/*
* Copyright (c) 2003 The Visigoth Software Society. 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 acknowledgement:
* "This product includes software developed by the
* Visigoth Software Society (http://www.visigoths.org/)."
* Alternately, this acknowledgement may appear in the software itself,
* if and wherever such third-party acknowledgements normally appear.
*
* 4. Neither the name "FreeMarker", "Visigoth", nor any of the names of the
* project contributors may be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact [email protected].
*
* 5. Products derived from this software may not be called "FreeMarker" or "Visigoth"
* nor may "FreeMarker" or "Visigoth" appear in their names
* without prior written permission of the Visigoth Software Society.
*
* 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 VISIGOTH SOFTWARE SOCIETY 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 Visigoth Software Society. For more
* information on the Visigoth Software Society, please see
* http://www.visigoths.org/
*/
package freemarker.template;
import java.io.IOException;
import java.io.Writer;
import java.util.Map;
import freemarker.template.utility.DeepUnwrap;
/**
* Objects that implement this interface can be used as user-defined directives
* (much like macros); you should rather use the newer {@link TemplateDirectiveModel}
* instead. Altough implementing output filters is more handy with this interface,
* this interface will be certainly deprecated as superfluous, starting from
* FreeMarker 2.4. But as far as the template engine is concerned, you can use both
* equivalently as a user-defined directive.
*
* <P>Note that, as of FreeMarker 2.1, <tt>TemplateTransformModel</tt>
* has changed. This is a more powerful implementation.
* There is a quick-and-dirty way to patch any legacy
* TemplateTransformModel so that it implements the new API.
* You simply add the following as your implementation
* of the getWriter() call:
* <PRE>
*
* public Writer getWriter(final Writer out,
* Map args)
* {
* final StringBuffer buf = new StringBuffer();
* return new Writer() {
* public void write(char cbuf[], int off, int len) {
* buf.append(cbuf, off, len);
* }
*
* public void flush() throws IOException {
* out.flush();
* }
*
* public void close() throws IOException {
* StringReader sr = new StringReader(buf.toString());
* StringWriter sw = new StringWriter();
* transform(sr, sw);
* out.write(sw.toString());
* }
* };
* }
*
*
* </PRE>
*
* @author Attila Szegedi
* @version $Id: TemplateTransformModel.java,v 1.36 2003/04/11 20:57:32 revusky Exp $
*/
public interface TemplateTransformModel extends TemplateModel {
/**
* Returns a writer that will be used by the engine to feed the
* transformation input to the transform. Each call to this method
* must return a new instance of the writer so that the transformation
* is thread-safe.
* @param out the character stream to which to write the transformed output
* @param args the arguments (if any) passed to the transformation as a
* map of key/value pairs where the keys are strings and the arguments are
* TemplateModel instances. This is never null. If you need to convert the
* template models to POJOs, you can use the utility methods in the
* {@link DeepUnwrap} class.
* @return a writer to which the engine will feed the transformation
* input, or null if the transform does not support nested content (body).
* The returned writer can implement the {@link TransformControl}
* interface if it needs advanced control over the evaluation of the
* transformation body.
*/
Writer getWriter(Writer out, Map args)
throws TemplateModelException, IOException;
}
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