org.apache.hadoop.fs.impl.StoreImplementationUtils Maven / Gradle / Ivy
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* 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.impl;
import java.io.InputStream;
import java.io.OutputStream;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.fs.StreamCapabilities;
import static org.apache.hadoop.fs.StreamCapabilities.HFLUSH;
import static org.apache.hadoop.fs.StreamCapabilities.HSYNC;
/**
* Utility classes to help implementing filesystems and streams.
*/
@InterfaceAudience.Private
@InterfaceStability.Unstable
public final class StoreImplementationUtils {
private StoreImplementationUtils() {
}
/**
* Check the probe capability being for {@link StreamCapabilities#HSYNC}
* or {@link StreamCapabilities#HFLUSH}
* {@code Syncable.hsync()} and {@code Syncable.hflush()} functionality.
* @param capability capability string.
* @return true if either refers to one of the Syncable operations.
*/
public static boolean isProbeForSyncable(String capability) {
return capability.equalsIgnoreCase(HSYNC) ||
capability.equalsIgnoreCase(HFLUSH);
}
/**
* Probe for an object having a capability; returns true
* if the stream implements {@link StreamCapabilities} and its
* {@code hasCapabilities()} method returns true for the capability.
* This is a package private method intended to provided a common
* implementation for input and output streams.
* {@link StreamCapabilities#hasCapability(String)} call is for public use.
* @param object object to probe.
* @param capability capability to probe for
* @return true if the object implements stream capabilities and
* declares that it supports the capability.
*/
static boolean objectHasCapability(Object object, String capability) {
if (object instanceof StreamCapabilities) {
return ((StreamCapabilities) object).hasCapability(capability);
}
return false;
}
/**
* Probe for an output stream having a capability; returns true
* if the stream implements {@link StreamCapabilities} and its
* {@code hasCapabilities()} method returns true for the capability.
* @param out output stream
* @param capability capability to probe for
* @return true if the stream declares that it supports the capability.
*/
public static boolean hasCapability(OutputStream out, String capability) {
return objectHasCapability(out, capability);
}
/**
* Probe for an input stream having a capability; returns true
* if the stream implements {@link StreamCapabilities} and its
* {@code hasCapabilities()} method returns true for the capability.
* @param in input stream
* @param capability capability to probe for
* @return true if the stream declares that it supports the capability.
*/
public static boolean hasCapability(InputStream in, String capability) {
return objectHasCapability(in, capability);
}
}