/*
* Copyright 2014 Attila Szegedi, Daniel Dekany, Jonathan Revusky
*
* 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 freemarker.template.utility;
import java.io.IOException;
import java.io.Writer;
import java.util.Map;
import freemarker.core.Environment;
import freemarker.template.SimpleScalar;
import freemarker.template.TemplateModel;
import freemarker.template.TemplateModelException;
import freemarker.template.TemplateScalarModel;
import freemarker.template.TemplateTransformModel;
/**
* A transform that captures the output of a block of FTL code and stores that in a variable.
*
* <p>As this transform is initially present in the shared variable set, you can always
* access it from the templates:</p>
*
* <pre>
* <@capture_output var="captured">
* ...
* </@capture_output>
* </pre>
*
* <p>And later in the template you can use the captured output:</p>
*
* ${captured}
*
* <p>This transform requires one of three parameters: <code>var</code>, <code>local</code>, or <code>global</code>.
* 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>).
* </p>
* <p>In the case of an assignment within a namespace, there is an optional parameter
* <code>namespace</code> 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.</p>
*
* @deprecated Use block-assignments instead, like <code><assign x>...</assign></code>.
*/
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());
}
}
};
}
}