/*
* (C) Copyright 2006-2011 Nuxeo SA (http://nuxeo.com/) and others.
*
* Licensed 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.
*
* Contributors:
* Florent Guillaume
*/
package org.nuxeo.ecm.core.storage.sql.jdbc;
import java.io.Serializable;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Iterator;
import java.util.Map;
import java.util.NoSuchElementException;
import org.nuxeo.ecm.core.api.IterableQueryResult;
import org.nuxeo.ecm.core.query.QueryFilter;
import org.nuxeo.ecm.core.storage.sql.Session.PathResolver;
/**
* Iterable query result implemented as a cursor on a SQL {@link ResultSet}.
*/
public class ResultSetQueryResult implements IterableQueryResult, Iterator<Map<String, Serializable>> {
private QueryMaker.Query q;
private PreparedStatement ps;
private ResultSet rs;
private Map<String, Serializable> next;
private boolean eof;
private long pos;
private long size = -1;
private final JDBCLogger logger;
public ResultSetQueryResult(QueryMaker queryMaker, String query, QueryFilter queryFilter, PathResolver pathResolver,
JDBCMapper mapper, Object... params) throws SQLException {
logger = mapper.logger;
q = queryMaker.buildQuery(mapper.sqlInfo, mapper.model, pathResolver, query, queryFilter, params);
if (q == null) {
// no result
size = 0;
ps = null;
rs = null;
eof = true;
return;
} else {
eof = false;
}
if (logger.isLogEnabled()) {
logger.logSQL(q.selectInfo.sql, q.selectParams);
}
ps = mapper.connection.prepareStatement(q.selectInfo.sql, ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_READ_ONLY);
int i = 1;
for (Serializable object : q.selectParams) {
mapper.setToPreparedStatement(ps, i++, object);
}
rs = ps.executeQuery();
mapper.countExecute();
// rs.setFetchDirection(ResultSet.FETCH_UNKNOWN); fails in H2
}
protected static void closePreparedStatement(PreparedStatement ps) throws SQLException {
try {
ps.close();
} catch (IllegalArgumentException e) {
// ignore
// http://bugs.mysql.com/35489 with JDBC 4 and driver <= 5.1.6
}
}
@Override
public void close() {
if (rs == null) {
return;
}
try {
rs.close();
closePreparedStatement(ps);
} catch (SQLException e) {
logger.error("Error closing statement: " + e.getMessage(), e);
} finally {
pos = -1;
rs = null;
ps = null;
}
}
@Override
public boolean isLife() {
return rs != null;
}
@Override
public boolean mustBeClosed() {
return rs != null;
}
public static class ClosedIteratorException extends IllegalStateException {
private static final long serialVersionUID = 1L;
public final QueryMaker.Query query;
protected ClosedIteratorException(QueryMaker.Query q) {
super("Query results iterator closed (" + q.selectInfo.sql + ")");
this.query = q;
}
}
protected void checkNotClosed() {
if (rs == null) {
throw new ClosedIteratorException(q);
}
}
@Override
public long size() {
if (size != -1) {
return size;
}
checkNotClosed();
try {
// save cursor pos
int old = rs.isBeforeFirst() ? -1 : rs.isAfterLast() ? -2 : rs.getRow();
// find size
rs.last();
size = rs.getRow();
// set back cursor
if (old == -1) {
rs.beforeFirst();
} else if (old == -2) {
rs.afterLast();
} else if (old != 0) {
rs.absolute(old);
}
return size;
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
@Override
public long pos() {
checkNotClosed();
return pos;
}
@Override
public void skipTo(long pos) {
checkNotClosed();
try {
boolean available = rs.absolute((int) pos + 1);
if (available) {
next = fetchCurrent();
eof = false;
this.pos = pos;
} else {
// after last row
next = null;
eof = true;
this.pos = -1; // XXX
}
} catch (SQLException e) {
logger.error("Error skipping to: " + pos + ": " + e.getMessage(), e);
}
}
@Override
public Iterator<Map<String, Serializable>> iterator() {
checkNotClosed();
return this;
}
protected Map<String, Serializable> fetchNext() throws SQLException {
checkNotClosed();
if (!rs.next()) {
if (logger.isLogEnabled()) {
logger.log(" -> END");
}
return null;
}
return fetchCurrent();
}
protected Map<String, Serializable> fetchCurrent() throws SQLException {
checkNotClosed();
Map<String, Serializable> map = q.selectInfo.mapMaker.makeMap(rs);
if (logger.isLogEnabled()) {
logger.logMap(map);
}
return map;
}
@Override
public boolean hasNext() {
if (eof) {
return false;
}
checkNotClosed();
if (next != null) {
return true;
}
try {
next = fetchNext();
} catch (SQLException e) {
logger.error("Error fetching next: " + e.getMessage(), e);
}
eof = next == null;
return !eof;
}
@Override
public Map<String, Serializable> next() {
checkNotClosed();
if (!hasNext()) {
pos = -1;
throw new NoSuchElementException();
}
Map<String, Serializable> n = next;
next = null;
pos++;
return n;
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
}