Update port related code in UriComponentsBuilder

Use null to indicate no port has been provided.
Raise exception when port has not been expanded.

Issue: SPR-12123

spring-web/src/main/java/org/springframework/web/util/HierarchicalUriComponents.java

@@ -109,6 +109,13 @@ final class HierarchicalUriComponents extends UriComponents {
 
 	@Override
 	public int getPort() {
+		if (this.port == null) {
+			return -1;
+		}
+		else if (this.port.contains("{")) {
+			throw new IllegalStateException(
+					"The port contains a URI variable but has not been expanded yet: " + this.port);
+		}
 		return Integer.parseInt(this.port);
 	}
 
@@ -360,7 +367,7 @@ final class HierarchicalUriComponents extends UriComponents {
 			if (this.host != null) {
 				uriBuilder.append(host);
 			}
-			if (!"-1".equals(this.port)) {
+			if (getPort() != -1) {
 				uriBuilder.append(':');
 				uriBuilder.append(port);
 			}

spring-web/src/main/java/org/springframework/web/util/UriComponentsBuilder.java

@@ -96,7 +96,7 @@ public class UriComponentsBuilder {
 
 	private String host;
 
-	private String port = "-1";
+	private String port;
 
 	private CompositePathComponentBuilder pathBuilder = new CompositePathComponentBuilder();
 
@@ -272,7 +272,7 @@ public class UriComponentsBuilder {
 			return new OpaqueUriComponents(this.scheme, this.ssp, this.fragment);
 		}
 		else {
-			return new HierarchicalUriComponents(this.scheme, this.userInfo, this.host, String.valueOf(this.port),
+			return new HierarchicalUriComponents(this.scheme, this.userInfo, this.host, this.port,
 					this.pathBuilder.build(), this.queryParams, this.fragment, encoded, true);
 		}
 	}
@@ -353,7 +353,7 @@ public class UriComponentsBuilder {
 	private void resetHierarchicalComponents() {
 		this.userInfo = null;
 		this.host = null;
-		this.port = "-1";
+		this.port = null;
 		this.pathBuilder = new CompositePathComponentBuilder();
 		this.queryParams.clear();
 	}
@@ -468,8 +468,9 @@ public class UriComponentsBuilder {
 	}
 
 	/**
-	 * Set the URI port. Passing {@code "-1"} will clear the port of this builder.
-	 * The given port may contain URI template variables.
+	 * Set the URI port. Use this method only when the port needs to be
+	 * parameterized with a URI variable. Otherwise use {@link #port(int)}.
+	 * Passing {@code null} will clear the port of this builder.
 	 * @param port the URI port
 	 * @return this UriComponentsBuilder
 	 */

spring-web/src/test/java/org/springframework/web/util/UriComponentsTests.java

 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2014 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.
@@ -16,6 +16,8 @@
 
 package org.springframework.web.util;
 
+import org.junit.Test;
+
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.ObjectInputStream;
@@ -23,10 +25,12 @@ import java.io.ObjectOutputStream;
 import java.net.URI;
 import java.net.URISyntaxException;
 
-import org.junit.Test;
-
-import static org.hamcrest.Matchers.*;
-import static org.junit.Assert.*;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.instanceOf;
+import static org.hamcrest.Matchers.not;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertThat;
+import static org.springframework.web.util.UriComponentsBuilder.fromUriString;
 
 /**
  * @author Arjen Poutsma
@@ -84,22 +88,18 @@ public class UriComponentsTests {
 
 	@Test
 	public void port() {
-		UriComponents uriComponents1 = UriComponentsBuilder.fromUriString(
-				"http://example.com:8080/bar").build();
-		UriComponents uriComponents2 = UriComponentsBuilder.fromUriString(
-				"http://example.com/bar").port(8080).build();
-		UriComponents uriComponents3 = UriComponentsBuilder.fromUriString(
-				"http://example.com/bar").port("{port}").build().expand(8080);
-		UriComponents uriComponents4 = UriComponentsBuilder.fromUriString(
-				"http://example.com/bar").port("808{digit}").build().expand(0);
-		assertEquals(8080, uriComponents1.getPort());
-		assertEquals("http://example.com:8080/bar", uriComponents1.toUriString());
-		assertEquals(8080, uriComponents2.getPort());
-		assertEquals("http://example.com:8080/bar", uriComponents2.toUriString());
-		assertEquals(8080, uriComponents3.getPort());
-		assertEquals("http://example.com:8080/bar", uriComponents3.toUriString());
-		assertEquals(8080, uriComponents4.getPort());
-		assertEquals("http://example.com:8080/bar", uriComponents4.toUriString());
+		UriComponents uri1 = fromUriString("http://example.com:8080/bar").build();
+		UriComponents uri2 = fromUriString("http://example.com/bar").port(8080).build();
+		UriComponents uri3 = fromUriString("http://example.com/bar").port("{port}").build().expand(8080);
+		UriComponents uri4 = fromUriString("http://example.com/bar").port("808{digit}").build().expand(0);
+		assertEquals(8080, uri1.getPort());
+		assertEquals("http://example.com:8080/bar", uri1.toUriString());
+		assertEquals(8080, uri2.getPort());
+		assertEquals("http://example.com:8080/bar", uri2.toUriString());
+		assertEquals(8080, uri3.getPort());
+		assertEquals("http://example.com:8080/bar", uri3.toUriString());
+		assertEquals(8080, uri4.getPort());
+		assertEquals("http://example.com:8080/bar", uri4.toUriString());
 	}
 
 	@Test(expected = IllegalStateException.class)