org.camunda.bpm.engine.impl.interceptor
Class CommandContextInterceptor

java.lang.Object
  org.camunda.bpm.engine.impl.interceptor.CommandInterceptor
      org.camunda.bpm.engine.impl.interceptor.CommandContextInterceptor

All Implemented Interfaces:

CommandExecutor

public class CommandContextInterceptor
extends CommandInterceptor

Interceptor used for opening the CommandContext and CommandInvocationContext.

Since 7.1, this interceptor will not always open a new command context but instead reuse an existing command context if possible. This is required for supporting process engine public API access from delegation code (see ProcessEngineServicesAware.). However, for every command, a new command invocation context is created. While a command context holds resources that are shared between multiple commands, such as database sessions, a command invocation context holds resources specific for a single command.

The interceptor will check whether an open command context exists. If true, it will reuse the command context. If false, it will open a new one. We will always push the context to the Context stack. So ins some situations, you will see the same context being pushed to the sack multiple times. The rationale is that the size of the stack should allow you to determine whether you are currently running an 'inner' command or an 'outer' command as well as your current stack size. Existing code may rely on this behavior.

The interceptor can be configured using the property alwaysOpenNew. If this property is set to true, we will always open a new context regardless whether there already exists an active context or not. This is required for properly supporting REQUIRES_NEW semantics for commands run through the ProcessEngineConfigurationImpl.getCommandInterceptorsTxRequiresNew() chain. In that context the 'inner' command must be able to succeed / fail independently from the 'outer' command.

Author:

Tom Baeyens, Daniel Meyer, Thorben Lindhauer

Field Summary

protected boolean	alwaysOpenNew if true, we will always open a new command context
protected CommandContextFactory	commandContextFactory
protected ProcessEngineConfigurationImpl	processEngineConfiguration

Fields inherited from class org.camunda.bpm.engine.impl.interceptor.CommandInterceptor

next

Constructor Summary

CommandContextInterceptor()

CommandContextInterceptor(CommandContextFactory commandContextFactory, ProcessEngineConfigurationImpl processEngineConfiguration)

CommandContextInterceptor(CommandContextFactory commandContextFactory, ProcessEngineConfigurationImpl processEngineConfiguration, boolean alwaysOpenNew)

Method Summary

<T> T	execute(Command<T> command)
CommandContextFactory	getCommandContextFactory()
ProcessEngineConfigurationImpl	getProcessEngineConfiguration()
protected boolean	isFromSameEngine(CommandContext existingCommandContext)
void	setCommandContextFactory(CommandContextFactory commandContextFactory)
void	setProcessEngineContext(ProcessEngineConfigurationImpl processEngineContext)

Methods inherited from class org.camunda.bpm.engine.impl.interceptor.CommandInterceptor

getNext, setNext

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

commandContextFactory

protected CommandContextFactory commandContextFactory

processEngineConfiguration

protected ProcessEngineConfigurationImpl processEngineConfiguration

alwaysOpenNew

protected boolean alwaysOpenNew

if true, we will always open a new command context

Constructor Detail

CommandContextInterceptor

public CommandContextInterceptor()

CommandContextInterceptor

public CommandContextInterceptor(CommandContextFactory commandContextFactory,
                                 ProcessEngineConfigurationImpl processEngineConfiguration)

CommandContextInterceptor

public CommandContextInterceptor(CommandContextFactory commandContextFactory,
                                 ProcessEngineConfigurationImpl processEngineConfiguration,
                                 boolean alwaysOpenNew)

Method Detail

execute

public <T> T execute(Command<T> command)

isFromSameEngine

protected boolean isFromSameEngine(CommandContext existingCommandContext)

getCommandContextFactory

public CommandContextFactory getCommandContextFactory()

setCommandContextFactory

public void setCommandContextFactory(CommandContextFactory commandContextFactory)

getProcessEngineConfiguration

public ProcessEngineConfigurationImpl getProcessEngineConfiguration()

setProcessEngineContext

public void setProcessEngineContext(ProcessEngineConfigurationImpl processEngineContext)