/* The contents of this file are subject to the license and copyright terms
* detailed in the license directory at the root of the source tree (also
* available online at http://fedora-commons.org/license/).
*/
package org.fcrepo.server.utilities;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import org.jrdf.graph.Triple;
import org.trippi.TripleIterator;
import org.trippi.TrippiException;
public class FilteredTripleIterator
extends TripleIterator {
TripleIterator m_baseIter;
boolean m_add;
Triple m_filter;
Triple m_next;
boolean m_changeMade = false;
public FilteredTripleIterator(TripleIterator baseIter,
Triple filter,
boolean add)
throws TrippiException {
m_baseIter = baseIter;
m_filter = filter;
m_add = add;
// FIXME restore these later - eddie
// Map<String, String> map = m_baseIter.getAliasMap();
// setAliasMap(map);
m_next = getNext();
}
public FilteredTripleIterator(Map<String, String> aliasMap,
Triple filter,
boolean add)
throws TrippiException {
m_baseIter = null;
m_filter = filter;
m_add = add;
// FIXME restore this later - eddie
// setAliasMap(aliasMap);
m_next = getNext();
}
@Override
public boolean hasNext() throws TrippiException {
return m_next != null;
}
@Override
public Triple next() throws TrippiException {
Triple last = m_next;
m_next = getNext();
return last;
}
private Triple getNext() throws TrippiException {
Triple next;
if (!m_add) // purging entries
{
next = m_baseIter.next();
while (next != null && matches(next, m_filter)) {
m_changeMade = true;
next = m_baseIter.next();
}
return next;
} else if (m_baseIter == null) { // adding entry to empty set
m_changeMade = true;
next = m_filter;
m_filter = null;
return next;
} else { // adding entry to existing set
next = m_baseIter.next();
if (matches(next, m_filter)) {
m_filter = null; // Triple to be added already present
}
if (next == null) {
if (m_filter != null) {
m_changeMade = true;
}
next = m_filter;
m_filter = null;
}
return next;
}
}
private boolean matches(Triple next, Triple filter) {
if (filter == null || next == null) {
return false;
}
return partMatches(next.getSubject().toString(), filter.getSubject()
.toString())
&& partMatches(next.getPredicate().toString(), filter
.getPredicate().toString())
&& (filter.getObject() == null || partMatches(next.getObject().toString(), filter.getObject()
.toString()));
}
private boolean partMatches(String next, String filter) {
if (next.equals(filter)) {
return true;
}
Map<String, String> map = getAliasMap();
Set<String> keys = map.keySet();
Iterator<String> iter = keys.iterator();
while (iter.hasNext()) {
String key = iter.next();
if (next.startsWith(key + ":")) {
next = next.replaceFirst(key + ":", map.get(key));
}
if (filter.startsWith(key + ":")) {
filter = filter.replaceFirst(key + ":", map.get(key));
}
if (next.equals(filter)) {
return true;
}
}
return false;
}
@Override
public void close() throws TrippiException {
m_filter = null;
if (m_baseIter != null) {
m_baseIter.close();
}
}
public boolean wasChangeMade() {
return m_changeMade;
}
}