/
ShardsetConfig.java
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/
ShardsetConfig.java
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/*
* Copyright 2013 Gordon Burgett and individual contributors
*
* 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 org.xflatdb.xflat;
import org.xflatdb.xflat.query.IntervalProvider;
import org.jdom2.xpath.XPathExpression;
import org.jdom2.xpath.XPathFactory;
/**
* Represents the configuration for a sharded table. A sharded table is one which
* splits its data up among several files.
* @author Gordon
*/
public class ShardsetConfig<T> {
private ShardsetConfig(){
}
private ShardsetConfig(ShardsetConfig other){
this.shardPropertyClass = other.shardPropertyClass;
this.shardPropertySelector = other.shardPropertySelector;
this.intervalProvider = other.intervalProvider;
}
private Class<T> shardPropertyClass;
public Class<T> getShardPropertyClass(){
return shardPropertyClass;
}
private XPathExpression<?> shardPropertySelector;
public XPathExpression<?> getShardPropertySelector(){
return shardPropertySelector;
}
private IntervalProvider<T> intervalProvider;
public IntervalProvider<T> getIntervalProvider(){
return intervalProvider;
}
/**
* Creates a ShardsetConfig with the minimum configuration necessary for static-range sharding.
* The remainder can be left default or set as desired.
* @param <U>
* @param xpathProperty An XPath expression selecting a property of the data to shard on.
* @param propertyClass The class of the property selected by the xpath expression.
* @param intervalProvider A RangeProvider that determines the static ranges for the
* property, each range will have its own file.
* @return A new shardset config.
*/
public static <U> ShardsetConfig<U> create(String xpathProperty, Class<U> propertyClass, IntervalProvider<U> intervalProvider){
return create(XPathFactory.instance().compile(xpathProperty), propertyClass, intervalProvider);
}
/**
* Creates a ShardsetConfig with the minimum configuration necessary for static-range sharding.
* The remainder can be left default or set as desired.
* @param <U>
* @param xpathProperty An XPath expression selecting a property of the data to shard on.
* @param propertyClass The class of the property selected by the xpath expression.
* @param rangeProvider A RangeProvider that determines the static ranges for the
* property, each range will have its own file.
* @return A new shardset config.
*/
public static <U> ShardsetConfig<U> create(XPathExpression<?> xpathProperty, Class<U> propertyClass, IntervalProvider<U> rangeProvider){
if(xpathProperty == null){
throw new IllegalArgumentException("xpathProperty cannot be null");
}
if(propertyClass == null){
throw new IllegalArgumentException("propertyClass cannot be null");
}
if(rangeProvider == null){
throw new IllegalArgumentException("rangeProvider cannot be null");
}
ShardsetConfig<U> ret = new ShardsetConfig<>();
ret.shardPropertySelector = xpathProperty;
ret.shardPropertyClass = propertyClass;
ret.intervalProvider = rangeProvider;
return ret;
}
}