How to use org.camunda.bpm.engine.impl.interceptor

protected void closeSessions(CommandInvocationContext commandInvocationContext) {
 for (Session session : sessionList) {
  try {
   session.close();
  } catch (Throwable exception) {
   commandInvocationContext.trySetThrowable(exception);
  }
 }
}

protected void fireCommandFailed(Throwable t) {
 for (CommandContextListener listener : commandContextListeners) {
  try {
   listener.onCommandFailed(this, t);
  }
  catch(Throwable ex) {
   LOG.exceptionWhileInvokingOnCommandFailed(t);
  }
 }
}

protected <T> T execute(Command<T> command) {
 if(commandExecutor != null) {
  return commandExecutor.execute(command);
 } else {
  return command.execute(commandContext);
 }
}

public void execute(CommandContext commandContext) {
 // passed commandContext may be in an inconsistent state
 commandExecutor.execute(new Command<Void>() {
  @Override
  public Void execute(CommandContext commandContext) {
   Map<String, Long> report = reportMetrics();
   boolean isRescheduleNow = shouldRescheduleNow();
   new HistoryCleanupSchedulerCmd(isRescheduleNow, report, configuration, jobId).execute(commandContext);
   return null;
  }
 });
}

@Override
protected Collection< ? extends CommandInterceptor> getDefaultCommandInterceptorsTxRequired() {
 List<CommandInterceptor> defaultCommandInterceptorsTxRequired = new ArrayList<CommandInterceptor>();
 defaultCommandInterceptorsTxRequired.add(new LogInterceptor());
 defaultCommandInterceptorsTxRequired.add(new ProcessApplicationContextInterceptor(this));
 defaultCommandInterceptorsTxRequired.add(new JtaTransactionInterceptor(transactionManager, false));
 defaultCommandInterceptorsTxRequired.add(new CommandContextInterceptor(commandContextFactory, this));
 return defaultCommandInterceptorsTxRequired;
}

protected void initCommandContextFactory() {
 if (commandContextFactory == null) {
  commandContextFactory = new CommandContextFactory();
  commandContextFactory.setProcessEngineConfiguration(this);
 }
}

public void bpmnStackTrace(String string) {
 logError(
   "006",
   string);
}

public void debugExecutingAtomicOperation(CoreAtomicOperation<?> executionOperation, CoreExecution execution) {
 logDebug(
   "001",
   "Executing atomic operation {} on {}", executionOperation, execution);
}

protected void fireCommandContextClose() {
 for (CommandContextListener listener : commandContextListeners) {
  listener.onCommandContextClose(this);
 }
}

public long sum() {
 callback = new Command() {
  @Override
  public Object execute(CommandContext commandContext) {
   return commandContext.getMeterLogManager()
    .executeSelectSum(MetricsQueryImpl.this);
  }
 };
 return (Long) commandExecutor.execute(this);
}

protected <T> T execute(Command<T> command) {
 if(commandExecutor != null) {
  return commandExecutor.execute(command);
 } else {
  return command.execute(commandContext);
 }
}

@Override
protected Collection< ? extends CommandInterceptor> getDefaultCommandInterceptorsTxRequiresNew() {
 List<CommandInterceptor> defaultCommandInterceptorsTxRequiresNew = new ArrayList<CommandInterceptor>();
 defaultCommandInterceptorsTxRequiresNew.add(new LogInterceptor());
 defaultCommandInterceptorsTxRequiresNew.add(new ProcessApplicationContextInterceptor(this));
 defaultCommandInterceptorsTxRequiresNew.add(new JtaTransactionInterceptor(transactionManager, true));
 defaultCommandInterceptorsTxRequiresNew.add(new CommandContextInterceptor(commandContextFactory, this, true));
 return defaultCommandInterceptorsTxRequiresNew;
}

protected void closeSessions(CommandInvocationContext commandInvocationContext) {
 for (Session session : sessionList) {
  try {
   session.close();
  } catch (Throwable exception) {
   commandInvocationContext.trySetThrowable(exception);
  }
 }
}

protected void fireCommandFailed(Throwable t) {
 for (CommandContextListener listener : commandContextListeners) {
  try {
   listener.onCommandFailed(this, t);
  }
  catch(Throwable ex) {
   LOG.exceptionWhileInvokingOnCommandFailed(t);
  }
 }
}

public List<TaskCountByCandidateGroupResult> taskCountByCandidateGroup() {
 return commandExecutor.execute(new Command<List<TaskCountByCandidateGroupResult>>() {
  @Override
  public List<TaskCountByCandidateGroupResult> execute(CommandContext commandContext) {
   return createTaskCountByCandidateGroupReport(commandContext);
  }
 });
}

@Override
protected Collection< ? extends CommandInterceptor> getDefaultCommandInterceptorsTxRequired() {
 List<CommandInterceptor> defaultCommandInterceptorsTxRequired = new ArrayList<CommandInterceptor>();
 defaultCommandInterceptorsTxRequired.add(new LogInterceptor());
 defaultCommandInterceptorsTxRequired.add(new ProcessApplicationContextInterceptor(this));
 defaultCommandInterceptorsTxRequired.add(new JtaTransactionInterceptor(transactionManager, false));
 defaultCommandInterceptorsTxRequired.add(new CommandContextInterceptor(commandContextFactory, this));
 return defaultCommandInterceptorsTxRequired;
}

public Set<String> getRegisteredDeployments() {
 return commandExecutor.execute(new Command<Set<String>>() {
  public Set<String> execute(CommandContext commandContext) {
   commandContext.getAuthorizationManager().checkCamundaAdmin();
   Set<String> registeredDeployments = Context.getProcessEngineConfiguration().getRegisteredDeployments();
   return new HashSet<String>(registeredDeployments);
  }
 });
}

@Override
protected Collection< ? extends CommandInterceptor> getDefaultCommandInterceptorsTxRequiresNew() {
 List<CommandInterceptor> defaultCommandInterceptorsTxRequiresNew = new ArrayList<CommandInterceptor>();
 defaultCommandInterceptorsTxRequiresNew.add(new LogInterceptor());
 defaultCommandInterceptorsTxRequiresNew.add(new ProcessApplicationContextInterceptor(this));
 defaultCommandInterceptorsTxRequiresNew.add(new JtaTransactionInterceptor(transactionManager, true));
 defaultCommandInterceptorsTxRequiresNew.add(new CommandContextInterceptor(commandContextFactory, this, true));
 return defaultCommandInterceptorsTxRequiresNew;
}

public String databaseSchemaUpgrade(final Connection connection, final String catalog, final String schema) {
 return commandExecutor.execute(new Command<String>() {
  public String execute(CommandContext commandContext) {
   commandContext.getAuthorizationManager().checkCamundaAdmin();
   DbSqlSessionFactory dbSqlSessionFactory = (DbSqlSessionFactory) commandContext.getSessionFactories().get(DbSqlSession.class);
   DbSqlSession dbSqlSession = new DbSqlSession(dbSqlSessionFactory, connection, catalog, schema);
   commandContext.getSessions().put(DbSqlSession.class, dbSqlSession);
   dbSqlSession.dbSchemaUpdate();
   return "";
  }
 });
}

 @Override
 public T call() throws Exception {
  return next.execute(command);
 }
},