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Tinder is a Java based XMPP library, providing an implementation for XMPP stanzas and components. Tinders origins lie in code that's shared between Jive Software's Openfire and Whack implementations. The implementation that's provided in Tinder hasn't been written again from scratch. Instead, code has been moved from the original projects into Tinder, preserving al of the existing features and functionality. Most of the code that's now in Tinder is based on the org.xmpp package implementation that previously existed in Openfire and Whack. This is the code that defines classes such as Packet, JID, IQ, Component and their extensions. Additionally, some multi-purpose code (such as the DataForm and Result Set Management implementations have been moved to Tinder as well.
/**
* $Revision: $
* $Date: $
*
* Copyright (C) 2005-2008 Jive Software. All rights reserved.
*
* This software is published under the terms of the GNU Public License (GPL),
* a copy of which is included in this distribution, or a commercial license
* agreement with Jive.
*/
package org.xmpp.resultsetmanagement;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.QName;
import java.util.*;
/**
* A result set representation as described in XEP-0059. A result set is a
* collection of objects that each have a unique identifier (UID).
*
* It's expected that some implementations will have the complete result set
* loaded into memory, whereas more complex implementations might keep
* references to partial sets only. This latter would have considerable
* advantages if the result set is extremely large, or if the operation to get
* all results in the set is expensive.
*
* @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.
*/
public abstract class ResultSet extends AbstractCollection {
/**
* A list of field names that are valid in jabber:iq:search
*/
private final static Collection validRequestFields = new ArrayList();
static {
validRequestFields.add("max"); // required
validRequestFields.add("before");
validRequestFields.add("after");
validRequestFields.add("index");
}
/**
* The namespace that identifies Result Set Management functionality.
*/
public static final String NAMESPACE_RESULT_SET_MANAGEMENT = "http://jabber.org/protocol/rsm";
/**
* Returns a List of results starting with the first result after the
* provided result (the returned List is exclusive).
*
* The lenght of the list is equal to 'maxAmount', unless there are no more
* elements available (in which case the length of the result will be
* truncated).
*
* @param result
* The element that is right before the first element in the
* result.
* @param maxAmount
* The maximum number of elements to return.
* @return A List of elements the are exactly after the element that is
* provided as a parameter.
* @throws NullPointerException
* if the result does not exist in the result set.
*/
public List getAfter(E result, int maxAmount) {
return getAfter(result.getUID(), maxAmount);
}
/**
* Returns a List of results starting with the first result after the result
* that's identified by the provided UID (the returned List is exclusive).
*
* The lenght of the list is equal to 'maxAmount', unless there are no more
* elements available (in which case the length of the result will be
* truncated).
*
* @param uid
* The UID of the element that is right before the first element
* in the result.
* @param maxAmount
* The maximum number of elements to return.
* @return A List of elements the are exactly after the element that is
* provided as a parameter.
* @throws NullPointerException
* if there is no result in the result set that matches the UID.
*/
public abstract List getAfter(String uid, int maxAmount);
/**
* Returns a list of results ending with the element right before the
* provided result (the returned List is exclusive).
*
* At most 'maxAmount' elements are in the returned List, but the lenght of
* the result might be smaller if no more applicable elements are available.
*
* Note that the order of the result is equal to the order of the results of
* other methods of this class: the last element in the returned List
* immediately preceeds the element denoted by the 'result' parameter.
*
* @param result
* The element preceding the last element returned by this
* function.
* @param maxAmount
* The length of the List that is being returned.
* @return A List of elements that are exactly before the element that's
* provided as a parameter.
* @throws NullPointerException
* if the result does not exist in the result set.
*
*/
public List getBefore(E result, int maxAmount) {
return getBefore(result.getUID(), maxAmount);
}
/**
* Returns a list of results ending with the element right before the
* element identified by the provided UID (the returned List is exclusive).
*
* At most 'maxAmount' elements are in the returned List, but the lenght of
* the result might be smaller if no more applicable elements are available.
*
* Note that the order of the result is equal to the order of the results of
* other methods of this class: the last element in the returned List
* immediately preceeds the element denoted by the 'result' parameter.
*
* @param uid
* The UID of the element preceding the last element returned by
* this function.
* @param maxAmount
* The length of the List that is being returned.
* @return A List of elements that are exactly before the element that's
* provided as a parameter.
* @throws NullPointerException
* if there is no result in the result set that matches the UID.
*/
public abstract List getBefore(String uid, int maxAmount);
/**
* Returns the first elements from this result set.
*
* @param maxAmount
* the number of elements to return.
* @return the last 'maxAmount' elements of this result set.
*/
public abstract List getFirst(int maxAmount);
/**
* Returns the last elements from this result set.
*
* @param maxAmount
* the number of elements to return.
* @return the last 'maxAmount' elements of this result set.
*/
public abstract List getLast(int maxAmount);
/**
* Returns the element denoted by the index.
*
* @param index
* Index of the element to be returned
* @return the Element at 'index'.
*/
public abstract E get(int index);
/**
* Returns a list of results, starting with the result that's at the
* specified index. If the difference between the startIndex and the index
* of the last element in the entire resultset is smaller than the size
* supplied in the 'amount' parameter, the length of the returned list will
* be smaller than the 'amount' paramater. If the supplied index is equal
* to, or larger than the size of the result set, an empty List is returned.
*
* @param fromIndex
* The index of the first element to be returned.
* @param maxAmount
* The maximum number of elements to return.
* @return A list of elements starting with (inclusive) the element
* referenced by 'fromIndex'. An empty List if startIndex is equal
* to or bigger than the size of this entire result set.
*/
public abstract List get(int fromIndex, int maxAmount);
/**
* Returns the UID of the object at the specified index in this result set.
*
* @param index
* The index of the UID to be returned.
* @return UID of the object on the specified index.
*/
public String getUID(int index) {
return get(index).getUID();
}
/**
* Returns the index in the full resultset of the element identified by the
* UID in te supplied argument.
*
* @param uid
* The UID of the element to search for
* @return The index of the element.
* @throws NullPointerException
* if there is no result in the result set that matches the UID.
*
*/
public abstract int indexOf(String uid);
/**
* Returns the index in the full resultset of the supplied argument.
*
* @param element
* The element to search for
* @return The index of the element.
*/
public int indexOf(E element) {
return indexOf(element.getUID());
}
/*
* (non-Javadoc)
*
* @see java.util.AbstractCollection#iterator()
*/
@Override
public Iterator iterator() {
return new Itr();
}
/**
* Applies the 'result set management' directives to this result set, and
* returns a list of Results that matches the directives. Note that the
* orignal set is untouched. Instead, a new List is returned.
*
* @param rsmElement
* The XML element that contains the 'result set management'
* directives.
* @return a list of Results that matches the directives.
*/
public List applyRSMDirectives(Element rsmElement) {
if (rsmElement == null || !isValidRSMRequest(rsmElement)) {
throw new IllegalArgumentException(
"The 'rsmElement' argument must be a valid, non-null RSM element.");
}
final int max = Integer.parseInt(rsmElement.element("max").getText());
if (max == 0) {
// this is a request for a resultset count.
return Collections.emptyList();
}
// optional elements
final Element afterElement = rsmElement.element("after");
final Element beforeElement = rsmElement.element("before");
final Element indexElement = rsmElement.element("index");
// Identify the pointer object in this set. This is the object before
// (or after) the first (respectivly last) element of the subset that
// should be returned. If no pointer is specified, the pointer is said
// to be before or after the first respectivly last element of the set.
String pointerUID = null; // by default, the pointer is before the
// first element of the set.
// by default, the search list is forward oriented.
boolean isForwardOriented = true;
if (afterElement != null) {
pointerUID = afterElement.getText();
} else if (beforeElement != null) {
pointerUID = beforeElement.getText();
isForwardOriented = false;
} else if (indexElement != null) {
final int index = Integer.parseInt(indexElement.getText());
if (index > 0) {
pointerUID = getUID(index - 1);
}
}
if (pointerUID != null && pointerUID.equals("")) {
pointerUID = null;
}
if (isForwardOriented) {
if (pointerUID == null) {
return getFirst(max);
}
return getAfter(pointerUID, max);
}
if (pointerUID == null) {
return getLast(max);
}
return getBefore(pointerUID, max);
}
/**
* Generates a Result Set Management 'set' element that describes the parto
* of the result set that was generated. You typically would use the List
* that was returned by {@link #applyRSMDirectives(Element)} as an argument
* to this method.
*
* @param returnedResults
* The subset of Results that is returned by the current query.
* @return An Element named 'set' that can be included in the result IQ
* stanza, which returns the subset of results.
*/
public Element generateSetElementFromResults(List returnedResults) {
if (returnedResults == null) {
throw new IllegalArgumentException(
"Argument 'returnedResults' cannot be null.");
}
final Element setElement = DocumentHelper.createElement(QName.get(
"set", ResultSet.NAMESPACE_RESULT_SET_MANAGEMENT));
// the size element contains the size of this entire result set.
setElement.addElement("count").setText(String.valueOf(size()));
// if the query wasn't a 'count only' query, add two more elements
if (returnedResults.size() > 0) {
final Element firstElement = setElement.addElement("first");
firstElement.addText(returnedResults.get(0).getUID());
firstElement.addAttribute("index", String
.valueOf(indexOf(returnedResults.get(0))));
setElement.addElement("last").addText(
returnedResults.get(returnedResults.size() - 1).getUID());
}
return setElement;
}
/**
* Checks if the Element that has been passed as an argument is a valid
* Result Set Management element, in a request context.
*
* @param rsmElement
* The Element to check.
* @return ''true'' if this is a valid RSM query representation, ''false''
* otherwise.
*/
// Dom4J doesn't do generics, sadly.
@SuppressWarnings("unchecked")
public static boolean isValidRSMRequest(Element rsmElement) {
if (rsmElement == null) {
throw new IllegalArgumentException(
"The argument 'rsmElement' cannot be null.");
}
if (!rsmElement.getName().equals("set")) {
// the name of the element must be "set".
return false;
}
if (!rsmElement.getNamespaceURI().equals(
NAMESPACE_RESULT_SET_MANAGEMENT)) {
// incorrect namespace
return false;
}
final Element maxElement = rsmElement.element("max");
if (maxElement == null) {
// The 'max' element in an RSM request must be available
return false;
}
final String sMax = maxElement.getText();
if (sMax == null || sMax.length() == 0) {
// max element must contain a value.
return false;
}
try {
if (Integer.parseInt(sMax) < 0) {
// must be a postive integer.
return false;
}
} catch (NumberFormatException e) {
// the value of 'max' must be an integer value.
return false;
}
List allElements = rsmElement.elements();
int optionalElements = 0;
for (Element element : allElements) {
final String name = element.getName();
if (!validRequestFields.contains(name)) {
// invalid element.
return false;
}
if (!name.equals("max")) {
optionalElements++;
}
if (optionalElements > 1) {
// only one optional element is allowed.
return false;
}
if (name.equals("index")) {
final String value = element.getText();
if (value == null || value.equals("")) {
// index elements must have a numberic value.
return false;
}
try {
if (Integer.parseInt(value) < 0) {
// index values must be positive.
return false;
}
} catch (NumberFormatException e) {
// index values must be numeric.
return false;
}
}
}
return true;
}
/**
* Basic Iterator implementation. Forward scrolling only. Does not support
* modification.
*
* @author Guus der Kinderen, [email protected]
*
*/
class Itr implements Iterator {
/**
* Index of element to be returned by subsequent call to next.
*/
int cursor = 0;
/*
* (non-Javadoc)
*
* @see java.util.Iterator#hasNext()
*/
public boolean hasNext() {
return cursor != size();
}
/*
* (non-Javadoc)
*
* @see java.util.Iterator#next()
*/
public E next() {
return get(cursor++);
}
/*
* (non-Javadoc)
*
* @see java.util.Iterator#remove()
*/
public void remove() {
throw new UnsupportedOperationException();
}
}
}