add fromString() method to enums as required by JAX RS spec (#7494)

Author: upachler

modules/openapi-generator/src/main/resources/JavaJaxRS/spec/enumClass.mustache

@@ -21,6 +21,21 @@
         return String.valueOf(value);
     }
 
+    /**
+     * Convert a String into {{dataType}}, as specified in the
+     * <a href="https://download.oracle.com/otndocs/jcp/jaxrs-2_0-fr-eval-spec/index.html">See JAX RS 2.0 Specification, section 3.2, p. 12</a>
+     */
+	public static {{datatypeWithEnum}} fromString(String s) {
+        for ({{#datatypeWithEnum}}{{{.}}}{{/datatypeWithEnum}}{{^datatypeWithEnum}}{{{classname}}}{{/datatypeWithEnum}} b : {{#datatypeWithEnum}}{{{.}}}{{/datatypeWithEnum}}{{^datatypeWithEnum}}{{{classname}}}{{/datatypeWithEnum}}.values()) {
+            // using Objects.toString() to be safe if value type non-object type
+            // because types like 'int' etc. will be auto-boxed
+            if (java.util.Objects.toString(b.value).equals(s)) {
+                return b;
+            }
+        }
+        {{#isNullable}}return null;{{/isNullable}}{{^isNullable}}throw new IllegalArgumentException("Unexpected string value '" + s + "'");{{/isNullable}}
+	}
+	
     @JsonCreator
     public static {{datatypeWithEnum}} fromValue({{dataType}} value) {
         for ({{{datatypeWithEnum}}}{{^datatypeWithEnum}}{{{classname}}}{{/datatypeWithEnum}} b : {{{datatypeWithEnum}}}{{^datatypeWithEnum}}{{{classname}}}{{/datatypeWithEnum}}.values()) {

modules/openapi-generator/src/main/resources/JavaJaxRS/spec/enumOuterClass.mustache

@@ -25,6 +25,21 @@ import com.fasterxml.jackson.annotation.JsonValue;
     this.value = value;
   }
 
+    /**
+     * Convert a String into {{dataType}}, as specified in the
+     * <a href="https://download.oracle.com/otndocs/jcp/jaxrs-2_0-fr-eval-spec/index.html">See JAX RS 2.0 Specification, section 3.2, p. 12</a>
+     */
+	public static {{#datatypeWithEnum}}{{{.}}}{{/datatypeWithEnum}}{{^datatypeWithEnum}}{{{classname}}}{{/datatypeWithEnum}} fromString(String s) {
+      for ({{#datatypeWithEnum}}{{{.}}}{{/datatypeWithEnum}}{{^datatypeWithEnum}}{{{classname}}}{{/datatypeWithEnum}} b : {{#datatypeWithEnum}}{{{.}}}{{/datatypeWithEnum}}{{^datatypeWithEnum}}{{{classname}}}{{/datatypeWithEnum}}.values()) {
+        // using Objects.toString() to be safe if value type non-object type
+        // because types like 'int' etc. will be auto-boxed
+        if (java.util.Objects.toString(b.value).equals(s)) {
+          return b;
+        }
+      }
+      {{#isNullable}}return null;{{/isNullable}}{{^isNullable}}throw new IllegalArgumentException("Unexpected string value '" + s + "'");{{/isNullable}}
+	}
+	
   @Override
   @JsonValue
   public String toString() {