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I have such piece of code:

DataTableFactory<Object> TempDataTableFactory = new DataTableFactory<Object>();
DataTable<Object> tempDataTable = TempDataTableFactory.getInstance();
tempDataTable = dataTable;
ExecutedArguments e = new ExecutedArguments(); 
e.setDataTable(tempDataTable);
e.setExecutedCommand(cmd);
stack.addNewExecutedCommand(e);
result = operation.execute();

Now I just want to keep the olddataTable before execution. When I debug my code till the line result = operation.execute(); there is no problem. In that line I change the dataTable. But because tempDataTable points to dataTable it also changes. But I don't want tempDataTable to change. How can I do this?

Anne
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brtb
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    This has ... nothing to do with pass-by-value or pass-by-reference. – Brian Roach Nov 14 '11 at 00:02
  • @Brian I'm not sure that's true. If it was pass by value, the entire object would get passed but not modified in the calling procedure, wouldn't it? – corsiKa Nov 14 '11 at 01:09
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    Java is *only* pass by value. It just so happens the value is a memory address ;) Aside from that ... I really can't make heads or tails of his question and why that has anything to do with the price of tea in China :) – Brian Roach Nov 14 '11 at 01:14
  • @Brian I know that Java is strictly pass by value; but if the object was passed by value instead of the reference, his problem would be solved without code changes. But of course, you can't, so you have to `clone` it or something similar and pass your clone in. – corsiKa Nov 14 '11 at 18:13

1 Answers1

2

If it supports cloning, I would use tempDataTable.clone(). Otherwise you'll have to implement a copy constructor.

corsiKa
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