How to use

KeycloakSubsystemWriteAttributeHandler

in

org.keycloak.subsystem.server.extension

@Override
protected void finishModelStage(OperationContext context, ModelNode operation, String attributeName, ModelNode newValue, ModelNode oldValue, Resource model) throws OperationFailedException {
  if (!context.isNormalServer() || attribNotChanging(attributeName, newValue, oldValue)) {
    super.finishModelStage(context, operation, attributeName, newValue, oldValue, model);
    return;
  }
  String deploymentName = ServerUtil.getDeploymentName(operation);
  if (attributeName.equals(KeycloakSubsystemDefinition.WEB_CONTEXT.getName())) {
    KeycloakAdapterConfigService.INSTANCE.setWebContext(newValue.asString());
    ServerUtil.addStepToRedeployServerWar(context, deploymentName);
  }
  super.finishModelStage(context, operation, attributeName, newValue, oldValue, model);
}

@Override
protected void finishModelStage(OperationContext context, ModelNode operation, String attributeName, ModelNode newValue, ModelNode oldValue, Resource model) throws OperationFailedException {
  if (!context.isNormalServer() || attribNotChanging(attributeName, newValue, oldValue)) {
    super.finishModelStage(context, operation, attributeName, newValue, oldValue, model);
    return;
  }
  String deploymentName = ServerUtil.getDeploymentName(operation);
  if (attributeName.equals(KeycloakSubsystemDefinition.WEB_CONTEXT.getName())) {
    KeycloakAdapterConfigService.INSTANCE.setWebContext(newValue.asString());
    ServerUtil.addStepToRedeployServerWar(context, deploymentName);
  }
  super.finishModelStage(context, operation, attributeName, newValue, oldValue, model);
}