Fix java examples (#10257)

* TAP-655 fix examples java

* update samples

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java

@@ -1087,7 +1087,12 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
     public void setParameterExampleValue(CodegenParameter p) {
         String example;
 
-        if (p.defaultValue == null) {
+        boolean hasAllowableValues = p.allowableValues != null && !p.allowableValues.isEmpty();
+        if (hasAllowableValues) {
+            //support examples for inline enums
+            final List<Object> values = (List<Object>) p.allowableValues.get("values");
+            example = String.valueOf(values.get(0));
+        } else if (p.defaultValue == null) {
             example = p.example;
         } else {
             example = p.defaultValue;
@@ -1133,14 +1138,33 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
             example = "new File(\"" + escapeText(example) + "\")";
         } else if ("Date".equals(type)) {
             example = "new Date()";
+        } else if ("LocalDate".equals(type)) {
+            if (example == null) {
+                example = "LocalDate.now()";
+            } else {
+                example = "LocalDate.parse(\"" + example + "\")";
+            }
         } else if ("OffsetDateTime".equals(type)) {
-            example = "OffsetDateTime.now()";
+            if (example == null) {
+                example = "OffsetDateTime.now()";
+            } else {
+                example = "OffsetDateTime.parse(\"" + example + "\")";
+            }
         } else if ("BigDecimal".equals(type)) {
-            example = "new BigDecimal(78)";
-        } else if (p.allowableValues != null && !p.allowableValues.isEmpty()) {
-            Map<String, Object> allowableValues = p.allowableValues;
-            List<Object> values = (List<Object>) allowableValues.get("values");
-            example = type + ".fromValue(\"" + String.valueOf(values.get(0)) + "\")";
+            if (example == null) {
+                example = "new BigDecimal(78)";
+            } else {
+                example = "new BigDecimal(\"" + example + "\")";
+            }
+        } else if ("UUID".equals(type)) {
+            if (example == null) {
+                example = "UUID.randomUUID()";
+            } else {
+                example = "UUID.fromString(\"" + example + "\")";
+            }
+        } else if (hasAllowableValues) {
+            //parameter is enum defined as a schema component
+            example = type + ".fromValue(\"" + example + "\")";
         } else if (!languageSpecificPrimitives.contains(type)) {
             // type is a model class, e.g. User
             example = "new " + type + "()";

modules/openapi-generator/src/test/java/org/openapitools/codegen/java/AbstractJavaCodegenExampleValuesTest.java

@@ -0,0 +1,157 @@
+/*
+ * Copyright 2018 OpenAPI-Generator Contributors (https://openapi-generator.tech)
+ * Copyright 2018 SmartBear Software
+ *
+ * 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
+ *
+ *     https://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.openapitools.codegen.java;
+
+import org.openapitools.codegen.CodegenParameter;
+import org.openapitools.codegen.CodegenProperty;
+import org.openapitools.codegen.CodegenType;
+import org.openapitools.codegen.languages.AbstractJavaCodegen;
+import org.testng.Assert;
+import org.testng.annotations.Test;
+
+import java.util.Arrays;
+import java.util.Collections;
+
+public class AbstractJavaCodegenExampleValuesTest {
+
+    private final AbstractJavaCodegen fakeJavaCodegen = new P_AbstractJavaCodegen();
+
+    @Test
+    void referencedEnumTakeFirstName() {
+        final CodegenParameter p = new CodegenParameter();
+        p.allowableValues = Collections.singletonMap("values", Arrays.asList("first", "second"));
+        p.dataType = "WrappedEnum";
+
+        fakeJavaCodegen.setParameterExampleValue(p);
+        Assert.assertEquals(p.example, "WrappedEnum.fromValue(\"first\")");
+    }
+
+    @Test
+    void inlineEnum() {
+        final CodegenParameter p = new CodegenParameter();
+        p.allowableValues = Collections.singletonMap("values", Arrays.asList("first", "second"));
+        p.isEnum = true;
+        p.dataType = "String";
+
+        fakeJavaCodegen.setParameterExampleValue(p);
+        Assert.assertEquals(p.example, "\"first\"");
+    }
+
+    @Test
+    void inlineEnumArray() {
+        final CodegenParameter p = new CodegenParameter();
+        p.allowableValues = Collections.singletonMap("values", Arrays.asList("first", "second"));
+        p.isEnum = true;
+        p.isArray = true;
+        p.dataType = "List<String>";
+        p.items = new CodegenProperty();
+
+        fakeJavaCodegen.setParameterExampleValue(p);
+        Assert.assertEquals(p.example, "Arrays.asList()");
+    }
+
+    @Test
+    void dateDefault() {
+        final CodegenParameter p = new CodegenParameter();
+        p.isDate = true;
+        p.dataType = "LocalDate";
+
+        fakeJavaCodegen.setParameterExampleValue(p);
+        Assert.assertEquals(p.example, "LocalDate.now()");
+    }
+
+    @Test
+    void dateGivenExample() {
+        final CodegenParameter p = new CodegenParameter();
+        p.isDate = true;
+        p.dataType = "LocalDate";
+        p.example = "2017-03-30";
+
+        fakeJavaCodegen.setParameterExampleValue(p);
+        Assert.assertEquals(p.example, "LocalDate.parse(\"2017-03-30\")");
+    }
+
+    @Test
+    void dateTimeDefault() {
+        final CodegenParameter p = new CodegenParameter();
+        p.isDateTime = true;
+        p.dataType = "OffsetDateTime";
+
+        fakeJavaCodegen.setParameterExampleValue(p);
+        Assert.assertEquals(p.example, "OffsetDateTime.now()");
+    }
+
+    @Test
+    void dateTimeGivenExample() {
+        final CodegenParameter p = new CodegenParameter();
+        p.isDateTime = true;
+        p.dataType = "OffsetDateTime";
+        p.example = "2007-12-03T10:15:30+01:00";
+
+        fakeJavaCodegen.setParameterExampleValue(p);
+        Assert.assertEquals(p.example, "OffsetDateTime.parse(\"2007-12-03T10:15:30+01:00\")");
+    }
+
+    @Test
+    void uuidDefault() {
+        final CodegenParameter p = new CodegenParameter();
+        p.isUuid = true;
+        p.dataType = "UUID";
+
+        fakeJavaCodegen.setParameterExampleValue(p);
+        Assert.assertEquals(p.example, "UUID.randomUUID()");
+    }
+
+    @Test
+    void uuidGivenExample() {
+        final CodegenParameter p = new CodegenParameter();
+        p.isUuid = true;
+        p.dataType = "UUID";
+        p.example = "13b48713-b931-45ea-bd60-b07491245960";
+
+        fakeJavaCodegen.setParameterExampleValue(p);
+        Assert.assertEquals(p.example, "UUID.fromString(\"13b48713-b931-45ea-bd60-b07491245960\")");
+    }
+
+    private static class P_AbstractJavaCodegen extends AbstractJavaCodegen {
+        @Override
+        public CodegenType getTag() {
+            return null;
+        }
+
+        @Override
+        public String getName() {
+            return null;
+        }
+
+        @Override
+        public String getHelp() {
+            return null;
+        }
+
+        /**
+         * Gets artifact version.
+         * Only for testing purposes.
+         *
+         * @return version
+         */
+        public String getArtifactVersion() {
+            return this.artifactVersion;
+        }
+    }
+}