Class CommandContextInterceptor

All Implemented Interfaces:

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.

Tom Baeyens, Daniel Meyer, Thorben Lindhauer