org.apache.openjpa.jdbc.kernel.SelectResultObjectProvider Maven / Gradle / Ivy
/*
* 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.jdbc.kernel;
import java.sql.SQLException;
import org.apache.openjpa.jdbc.sql.Result;
import org.apache.openjpa.jdbc.sql.SQLExceptions;
import org.apache.openjpa.jdbc.sql.Select;
import org.apache.openjpa.jdbc.sql.SelectExecutor;
import org.apache.openjpa.lib.rop.ResultObjectProvider;
import org.apache.openjpa.util.StoreException;
/**
* Abstract provider implementation wrapped around a {@link Select}.
*
* @author Abe White
* @nojavadoc
*/
public abstract class SelectResultObjectProvider
implements ResultObjectProvider {
private final SelectExecutor _sel;
private final JDBCStore _store;
private final JDBCFetchConfiguration _fetch;
protected Result _res = null;
private int _size = -1;
private Boolean _ra = null;
/**
* Constructor.
*
* @param sel the select to execute
* @param store the store to delegate loading to
* @param fetch the fetch configuration, or null for the default
*/
public SelectResultObjectProvider(SelectExecutor sel, JDBCStore store,
JDBCFetchConfiguration fetch) {
_sel = sel;
_store = store;
_fetch = fetch;
}
public SelectExecutor getSelect() {
return _sel;
}
public JDBCStore getStore() {
return _store;
}
public JDBCFetchConfiguration getFetchConfiguration() {
return _fetch;
}
public Result getResult() {
return _res;
}
public boolean supportsRandomAccess() {
if (_ra == null) {
boolean ra;
if (_res != null) {
try {
ra = _res.supportsRandomAccess();
} catch (SQLException se) {
throw SQLExceptions.getStore(se, _store.getDBDictionary());
}
} else
ra = _sel.supportsRandomAccess(_fetch.getReadLockLevel() > 0);
_ra = (ra) ? Boolean.TRUE : Boolean.FALSE;
}
return _ra.booleanValue();
}
public void open()
throws SQLException {
_res = _sel.execute(_store, _fetch);
}
public boolean next()
throws SQLException {
return _res.next();
}
public boolean absolute(int pos)
throws SQLException {
return _res.absolute(pos);
}
public int size()
throws SQLException {
if (_size == -1) {
// if res is null, don't cache size
if (_res == null)
return Integer.MAX_VALUE;
switch (_fetch.getLRSSize()) {
case LRSSizes.SIZE_UNKNOWN:
_size = Integer.MAX_VALUE;
break;
case LRSSizes.SIZE_LAST:
if (supportsRandomAccess())
_size = _res.size();
else
_size = Integer.MAX_VALUE;
break;
default: // query
_size = _sel.getCount(_store);
}
}
return _size;
}
/**
* Allow subclasses that know the size to set it; otherwise we calculate
* it internally.
*/
protected void setSize(int size) {
if (_size == -1)
_size = size;
}
public void reset()
throws SQLException {
close();
open();
}
public void close() {
if (_res != null) {
_res.close();
_res = null;
}
}
public void handleCheckedException(Exception e) {
if (e instanceof SQLException)
throw SQLExceptions.getStore((SQLException) e, _store.getDBDictionary(), _fetch.getReadLockLevel());
throw new StoreException(e);
}
}