ByteBuf.setIndex

Sets the {@code readerIndex} and {@code writerIndex} of this buffer in one shot. This method is useful when you have to worry about the invocation order of {@link #readerIndex(int)} and {@link #writerIndex(int)} methods. For example, the following code will fail:

<pre> // Create a buffer whose readerIndex, writerIndex and capacity are // 0, 0 and 8 respectively. {@link ByteBuf} buf = {@link Unpooled}.buffer(8);

// IndexOutOfBoundsException is thrown because the specified // readerIndex (2) cannot be greater than the current writerIndex (0). buf.readerIndex(2); buf.writerIndex(4); </pre>

The following code will also fail:

<pre> // Create a buffer whose readerIndex, writerIndex and capacity are // 0, 8 and 8 respectively. {@link ByteBuf} buf = {@link Unpooled}.wrappedBuffer(new byte[8]);

// readerIndex becomes 8. buf.readLong();

// IndexOutOfBoundsException is thrown because the specified // writerIndex (4) cannot be less than the current readerIndex (8). buf.writerIndex(4); buf.readerIndex(2); </pre>

By contrast, this method guarantees that it never throws an {@link IndexOutOfBoundsException} as long as the specified indexes meet basic constraints, regardless what the current index values of the buffer are:

<pre> // No matter what the current state of the buffer is, the following // call always succeeds as long as the capacity of the buffer is not // less than 4. buf.setIndex(2, 4); </pre>

@throws IndexOutOfBoundsException if the specified {@code readerIndex} is less than 0, if the specified {@code writerIndex} is less than the specified {@code readerIndex} or if the specified {@code writerIndex} is greater than {@code this.capacity}