/*
* 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.myfaces.commons.resourcehandler.resource;
import java.io.IOException;
import java.io.InputStream;
import java.io.PushbackInputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.el.ELContext;
import javax.el.ELException;
import javax.el.ValueExpression;
import javax.faces.context.FacesContext;
import javax.faces.event.ExceptionQueuedEvent;
import javax.faces.event.ExceptionQueuedEventContext;
public class ValueExpressionFilterInputStream extends InputStream
{
private PushbackInputStream delegate;
private String libraryName;
private String resourceName;
public ValueExpressionFilterInputStream(InputStream in, String libraryName, String resourceName)
{
super();
delegate = new PushbackInputStream(in,255);
}
@Override
public int read() throws IOException
{
int c1 = delegate.read();
if (c1 == -1) return -1;
if ( ((char)c1) == '#')
{
int c2 = delegate.read();
if (c2 == -1) return -1;
if (((char)c2) == '{')
{
//It is a value expression. We need
//to look for a occurrence of } to
//extract the expression and evaluate it,
//the result should be unread.
List<Integer> expressionList = new ArrayList<Integer>();
int c3 = delegate.read();
while ( c3 != -1 && ((char)c3) != '}' )
{
expressionList.add(c3);
c3 = delegate.read();
}
if (c3 == -1)
{
//get back the data, because we can't
//extract any value expression
for (int i = 0; i < expressionList.size(); i++)
{
delegate.unread(expressionList.get(i));
}
delegate.unread(c2);
return c1;
}
else
{
//EL expression found. Evaluate it and pushback
//the result into the stream
FacesContext context = FacesContext.getCurrentInstance();
ELContext elContext = context.getELContext();
try
{
ValueExpression ve = context.getApplication().
getExpressionFactory().createValueExpression(
elContext,
"#{"+convertToExpression(expressionList)+"}",
String.class);
String value = (String) ve.getValue(elContext);
for (int i = value.length()-1; i >= 0 ; i--)
{
delegate.unread((int) value.charAt(i));
}
}
catch(ELException e)
{
ExceptionQueuedEventContext equecontext = new ExceptionQueuedEventContext (context, e, null);
context.getApplication().publishEvent (context, ExceptionQueuedEvent.class, equecontext);
Logger log = Logger.getLogger(ResourceImpl.class.getName());
if (log.isLoggable(Level.SEVERE))
log.severe("Cannot evaluate EL expression "+convertToExpression(expressionList)+ " in resource " + (libraryName == null ? "" : libraryName)+":"+resourceName);
delegate.unread(c3);
for (int i = expressionList.size()-1; i >= 0; i--)
{
delegate.unread(expressionList.get(i));
}
delegate.unread(c2);
return c1;
}
//read again
return delegate.read();
}
}
else
{
delegate.unread(c2);
return c1;
}
}
else
{
//just continue
return c1;
}
}
private String convertToExpression(List<Integer> expressionList)
{
char[] exprArray = new char[expressionList.size()];
for (int i = 0; i < expressionList.size(); i++)
{
exprArray[i] = (char) expressionList.get(i).intValue();
}
return String.valueOf(exprArray);
}
}