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org.aksw.sparqlify.database.PrefixIndex Maven / Gradle / Ivy
package org.aksw.sparqlify.database;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.NavigableMap;
import java.util.Set;
import java.util.TreeMap;
import java.util.function.Function;
import org.aksw.commons.util.strings.StringUtils;
import com.google.common.collect.Sets;
interface PrefixIndexValue
{
}
enum LookupDirection
{
SHORTER,
LONGER,
BOTH;
}
public class PrefixIndex
implements Index
{
// The table this index is bound to
private Table table;
private int[] indexColumns;
private List indexColumnNames;
private Function> prefixExtractor;
private NavigableMap map = new TreeMap();
public PrefixIndex(Table table, int[] indexColumns, Function> prefixExtractor) {
this.table = table;
this.indexColumns = indexColumns;
this.prefixExtractor = prefixExtractor;
this.indexColumnNames = new ArrayList();
for(int index : indexColumns) {
this.indexColumnNames.add(table.getColumns().getKey(index));
}
}
//private Transformer transformer;
public void index(String ... row) {
}
@Override
public void add(List row) {
NavigableMap current = map;
for(int i = 0; i < indexColumns.length; ++i) {
boolean isLast = i == indexColumns.length - 1;
int index = indexColumns[i];
T value = row.get(index);
Set prefixes = prefixExtractor.apply(value);
for(String prefix : prefixes) {
Object o = current.get(prefix);
if(isLast) {
Set values = (Set)o;
if(values == null) {
values = new HashSet();
current.put(prefix, values);
}
/*
else {
throw new RuntimeException("Duplicate row");
}*/
values.add(row);
} else {
NavigableMap next = (NavigableMap) o;
if(next == null) {
next = new TreeMap();
current.put(prefix, next);
}
current = next;
}
}
}
}
///*protected PrefixMap
/**
* The constraints given as arguments are interpreted as conjunctions.
* The set of prefixes within a constraint is interpreted as a disjunction.
*
*
* @param constraints
*/
public void lookup(Constraint ... constraints) {
/*
for(VariableConstraintPrefix constraint : constraints) {
String columnName = constraint.getVariableName();
}*/
}
public Collection> lookupSimple(List prefixList)
{
List> result = new ArrayList>();
lookupSimple(prefixList, 0, map, result);
return result;
}
public Collection> lookupSimpleLonger(List prefixList)
{
List> result = new ArrayList>();
lookupSimpleLonger(prefixList, 0, map, result);
return result;
}
public void lookupSimple(List prefixList, int i, Object tmp, Collection> result)
{
boolean isLast = i == prefixList.size();
//Entry o;
if(isLast) {
lookupRemaining(tmp, i, result);
} else {
NavigableMap current = (NavigableMap)tmp;
//int index = indexColumns[i];
String prefix = prefixList.get(i);
Map candidates = StringUtils.getAllPrefixes(prefix, true, current);
for(Entry entry : candidates.entrySet()) {
Object next = entry.getValue();
lookupSimple(prefixList, i + 1, next, result);
}
}
}
public void lookupSimpleLonger(List prefixList, int i, NavigableMap current, Collection> result)
{
boolean isLast = i == prefixList.size();
//Entry o;
if(isLast) {
lookupRemaining(current, i, result);
} else {
int index = indexColumns[i];
String prefix = prefixList.get(index);
Map candidates = StringUtils.getAllPrefixedEntries(prefix, true, current);
for(Entry entry : candidates.entrySet()) {
NavigableMap next = (NavigableMap) entry.getValue();
lookupSimpleLonger(prefixList, i + 1, next, result);
}
}
}
public void lookupRemaining(Object tmp, int i, Collection> result) {
// Add everything that is left
boolean isLast = i == indexColumns.length - 1;
int index = indexColumns[i];
if(isLast) {
Set> current = (Set>)tmp;
result.addAll(current);
/*
for(Object o : current) {
Set> rows = (Set>) o;
//List row = (List) o;
result.addAll(rows);
}*/
} else {
NavigableMap current = (NavigableMap)tmp;
for(Object o : current.values()) {
NavigableMap next = (NavigableMap) o;
lookupRemaining(next, i + 1, result);
}
}
}
public Collection> lookup(List> prefixesList) {
List> result = new ArrayList>();
lookup(prefixesList, 0, map, result);
return result;
}
public void lookup(List> prefixesList, int i, NavigableMap current, Collection> result) {
boolean isLast = i == indexColumns.length - 1;
int index = indexColumns[i];
Set prefixes = prefixesList.get(index);
for(String prefix : prefixes) {
Object o = current.get(prefix);
if(isLast) {
if(o == null) {
return;
}
List row = (List) o;
result.add(row);
} else {
NavigableMap next = (NavigableMap) o;
if(next == null) {
return;
}
lookup(prefixesList, i + 1, next, result);
}
}
}
public static PrefixIndex attach(Function> prefixExtractor, Table table, String ... columnNames) {
List names = Arrays.asList(columnNames);
Set nameSet = new HashSet(names);
Set dangling = Sets.difference(nameSet, table.getColumns().keySet());
if(!dangling.isEmpty()) {
throw new RuntimeException("Columns " + dangling + " referenced, but not present in table");
}
int[] indexColumns = new int[columnNames.length];
for(int i = 0; i < columnNames.length; ++i) {
Integer index = table.getColumns().getIndex(columnNames[i]);
if(index == null) {
throw new NullPointerException("Column name does not have an index");
}
indexColumns[i] = index;
}
PrefixIndex index = new PrefixIndex(table, indexColumns, prefixExtractor);
table.addIndex(index);
return index;
}
@Override
public boolean preAdd(List row) {
return true;
}
@Override
public void postAdd(List row) {
}
@Override
public Table getTable() {
return table;
}
@Override
public int[] getIndexColumns() {
return indexColumns;
}
@Override
public List getIndexColumnNames() {
return indexColumnNames;
}
@Override
public String toString() {
return "PrefixIndex [table=" + table + ", indexColumnNames="
+ indexColumnNames + "]";
}
@Override
public IndexMetaNode getRoot() {
// TODO Auto-generated method stub
return null;
}
@Override
public Object getStore() {
// TODO Auto-generated method stub
return null;
}
}
