Details
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Improvement
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Status: Resolved
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Critical
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Resolution: Fixed
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4.0.0 M1
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None
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None
Description
Following is the MessageProcessor interface with this change.
package org.apache.stratos.messaging.message.processor;
import org.apache.stratos.messaging.domain.topology.Topology;
/**
- Message processor interface. Every Message Processor should implement this.
*/
public interface MessageProcessor {
/**
- Link a message processor and its successor, if there's any.
- @param nextProcessor
*/
public abstract void setNext(MessageProcessor nextProcessor);
/**
- Message processing and delegating logic.
- @param type type of the message.
- @param message real message body.
- @param topology Topology that will get updated.
- @return whether the processing was successful or not.
*/
public abstract boolean process(String type, String message, Topology topology);
}
I've implemented initial Message Processors:
├── ClusterCreatedEventProcessor.java
├── ClusterRemovedEventProcessor.java
├── CompleteTopologyEventProcessor.java
├── MemberActivatedEventProcessor.java
├── MemberStartedEventProcessor.java
├── MemberSuspendedEventProcessor.java
├── MemberTerminatedEventProcessor.java
├── ServiceCreatedEventProcessor.java
└── ServiceRemovedEventProcessor.java
Now, it is up to the Message Processor Delegator to build the Message processor chain.
// instantiate all the relevant processors
ServiceCreatedEventProcessor processor1 = new ServiceCreatedEventProcessor();
ServiceRemovedEventProcessor processor2 = new ServiceRemovedEventProcessor();
ClusterCreatedEventProcessor processor3 = new ClusterCreatedEventProcessor();
// link all the relevant processors in the required order
processor1.setNext(processor2);
processor2.setNext(processor3);
processor3.setNext(processor4);
and also it's a duty of the deligator to start the flow:
boolean hasProcessed = processor1.process(type, json, TopologyManager.getTopology());
After the flow started, Processor who is capable of handling the message would eventually receive it and will process the message and other Processors will simply delegate the message to its successor.