package org.apache.velocity;
/*
* The Apache Software License, Version 1.1
*
* Copyright (c) 2000-2001 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowlegement:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
*
* 4. The names "The Jakarta Project", "Velocity", and "Apache Software
* Foundation" must not be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache"
* nor may "Apache" appear in their names without prior written
* permission of the Apache Group.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*/
import java.io.InputStream;
import java.io.IOException;
import java.io.Writer;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import org.apache.velocity.runtime.resource.Resource;
import org.apache.velocity.runtime.parser.ParseException;
import org.apache.velocity.runtime.parser.node.SimpleNode;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.context.Context;
import org.apache.velocity.context.InternalContextAdapter;
import org.apache.velocity.context.InternalContextAdapterImpl;
import org.apache.velocity.exception.ResourceNotFoundException;
import org.apache.velocity.exception.ParseErrorException;
import org.apache.velocity.exception.MethodInvocationException;
/**
* This class is used for controlling all template
* operations. This class uses a parser created
* by JavaCC to create an AST that is subsequently
* traversed by a Visitor.
*
* <pre>
* Template template = Velocity.getTemplate("test.wm");
* Context context = new VelocityContext();
*
* context.put("foo", "bar");
* context.put("customer", new Customer());
*
* template.merge(context, writer);
* </pre>
*
* @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
* @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
* @version $Id: Template.java,v 1.35 2001/10/22 03:53:22 jon Exp $
*/
public class Template extends Resource
{
/**
* To keep track of whether this template has been
* initialized. We use the document.init(context)
* to perform this.
*/
private boolean initialized = false;
private Exception errorCondition = null;
/** Default constructor */
public Template()
{
}
/**
* gets the named resource as a stream, parses and inits
*
* @return true if successful
* @throws ResourceNotFoundException if template not found
* from any available source.
* @throws ParseErrorException if template cannot be parsed due
* to syntax (or other) error.
* @throws Exception some other problem, should only be from
* initialization of the template AST.
*/
public boolean process()
throws ResourceNotFoundException, ParseErrorException, Exception
{
data = null;
InputStream is = null;
errorCondition = null;
/*
* first, try to get the stream from the loader
*/
try
{
is = resourceLoader.getResourceStream(name);
}
catch( ResourceNotFoundException rnfe )
{
/*
* remember and re-throw
*/
errorCondition = rnfe;
throw rnfe;
}
/*
* if that worked, lets protect in case a loader impl
* forgets to throw a proper exception
*/
if (is != null)
{
/*
* now parse the template
*/
try
{
BufferedReader br = new BufferedReader( new InputStreamReader( is, encoding ) );
data = rsvc.parse( br, name);
initDocument();
return true;
}
catch( UnsupportedEncodingException uce )
{
String msg = "Template.process : Unsupported input encoding : " + encoding
+ " for template " + name;
errorCondition = new ParseErrorException( msg );
throw errorCondition;
}
catch ( ParseException pex )
{
/*
* remember the error and convert
*/
errorCondition = new ParseErrorException( pex.getMessage() );
throw errorCondition;
}
catch( Exception e )
{
/*
* who knows? Something from initDocument()
*/
errorCondition = e;
throw e;
}
finally
{
/*
* Make sure to close the inputstream when we are done.
*/
is.close();
}
}
else
{
/*
* is == null, therefore we have some kind of file issue
*/
errorCondition = new ResourceNotFoundException("Unknown resource error for resource " + name );
throw errorCondition;
}
}
/**
* initializes the document. init() is not longer
* dependant upon context, but we need to let the
* init() carry the template name down throught for VM
* namespace features
*/
public void initDocument()
throws Exception
{
/*
* send an empty InternalContextAdapter down into the AST to initialize it
*/
InternalContextAdapterImpl ica = new InternalContextAdapterImpl( new VelocityContext() );
try
{
/*
* put the current template name on the stack
*/
ica.pushCurrentTemplateName( name );
/*
* init the AST
*/
((SimpleNode)data).init( ica, rsvc);
}
finally
{
/*
* in case something blows up...
* pull it off for completeness
*/
ica.popCurrentTemplateName();
}
}
/**
* The AST node structure is merged with the
* context to produce the final output.
*
* Throws IOException if failure is due to a file related
* issue, and Exception otherwise
*
* @param context Conext with data elements accessed by template
* @param writer output writer for rendered template
* @throws ResourceNotFoundException if template not found
* from any available source.
* @throws ParseErrorException if template cannot be parsed due
* to syntax (or other) error.
* @throws Exception anything else.
*/
public void merge( Context context, Writer writer)
throws ResourceNotFoundException, ParseErrorException, MethodInvocationException, Exception
{
/*
* we shouldn't have to do this, as if there is an error condition,
* the application code should never get a reference to the
* Template
*/
if (errorCondition != null)
{
throw errorCondition;
}
if( data != null)
{
/*
* create an InternalContextAdapter to carry the user Context down
* into the rendering engine. Set the template name and render()
*/
InternalContextAdapterImpl ica = new InternalContextAdapterImpl( context );
try
{
ica.pushCurrentTemplateName( name );
ica.setCurrentResource( this );
( (SimpleNode) data ).render( ica, writer);
}
finally
{
/*
* lets make sure that we always clean up the context
*/
ica.popCurrentTemplateName();
ica.setCurrentResource( null );
}
}
else
{
/*
* this shouldn't happen either, but just in case.
*/
String msg = "Template.merge() failure. The document is null, " +
"most likely due to parsing error.";
rsvc.error(msg);
throw new Exception(msg);
}
}
}