org.teiid.query.processor.proc

Class ProgramInstruction

java.lang.Object

org.teiid.query.processor.proc.ProgramInstruction

All Implemented Interfaces:

Cloneable

Direct Known Subclasses:

AssignmentInstruction, BlockInstruction, BranchingInstruction, CreateCursorResultSetInstruction, ErrorInstruction, ExecDynamicSqlInstruction, IfInstruction, ReturnInstruction, WhileInstruction

public abstract class ProgramInstruction
extends Object
implements Cloneable

Abstract superclass of all program instructions.

All processor instructions need to be cloneable, but it most cases the default Object.clone operation will suffice, since in most cases the processing instructions will be stateless, or the state will be immutable. The exception to this are instructions that have sub programs in them - those sub programs need to be cloned.

Constructor Summary

Constructors

Constructor and Description
ProgramInstruction()

Method Summary

Modifier and Type	Method and Description
ProgramInstruction	clone() Override Object.clone() to make the method public.
abstract PlanNode	getDescriptionProperties()
abstract void	process(ProcedurePlan env) Allow this instruction to do whatever processing it needs, and to in turn manipulate the running program.
Boolean	requiresTransaction(boolean transactionalReads)

Methods inherited from class java.lang.Object

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

Constructor Detail

ProgramInstruction

public ProgramInstruction()

Method Detail

process

public abstract void process(ProcedurePlan env)
                      throws TeiidComponentException,
                             TeiidProcessingException,
                             TeiidSQLException

Allow this instruction to do whatever processing it needs, and to in turn manipulate the running program. A typical instruction should simply increment the program counter of the current program, but specialized instructions may add sub programs to the stack or not increment the counter (so that they are executed again.)

Throws:

TeiidSQLException

TeiidComponentException

TeiidProcessingException

clone

public ProgramInstruction clone()

Override Object.clone() to make the method public. This method simply calls super.clone(), deferring to the default shallow cloning. Some ProcessorInstruction subclasses may need to override with custom safe or deep cloning.

Overrides:

clone in class Object

Returns:

shallow clone

getDescriptionProperties

public abstract PlanNode getDescriptionProperties()

requiresTransaction

public Boolean requiresTransaction(boolean transactionalReads)