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/*
* Copyright (C) 2005-2008 Jive Software. All rights reserved.
*
* 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.jivesoftware.openfire.resultsetmanager;
import java.util.*;
/**
* A result set representation as described in XEP-0059. Note that this result
* 'set' actually makes use of a List implementations, as the Java Set
* definition disallows duplicate elements, while the List definition supplies
* most of the required indexing operations.
*
* This ResultSet implementation loads all all results from the set into memory,
* which might be undesirable for very large sets, or for sets where the
* retrieval of a result is an expensive operation. sets.
*
* As most methods are backed by the {@link List#subList(int, int)} method,
* non-structural changes in the returned lists are reflected in the ResultSet,
* and vice-versa.
*
* @author Guus der Kinderen, [email protected]
*
* @param
* Each result set should be a collection of instances of the exact
* same class. This class must implement the {@link Result}
* interface.
* @see java.util.List#subList(int, int)
* @deprecated Replaced by {@link org.xmpp.resultsetmanagement.ResultSetImpl}
*/
/*
* TODO: do we want changes to the returned Lists of methods in this class be
* applied to the content of the ResultSet itself? Currently, because of the
* usage of java.util.List#subList(int, int), it does. I'm thinking a
* immodifiable solution would cause less problems. -Guus
*/
@Deprecated
public class ResultSetImpl extends ResultSet {
/**
* A list of all results in this ResultSet
*/
public final List resultList;
/**
* A mapping of the UIDs of all results in resultList, to the index of those
* entries in that list.
*/
public final Map uidToIndex;
/**
* Creates a new Result Set instance, based on a collection of Result
* implementing objects. The collection should contain elements of the exact
* same class only, and cannot contain 'null' elements.
*
* The order that's being used in the new ResultSet instance is the same
* order in which {@link Collection#iterator()} iterates over the
* collection.
*
* Note that this constructor throws an IllegalArgumentException if the
* Collection that is provided contains Results that have duplicate UIDs.
*
* @param results
* The collection of Results that make up this result set.
*/
public ResultSetImpl(Collection results) {
this(results, null);
}
/**
* Creates a new Result Set instance, based on a collection of Result
* implementing objects. The collection should contain elements of the exact
* same class only, and cannot contain 'null' elements.
*
* The order that's being used in the new ResultSet instance is defined by
* the supplied Comparator class.
*
* Note that this constructor throws an IllegalArgumentException if the
* Collection that is provided contains Results that have duplicate UIDs.
*
* @param results
* The collection of Results that make up this result set.
* @param comparator
* The Comparator that defines the order of the Results in this
* result set.
*/
public ResultSetImpl(Collection results, Comparator comparator) {
if (results == null) {
throw new NullPointerException("Argument 'results' cannot be null.");
}
final int size = results.size();
resultList = new ArrayList<>(size);
uidToIndex = new Hashtable<>(size);
// sort the collection, if need be.
List sortedResults = null;
if (comparator != null) {
sortedResults = new ArrayList<>(results);
Collections.sort(sortedResults, comparator);
}
int index = 0;
// iterate over either the sorted or unsorted collection
for (final E result : (sortedResults != null ? sortedResults : results)) {
if (result == null) {
throw new NullPointerException(
"The result set must not contain 'null' elements.");
}
final String uid = result.getUID();
if (uidToIndex.containsKey(uid)) {
throw new IllegalArgumentException(
"The result set can not contain elements that have the same UID.");
}
resultList.add(result);
uidToIndex.put(uid, index);
index++;
}
}
/*
* (non-Javadoc)
*
* @see com.buzzaa.xmpp.resultsetmanager.ResultSet#size()
*/
@Override
public int size() {
return resultList.size();
}
/*
* (non-Javadoc)
*
* @see com.buzzaa.xmpp.resultsetmanager.ResultSet#getAfter(E, int)
*/
@Override
public List getAfter(String uid, int maxAmount) {
if (uid == null || uid.length() == 0) {
throw new NullPointerException("Argument 'uid' cannot be null or an empty String.");
}
if (maxAmount < 1) {
throw new IllegalArgumentException(
"Argument 'maxAmount' must be a integer higher than zero.");
}
// the result of this method is exclusive 'result'
final int index = uidToIndex.get(uid) + 1;
return get(index, maxAmount);
}
/*
* (non-Javadoc)
*
* @see com.buzzaa.xmpp.resultsetmanager.ResultSet#getBefore(E, int)
*/
@Override
public List getBefore(String uid, int maxAmount) {
if (uid == null || uid.length() == 0) {
throw new NullPointerException("Argument 'uid' cannot be null or an empty String.");
}
if (maxAmount < 1) {
throw new IllegalArgumentException(
"Argument 'maxAmount' must be a integer higher than zero.");
}
// the result of this method is exclusive 'result'
final int indexOfLastElement = uidToIndex.get(uid);
final int indexOfFirstElement = indexOfLastElement - maxAmount;
if (indexOfFirstElement < 0) {
return get(0, indexOfLastElement);
}
return get(indexOfFirstElement, maxAmount);
}
/*
* (non-Javadoc)
*
* @see com.buzzaa.xmpp.resultsetmanager.ResultSet#get(int)
*/
@Override
public E get(int index) {
return resultList.get(index);
}
/*
* (non-Javadoc)
*
* @see com.buzzaa.xmpp.resultsetmanager.ResultSet#getFirst(int)
*/
@Override
public List getFirst(int maxAmount) {
if (maxAmount < 1) {
throw new IllegalArgumentException(
"Argument 'maxAmount' must be a integer higher than zero.");
}
return get(0, maxAmount);
}
/*
* (non-Javadoc)
*
* @see com.buzzaa.xmpp.resultsetmanager.ResultSet#getLast(int)
*/
@Override
public List getLast(int maxAmount) {
if (maxAmount < 1) {
throw new IllegalArgumentException(
"Argument 'maxAmount' must be a integer higher than zero.");
}
final int indexOfFirstElement = size() - maxAmount;
if (indexOfFirstElement < 0) {
return get(0, maxAmount);
}
return get(indexOfFirstElement, maxAmount);
}
/*
* (non-Javadoc)
*
* @see com.buzzaa.xmpp.resultsetmanager.ResultSet#get(int, int)
*/
@Override
public List get(int fromIndex, int maxAmount) {
if (fromIndex < 0) {
throw new IllegalArgumentException(
"Argument 'fromIndex' must be zero or higher.");
}
if (maxAmount < 1) {
throw new IllegalArgumentException(
"Argument 'maxAmount' must be a integer higher than zero.");
}
if (fromIndex >= size()) {
return new ArrayList<>(0);
}
// calculate the last index to return, or return up to the end of last
// index if 'amount' surpasses the list length.
final int absoluteTo = fromIndex + maxAmount;
final int toIndex = (absoluteTo > size() ? size() : absoluteTo);
return resultList.subList(fromIndex, toIndex);
}
/*
* (non-Javadoc)
* @see org.jivesoftware.util.resultsetmanager.ResultSet#indexOf(java.lang.String)
*/
@Override
public int indexOf(String uid) {
return uidToIndex.get(uid);
}
}
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