Allowed derived classes to modify the behavior of operations which change
the current stream position by adjusting the target token index of a seek
operation. The default implementation simply returns {@code i}. If an
exception is thrown in this method, the current stream index should not be
changed.
<p>For example, {@link CommonTokenStream} overrides this method to ensure that
the seek target is always an on-channel token.</p>
@param i The target token index.
@return The adjusted target token index.
Allowed derived classes to modify the behavior of operations which change the current stream position by adjusting the target token index of a seek operation. The default implementation simply returns {@code i}. If an exception is thrown in this method, the current stream index should not be changed.
<p>For example, {@link CommonTokenStream} overrides this method to ensure that the seek target is always an on-channel token.</p>
@param i The target token index. @return The adjusted target token index.