPort) >= numRequested,
-				"'numRequested' must not be greater than 'maxPort' - 'minPort'");
+					"'numRequested' must not be greater than 'maxPort' - 'minPort'");
 
-			final SortedSet<Integer> availablePorts = new TreeSet<Integer>();
+			SortedSet<Integer> availablePorts = new TreeSet<Integer>();
 			int attemptCount = 0;
-			while ((++attemptCount <= numRequested + 100) && (availablePorts.size() < numRequested)) {
+			while ((++attemptCount <= numRequested + 100) && availablePorts.size() < numRequested) {
 				availablePorts.add(findAvailablePort(minPort, maxPort));
 			}
 
 			if (availablePorts.size() != numRequested) {
 				throw new IllegalStateException(String.format(
-					"Could not find %d available %s ports in the range [%d, %d]", numRequested, name(), minPort,
-					maxPort));
+						"Could not find %d available %s ports in the range [%d, %d]",
+						numRequested, name(), minPort, maxPort));
 			}
 
 			return availablePorts;

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -35,19 +35,7 @@ import static org.springframework.util.SocketUtils.*;
  */
 public class SocketUtilsTests {
 
-	private void assertPortInRange(int port, int minPort, int maxPort) {
-		assertTrue("port [" + port + "] >= " + minPort, port >= minPort);
-		assertTrue("port [" + port + "] <= " + maxPort, port <= maxPort);
-	}
-
-	private void assertAvailablePorts(SortedSet<Integer> ports, int numRequested, int minPort, int maxPort) {
-		assertEquals("number of ports requested", numRequested, ports.size());
-		for (int port : ports) {
-			assertPortInRange(port, minPort, maxPort);
-		}
-	}
-
-	// --- TCP -----------------------------------------------------------------
+	// TCP
 
 	@Test(expected = IllegalArgumentException.class)
 	public void findAvailableTcpPortWithZeroMinPort() {
@@ -70,8 +58,7 @@ public class SocketUtilsTests {
 		int port = SocketUtils.findAvailableTcpPort();
 		ServerSocket socket = ServerSocketFactory.getDefault().createServerSocket(port, 1, InetAddress.getByName("localhost"));
 		try {
-			// will only look for the exact port, since random.nextInt(1) always returns 0
-			SocketUtils.findAvailableTcpPort(port, port + 1);
+			SocketUtils.findAvailableTcpPort(port, port);
 		}
 		finally {
 			socket.close();
@@ -117,17 +104,8 @@ public class SocketUtilsTests {
 		findAvailableTcpPorts(50, 45000, 45010);
 	}
 
-	private void findAvailableTcpPorts(int numRequested) {
-		SortedSet<Integer> ports = SocketUtils.findAvailableTcpPorts(numRequested);
-		assertAvailablePorts(ports, numRequested, PORT_RANGE_MIN, PORT_RANGE_MAX);
-	}
 
-	private void findAvailableTcpPorts(int numRequested, int minPort, int maxPort) {
-		SortedSet<Integer> ports = SocketUtils.findAvailableTcpPorts(numRequested, minPort, maxPort);
-		assertAvailablePorts(ports, numRequested, minPort, maxPort);
-	}
-
-	// --- UDP -----------------------------------------------------------------
+	// UDP
 
 	@Test(expected = IllegalArgumentException.class)
 	public void findAvailableUdpPortWithZeroMinPort() {
@@ -150,8 +128,8 @@ public class SocketUtilsTests {
 		int port = SocketUtils.findAvailableUdpPort();
 		DatagramSocket socket = new DatagramSocket(port, InetAddress.getByName("localhost"));
 		try {
-			// will only look for the exact port, since random.nextInt(1) always returns 0
-			SocketUtils.findAvailableUdpPort(port, port + 1);
+			// will only look for the exact port
+			SocketUtils.findAvailableUdpPort(port, port);
 		}
 		finally {
 			socket.close();
@@ -197,6 +175,19 @@ public class SocketUtilsTests {
 		findAvailableUdpPorts(50, 45000, 45010);
 	}
 
+
+	// Helpers
+
+	private void findAvailableTcpPorts(int numRequested) {
+		SortedSet<Integer> ports = SocketUtils.findAvailableTcpPorts(numRequested);
+		assertAvailablePorts(ports, numRequested, PORT_RANGE_MIN, PORT_RANGE_MAX);
+	}
+
+	private void findAvailableTcpPorts(int numRequested, int minPort, int maxPort) {
+		SortedSet<Integer> ports = SocketUtils.findAvailableTcpPorts(numRequested, minPort, maxPort);
+		assertAvailablePorts(ports, numRequested, minPort, maxPort);
+	}
+
 	private void findAvailableUdpPorts(int numRequested) {
 		SortedSet<Integer> ports = SocketUtils.findAvailableUdpPorts(numRequested);
 		assertAvailablePorts(ports, numRequested, PORT_RANGE_MIN, PORT_RANGE_MAX);
@@ -206,5 +197,16 @@ public class SocketUtilsTests {
 		SortedSet<Integer> ports = SocketUtils.findAvailableUdpPorts(numRequested, minPort, maxPort);
 		assertAvailablePorts(ports, numRequested, minPort, maxPort);
 	}
+	private void assertPortInRange(int port, int minPort, int maxPort) {
+		assertTrue("port [" + port + "] >= " + minPort, port >= minPort);
+		assertTrue("port [" + port + "] <= " + maxPort, port <= maxPort);
+	}
+
+	private void assertAvailablePorts(SortedSet<Integer> ports, int numRequested, int minPort, int maxPort) {
+		assertEquals("number of ports requested", numRequested, ports.size());
+		for (int port : ports) {
+			assertPortInRange(port, minPort, maxPort);
+		}
+	}
 
 }