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Access in beforeSubmit: Program can access stream/dataset in beforeSubmit() by its name. But theses methods are deprecated now and we expect users to use APIs which take Input class (changes proposed above). Since cross namespace access is a new feature we will not support it through deprecated APIs. In place of these deprecated, initialize/destroy APIs will be added soon and we will support accessing dataset across namespaces in these.
Admin interface for Dataset: We allow users to perform various dataset operation through Admin interface. For example exists(String name), getProperties(String name) etc. We will need to support cross namespace lookup through this interface too but since we don't have any use case for this in this release we are keeping this out of scope.
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