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FreeMarker is a "template engine"; a generic tool to generate text output based on templates.
/*
* 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 freemarker.core;
import java.io.IOException;
import java.util.List;
import java.util.Map;
import freemarker.template.MalformedTemplateNameException;
import freemarker.template.SimpleHash;
import freemarker.template.Template;
import freemarker.template.TemplateBooleanModel;
import freemarker.template.TemplateDirectiveBody;
import freemarker.template.TemplateDirectiveModel;
import freemarker.template.TemplateException;
import freemarker.template.TemplateHashModelEx;
import freemarker.template.TemplateHashModelEx2.KeyValuePair;
import freemarker.template.TemplateHashModelEx2.KeyValuePairIterator;
import freemarker.template.TemplateMethodModelEx;
import freemarker.template.TemplateModel;
import freemarker.template.TemplateModelException;
import freemarker.template.TemplateScalarModel;
import freemarker.template._TemplateAPI;
import freemarker.template.utility.TemplateModelUtils;
/**
* Implements {@code .get_optional_template(name, options)}.
*/
class GetOptionalTemplateMethod implements TemplateMethodModelEx {
static final GetOptionalTemplateMethod INSTANCE = new GetOptionalTemplateMethod(
BuiltinVariable.GET_OPTIONAL_TEMPLATE);
static final GetOptionalTemplateMethod INSTANCE_CC = new GetOptionalTemplateMethod(
BuiltinVariable.GET_OPTIONAL_TEMPLATE_CC);
private static final String OPTION_ENCODING = "encoding";
private static final String OPTION_PARSE = "parse";
private static final String RESULT_INCLUDE = "include";
private static final String RESULT_IMPORT = "import";
private static final String RESULT_EXISTS = "exists";
/** Used in error messages */
private final String methodName;
private GetOptionalTemplateMethod(String builtInVarName) {
this.methodName = "." + builtInVarName;
}
@Override
public Object exec(List args) throws TemplateModelException {
final int argCnt = args.size();
if (argCnt < 1 || argCnt > 2) {
throw _MessageUtil.newArgCntError(methodName, argCnt, 1, 2);
}
final Environment env = Environment.getCurrentEnvironment();
if (env == null) {
throw new IllegalStateException("No freemarer.core.Environment is associated to the current thread.");
}
final String absTemplateName;
{
TemplateModel arg = (TemplateModel) args.get(0);
if (!(arg instanceof TemplateScalarModel)) {
throw _MessageUtil.newMethodArgMustBeStringException(methodName, 0, arg);
}
String templateName = EvalUtil.modelToString((TemplateScalarModel) arg, null, env);
try {
absTemplateName = env.toFullTemplateName(env.getCurrentTemplate().getName(), templateName);
} catch (MalformedTemplateNameException e) {
throw new _TemplateModelException(
e, "Failed to convert template path to full path; see cause exception.");
}
}
final TemplateHashModelEx options;
if (argCnt > 1) {
TemplateModel arg = (TemplateModel) args.get(1);
if (!(arg instanceof TemplateHashModelEx)) {
throw _MessageUtil.newMethodArgMustBeExtendedHashException(methodName, 1, arg);
}
options = (TemplateHashModelEx) arg;
} else {
options = null;
}
String encoding = null;
boolean parse = true;
if (options != null) {
final KeyValuePairIterator kvpi = TemplateModelUtils.getKeyValuePairIterator(options);
while (kvpi.hasNext()) {
final KeyValuePair kvp = kvpi.next();
final String optName;
{
TemplateModel optNameTM = kvp.getKey();
if (!(optNameTM instanceof TemplateScalarModel)) {
throw _MessageUtil.newMethodArgInvalidValueException(methodName, 1,
"All keys in the options hash must be strings, but found ",
new _DelayedAOrAn(new _DelayedFTLTypeDescription(optNameTM)));
}
optName = ((TemplateScalarModel) optNameTM).getAsString();
}
final TemplateModel optValue = kvp.getValue();
if (OPTION_ENCODING.equals(optName)) {
encoding = getStringOption(OPTION_ENCODING, optValue);
} else if (OPTION_PARSE.equals(optName)) {
parse = getBooleanOption(OPTION_PARSE, optValue);
} else {
throw _MessageUtil.newMethodArgInvalidValueException(methodName, 1,
"Unsupported option ", new _DelayedJQuote(optName), "; valid names are: ",
new _DelayedJQuote(OPTION_ENCODING), ", ", new _DelayedJQuote(OPTION_PARSE), ".");
}
}
}
final Template template;
try {
template = env.getTemplateForInclusion(absTemplateName, encoding, parse, true);
} catch (IOException e) {
throw new _TemplateModelException(
e, "I/O error when trying to load optional template ", new _DelayedJQuote(absTemplateName),
"; see cause exception");
}
SimpleHash result = new SimpleHash(_TemplateAPI.SAFE_OBJECT_WRAPPER);
result.put(RESULT_EXISTS, template != null);
// If the template is missing, result.include and such will be missing too, so that a default can be
// conveniently provided like in <@optTemp.include!myDefaultMacro />.
if (template != null) {
result.put(RESULT_INCLUDE, new TemplateDirectiveModel() {
@Override
public void execute(Environment env, Map params, TemplateModel[] loopVars, TemplateDirectiveBody body)
throws TemplateException, IOException {
if (!params.isEmpty()) {
throw new TemplateException("This directive supports no parameters.", env);
}
if (loopVars.length != 0) {
throw new TemplateException("This directive supports no loop variables.", env);
}
if (body != null) {
throw new TemplateException("This directive supports no nested content.", env);
}
env.include(template);
}
});
result.put(RESULT_IMPORT, new TemplateMethodModelEx() {
@Override
public Object exec(List args) throws TemplateModelException {
if (!args.isEmpty()) {
throw new TemplateModelException("This method supports no parameters.");
}
try {
return env.importLib(template, null);
} catch (IOException | TemplateException e) {
throw new _TemplateModelException(e, "Failed to import loaded template; see cause exception");
}
}
});
}
return result;
}
private boolean getBooleanOption(String optionName, TemplateModel value) throws TemplateModelException {
if (!(value instanceof TemplateBooleanModel)) {
throw _MessageUtil.newMethodArgInvalidValueException(methodName, 1,
"The value of the ", new _DelayedJQuote(optionName), " option must be a boolean, but it was ",
new _DelayedAOrAn(new _DelayedFTLTypeDescription(value)), ".");
}
return ((TemplateBooleanModel) value).getAsBoolean();
}
private String getStringOption(String optionName, TemplateModel value) throws TemplateModelException {
if (!(value instanceof TemplateScalarModel)) {
throw _MessageUtil.newMethodArgInvalidValueException(methodName, 1,
"The value of the ", new _DelayedJQuote(optionName), " option must be a string, but it was ",
new _DelayedAOrAn(new _DelayedFTLTypeDescription(value)), ".");
}
return EvalUtil.modelToString((TemplateScalarModel) value, null, null);
}
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