nl.topicus.jdbc.shaded.io.grpc.netty.NettyWritableBufferAllocator Maven / Gradle / Ivy
Show all versions of spanner-jdbc Show documentation
/*
* Copyright 2015, gRPC Authors All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package nl.topicus.jdbc.shaded.io.grpc.netty;
import nl.topicus.jdbc.shaded.io.grpc.internal.WritableBuffer;
import nl.topicus.jdbc.shaded.io.grpc.internal.WritableBufferAllocator;
import nl.topicus.jdbc.shaded.io.netty.buffer.ByteBufAllocator;
/**
* The default allocator for {@link NettyWritableBuffer}s used by the Netty transport. We set a
* minimum bound to avoid unnecessary re-allocation for small follow-on writes and to facilitate
* Netty's caching of buffer objects for small writes. We set an upper-bound to avoid allocations
* outside of the arena-pool which are orders of magnitude slower. The Netty transport can receive
* buffers of arbitrary size and will chunk them based on flow-control so there is no transport
* requirement for an upper bound.
*
* Note: It is assumed that most applications will be using Netty's direct buffer pools for
* maximum performance.
*/
class NettyWritableBufferAllocator implements WritableBufferAllocator {
// Use 4k as our minimum buffer size.
private static final int MIN_BUFFER = 4096;
// Set the maximum buffer size to 1MB
private static final int MAX_BUFFER = 1024 * 1024;
private final ByteBufAllocator allocator;
NettyWritableBufferAllocator(ByteBufAllocator allocator) {
this.allocator = allocator;
}
@Override
public WritableBuffer allocate(int capacityHint) {
capacityHint = Math.min(MAX_BUFFER, Math.max(MIN_BUFFER, capacityHint));
return new NettyWritableBuffer(allocator.buffer(capacityHint, capacityHint));
}
}