CEM-9557: Change C2 OperandType to Enum

Signed-off-by: Matthew Burgess <mattyb149@apache.org>

This closes #5649

c2/c2-protocol/c2-protocol-api/src/main/java/org/apache/nifi/c2/protocol/api/C2Operation.java

@@ -17,6 +17,8 @@
 
 package org.apache.nifi.c2.protocol.api;
 
+import static java.lang.String.format;
+
 import io.swagger.annotations.ApiModel;
 import io.swagger.annotations.ApiModelProperty;
 import java.io.Serializable;
@@ -29,7 +31,7 @@ public class C2Operation implements Serializable {
 
     private String identifier;
     private OperationType operation;
-    private String operand;
+    private OperandType operand;
     private Map<String, String> args;
     private Set<String> dependencies;
 
@@ -48,6 +50,10 @@ public class C2Operation implements Serializable {
     }
 
     public void setOperation(OperationType operation) {
+        if (operand != null && !operation.isSupportedOperand(operand)) {
+            throw new IllegalArgumentException(format("%s is not a valid operand for %s", operand, operation));
+        }
+
         this.operation = operation;
     }
 
@@ -58,11 +64,15 @@ public class C2Operation implements Serializable {
             "If no operand is needed, this field will be absent." +
             "If one operand is insufficient, the operation will contain an args map" +
             "with additional keyword parameters and values (see 'args').")
-    public String getOperand() {
+    public OperandType getOperand() {
         return operand;
     }
 
-    public void setOperand(String operand) {
+    public void setOperand(OperandType operand) {
+        if (operation != null && !operation.isSupportedOperand(operand)) {
+            throw new IllegalArgumentException(format("%s is not a valid operand for %s", operand, operation));
+        }
+
         this.operand = operand;
     }
 

c2/c2-protocol/c2-protocol-api/src/main/java/org/apache/nifi/c2/protocol/api/OperandType.java

@@ -0,0 +1,37 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.apache.nifi.c2.protocol.api;
+
+import java.util.Arrays;
+import java.util.Optional;
+
+public enum OperandType {
+
+    CONFIGURATION,
+    CONNECTION,
+    DEBUG,
+    MANIFEST,
+    REPOSITORY;
+
+    public static Optional<OperandType> fromString(String value) {
+        return Arrays.stream(values())
+            .filter(operandType -> operandType.name().equalsIgnoreCase(value))
+            .findAny();
+    }
+}
+

c2/c2-protocol/c2-protocol-api/src/main/java/org/apache/nifi/c2/protocol/api/OperationType.java

@@ -17,6 +17,15 @@
 
 package org.apache.nifi.c2.protocol.api;
 
+import static org.apache.nifi.c2.protocol.api.OperandType.CONFIGURATION;
+import static org.apache.nifi.c2.protocol.api.OperandType.CONNECTION;
+import static org.apache.nifi.c2.protocol.api.OperandType.DEBUG;
+import static org.apache.nifi.c2.protocol.api.OperandType.MANIFEST;
+
+import java.util.Arrays;
+import java.util.Set;
+import java.util.stream.Collectors;
+
 public enum OperationType {
 
     // C2 Client Status Updates -> C2 Server
@@ -24,14 +33,25 @@ public enum OperationType {
     HEARTBEAT,
 
     // C2 Server -> C2 Client Commands
-    CLEAR,
+    CLEAR(CONNECTION),
-    DESCRIBE,
+    DESCRIBE(MANIFEST),
-    UPDATE,
+    UPDATE(CONFIGURATION),
     RESTART,
     START,
     STOP,
     PAUSE,
     REPLICATE,
     SUBSCRIBE,
-    TRANSFER
+    TRANSFER(DEBUG);
+
+    private final Set<OperandType> supportedOperands;
+
+    OperationType(OperandType... supportedOperands) {
+        this.supportedOperands = Arrays.stream(supportedOperands).collect(Collectors.toSet());
+    }
+
+    public boolean isSupportedOperand(OperandType operand) {
+        return supportedOperands.contains(operand);
+    }
+
 }