apex-pdp reported an exception when creating policies. The policies are defined in CLAMP. According to the definition of policy type onap.policies.controlloop.operational.common.Apex, the type of engineServiceParameters (along with some other parameters) is string. But current apex-pdp does not support the parameter as string.

https://gerrit.onap.org/r/gitweb?p=policy/models.git;a=blob;f=models-examples/src/main/resources/policytypes/onap.policies.controlloop.operational.common.Apex.yaml;h=54b69c2d8a78ab7fd8d41d3f7c05632c4d7e433d;hb=HEAD

[2020-08-18T07:26:23.368+00:00|ERROR|PdpUpdateMessageHandler|DMAAP-source-POLICY-PDP-PAP] Apex engine service running failed.
org.onap.policy.apex.services.onappf.exception.ApexStarterException: org.onap.policy.common.utils.coder.CoderException: com.google.gson.JsonSyntaxException: Expected a com.google.gson.JsonObject but was com.google.gson.JsonPrimitive
at org.onap.policy.apex.services.onappf.handler.ApexEngineHandler.createPolicyArgsMap(ApexEngineHandler.java:109)
at org.onap.policy.apex.services.onappf.handler.ApexEngineHandler.updateApexEngine(ApexEngineHandler.java:82)
at org.onap.policy.apex.services.onappf.handler.PdpUpdateMessageHandler.startApexEngineBasedOnPolicies(PdpUpdateMessageHandler.java:167)
at org.onap.policy.apex.services.onappf.handler.PdpUpdateMessageHandler.startOrStopApexEngineBasedOnPolicies(PdpUpdateMessageHandler.java:139)
at org.onap.policy.apex.services.onappf.handler.PdpUpdateMessageHandler.handlePdpUpdate(PdpUpdateMessageHandler.java:98)
at org.onap.policy.apex.services.onappf.handler.PdpUpdateMessageHandler.handlePdpUpdateEvent(PdpUpdateMessageHandler.java:65)
at org.onap.policy.apex.services.onappf.comm.PdpUpdateListener.onTopicEvent(PdpUpdateListener.java:51)
at org.onap.policy.apex.services.onappf.comm.PdpUpdateListener.onTopicEvent(PdpUpdateListener.java:36)
at org.onap.policy.common.endpoints.listeners.ScoListener.onTopicEvent(ScoListener.java:79)
at org.onap.policy.common.endpoints.listeners.MessageTypeDispatcher.onTopicEvent(MessageTypeDispatcher.java:96)
at org.onap.policy.common.endpoints.listeners.JsonListener.onTopicEvent(JsonListener.java:63)
at org.onap.policy.common.endpoints.event.comm.bus.internal.TopicBase.broadcast(TopicBase.java:164)
at org.onap.policy.common.endpoints.event.comm.bus.internal.SingleThreadedBusTopicSource.fetchAllMessages(SingleThreadedBusTopicSource.java:242)
at org.onap.policy.common.endpoints.event.comm.bus.internal.SingleThreadedBusTopicSource.run(SingleThreadedBusTopicSource.java:225)
at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: org.onap.policy.common.utils.coder.CoderException: com.google.gson.JsonSyntaxException: Expected a com.google.gson.JsonObject but was com.google.gson.JsonPrimitive
at org.onap.policy.common.utils.coder.StandardCoder.decode(StandardCoder.java:189)
at org.onap.policy.apex.services.onappf.handler.ApexEngineHandler.createPolicyArgsMap(ApexEngineHandler.java:100)
... 14 common frames omitted
Caused by: com.google.gson.JsonSyntaxException: Expected a com.google.gson.JsonObject but was com.google.gson.JsonPrimitive
at com.google.gson.internal.bind.TypeAdapters$35$1.read(TypeAdapters.java:897)
at com.google.gson.Gson.fromJson(Gson.java:932)
at com.google.gson.Gson.fromJson(Gson.java:897)
at com.google.gson.Gson.fromJson(Gson.java:846)
at com.google.gson.Gson.fromJson(Gson.java:817)
at org.onap.policy.common.utils.coder.StandardCoder.fromJson(StandardCoder.java:346)
at org.onap.policy.common.utils.coder.StandardCoder.decode(StandardCoder.java:186)
... 15 common frames omitted