io.druid.indexing.common.tasklogs.SwitchingTaskLogStreamer Maven / Gradle / Ivy
/*
* Licensed to Metamarkets Group Inc. (Metamarkets) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. Metamarkets licenses this file
* to you 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 io.druid.indexing.common.tasklogs;
import com.google.common.base.Optional;
import com.google.common.collect.ImmutableList;
import com.google.common.io.ByteSource;
import com.google.inject.Inject;
import io.druid.tasklogs.TaskLogStreamer;
import java.io.IOException;
import java.util.List;
/**
* Provides task logs based on a series of underlying task log providers.
*/
public class SwitchingTaskLogStreamer implements TaskLogStreamer
{
private final List providers;
@Inject
public SwitchingTaskLogStreamer(List providers)
{
this.providers = ImmutableList.copyOf(providers);
}
@Override
public Optional streamTaskLog(String taskid, long offset) throws IOException
{
for (TaskLogStreamer provider : providers) {
final Optional stream = provider.streamTaskLog(taskid, offset);
if (stream.isPresent()) {
return stream;
}
}
return Optional.absent();
}
}