Java Sample Code for Custom Conflict Resolution

Java Sample Code for Custom Conflict Resolution

Example 1

The sample custom conflict implementation provides the conflict resolution for client create and server exists.

Consider a scenario where an employee entity exists with the name as the primary key. This primary key is not auto-generated.

A user with name Mike exists in the server. A client uses the Create action to upload a record with the name Mike. A Create conflict occurs, as a record already exists. If you want to overwrite the existing record, you must give the action as Update to submit the data to the backend.

In the given example, if a record exists with the name John, then the code returns the record without submitting the record to the backend. The data at the server returns to the client.

The following is a sample Conflict Resolution for Client Create Server Exists:

package com.customcode.conflict;

import com.google.gson.JsonObject;
import com.hcl.voltmx.middleware.common.ActionType;
import com.hcl.voltmx.middleware.customconflict.ConflictContext;
import com.hcl.voltmx.middleware.customconflict.ConflictResolutionResult;
import com.hcl.voltmx.middleware.customconflict.CustomConflictResolver;

/**
 * This class represents sample custom conflict implementation
 */
public class JavaCustomConflict implements CustomConflictResolver {

  @Override
  public ConflictResolutionResult resolveClientCreateServerExists(JsonObject clientData,
      JsonObject serverData, ConflictContext conflictContext) {
    ConflictResolutionResult conflictResult = null;
    if (conflictContext.getObjectId().equals("categories")) {
      if (clientData.get("CustomerID").getAsString().equals("John")) { // returning without submitting to the backend, serverwins                  
        conflictResult = new ConflictResolutionResult(serverData, ActionType.update, false);
      } else { // clientwins
        conflictResult = new ConflictResolutionResult(clientData, ActionType.update, true);
      }
    }
}

Example 2

The sample custom conflict implementation provides the conflict resolution for client update and server update.

The following is a sample conflict resolution for Client Update Server Update:

package com.customcode.conflict;

import com.google.gson.JsonObject;
import com.hcl.voltmx.middleware.common.ActionType;
import com.hcl.voltmx.middleware.customconflict.ConflictContext;
import com.hcl.voltmx.middleware.customconflict.ConflictResolutionResult;
import com.hcl.voltmx.middleware.customconflict.CustomConflictResolver;

/**
 * This class represents sample custom conflict implementation
 */
public class JavaCustomConflict implements CustomConflictResolver {
  @Override
  public ConflictResolutionResult resolveClientUpdateServerUpdate(JsonObject clientData,
      JsonObject serverData, ConflictContext conflictcontext) {
    ConflictResolutionResult conflictResult = null;
    if (conflictcontext.getObjectId().equals("categories")) {
      if (clientData.get("CategoryID").getAsInt() == 4) {//New custom conflict data is returned with server data.
        JsonObject resolvedData = getResolvedData(serverData, conflictcontext);
        conflictResult = new ConflictResolutionResult(resolvedData, ActionType.update, true);
      } else {//clientwins with categoryname overwritten with server value
        if (clientData.get("CategoryID").getAsInt() == 3) {
          clientData.addProperty("CategoryName", serverData.get("CategoryName").getAsString());
        }
        conflictResult = new ConflictResolutionResult(clientData, ActionType.update, true);
      }
    }
    return conflictResult;
  }

  private JsonObject getResolvedData(JsonObject serverData, ConflictContext conflictcontext) {
    JsonObject resolvedData = new JsonObject();
    for (String field : conflictcontext.getFields()) {
      resolvedData.add(field, serverData.get(field));
    }
    return resolvedData;  
}  
}  

Example 3

The sample custom conflict implementation provides the conflict resolution for client update and server delete.

An Update conflict occurs when the client performs an Update action on a deleted record. For a hard-deleted record, the server considers the Update action as a Create action.

The following is a sample Conflict Resolution for Client Update Server Delete:

package com.customcode.conflict;

import com.google.gson.JsonObject;
import com.hcl.voltmx.middleware.common.ActionType;
import com.hcl.voltmx.middleware.customconflict.ConflictContext;
import com.hcl.voltmx.middleware.customconflict.ConflictResolutionResult;
import com.hcl.voltmx.middleware.customconflict.CustomConflictResolver;

/**
 * This class represents sample custom conflict implementation
 */
public class JavaCustomConflict implements CustomConflictResolver {  

public ConflictResolutionResult resolveClientUpdateServerDelete(JsonObject clientData,
      JsonObject serverData, ConflictContext conflictContext) {
    ConflictResolutionResult conflictResult = null;
    if (conflictContext.getObjectId().equals("categories")) {
      if (clientData.get("CategoryID").getAsInt() == 1) {
        return new ConflictResolutionResult(); // returning without submitting to backend, serverwins
   } else {// clientwins
        conflictResult = new ConflictResolutionResult(clientData, ActionType.update, true);
      }
    }
    return conflictResult;
  }    
}  

Example 4

The sample custom conflict implementation provides the conflict resolution for client delete and server update.

The following is a sample Conflict Resolution for Client Delete Server Update:

package com.customcode.conflict;

import com.google.gson.JsonObject;
import com.hcl.voltmx.middleware.common.ActionType;
import com.hcl.voltmx.middleware.customconflict.ConflictContext;
import com.hcl.voltmx.middleware.customconflict.ConflictResolutionResult;
import com.hcl.voltmx.middleware.customconflict.CustomConflictResolver;

/**
 * This class represents sample custom conflict implementation
 */
public class JavaCustomConflict implements CustomConflictResolver {  

 @Override
  public ConflictResolutionResult resolveClientDeleteServerUpdate(JsonObject clientData,
      JsonObject serverData, ConflictContext conflictContext) {
    ConflictResolutionResult conflictResult = null;
    if (conflictContext.getObjectId().equals("categories")) {
      if (clientData.get("CategoryID").getAsInt() == 7) { // returning without submitting to the backend, serverwins
        conflictResult = new ConflictResolutionResult();
      } else { // clientwins
        conflictResult = new ConflictResolutionResult(clientData, ActionType.delete, true);
      }
    }
    return conflictResult;
  }
}