org.apache.hadoop.hdfs.server.datanode.CachingStrategy 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.hdfs.server.datanode;
/**
* The caching strategy we should use for an HDFS read or write operation.
*/
public class CachingStrategy {
private final Boolean dropBehind; // null = use server defaults
private final Long readahead; // null = use server defaults
public static CachingStrategy newDefaultStrategy() {
return new CachingStrategy(null, null);
}
public static CachingStrategy newDropBehind() {
return new CachingStrategy(true, null);
}
public static class Builder {
private Boolean dropBehind;
private Long readahead;
public Builder(CachingStrategy prev) {
this.dropBehind = prev.dropBehind;
this.readahead = prev.readahead;
}
public Builder setDropBehind(Boolean dropBehind) {
this.dropBehind = dropBehind;
return this;
}
public Builder setReadahead(Long readahead) {
this.readahead = readahead;
return this;
}
public CachingStrategy build() {
return new CachingStrategy(dropBehind, readahead);
}
}
public CachingStrategy(Boolean dropBehind, Long readahead) {
this.dropBehind = dropBehind;
this.readahead = readahead;
}
public Boolean getDropBehind() {
return dropBehind;
}
public Long getReadahead() {
return readahead;
}
public String toString() {
return "CachingStrategy(dropBehind=" + dropBehind +
", readahead=" + readahead + ")";
}
}