/*
* 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.raptor.util;
import com.facebook.presto.spi.ConnectorPageSource;
import com.facebook.presto.spi.Page;
import java.io.IOException;
import java.util.Iterator;
import static java.util.Objects.requireNonNull;
public class ConcatPageSource
implements ConnectorPageSource
{
private final Iterator<ConnectorPageSource> iterator;
private ConnectorPageSource current;
private long totalBytes;
private long completedBytes;
private long readTimeNanos;
public ConcatPageSource(Iterator<ConnectorPageSource> iterator)
{
this.iterator = requireNonNull(iterator, "iterator is null");
}
@Override
public long getTotalBytes()
{
setup();
return totalBytes + ((current != null) ? current.getTotalBytes() : 0);
}
@Override
public long getCompletedBytes()
{
setup();
return completedBytes + ((current != null) ? current.getCompletedBytes() : 0);
}
@Override
public long getReadTimeNanos()
{
setup();
return readTimeNanos + ((current != null) ? current.getReadTimeNanos() : 0);
}
@Override
public boolean isFinished()
{
setup();
return current == null;
}
@Override
public Page getNextPage()
{
while (true) {
setup();
if (current == null) {
return null;
}
if (!current.isFinished()) {
return current.getNextPage();
}
totalBytes += current.getTotalBytes();
completedBytes += current.getCompletedBytes();
readTimeNanos += current.getReadTimeNanos();
current = null;
}
}
@Override
public long getSystemMemoryUsage()
{
return (current != null) ? current.getSystemMemoryUsage() : 0;
}
@Override
public void close()
throws IOException
{
if (current != null) {
current.close();
}
}
private void setup()
{
if ((current == null) && iterator.hasNext()) {
current = iterator.next();
}
}
}