/*
* JBoss, Home of Professional Open Source.
* Copyright 2011, Red Hat Middleware LLC, and individual contributors
* as indicated by the @author tags. See the copyright.txt file in the
* distribution for a full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.infinispan.query.clustered;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.SortField;
import org.apache.lucene.util.PriorityQueue;
import org.hibernate.search.SearchException;
import org.infinispan.util.ReflectionUtil;
/**
* ISPNPriorityQueueFactory.
*
* Factory to construct a lucene PriotityQueue (unfortunately not public classes)
*
* @author Israel Lacerra <israeldl@gmail.com>
* @author Sanne Grinovero <sanne@hibernate.org> (C) 2011 Red Hat Inc.
* @since 5.1
*/
class ISPNPriorityQueueFactory {
private ISPNPriorityQueueFactory() {
}
/**
* Creates a org.apache.lucene.search.FieldDocSortedHitQueue instance and set the size and sort
* fields
*
* @param size
* @param sort
* @return a PriorityQueue<FieldDoc> instance
*/
public static PriorityQueue<ScoreDoc> getFieldDocSortedHitQueue(int size, SortField[] sort) {
String className = "org.apache.lucene.search.FieldDocSortedHitQueue";
Object[] constructorArgument = new Object[]{ size };
Class<?>[] types = new Class[]{ int.class };
PriorityQueue<ScoreDoc> queue = buildPriorityQueueSafe(className, types, constructorArgument);
Method[] methods = queue.getClass().getDeclaredMethods();
for (Method method : methods) {
if (method.getName().equals("setFields")) {
Object[] parameters = new Object[1];
parameters[0] = sort;
ReflectionUtil.invokeAccessibly(queue, method, parameters);
return queue;
}
}
//The setFields should have been found
throw new SearchException( "Method org.apache.lucene.search.FieldDocSortedHitQueue.setFields not found. This version of Lucene is not compatible." );
}
/**
* Creates a org.apache.lucene.search.HitQueue instance and set the size
*
* @param size
* @param sort
* @return a PriorityQueue<FieldDoc> instance
*/
public static PriorityQueue<ScoreDoc> getHitQueue(int size) {
String className = "org.apache.lucene.search.HitQueue";
Object[] constructorArgument = new Object[]{ size, false };
Class<?>[] types = new Class[]{ int.class, boolean.class };
return buildPriorityQueueSafe(className, types, constructorArgument);
}
/**
* @param className fully qualified name of the class to construct
* @param types types of the constructor to use
* @param constructorArgument arguments for the chosen constructor
*/
private static PriorityQueue<ScoreDoc> buildPriorityQueueSafe(String className,
Class<?>[] types, Object[] constructorArgument) {
try {
return buildPriorityQueue(className, types, constructorArgument);
} catch (Exception e) {
throw new SearchException("Could not initialize required Lucene class: " + className +
". Either the Lucene version is incompatible, or security is preventing me to access it.", e);
}
}
/**
* Creates a class instance from classname, types and arguments, to workaround the
* fact that these Lucene PriorityQueues are not public.
* @param className
* @param types
* @param constructorArgument
*/
private static PriorityQueue<ScoreDoc> buildPriorityQueue(String className, Class<?>[] types,
java.lang.Object[] constructorArgument) throws ClassNotFoundException, SecurityException, NoSuchMethodException, IllegalArgumentException, InstantiationException, IllegalAccessException, InvocationTargetException {
Class<?> clazz = Class.forName(className);
Constructor<?> c = clazz.getDeclaredConstructor(types);
c.setAccessible(true);
Object newInstance = c.newInstance(constructorArgument);
return (PriorityQueue<ScoreDoc>) newInstance;
}
}