Add UriTemplateHandler

This change introduces a strategy for expanding a URI template into a
URI and makes it a property of the RestTemplate and AsyncRestTemplate
so that they can be pre-configured with such a strategy.

The DefaultUriTemplateHandler relies on UriComponentsBuilder internally
and provides functionality equivalent to using the UriTemplate.
A DefaultUriTemplateHandler can also be configured to parse the path
of a URI template into path segments in order to allow expanding URI
variables according to path segment encoding rules.

Issue: SPR-12750

spring-web/src/test/java/org/springframework/web/client/RestTemplateTests.java

@@ -42,6 +42,7 @@ import org.springframework.http.client.ClientHttpRequestFactory;
 import org.springframework.http.client.ClientHttpResponse;
 import org.springframework.http.converter.GenericHttpMessageConverter;
 import org.springframework.http.converter.HttpMessageConverter;
+import org.springframework.web.util.DefaultUriTemplateHandler;
 
 import static org.junit.Assert.*;
 import static org.mockito.BDDMockito.*;
@@ -259,6 +260,35 @@ public class RestTemplateTests {
 		verify(response).close();
 	}
 
+	@Test
+	public void getForObjectWithCustomUriTemplateHandler() throws Exception {
+
+		DefaultUriTemplateHandler uriTemplateHandler = new DefaultUriTemplateHandler();
+		uriTemplateHandler.setParsePath(true);
+		template.setUriTemplateHandler(uriTemplateHandler);
+
+		URI expectedUri = new URI("http://example.com/hotels/1/pic/pics%2Flogo.png/size/150x150");
+		given(requestFactory.createRequest(expectedUri, HttpMethod.GET)).willReturn(request);
+
+		given(request.getHeaders()).willReturn(new HttpHeaders());
+		given(request.execute()).willReturn(response);
+		given(errorHandler.hasError(response)).willReturn(false);
+
+		given(response.getStatusCode()).willReturn(HttpStatus.OK);
+		given(response.getHeaders()).willReturn(new HttpHeaders());
+		given(response.getBody()).willReturn(null);
+
+		Map<String, String> uriVariables = new HashMap<String, String>(2);
+		uriVariables.put("hotel", "1");
+		uriVariables.put("publicpath", "pics/logo.png");
+		uriVariables.put("scale", "150x150");
+
+		String url = "http://example.com/hotels/{hotel}/pic/{publicpath}/size/{scale}";
+		template.getForObject(url, String.class, uriVariables);
+
+		verify(response).close();
+	}
+
 
 	@Test
 	public void headForHeaders() throws Exception {

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

@@ -0,0 +1,70 @@
+/*
+ * Copyright 2002-2015 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
+ *
+ *      http://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.web.util;
+
+import static org.junit.Assert.assertEquals;
+
+import java.net.URI;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * Unit tests for {@link DefaultUriTemplateHandler}.
+ * @author Rossen Stoyanchev
+ */
+public class DefaultUriTemplateHandlerTests {
+
+	private DefaultUriTemplateHandler handler;
+
+
+	@Before
+	public void setUp() throws Exception {
+		this.handler = new DefaultUriTemplateHandler();
+	}
+
+
+	@Test
+	public void expandWithFullPath() throws Exception {
+		Map<String, String> vars = new HashMap<String, String>(2);
+		vars.put("hotel", "1");
+		vars.put("publicpath", "pics/logo.png");
+		String template = "http://example.com/hotels/{hotel}/pic/{publicpath}";
+
+		URI actual = this.handler.expand(template, vars);
+
+		URI expected = new URI("http://example.com/hotels/1/pic/pics/logo.png");
+		assertEquals("Invalid expanded template", expected, actual);
+	}
+
+	@Test
+	public void expandWithFullPathParsedIntoPathSegments() throws Exception {
+		Map<String, String> vars = new HashMap<String, String>(2);
+		vars.put("hotel", "1");
+		vars.put("publicpath", "pics/logo.png");
+		vars.put("scale", "150x150");
+		String template = "http://example.com/hotels/{hotel}/pic/{publicpath}/size/{scale}";
+
+		this.handler.setParsePath(true);
+		URI actual = this.handler.expand(template, vars);
+
+		URI expected = new URI("http://example.com/hotels/1/pic/pics%2Flogo.png/size/150x150");
+		assertEquals("Invalid expanded template", expected, actual);
+	}
+
+}