Add ability to clone to UriComponentsBuilder hierarchy

Issue: SPR-12494

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

@@ -54,7 +54,7 @@ import org.springframework.web.util.HierarchicalUriComponents.PathComponent;
  * @see #fromPath(String)
  * @see #fromUri(URI)
  */
-public class UriComponentsBuilder {
+public class UriComponentsBuilder implements Cloneable {
 
 	private static final Pattern QUERY_PARAM_PATTERN = Pattern.compile("([^&=]+)(=?)([^&]+)?");
 
@@ -98,7 +98,7 @@ public class UriComponentsBuilder {
 
 	private String port;
 
-	private CompositePathComponentBuilder pathBuilder = new CompositePathComponentBuilder();
+	private CompositePathComponentBuilder pathBuilder;
 
 	private final MultiValueMap<String, String> queryParams = new LinkedMultiValueMap<String, String>();
 
@@ -112,6 +112,22 @@ public class UriComponentsBuilder {
 	 * @see #fromUri(URI)
 	 */
 	protected UriComponentsBuilder() {
+		this.pathBuilder = new CompositePathComponentBuilder();
+	}
+
+	/**
+	 * Create a deep copy of the given UriComponentsBuilder.
+	 * @param other the other builder to copy from
+	 */
+	protected UriComponentsBuilder(UriComponentsBuilder other) {
+		this.scheme = other.scheme;
+		this.ssp = other.ssp;
+		this.userInfo = other.userInfo;
+		this.host = other.host;
+		this.port = other.port;
+		this.pathBuilder = (CompositePathComponentBuilder) other.pathBuilder.clone();
+		this.queryParams.putAll(other.queryParams);
+		this.fragment = other.fragment;
 	}
 
 
@@ -627,16 +643,23 @@ public class UriComponentsBuilder {
 		return this;
 	}
 
+	@Override
+	protected Object clone() {
+		return new UriComponentsBuilder(this);
+	}
+
 
-	private interface PathComponentBuilder {
+	private interface PathComponentBuilder extends Cloneable {
 
 		PathComponent build();
+
+		Object clone();
 	}
 
 
 	private static class CompositePathComponentBuilder implements PathComponentBuilder {
 
-		private final LinkedList<PathComponentBuilder> componentBuilders = new LinkedList<PathComponentBuilder>();
+		private final LinkedList<PathComponentBuilder> builders = new LinkedList<PathComponentBuilder>();
 
 		public CompositePathComponentBuilder() {
 		}
@@ -651,7 +674,7 @@ public class UriComponentsBuilder {
 				FullPathComponentBuilder fpBuilder = getLastBuilder(FullPathComponentBuilder.class);
 				if (psBuilder == null) {
 					psBuilder = new PathSegmentComponentBuilder();
-					this.componentBuilders.add(psBuilder);
+					this.builders.add(psBuilder);
 					if (fpBuilder != null) {
 						fpBuilder.removeTrailingSlash();
 					}
@@ -669,7 +692,7 @@ public class UriComponentsBuilder {
 				}
 				if (fpBuilder == null) {
 					fpBuilder = new FullPathComponentBuilder();
-					this.componentBuilders.add(fpBuilder);
+					this.builders.add(fpBuilder);
 				}
 				fpBuilder.append(path);
 			}
@@ -677,8 +700,8 @@ public class UriComponentsBuilder {
 
 		@SuppressWarnings("unchecked")
 		private <T> T getLastBuilder(Class<T> builderClass) {
-			if (!this.componentBuilders.isEmpty()) {
-				PathComponentBuilder last = this.componentBuilders.getLast();
+			if (!this.builders.isEmpty()) {
+				PathComponentBuilder last = this.builders.getLast();
 				if (builderClass.isInstance(last)) {
 					return (T) last;
 				}
@@ -688,9 +711,9 @@ public class UriComponentsBuilder {
 
 		@Override
 		public PathComponent build() {
-			int size = this.componentBuilders.size();
+			int size = this.builders.size();
 			List<PathComponent> components = new ArrayList<PathComponent>(size);
-			for (PathComponentBuilder componentBuilder : this.componentBuilders) {
+			for (PathComponentBuilder componentBuilder : this.builders) {
 				PathComponent pathComponent = componentBuilder.build();
 				if (pathComponent != null) {
 					components.add(pathComponent);
@@ -704,6 +727,15 @@ public class UriComponentsBuilder {
 			}
 			return new HierarchicalUriComponents.PathComponentComposite(components);
 		}
+
+		@Override
+		public Object clone() {
+			CompositePathComponentBuilder compositeBuilder = new CompositePathComponentBuilder();
+			for (PathComponentBuilder builder : this.builders) {
+				compositeBuilder.builders.add((PathComponentBuilder) builder.clone());
+			}
+			return compositeBuilder;
+		}
 	}
 
 
@@ -737,6 +769,13 @@ public class UriComponentsBuilder {
 				this.path.deleteCharAt(index);
 			}
 		}
+
+		@Override
+		public Object clone() {
+			FullPathComponentBuilder builder = new FullPathComponentBuilder();
+			builder.append(this.path.toString());
+			return builder;
+		}
 	}
 
 
@@ -757,6 +796,13 @@ public class UriComponentsBuilder {
 			return (this.pathSegments.isEmpty() ? null :
 					new HierarchicalUriComponents.PathSegmentComponent(this.pathSegments));
 		}
+
+		@Override
+		public Object clone() {
+			PathSegmentComponentBuilder builder = new PathSegmentComponentBuilder();
+			builder.pathSegments.addAll(this.pathSegments);
+			return builder;
+		}
 	}
 
 }

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

@@ -16,6 +16,14 @@
 
 package org.springframework.web.util;
 
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.nullValue;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertThat;
+import static org.junit.Assert.assertTrue;
+
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.util.Arrays;
@@ -23,14 +31,10 @@ import java.util.HashMap;
 import java.util.Map;
 
 import org.junit.Test;
-
 import org.springframework.util.LinkedMultiValueMap;
 import org.springframework.util.MultiValueMap;
 import org.springframework.util.StringUtils;
 
-import static org.hamcrest.Matchers.*;
-import static org.junit.Assert.*;
-
 /**
  * @author Arjen Poutsma
  * @author Phillip Webb
@@ -436,4 +440,28 @@ public class UriComponentsBuilderTests {
 		assertThat(components.getFragment(), is(nullValue()));
 		assertThat(components.toString(), equalTo("/example"));
 	}
+
+	@Test
+	public void testClone() throws URISyntaxException {
+		UriComponentsBuilder builder1 = UriComponentsBuilder.newInstance();
+		builder1.scheme("http").host("e1.com").path("/p1").pathSegment("ps1").queryParam("q1").fragment("f1");
+
+		UriComponentsBuilder builder2 = (UriComponentsBuilder) builder1.clone();
+		builder2.scheme("https").host("e2.com").path("p2").pathSegment("ps2").queryParam("q2").fragment("f2");
+
+		UriComponents result1 = builder1.build();
+		assertEquals("http", result1.getScheme());
+		assertEquals("e1.com", result1.getHost());
+		assertEquals("/p1/ps1", result1.getPath());
+		assertEquals("q1", result1.getQuery());
+		assertEquals("f1", result1.getFragment());
+
+		UriComponents result2 = builder2.build();
+		assertEquals("https", result2.getScheme());
+		assertEquals("e2.com", result2.getHost());
+		assertEquals("/p1/ps1/p2/ps2", result2.getPath());
+		assertEquals("q1&q2", result2.getQuery());
+		assertEquals("f2", result2.getFragment());
+	}
+
 }

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/MvcUriComponentsBuilder.java

@@ -93,6 +93,26 @@ public class MvcUriComponentsBuilder extends UriComponentsBuilder {
 	}
 
 
+	/**
+	 * Default constructor. Protected to prevent direct instantiation.
+	 *
+	 * @see #fromController(Class)
+	 * @see #fromMethodName(Class, String, Object...)
+	 * @see #fromMethodCall(Object)
+	 * @see #fromMappingName(String)
+	 * @see #fromMethod(java.lang.reflect.Method, Object...)
+	 */
+	protected MvcUriComponentsBuilder() {
+	}
+
+	/**
+	 * Create a deep copy of the given MvcUriComponentsBuilder.
+	 * @param other the other builder to copy from
+	 */
+	protected MvcUriComponentsBuilder(MvcUriComponentsBuilder other) {
+		super(other);
+	}
+
 	/**
 	 * Create a {@link UriComponentsBuilder} from the mapping of a controller class
 	 * and current request information including Servlet mapping. If the controller
@@ -431,6 +451,11 @@ public class MvcUriComponentsBuilder extends UriComponentsBuilder {
 		}
 	}
 
+	@Override
+	protected Object clone() {
+		return new MvcUriComponentsBuilder(this);
+	}
+
 
 	private static class ControllerMethodInvocationInterceptor
 			implements org.springframework.cglib.proxy.MethodInterceptor, MethodInterceptor {

spring-webmvc/src/main/java/org/springframework/web/servlet/support/ServletUriComponentsBuilder.java

@@ -51,6 +51,15 @@ public class ServletUriComponentsBuilder extends UriComponentsBuilder {
 	protected ServletUriComponentsBuilder() {
 	}
 
+	/**
+	 * Create a deep copy of the given ServletUriComponentsBuilder.
+	 * @param other the other builder to copy from
+	 */
+	protected ServletUriComponentsBuilder(ServletUriComponentsBuilder other) {
+		super(other);
+		this.originalPath = other.originalPath;
+	}
+
 	/**
 	 * Prepare a builder from the host, port, scheme, and context path of the
 	 * given HttpServletRequest.
@@ -232,4 +241,9 @@ public class ServletUriComponentsBuilder extends UriComponentsBuilder {
 		return extension;
 	}
 
+	@Override
+	protected Object clone() {
+		return new ServletUriComponentsBuilder(this);
+	}
+
 }