/*
* Copyright 2005 Joe Walker
*
* 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.
*/
package org.directwebremoting.convert;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import java.util.SortedSet;
import java.util.StringTokenizer;
import java.util.TreeSet;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.directwebremoting.ConversionException;
import org.directwebremoting.extend.AbstractConverter;
import org.directwebremoting.extend.ArrayOutboundVariable;
import org.directwebremoting.extend.ConvertUtil;
import org.directwebremoting.extend.ConverterManager;
import org.directwebremoting.extend.ErrorOutboundVariable;
import org.directwebremoting.extend.InboundVariable;
import org.directwebremoting.extend.OutboundContext;
import org.directwebremoting.extend.OutboundVariable;
import org.directwebremoting.extend.Property;
import org.directwebremoting.extend.ProtocolConstants;
/**
* An implementation of Converter for Collections of Strings.
* @author Joe Walker [joe at getahead dot ltd dot uk]
*/
public class CollectionConverter extends AbstractConverter
{
/* (non-Javadoc)
* @see org.directwebremoting.convert.BaseV20Converter#setConverterManager(org.directwebremoting.ConverterManager)
*/
@Override
public void setConverterManager(ConverterManager converterManager)
{
this.converterManager = converterManager;
}
/* (non-Javadoc)
* @see org.directwebremoting.Converter#convertInbound(java.lang.Class, org.directwebremoting.InboundVariable, org.directwebremoting.InboundContext)
*/
@SuppressWarnings("unchecked")
public Object convertInbound(Class<?> paramType, InboundVariable data) throws ConversionException
{
if (data.isNull())
{
return null;
}
String value = data.getValue();
// If the text is null then the whole bean is null
if (value.trim().equals(ProtocolConstants.INBOUND_NULL))
{
return null;
}
if (!value.startsWith(ProtocolConstants.INBOUND_ARRAY_START) || !value.endsWith(ProtocolConstants.INBOUND_ARRAY_END))
{
log.warn("Expected collection while converting data for " + paramType.getName() + " in " + data.getContext().getCurrentProperty() + ". Passed: " + value);
throw new ConversionException(paramType, "Data conversion error. See logs for more details.");
}
value = value.substring(1, value.length() - 1);
try
{
Property parent = data.getContext().getCurrentProperty();
Property child = parent.createChild(0);
child = converterManager.checkOverride(child);
Class<?> subtype = child.getPropertyType();
// subtype.getMethod("h", null).getTypeParameters();
Collection<Object> col;
// If they want an iterator then just use an array list and fudge
// at the end.
if (Iterator.class.isAssignableFrom(paramType))
{
col = new ArrayList<Object>();
}
// If paramType is concrete then just use whatever we've got.
else if (!paramType.isInterface() && !Modifier.isAbstract(paramType.getModifiers()))
{
// If there is a problem creating the type then we have no way
// of completing this - they asked for a specific type and we
// can't create that type. I don't know of a way of finding
// subclasses that might be instaniable so we accept failure.
//noinspection unchecked
col = (Collection<Object>) paramType.newInstance();
}
// If they want a SortedSet then use TreeSet
else if (SortedSet.class.isAssignableFrom(paramType))
{
col = new TreeSet<Object>();
}
// If they want a Set then use HashSet
else if (Set.class.isAssignableFrom(paramType))
{
col = new HashSet<Object>();
}
// If they want a List then use an ArrayList
else if (List.class.isAssignableFrom(paramType))
{
col = new ArrayList<Object>();
}
// If they just want a Collection then just use an ArrayList
else if (Collection.class.isAssignableFrom(paramType))
{
col = new ArrayList<Object>();
}
else
{
throw new ConversionException(paramType);
}
// We should put the new object into the working map in case it
// is referenced later nested down in the conversion process.
data.getContext().addConverted(data, paramType, col);
StringTokenizer st = new StringTokenizer(value, ProtocolConstants.INBOUND_ARRAY_SEPARATOR);
int size = st.countTokens();
for (int i = 0; i < size; i++)
{
String token = st.nextToken();
String[] split = ConvertUtil.splitInbound(token);
String splitType = split[ConvertUtil.INBOUND_INDEX_TYPE];
String splitValue = split[ConvertUtil.INBOUND_INDEX_VALUE];
InboundVariable nested = new InboundVariable(data.getContext(), null, splitType, splitValue);
nested.dereference();
Object output = converterManager.convertInbound(subtype, nested, child);
col.add(output);
}
// If they wanted an Iterator then give them one otherwise use
// the type we created
if (Iterator.class.isAssignableFrom(paramType))
{
return col.iterator();
}
else
{
return col;
}
}
catch (ConversionException ex)
{
throw ex;
}
catch (Exception ex)
{
throw new ConversionException(paramType, ex);
}
}
/* (non-Javadoc)
* @see org.directwebremoting.Converter#convertOutbound(java.lang.Object, org.directwebremoting.OutboundContext)
*/
@SuppressWarnings("unchecked")
public OutboundVariable convertOutbound(Object data, OutboundContext outctx) throws ConversionException
{
// First we need to get ourselves the collection data
Iterator<Object> it;
if (data instanceof Collection)
{
Collection<Object> col = (Collection<Object>) data;
it = col.iterator();
}
else if (data instanceof Iterator)
{
it = (Iterator<Object>) data;
}
else
{
throw new ConversionException(data.getClass());
}
// Stash this bit of data to cope with recursion
ArrayOutboundVariable ov = new ArrayOutboundVariable(outctx);
outctx.put(data, ov);
// Convert all the data members
List<OutboundVariable> ovs = new ArrayList<OutboundVariable>();
while (it.hasNext())
{
Object member = it.next();
OutboundVariable nested;
try
{
nested = converterManager.convertOutbound(member, outctx);
}
catch (Exception ex)
{
String errorMessage = "Conversion error for " + data.getClass().getName() + ".";
log.warn(errorMessage, ex);
nested = new ErrorOutboundVariable(errorMessage);
}
ovs.add(nested);
}
// Group the list of converted objects into this OutboundVariable
ov.setChildren(ovs);
return ov;
}
/**
* For nested conversions
*/
private ConverterManager converterManager = null;
/**
* The log stream
*/
private static final Log log = LogFactory.getLog(CollectionConverter.class);
}