5029431: (bf) Add absolute bulk put and get methods
chris.hegarty at oracle.com
Tue Feb 12 09:18:17 UTC 2019
> On 12 Feb 2019, at 08:49, Alan Bateman <Alan.Bateman at oracle.com> wrote:
> On 11/02/2019 22:30, Brian Burkhalter wrote:
>> The presence of the absolute index into the buffer complicates the situation. In the absolute get() to an array, for example, get(index,$type$,offset,length) throwing a BufferUnderflowException would make sense for
>> 0 <= index < limit() && index + length > limit(),
>> but if index < 0 or index > limit() an IOOBE appears more logical. Likewise for put(index,$type$,offset,length), a BufferOverflowException would work for
>> 0 <= index < limit() && index + length > limit,
>> but IOOBE again seems more apropos for index < 0 or index > limit(). For any given method where an IOOBE could be thrown for different indexes being out of bounds, then a better disambiguation message as Roger suggested would be helpful. If an IOOBE can be thrown by only one particular index being out of range, then the default checkFromIndexSize() message might be enough. For example, for the code
>> byte ba = new byte;
>> bb.put(-1, ba, 0, 42);
>> the exception
>> java.lang.IndexOutOfBoundsException: Range [-1, -1 + 42) out of bounds for length 42
>> is thrown which looks to be sufficient if we know a priori which index is involved.
>> For the method put(index,$Type$Buffer,offset,length) the BufferUnderflowException would be for ‘src’ not having enough elements to copy to ‘this’ and the BufferOverflowException for ‘this’ not having enough space before limit() to contain the copied elements. Again, either ‘index’ or ‘offset’ being out of range would be better handled by an IOOBE.
>> Note that using Buffer*flowException would require an update to the specifications of these exceptions as now they are described as being specific to relative operations.
> I think you are on the right track with this thinking. That is, throw IOOBE when index is negative or >= limit, throw the Buffer*flowExceptions if the transfer would result in buffer overflow/underflow. I think that will fix the inconsistency with the current proposal and also helps with the troubleshooting a bit. Yes, it does mean a small adjustment to the wording in the exceptions.
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