/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.openjpa.slice.jdbc;
import java.util.Date;
import org.apache.openjpa.kernel.Filters;
import org.apache.openjpa.kernel.StoreQuery;
import org.apache.openjpa.kernel.exps.QueryExpressions;
import org.apache.openjpa.kernel.exps.Value;
import org.apache.openjpa.lib.rop.ResultObjectProvider;
import org.apache.openjpa.lib.util.Localizer;
import org.apache.openjpa.util.InternalException;
/**
* Aggregates individual single query results from different databases.
*
* @author Pinaki Poddar
*
*/
public class UniqueResultObjectProvider implements ResultObjectProvider {
private final ResultObjectProvider[] _rops;
private final StoreQuery _query;
private final QueryExpressions[] _exps;
private Object _single;
private boolean _opened;
private static final String COUNT = "Count";
private static final String MAX = "Max";
private static final String MIN = "Min";
private static final String SUM = "Sum";
private static final Localizer _loc =
Localizer.forPackage(UniqueResultObjectProvider.class);
public UniqueResultObjectProvider(ResultObjectProvider[] rops,
StoreQuery q, QueryExpressions[] exps) {
_rops = rops;
_query = q;
_exps = exps;
}
public boolean absolute(int pos) throws Exception {
return false;
}
public void close() throws Exception {
_opened = false;
for (ResultObjectProvider rop:_rops)
rop.close();
}
public Object getResultObject() throws Exception {
if (!_opened)
throw new InternalException(_loc.get("not-open"));
return _single;
}
public void handleCheckedException(Exception e) {
_rops[0].handleCheckedException(e);
}
public boolean next() throws Exception {
if (!_opened) {
open();
}
if (_single != null)
return false;
Value[] values = _exps[0].projections;
Object[] single = new Object[values.length];
for (int i=0; i<values.length; i++) {
Value v = values[i];
boolean isAggregate = v.isAggregate();
String op = v.getClass().getSimpleName();
for (ResultObjectProvider rop:_rops) {
if (i == 0)
rop.next();
Object[] row = (Object[]) rop.getResultObject();
if (isAggregate) {
if (COUNT.equals(op)) {
single[i] = count(single[i], row[i]);
} else if (MAX.equals(op)) {
single[i] = max(single[i], row[i]);
} else if (MIN.equals(op)) {
single[i] = min(single[i], row[i]);
} else if (SUM.equals(op)) {
single[i] = sum(single[i], row[i]);
} else {
throw new UnsupportedOperationException
(_loc.get("aggregate-unsupported", op).toString());
}
} else {
single[i] = row[i];
}
single[i] = Filters.convert(single[i], v.getType());
}
}
_single = single;
return true;
}
Object count(Object current, Object other) {
if (current == null)
return other;
if (other == null)
return current;
return ((Number)current).longValue() + ((Number)other).longValue();
}
Object max(Object current, Object other) {
if (current == null)
return other;
if (other == null)
return current;
if (current instanceof Number) {
return Math.max(((Number)current).doubleValue(),
((Number)other).doubleValue());
}
if (current instanceof String) {
return ((String)current).compareTo((String)other) > 0 ? current : other;
}
if (current instanceof Date) {
return ((Date)current).compareTo((Date)other) > 0 ? current : other;
}
if (current instanceof Character) {
return ((Character)current).compareTo((Character)other) > 0 ? current : other;
}
throw new UnsupportedOperationException(_loc.get("aggregate-unsupported-on-type",
"MAX()", (current == null ? other : current).getClass().getName()).toString());
}
Object min(Object current, Object other) {
if (current == null)
return other;
if (other == null)
return current;
if (current instanceof Number) {
return Math.min(((Number)current).doubleValue(),
((Number)other).doubleValue());
}
if (current instanceof String) {
return ((String)current).compareTo((String)other) < 0 ? current : other;
}
if (current instanceof Date) {
return ((Date)current).compareTo((Date)other) < 0 ? current : other;
}
if (current instanceof Character) {
return ((Character)current).compareTo((Character)other) < 0 ? current : other;
}
throw new UnsupportedOperationException(_loc.get("aggregate-unsupported-on-type",
"MIN()", (current == null ? other : current).getClass().getName()).toString());
}
Object sum(Object current, Object other) {
if (current == null)
return other;
if (other == null)
return current;
if (current instanceof Number) {
return (((Number)current).doubleValue() +
((Number)other).doubleValue());
}
throw new UnsupportedOperationException(_loc.get("aggregate-unsupported-on-type",
"SUM()", (current == null ? other : current).getClass().getName()).toString());
}
public void open() throws Exception {
for (ResultObjectProvider rop:_rops)
rop.open();
_opened = true;
}
public void reset() throws Exception {
_single = null;
for (ResultObjectProvider rop : _rops) {
rop.reset();
}
}
public int size() throws Exception {
return 1;
}
public boolean supportsRandomAccess() {
return false;
}
}