Able to lock without "nowait" for jBPM pessimistic locking

JpaProcessPersistenceContext.findProcessInstanceInfo() uses LockModeType.PESSIMISTIC_FORCE_INCREMENT

https://github.com/kiegroup/jbpm/blob/7.7.0.Final/jbpm-persistence/jbpm-persistence-jpa/src/main/java/org/jbpm/persistence/JpaProcessPersistenceContext.java#L68

LockModeType.PESSIMISTIC_FORCE_INCREMENT always issues "select for update" with "nowait".

https://github.com/hibernate/hibernate-orm/blob/5.1.10/hibernate-core/src/main/java/org/hibernate/dialect/Dialect.java#L1195-L1196

The request is to be able to:

• Use "select for update" without "nowait"
• Use "javax.persistence.lock.timeout" as a hint of pessimistic lock timeout. (Only feasible to some databases. https://docs.oracle.com/javaee/7/tutorial/persistence-locking002.htm#GKJIU)

It would be likely to change from LockModeType.PESSIMISTIC_FORCE_INCREMENT to LockModeType.PESSIMISTIC_WRITE.

This change would break backward compatibility so please introduce this feature with a environment entry switch e.g. "org.kie.api.persistence.pessimistic.wait" (= if you don't give the entry, the default behaviour would be the same ... "select for update nowait").

Additional note: PostgreSQLDialect (even PostgreSQL itself) doesn't support time based wait so the timeout value is meaningless.

https://github.com/hibernate/hibernate-orm/blob/5.1.10/hibernate-core/src/main/java/org/hibernate/dialect/PostgreSQL81Dialect.java#L502-L509

However, this enhancement is still useful because users can choose "select for update" without "nowait".