Add `deepCopy` for LogicalExpressions
-------------------------------------
Key: PIG-1510
URL: https://issues.apache.org/jira/browse/PIG-1510
Project: Pig
Issue Type: New Feature
Components: data
Affects Versions: 0.8.0
Reporter: Swati Jain
Assignee: Swati Jain
Fix For: 0.8.0
It would be useful to have a way to `deepCopy` an expression. `deepCopy` will
create a new object so that changes made to one object will not reflect in the
copy. There are 2 reasons why we don't override clone.
* It may be better to use `deepCopy` since the copy semantics are explicit
(since deepCopy may be expensive).
* A second important reason for defining `deepCopy` as a separate routine is
that it can be passed a plan as an argument which will be updated as the
expression is copied (through plan.add and plan.connect).
The usage would look like the following:
{noformat}
LogicalExpressionPlan logicalPlan = new LogicalExpressionPlan();
LogicalExpression copyExpression = origExpression.deepCopy( logicalPlan );
{noformat}
An immediate motivation for this would be for constructing the expressions that
constitute the CNF form of an expression.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
