#1172 - Provide static helpers to build TemplateVariable instance.

We now expose static factory methods to make code setting up a UriTemplate with TemplateVariable instances.

Original pull request: #1192.

Author: gregturn

src/main/java/org/springframework/hateoas/TemplateVariable.java

@@ -71,6 +71,66 @@ public TemplateVariable(String name, TemplateVariable.VariableType type, String
 		this.description = description;
 	}
 
+	/**
+	 * Static helper to fashion {@link VariableType#PATH_VARIABLE} variables.
+	 *
+	 * @param pathVariable
+	 * @return
+	 */
+	public static TemplateVariable pathVariable(String pathVariable) {
+		return new TemplateVariable(pathVariable, VariableType.PATH_VARIABLE);
+	}
+
+	/**
+	 * Static helper to fashion {@link VariableType#REQUEST_PARAM} variables.
+	 *
+	 * @param requestParam
+	 * @return
+	 */
+	public static TemplateVariable requestParam(String requestParam) {
+		return new TemplateVariable(requestParam, VariableType.REQUEST_PARAM);
+	}
+
+	/**
+	 * Static helper to fashion {@link VariableType#REQUEST_PARAM_CONTINUED} variables.
+	 *
+	 * @param requestParam
+	 * @return
+	 */
+	public static TemplateVariable requestParamContinued(String requestParam) {
+		return new TemplateVariable(requestParam, VariableType.REQUEST_PARAM_CONTINUED);
+	}
+
+	/**
+	 * Static helper to fashion {@link VariableType#SEGMENT} variables.
+	 *
+	 * @param segment
+	 * @return
+	 */
+	public static TemplateVariable segment(String segment) {
+		return new TemplateVariable(segment, VariableType.SEGMENT);
+	}
+
+	/**
+	 * Static helper to fashion {@link VariableType#FRAGMENT} variables.
+	 *
+	 * @param fragment
+	 * @return
+	 */
+	public static TemplateVariable fragment(String fragment) {
+		return new TemplateVariable(fragment, VariableType.FRAGMENT);
+	}
+
+	/**
+	 * Static helper to fashion {@link VariableType#COMPOSITE_PARAM} variables.
+	 *
+	 * @param compositeParam
+	 * @return
+	 */
+	public static TemplateVariable compositeParam(String compositeParam) {
+		return new TemplateVariable(compositeParam, VariableType.COMPOSITE_PARAM);
+	}
+	
 	/**
 	 * Returns whether the variable has a description.
 	 * 
@@ -192,7 +252,7 @@ public static TemplateVariable.VariableType from(String key) {
 					.orElseThrow(() -> new IllegalArgumentException("Unsupported variable type " + key + "!"));
 		}
 
-		/* 
+		/*
 		 * (non-Javadoc)
 		 * @see java.lang.Enum#toString()
 		 */

src/test/java/org/springframework/hateoas/UriTemplateUnitTest.java

@@ -16,6 +16,7 @@
 package org.springframework.hateoas;
 
 import static org.assertj.core.api.Assertions.*;
+import static org.springframework.hateoas.TemplateVariable.*;
 import static org.springframework.hateoas.UriTemplateUnitTest.EncodingFixture.*;
 
 import java.io.ByteArrayInputStream;
@@ -38,7 +39,7 @@
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.MethodSource;
-import org.springframework.hateoas.TemplateVariable.VariableType;
+import org.springframework.hateoas.TemplateVariable.*;
 
 /**
  * Unit tests for {@link UriTemplate}.
@@ -300,6 +301,25 @@ void expandsTemplateWithAddedVariable() {
 		assertThat(template.expand("value").toString()).isEqualTo("/foo?bar=value");
 	}
 
+	@Test // 1172
+	void useHelperMethodsToBuildUriTemplates() {
+
+		assertThat(UriTemplate.of("/foo").with(pathVariable("var")).getVariableNames()).containsExactly("var");
+
+		assertThat(UriTemplate.of("/foo").with(requestParam("var")).with(requestParamContinued("var2")).toString())
+				.isEqualTo("/foo{?var,var2}");
+		assertThat(UriTemplate.of("/foo").with(requestParam("var")).with(requestParam("var2")).toString())
+				.isEqualTo("/foo{?var,var2}");
+
+		assertThat(UriTemplate.of("/foo").with(requestParamContinued("var2")).toString()).isEqualTo("/foo{&var2}");
+
+		assertThat(UriTemplate.of("/foo").with(segment("var")).toString()).isEqualTo("/foo{/var}");
+
+		assertThat(UriTemplate.of("/foo").with(fragment("var")).toString()).isEqualTo("/foo{#var}");
+
+		assertThat(UriTemplate.of("/foo").with(compositeParam("var")).toString()).isEqualTo("/foo{*var}");
+	}
+
 	private static void assertVariables(UriTemplate template, TemplateVariable... variables) {
 		assertVariables(template, Arrays.asList(variables));
 	}