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Has anyone has ever seen an implementation of java.nio.ByteBuffer that will grow dynamically if a putX() call overruns the capacity?
The reason I want to do it this way is twofold:
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A ByteBuffer is created via the the two static factory methods: allocate(int) this will allocate a HeapByteBuffer with the capacity specified by the int argument. allocateDirect(int) this will allocate a DirectByteBuffer with the capacity specified by the int argument.
After you've written to the ByteBuffer, the number of bytes you've written can be found with the position() method. If you then flip() the buffer, the number of bytes in the buffer can be found with the limit() or remaining() methods.
A new ByteBuffer can be allocated using the method allocate() in the class java. nio. ByteBuffer. This method requires a single parameter i.e. the capacity of the buffer.
In order for asynchronous I/O to work, you must have continuous memory. In C you can attempt to re-alloc an array, but in Java you must allocate new memory. You could write to a ByteArrayOutputStream, and then convert it to a ByteBuffer at the time you are ready to send it. The downside is you are copying memory, and one of the keys to efficient IO is reducing the number of times memory is copied.
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A ByteBuffer cannot really work this way, as its design concept is to be just a view of a specific array, which you may also have a direct reference to. It could not try to swap that array for a larger array without weirdness happening.
What you want to use is a DataOutput. The most convenient way is to use the (pre-release) Guava library:
ByteArrayDataOutput out = ByteStreams.newDataOutput(); out.write(someBytes); out.writeInt(someInt); // ... return out.toByteArray(); But you could also create a DataOutputStream from a ByteArrayOutputStream manually, and just deal with the spurious IOExceptions by chaining them into AssertionErrors.
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