/*
Copyright 2012 Michael Mastroianni, Amol Kapila, Ryan Berdeen (fastlsh.org)
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.fastlsh.index;
import java.io.ObjectOutputStream;
import java.util.List;
import org.fastlsh.hash.HashFamily;
import org.fastlsh.parsers.VectorParser;
import org.fastlsh.util.Signature;
import org.fastlsh.util.ResourcePool;
public class SignatureIndexWriterTask<T> implements Runnable
{
List<T> inputs;
ResourcePool<ObjectOutputStream> vecWriters;
ResourcePool<ObjectOutputStream> sigWriters;
VectorParser<T> parser;
HashFamily family;
public SignatureIndexWriterTask()
{
}
public SignatureIndexWriterTask(ResourcePool<ObjectOutputStream> vecWriters,
ResourcePool<ObjectOutputStream> sigWriters,
List<T> curList,
VectorParser<T> parser,
HashFamily family)
{
this.vecWriters = vecWriters;
this.sigWriters = sigWriters;
inputs = curList;
this.parser = parser;
this.family = family;
}
@Override
public void run()
{
ObjectOutputStream sigStream = null;
ObjectOutputStream vecStream = null;
try
{
sigStream = sigWriters.acquire();
vecStream = vecWriters.acquire();
for(T line : inputs)
{
VectorWithId vec = parser.parse(line);
double norm = vec.norm2();
if(norm == 0.0) continue;
// Compute the signatures non-normalized, but normalize the raw vectors before serialization so that when we check
// cosine distances, we only have to do dot products
sigStream.writeObject(new Signature(vec.id, family.makeSignature(vec)));
// vec.scalarDivide(norm);
vecStream.writeObject(vec);
}
sigStream.reset();
vecStream.reset();
}
catch(Exception e)
{
throw(new RuntimeException(e));
}
finally
{
if(sigStream != null) sigWriters.release(sigStream);
if(vecStream != null) vecWriters.release(vecStream);
}
}
}