freemarker.template.utility.CaptureOutput Maven / Gradle / Ivy
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Google App Engine compliant variation of FreeMarker.
FreeMarker is a "template engine"; a generic tool to generate text output based on templates.
/*
* 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.utility;
import freemarker.template.*;
import freemarker.core.Environment;
import java.io.*;
import java.util.Map;
/**
* A transform that captures the output of a block of FTL code and stores that in a variable.
*
* As this transform is initially present in the shared variable set, you can always
* access it from the templates:
*
*
* <@capture_output var="captured">
* ...
* </@capture_output>
*
*
* And later in the template you can use the captured output:
*
* ${captured}
*
* This transform requires one of three parameters: var, local, or global.
* Each of them specifies the name of the variable that stores the captured output, but the first creates a
* variable in a name-space (as <#assign>), the second creates a macro-local variable (as <#local>),
* and the last creates a global variable (as <#global>).
*
* In the case of an assignment within a namespace, there is an optional parameter
* namespace that indicates in which namespace to do the assignment.
* if this is omitted, the current namespace is used, and this will be, by far, the most
* common usage pattern.
*
* @deprecated Use block-assignments instead, as <assign x>...</assign>.
*
* @version $Id: CaptureOutput.java,v 1.31 2004/01/06 17:06:43 szegedia Exp $
*/
public class CaptureOutput implements TemplateTransformModel {
public Writer getWriter(final Writer out, final Map args) throws TemplateModelException {
String errmsg = "Must specify the name of the variable in "
+ "which to capture the output with the 'var' or 'local' or 'global' parameter.";
if (args == null) throw new TemplateModelException(errmsg);
boolean local = false, global=false;
final TemplateModel nsModel = (TemplateModel) args.get("namespace");
Object varNameModel = args.get("var");
if (varNameModel == null) {
varNameModel = args.get("local");
if (varNameModel == null) {
varNameModel = args.get("global");
global = true;
} else {
local = true;
}
if (varNameModel == null) {
throw new TemplateModelException(errmsg);
}
}
if (args.size()==2) {
if (nsModel == null) {
throw new TemplateModelException("Second parameter can only be namespace");
}
if (local) {
throw new TemplateModelException("Cannot specify namespace for a local assignment");
}
if (global) {
throw new TemplateModelException("Cannot specify namespace for a global assignment");
}
if (!(nsModel instanceof Environment.Namespace)) {
throw new TemplateModelException("namespace parameter does not specify a namespace. It is a " + nsModel.getClass().getName());
}
}
else if (args.size() != 1) throw new TemplateModelException(
"Bad parameters. Use only one of 'var' or 'local' or 'global' parameters.");
if(!(varNameModel instanceof TemplateScalarModel)) {
throw new TemplateModelException("'var' or 'local' or 'global' parameter doesn't evaluate to a string");
}
final String varName = ((TemplateScalarModel) varNameModel).getAsString();
if(varName == null) {
throw new TemplateModelException("'var' or 'local' or 'global' parameter evaluates to null string");
}
final StringBuffer buf = new StringBuffer();
final Environment env = Environment.getCurrentEnvironment();
final boolean localVar = local;
final boolean globalVar = global;
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 {
SimpleScalar result = new SimpleScalar(buf.toString());
try {
if (localVar) {
env.setLocalVariable(varName, result);
} else if (globalVar) {
env.setGlobalVariable(varName, result);
}
else {
if (nsModel == null) {
env.setVariable(varName, result);
} else {
((Environment.Namespace) nsModel).put(varName, result);
}
}
} catch (java.lang.IllegalStateException ise) { // if somebody uses 'local' outside a macro
throw new IOException("Could not set variable " + varName + ": " + ise.getMessage());
}
}
};
}
}