package org.h2.index;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import java.util.TreeMap;
import org.h2.command.dml.AllColumnsForPlan;
import org.h2.engine.Mode.UniqueIndexNullsHandling;
import org.h2.engine.Session;
import org.h2.message.DbException;
import org.h2.result.Row;
import org.h2.result.SearchRow;
import org.h2.result.SortOrder;
import org.h2.table.Column;
import org.h2.table.IndexColumn;
import org.h2.table.PageStoreTable;
import org.h2.table.TableFilter;
import org.h2.value.DataType;
import org.h2.value.Value;
import org.h2.value.ValueNull;
public class HashIndex extends BaseIndex {
private final int indexColumn;
private final boolean totalOrdering;
private final PageStoreTable tableData;
private Map<Value, Long> rows;
private final ArrayList<Long> nullRows = new ArrayList<>();
public HashIndex(PageStoreTable table, int id, String indexName, IndexColumn[] columns, IndexType indexType) {
super(table, id, indexName, columns, indexType);
Column column = columns[0].column;
indexColumn = column.getColumnId();
totalOrdering = DataType.hasTotalOrdering(column.getType().getValueType());
this.tableData = table;
reset();
}
private void reset() {
rows = totalOrdering ? new HashMap<Value, Long>() : new TreeMap<Value, Long>(database.getCompareMode());
}
@Override
public void truncate(Session session) {
reset();
}
@Override
public void add(Session session, Row row) {
Value key = row.getValue(indexColumn);
if (key != ValueNull.INSTANCE
|| database.getMode().uniqueIndexNullsHandling == UniqueIndexNullsHandling.FORBID_ANY_DUPLICATES) {
Object old = rows.get(key);
if (old != null) {
throw getDuplicateKeyException(key.toString());
}
rows.put(key, row.getKey());
} else {
nullRows.add(row.getKey());
}
}
@Override
public void remove(Session session, Row row) {
Value key = row.getValue(indexColumn);
if (key != ValueNull.INSTANCE
|| database.getMode().uniqueIndexNullsHandling == UniqueIndexNullsHandling.FORBID_ANY_DUPLICATES) {
rows.remove(key);
} else {
nullRows.remove(row.getKey());
}
}
@Override
public Cursor find(Session session, SearchRow first, SearchRow last) {
if (first == null || last == null) {
throw DbException.throwInternalError(first + " " + last);
}
Value v = first.getValue(indexColumn);
if (v == ValueNull.INSTANCE
&& database.getMode().uniqueIndexNullsHandling != UniqueIndexNullsHandling.FORBID_ANY_DUPLICATES) {
return new NonUniqueHashCursor(session, tableData, nullRows);
}
v = v.convertTo(tableData.getColumn(indexColumn).getType(), database.getMode(), null);
Row result;
Long pos = rows.get(v);
if (pos == null) {
result = null;
} else {
result = tableData.getRow(session, pos.intValue());
}
return new SingleRowCursor(result);
}
@Override
public long getRowCount(Session session) {
return getRowCountApproximation();
}
@Override
public long getRowCountApproximation() {
return rows.size() + nullRows.size();
}
@Override
public long getDiskSpaceUsed() {
return 0;
}
@Override
public void close(Session session) {
}
@Override
public void remove(Session session) {
}
@Override
public double getCost(Session session, int[] masks,
TableFilter[] filters, int filter, SortOrder sortOrder,
AllColumnsForPlan allColumnsSet) {
for (Column column : columns) {
int index = column.getColumnId();
int mask = masks[index];
if ((mask & IndexCondition.EQUALITY) != IndexCondition.EQUALITY) {
return Long.MAX_VALUE;
}
}
return 2;
}
@Override
public void checkRename() {
}
@Override
public boolean needRebuild() {
return true;
}
@Override
public boolean canGetFirstOrLast() {
return false;
}
@Override
public Cursor findFirstOrLast(Session session, boolean first) {
throw DbException.getUnsupportedException("HASH");
}
@Override
public boolean canScan() {
return false;
}
}