/*
* 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.empire.data.bean;
import java.lang.reflect.Method;
import java.sql.Connection;
import java.util.ArrayList;
import org.apache.empire.db.DBColumn;
import org.apache.empire.db.DBCommand;
import org.apache.empire.db.DBDatabase;
import org.apache.empire.db.DBReader;
import org.apache.empire.db.DBRowSet;
import org.apache.empire.exceptions.BeanIncompatibleException;
import org.apache.empire.exceptions.InvalidArgumentException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* BeanResult
* This is a simple helper class that performs reading a list of beans from a query
* Internally DBReader.getBeanList() is used.
*
* @author doebele
*/
public class BeanResult<T> extends ArrayList<T>
{
/**
* Comment for <code>serialVersionUID</code>
*/
private static final long serialVersionUID = 1L;
private static final Logger log = LoggerFactory.getLogger(BeanResult.class);
private DBCommand cmd;
private Class<T> clazz;
/**
* Create a bean result from a command object.
* No checks will be performed here whether the command is compatible with the supplied class.
* @param clazz
* @param cmd
*/
public BeanResult(Class<T> clazz, DBCommand cmd)
{
this.clazz = clazz;
this.cmd = cmd;
// Invalid Argument
if (cmd==null || cmd.hasSelectExpr())
throw new InvalidArgumentException("cmd", cmd);
}
/**
* Creates a bean result for a Table, View or Query from the supplied columns.
* At least one column must match the given getters / setters on the supplied class otherwise an BeanIncompatibleException will be thrown.
* @param clazz the of T
* @param rowset the rowset
*/
public BeanResult(Class<T> clazz, DBRowSet rowset)
{
this.clazz = clazz;
// Create the command
DBDatabase db = rowset.getDatabase();
cmd = db.createCommand();
// Select all accessible columns
int count = 0;
Method[] methods = clazz.getMethods();
for (DBColumn col : rowset.getColumns())
{ // obtain the bean property Name
String property = col.getBeanPropertyName();
if (!isPropertyAcessible(methods, property)) {
// Property not found
log.debug("Unable to access the property {} on {}. Column will be ignored.", property, clazz.getName());
continue;
}
// Select
cmd.select(col);
count++;
}
// Check
if (count==0)
throw new BeanIncompatibleException(clazz, rowset);
}
private boolean isPropertyAcessible(Method[] methods, String property)
{
property = "et"+property.substring(0,1).toUpperCase()+property.substring(1);
for (int i=0; i<methods.length; i++)
{ // Find a matching getter or setter method
String name = methods[i].getName();
if (name.endsWith(property))
return true;
}
return false;
}
public DBCommand getCommand()
{
return cmd;
}
public int fetch(Connection conn, int maxItems)
{
clear();
DBReader reader = new DBReader();
try {
// Open and Read
reader.open(cmd, conn);
reader.getBeanList(this, clazz, maxItems);
return size();
} finally {
reader.close();
}
}
public final int fetch(Connection conn)
{
return fetch(conn, -1);
}
}