org.apache.hadoop.fs.StreamCapabilitiesPolicy Maven / Gradle / Ivy
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF 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 org.apache.hadoop.fs;
import java.io.InputStream;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Static methods to implement policies for {@link StreamCapabilities}.
*/
@InterfaceAudience.Public
@InterfaceStability.Evolving
public class StreamCapabilitiesPolicy {
public static final String CAN_UNBUFFER_NOT_IMPLEMENTED_MESSAGE =
"claims unbuffer capabilty but does not implement CanUnbuffer";
static final Logger LOG = LoggerFactory.getLogger(
StreamCapabilitiesPolicy.class);
/**
* Implement the policy for {@link CanUnbuffer#unbuffer()}.
*
* @param in the input stream
*/
public static void unbuffer(InputStream in) {
try {
if (in instanceof StreamCapabilities
&& ((StreamCapabilities) in).hasCapability(
StreamCapabilities.UNBUFFER)) {
((CanUnbuffer) in).unbuffer();
} else {
LOG.debug(in.getClass().getName() + ":"
+ " does not implement StreamCapabilities"
+ " and the unbuffer capability");
}
} catch (ClassCastException e) {
throw new UnsupportedOperationException(in.getClass().getName() + ": "
+ CAN_UNBUFFER_NOT_IMPLEMENTED_MESSAGE);
}
}
}