Remove JAXB and XML, use GSON for JSON

This review converst apex-pdp to use GSON for JSON handling. In order to
preserve backward compatibility with the JAXB format of JSON, custom
handling of maps was required. Therefore, the policy-common
StandardCoder could not be used.

There are a lot of small changes, removing annotations from concepts and
tweaking of test data. However, this cleans up the code base so it is
worth doing.

Issue-ID: POLICY-1820
Change-Id: I213fa64f6d7f3f1df8d10f111d9fbedbe80f9fe0
Signed-off-by: liamfallon <liam.fallon@est.tech>

6 files changed, 9 insertions, 85 deletions

diff --git a/model/engine-model/pom.xml b/model/engine-model/pom.xml
index 7a1b485f8..9db1b2053 100644
--- a/model/engine-model/pom.xml
+++ b/model/engine-model/pom.xml
@@ -2,6 +2,7 @@
   ============LICENSE_START=======================================================
    Copyright (C) 2018 Ericsson. All rights reserved.
    Modifications Copyright (C) 2022 Bell Canada.
+   Modifications Copyright (C) 2022 Nordix Foundation.
   ================================================================================
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
@@ -41,30 +42,4 @@
             <artifactId>simpleclient</artifactId>
         </dependency>
     </dependencies>
-
-    <build>
-        <plugins>
-            <plugin>
-                <groupId>org.codehaus.mojo</groupId>
-                <artifactId>exec-maven-plugin</artifactId>
-                <executions>
-                    <execution>
-                        <id>generate-xml-schema</id>
-                        <phase>process-classes</phase>
-                        <goals>
-                            <goal>java</goal>
-                        </goals>
-                        <configuration>
-                            <mainClass>org.onap.policy.apex.model.basicmodel.handling.ApexSchemaGenerator</mainClass>
-                            <classpathScope>compile</classpathScope>
-                            <arguments>
-                                <argument>org.onap.policy.apex.model.enginemodel.concepts.AxEngineModel</argument>
-                                <argument>${project.build.directory}/model/xml/apex-engine-model.xsd</argument>
-                            </arguments>
-                        </configuration>
-                    </execution>
-                </executions>
-            </plugin>
-        </plugins>
-    </build>
-</project>
\ No newline at end of file
+</project>
diff --git a/model/engine-model/src/main/java/org/onap/policy/apex/model/enginemodel/concepts/AxEngineModel.java b/model/engine-model/src/main/java/org/onap/policy/apex/model/enginemodel/concepts/AxEngineModel.java
index 97e85c596..1a590a411 100644
--- a/model/engine-model/src/main/java/org/onap/policy/apex/model/enginemodel/concepts/AxEngineModel.java
+++ b/model/engine-model/src/main/java/org/onap/policy/apex/model/enginemodel/concepts/AxEngineModel.java
@@ -24,11 +24,6 @@ package org.onap.policy.apex.model.enginemodel.concepts;
 
 import java.text.SimpleDateFormat;
 import java.util.List;
-import javax.xml.bind.annotation.XmlAccessType;
-import javax.xml.bind.annotation.XmlAccessorType;
-import javax.xml.bind.annotation.XmlElement;
-import javax.xml.bind.annotation.XmlRootElement;
-import javax.xml.bind.annotation.XmlType;
 import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxConcept;
 import org.onap.policy.apex.model.basicmodel.concepts.AxKey;
@@ -53,20 +48,12 @@ import org.onap.policy.common.utils.validation.Assertions;
  * <p>Validation checks that the current state {@link AxEngineState} is defined and that the time stamp
  * is set on the engine model.
  */
-@XmlRootElement(name = "apexEngineModel", namespace = "http://www.onap.org/policy/apex-pdp")
-@XmlAccessorType(XmlAccessType.FIELD)
-@XmlType(name = "AxEngineModel", namespace = "http://www.onap.org/policy/apex-pdp",
-        propOrder = {"timestamp", "state", "stats"})
-
 public class AxEngineModel extends AxContextModel {
     private static final long serialVersionUID = 6381235864606564046L;
     private static final int HASH_CODE_PRIME = 32;
 
     private long timestamp;
-
-    @XmlElement(required = true)
     private AxEngineState state;
-
     private AxEngineStats stats;
 
     /**
diff --git a/model/engine-model/src/main/java/org/onap/policy/apex/model/enginemodel/concepts/AxEngineState.java b/model/engine-model/src/main/java/org/onap/policy/apex/model/enginemodel/concepts/AxEngineState.java
index 63c8706d2..24c564b96 100644
--- a/model/engine-model/src/main/java/org/onap/policy/apex/model/enginemodel/concepts/AxEngineState.java
+++ b/model/engine-model/src/main/java/org/onap/policy/apex/model/enginemodel/concepts/AxEngineState.java
@@ -2,6 +2,7 @@
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
  *  Modifications Copyright (C) 2022 Bell Canada. All rights reserved.
+ *  Modifications Copyright (C) 2022 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,18 +22,12 @@
 
 package org.onap.policy.apex.model.enginemodel.concepts;
 
-import javax.xml.bind.annotation.XmlAccessType;
-import javax.xml.bind.annotation.XmlAccessorType;
-import javax.xml.bind.annotation.XmlType;
-
 /**
  * This enumeration indicates the execution state of an Apex engine.
  *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
 
-@XmlAccessorType(XmlAccessType.FIELD)
-@XmlType(name = "AxEngineState", namespace = "http://www.onap.org/policy/apex-pdp")
 public enum AxEngineState {
     /** The state of the engine is not known. */
     UNDEFINED(0),
@@ -54,4 +49,4 @@ public enum AxEngineState {
     public int getStateIdentifier() {
         return stateIdentifier;
     }
-}
\ No newline at end of file
+}
diff --git a/model/engine-model/src/main/java/org/onap/policy/apex/model/enginemodel/concepts/AxEngineStats.java b/model/engine-model/src/main/java/org/onap/policy/apex/model/enginemodel/concepts/AxEngineStats.java
index af5e8d458..36df645a5 100644
--- a/model/engine-model/src/main/java/org/onap/policy/apex/model/enginemodel/concepts/AxEngineStats.java
+++ b/model/engine-model/src/main/java/org/onap/policy/apex/model/enginemodel/concepts/AxEngineStats.java
@@ -26,11 +26,6 @@ import io.prometheus.client.Gauge;
 import io.prometheus.client.Histogram;
 import java.text.SimpleDateFormat;
 import java.util.List;
-import javax.xml.bind.annotation.XmlAccessType;
-import javax.xml.bind.annotation.XmlAccessorType;
-import javax.xml.bind.annotation.XmlElement;
-import javax.xml.bind.annotation.XmlRootElement;
-import javax.xml.bind.annotation.XmlType;
 import lombok.Getter;
 import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxConcept;
@@ -47,10 +42,6 @@ import org.onap.policy.common.utils.validation.Assertions;
  * engine, and the time stamp of the last engine start are recorded.
  */
 
-@XmlAccessorType(XmlAccessType.FIELD)
-@XmlRootElement(name = "apexEngineStats", namespace = "http://www.onap.org/policy/apex-pdp")
-@XmlType(name = "AxEngineStats", namespace = "http://www.onap.org/policy/apex-pdp", propOrder = {"key", "timeStamp",
-    "eventCount", "lastExecutionTime", "averageExecutionTime", "upTime", "lastStart"})
 public class AxEngineStats extends AxConcept {
     private static final long serialVersionUID = -6981129081962785368L;
     private static final int HASH_CODE_PRIME = 32;
@@ -71,28 +62,15 @@ public class AxEngineStats extends AxConcept {
             .name("apex_engine_last_execution_time").labelNames(ENGINE_INSTANCE_ID)
             .help("Time taken to execute the last APEX policy in seconds.").register();
 
-    @XmlElement(name = "key", required = true)
     private AxReferenceKey key;
-
-    @XmlElement(required = true)
     private long timeStamp;
-
-    @XmlElement(required = true)
     private long eventCount;
-
-    @XmlElement(required = true)
     private long lastExecutionTime;
-
-    @XmlElement(required = true)
     private double averageExecutionTime;
-
-    @XmlElement(required = true)
     private long upTime;
 
     @Getter
     private transient long lastEnterTime;
-
-    @XmlElement(required = true)
     private long lastStart;
 
     /**
diff --git a/model/engine-model/src/main/java/org/onap/policy/apex/model/enginemodel/concepts/package-info.java b/model/engine-model/src/main/java/org/onap/policy/apex/model/enginemodel/concepts/package-info.java
index ea47c6993..4557af7db 100644
--- a/model/engine-model/src/main/java/org/onap/policy/apex/model/enginemodel/concepts/package-info.java
+++ b/model/engine-model/src/main/java/org/onap/policy/apex/model/enginemodel/concepts/package-info.java
@@ -1,19 +1,20 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
+ *  Modifications Copyright (C) 2022 Nordix Foundation.
  * ================================================================================
  * 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.
- * 
+ *
  * SPDX-License-Identifier: Apache-2.0
  * ============LICENSE_END=========================================================
  */
@@ -21,14 +22,7 @@
 /**
  * Contains the concepts required to receive state information and statistcs from running APEX
  * engines.
- * 
+ *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-@XmlSchema(namespace = "http://www.onap.org/policy/apex-pdp", elementFormDefault = XmlNsForm.QUALIFIED,
-        xmlns = {@XmlNs(namespaceURI = "http://www.onap.org/policy/apex-pdp", prefix = "")})
-
 package org.onap.policy.apex.model.enginemodel.concepts;
-
-import javax.xml.bind.annotation.XmlNs;
-import javax.xml.bind.annotation.XmlNsForm;
-import javax.xml.bind.annotation.XmlSchema;
diff --git a/model/engine-model/src/test/java/org/onap/policy/apex/model/enginemodel/handling/ApexEngineModelTest.java b/model/engine-model/src/test/java/org/onap/policy/apex/model/enginemodel/handling/ApexEngineModelTest.java
index 8baa59b2f..e7fdd2d93 100644
--- a/model/engine-model/src/test/java/org/onap/policy/apex/model/enginemodel/handling/ApexEngineModelTest.java
+++ b/model/engine-model/src/test/java/org/onap/policy/apex/model/enginemodel/handling/ApexEngineModelTest.java
@@ -75,11 +75,6 @@ public class ApexEngineModelTest {
     }
 
     @Test
-    public void testModelWriteReadXml() throws Exception {
-        testApexModel.testApexModelWriteReadXml();
-    }
-
-    @Test
     public void testModelWriteReadJson() throws Exception {
         testApexModel.testApexModelWriteReadJson();
     }