Interface BufferAllocator

  • All Superinterfaces:
    AutoCloseable, io.netty5.util.SafeCloseable
    All Known Implementing Classes:
    PooledBufferAllocator

    public interface BufferAllocator
    extends io.netty5.util.SafeCloseable
    Interface for allocating Buffers.
    • Method Detail

      • isPooling

        boolean isPooling()
        Determine if this allocator is pooling and reusing its allocated memory.
        Returns:
        true if this allocator is pooling and reusing its memory, false otherwise.
      • allocate

        Buffer allocate​(int size)
        Allocate a Buffer of the given size in bytes. This method may throw an OutOfMemoryError if there is not enough free memory available to allocate a Buffer of the requested size.

        The buffer will use big endian byte order.

        Parameters:
        size - The size of Buffer to allocate.
        Returns:
        The newly allocated Buffer.
        Throws:
        IllegalStateException - if this allocator has been closed.
      • constBufferSupplier

        Supplier<Buffer> constBufferSupplier​(byte[] bytes)
        Create a supplier of "constant" Buffers from this allocator, that all have the given byte contents. The buffer has the same capacity as the byte array length, and its write offset is placed at the end, and its read offset is at the beginning, such that the entire buffer contents are readable.

        The buffers produced by the supplier will each have their own independent life-cycle, and closing them will make them inaccessible, just like normally allocated buffers.

        The buffers produced are "constants", in the sense that they are read-only.

        It can generally be expected, but is not guaranteed, that the returned supplier is more resource efficient than allocating and copying memory with other available APIs. In such optimised implementations, the underlying memory baking the buffers will be shared among all the buffers produced by the supplier.

        The primary use case for this API, is when you need to repeatedly produce buffers with the same contents, and you perhaps wish to keep a static final field with these contents. The supplier-based API enforces that each usage get their own distinct buffer instance. Each of these instances cannot interfere with each other, so bugs like closing, or modifying the contents, of a shared buffer cannot occur.

        Parameters:
        bytes - The byte contents of the buffers produced by the returned supplier.
        Returns:
        A supplier of read-only buffers with the given contents.
        Throws:
        IllegalStateException - if this allocator has been closed, but any supplier obtained prior to closing the allocator will continue to work.
      • copyOf

        default Buffer copyOf​(byte[] bytes)
        Allocate a Buffer with the same size and contents of the given byte array. The allocated buffer is NOT backed by the given byte array, and changes to the contents of either will not be reflected in the other. This may throw an OutOfMemoryError if there is not enough free memory available to allocate a Buffer of the requested size.

        The allocated buffer will use big endian byte order.

        Parameters:
        bytes - The byte array that determines the size and contents of the new buffer.
        Returns:
        The newly allocated Buffer.
        Throws:
        IllegalStateException - if this allocator has been closed.
      • copyOf

        default Buffer copyOf​(ByteBuffer buffer)
        Allocate a Buffer with the same size and contents, as the contents of the given ByteBuffer. The allocated buffer is NOT backed by the give byte buffer, and changes to the contents of either will not be reflected in the other. The position and limit of the given byte buffer defines the region of contents that will be copied. The position and limit are not modified by this method. This may throw an OutOfMemoryError if there is not enough free memory available to allocate a Buffer of the requested size.

        The allocated buffer will use big endian byte order, regardless of the byte order of the given buffer. The contents of the byte buffer will be copied without regard to the byte order, as if the bytes are copied one at a time.

        Parameters:
        buffer - The byte buffer, whose contents determine the capacity and contents of the allocated buffer.
        Returns:
        The newly allocated Buffer.
        Throws:
        IllegalStateException - if this allocator has been closed.
      • close

        void close()
        Close this allocator, freeing all of its internal resources.

        Existing (currently in-use) allocated buffers will not be impacted by calling this method. If this is a pooling or caching allocator, then existing buffers will be immediately freed when they are closed, instead of being pooled or cached.

        The allocator can no longer be used to allocate more buffers after calling this method. Attempting to allocate from a closed allocator will cause IllegalStateExceptions to be thrown.

        Specified by:
        close in interface AutoCloseable
        Specified by:
        close in interface io.netty5.util.SafeCloseable