/*
* 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.jena.atlas.data ;
/**
* A threshold policy based on the estimated memory size of the tuples added.
* <p>
* TODO This policy isn't ready to be used because the SerializationFactorys
* don't support generating memory estimates yet.
* <p>
* TODO It might be too expensive to examine each tuple individually. We could
* change it to sample the first 100 tuples to calculate an average tuple size.
*/
public class ThresholdPolicyMemory<T> implements ThresholdPolicy<T> {
protected final SerializationFactory<T> serializerFactory ;
protected final long threshold ;
protected long count ;
protected long size ;
public ThresholdPolicyMemory(long threshold, SerializationFactory<T> serializerFactory) {
if ( threshold < 0 ) { throw new IllegalArgumentException("Threshold must be greater than or equal to zero") ; }
this.threshold = threshold ;
this.serializerFactory = serializerFactory ;
reset() ;
}
/*
* (non-Javadoc)
*
* @see ThresholdPolicy#increment(java.lang.Object)
*/
@Override
public void increment(T item) {
count++ ;
size += serializerFactory.getEstimatedMemorySize(item) ;
}
/*
* (non-Javadoc)
*
* @see ThresholdPolicy#isThresholdExceeded()
*/
@Override
public boolean isThresholdExceeded() {
return (size >= threshold) ;
}
@Override
public void reset() {
count = 0 ;
size = 0 ;
}
/**
* Returns the threshold before the list is written to disk.
*
* @return The threshold point.
*/
public long getThreshold() {
return threshold ;
}
/**
* Returns the current count of the number of items incremented in this
* policy.
*
* @return The item count.
*/
public long getCount() {
return count ;
}
/**
* Returns the current total estimated memory size of all the items
* incremented in this policy.
*
* @return The item count.
*/
public long getMemorySize() {
return size ;
}
/*
* (non-Javadoc)
*
* @see java.lang.Object#toString()
*/
@Override
public String toString() {
return "ThresholdPolicyMemory: Threshold (bytes)=" + threshold + " Memory Size (bytes)=" + size + " Count="
+ count ;
}
}