/*
* 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.jsf2.app;
import java.beans.FeatureDescriptor;
import java.lang.reflect.Field;
import java.util.Iterator;
import javax.el.ELContext;
import javax.el.ELResolver;
import javax.faces.context.FacesContext;
import org.apache.empire.commons.StringUtils;
import org.apache.empire.data.Record;
import org.apache.empire.data.RecordData;
import org.apache.empire.db.DBColumnExpr;
import org.apache.empire.db.DBDatabase;
import org.apache.empire.db.DBRowSet;
import org.apache.empire.exceptions.NotSupportedException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class DBELResolver extends ELResolver
{
private static final Logger log = LoggerFactory.getLogger(DBELResolver.class);
@Override
public Class<?> getCommonPropertyType(ELContext context, Object base)
{
if (base==null)
log.warn("DBELResolver:getCommonPropertyType is not implemented!");
return null;
}
@Override
public Class<?> getType(ELContext context, Object base, Object property)
{
if ((base instanceof DBRowSet) ||
(base instanceof DBDatabase) ||
(base==null && property.equals("db")))
log.warn("DBELResolver:getType is not implemented!");
return null;
}
@Override
public Iterator<FeatureDescriptor> getFeatureDescriptors(ELContext arg0, Object arg1)
{
log.warn("DBELResolver:getFeatureDescriptors is not implemented!");
return null;
}
@Override
public Object getValue(ELContext context, Object base, Object property)
{
// Resolve database, table/view or column
if (base instanceof DBRowSet)
{ // Find matching column
String name = StringUtils.toString(property);
DBColumnExpr column = ((DBRowSet)base).getColumn(name);
if (column==null)
column = findExpressionField(base, name);
if (column!=null)
context.setPropertyResolved(true);
else
log.error("ELResolver error: Column '{}' cannot be resolved for table/view '{}'.", name.toUpperCase(), ((DBRowSet)base).getName());
// done
return column;
}
else if (base instanceof DBDatabase)
{ // Lookup RowSet
String name = StringUtils.toString(property);
DBRowSet rset = ((DBDatabase)base).getRowSet(name);
if (rset!=null)
context.setPropertyResolved(true);
else
log.error("ELResolver error: Table/View '{}' cannot be resolved.", name.toUpperCase());
// done
return rset;
}
else if (base instanceof RecordData)
{ // Lookup RowSet
String field= StringUtils.toString(property);
// field must start with a capital Letter
if (field==null || field.length()==0 || field.charAt(0)<'A' || field.charAt(0)>'Z')
return null;
// try to find field
int index = ((Record)base).getFieldIndex(field);
if (index<0)
{ // not a field, it may be a property
log.warn("ELResolver warning: field '{}' not found in record .", field);
// not resolved, continue search
return null;
}
// Found! Return field value.
context.setPropertyResolved(true);
return ((Record)base).getValue(index);
}
else if (base==null)
{ // LookupDatabase
String name = StringUtils.toString(property);
DBDatabase db = DBDatabase.findById(name);
if (db!=null)
context.setPropertyResolved(true);
// done
return db;
}
return null;
}
public static DBColumnExpr findExpressionField(Object rowset, String property)
{
Class<?> c = rowset.getClass();
try
{ // Find a matching field name
Field f = c.getField(property);
if (f==null)
return null;
Object v = f.get(rowset);
if (v==null)
{ // invalid data type
log.error("ELResolver error: Field '{}.{}' is null.", c.getSimpleName(), property);
return null;
}
if (!(v instanceof DBColumnExpr))
{ // invalid data type
log.error("ELResolver error: Field '{}.{}' is not a DBColumnExpr.", c.getSimpleName(), property);
return null;
}
return ((DBColumnExpr)v);
}
catch (SecurityException e)
{
log.error("ELResolver error: Unable to access field "+c.getSimpleName()+"."+property, e);
return null;
}
catch (NoSuchFieldException e)
{
return null;
}
catch (IllegalArgumentException e)
{
log.error("ELResolver error: Unable to access field "+c.getSimpleName()+"."+property, e);
return null;
}
catch (IllegalAccessException e)
{
log.error("ELResolver error: Unable to access field "+c.getSimpleName()+"."+property, e);
return null;
}
}
@Override
public boolean isReadOnly(ELContext context, Object base, Object property)
{
// is it our's?
if ((base instanceof DBRowSet) ||
(base instanceof DBDatabase) ||
(base==null && property.equals("db")))
{ // read only
log.info("ELResolver: property {} is read only.", property);
return true;
}
// not our business
return false;
}
@Override
public void setValue(ELContext context, Object base, Object property, Object value)
{
if (isReadOnly(context, base, property))
{
RuntimeException e = new NotSupportedException(this, "setValue");
FacesContext.getCurrentInstance().getExternalContext().log(e.getMessage(), e);
throw e;
}
}
}