com.facebook.presto.spi.ConnectorPageSource Maven / Gradle / Ivy
/*
* 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 com.facebook.presto.spi;
import java.io.Closeable;
import java.io.IOException;
import java.util.concurrent.CompletableFuture;
public interface ConnectorPageSource
extends Closeable
{
CompletableFuture NOT_BLOCKED = CompletableFuture.completedFuture(null);
/**
* Gets the number of input bytes processed by this page source so far.
* If size is not available, this method should return zero.
*/
long getCompletedBytes();
/**
* Gets the wall time this page source spent reading data from the input.
* If read time is not available, this method should return zero.
*/
long getReadTimeNanos();
/**
* Will this page source product more pages?
*/
boolean isFinished();
/**
* Gets the next page of data. This method is allowed to return null.
*/
Page getNextPage();
/**
* Get the total memory that needs to be reserved in the general memory pool.
* This memory should include any buffers, etc. that are used for reading data.
*
* @return the memory used so far in table read
*/
long getSystemMemoryUsage();
/**
* Immediately finishes this page source. Presto will always call this method.
*/
@Override
void close()
throws IOException;
/**
* Returns a future that will be completed when the page source becomes
* unblocked. If the page source is not blocked, this method should return
* {@code NOT_BLOCKED}.
*/
default CompletableFuture isBlocked()
{
return NOT_BLOCKED;
}
}