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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.
/*
* 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.template.utility;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.Map;
import freemarker.core.Environment;
import freemarker.ext.util.WrapperTemplateModel;
import freemarker.template.AdapterTemplateModel;
import freemarker.template.ObjectWrapper;
import freemarker.template.TemplateBooleanModel;
import freemarker.template.TemplateCollectionModel;
import freemarker.template.TemplateDateModel;
import freemarker.template.TemplateHashModelEx;
import freemarker.template.TemplateHashModelEx2;
import freemarker.template.TemplateHashModelEx2.KeyValuePair;
import freemarker.template.TemplateHashModelEx2.KeyValuePairIterator;
import freemarker.template.TemplateModel;
import freemarker.template.TemplateModelException;
import freemarker.template.TemplateModelIterator;
import freemarker.template.TemplateNumberModel;
import freemarker.template.TemplateScalarModel;
import freemarker.template.TemplateSequenceModel;
/**
* Utility methods for unwrapping {@link TemplateModel}-s.
*/
public class DeepUnwrap {
private static final Class OBJECT_CLASS = Object.class;
/**
* Unwraps {@link TemplateModel}-s recursively.
* The converting of the {@link TemplateModel} object happens with the following rules:
*
* - If the object implements {@link AdapterTemplateModel}, then the result
* of {@link AdapterTemplateModel#getAdaptedObject(Class)} for Object.class is returned.
*
- If the object implements {@link WrapperTemplateModel}, then the result
* of {@link WrapperTemplateModel#getWrappedObject()} is returned.
*
- If the object is identical to the null model of the current object
* wrapper, null is returned.
*
- If the object implements {@link TemplateScalarModel}, then the result
* of {@link TemplateScalarModel#getAsString()} is returned.
*
- If the object implements {@link TemplateNumberModel}, then the result
* of {@link TemplateNumberModel#getAsNumber()} is returned.
*
- If the object implements {@link TemplateDateModel}, then the result
* of {@link TemplateDateModel#getAsDate()} is returned.
*
- If the object implements {@link TemplateBooleanModel}, then the result
* of {@link TemplateBooleanModel#getAsBoolean()} is returned.
*
- If the object implements {@link TemplateSequenceModel} or
* {@link TemplateCollectionModel}, then a
java.util.ArrayList is
* constructed from the subvariables, and each subvariable is unwrapped with
* the rules described here (recursive unwrapping).
* - If the object implements {@link TemplateHashModelEx}, then a
*
java.util.HashMap is constructed from the subvariables, and each
* subvariable is unwrapped with the rules described here (recursive unwrapping).
* - Throw a
TemplateModelException, because it doesn't know how to
* unwrap the object.
*
*/
public static Object unwrap(TemplateModel model) throws TemplateModelException {
return unwrap(model, false);
}
/**
* Same as {@link #unwrap(TemplateModel)}, but it doesn't throw exception
* if it doesn't know how to unwrap the model, but rather returns it as-is.
* @since 2.3.14
*/
public static Object permissiveUnwrap(TemplateModel model) throws TemplateModelException {
return unwrap(model, true);
}
/**
* @deprecated the name of this method is mistyped. Use
* {@link #permissiveUnwrap(TemplateModel)} instead.
*/
@Deprecated
public static Object premissiveUnwrap(TemplateModel model) throws TemplateModelException {
return unwrap(model, true);
}
private static Object unwrap(TemplateModel model, boolean permissive) throws TemplateModelException {
Environment env = Environment.getCurrentEnvironment();
TemplateModel nullModel = null;
if (env != null) {
ObjectWrapper wrapper = env.getObjectWrapper();
if (wrapper != null) {
nullModel = wrapper.wrap(null);
}
}
return unwrap(model, nullModel, permissive);
}
private static Object unwrap(TemplateModel model, TemplateModel nullModel, boolean permissive) throws TemplateModelException {
if (model instanceof AdapterTemplateModel) {
return ((AdapterTemplateModel) model).getAdaptedObject(OBJECT_CLASS);
}
if (model instanceof WrapperTemplateModel) {
return ((WrapperTemplateModel) model).getWrappedObject();
}
if (model == nullModel) {
return null;
}
if (model instanceof TemplateScalarModel) {
return ((TemplateScalarModel) model).getAsString();
}
if (model instanceof TemplateNumberModel) {
return ((TemplateNumberModel) model).getAsNumber();
}
if (model instanceof TemplateDateModel) {
return ((TemplateDateModel) model).getAsDate();
}
if (model instanceof TemplateBooleanModel) {
return Boolean.valueOf(((TemplateBooleanModel) model).getAsBoolean());
}
if (model instanceof TemplateSequenceModel) {
TemplateSequenceModel seq = (TemplateSequenceModel) model;
int size = seq.size();
ArrayList list = new ArrayList(size);
for (int i = 0; i < size; ++i) {
list.add(unwrap(seq.get(i), nullModel, permissive));
}
return list;
}
if (model instanceof TemplateCollectionModel) {
TemplateCollectionModel coll = (TemplateCollectionModel) model;
ArrayList list = new ArrayList();
TemplateModelIterator it = coll.iterator();
while (it.hasNext()) {
list.add(unwrap(it.next(), nullModel, permissive));
}
return list;
}
if (model instanceof TemplateHashModelEx) {
TemplateHashModelEx hash = (TemplateHashModelEx) model;
Map map = new LinkedHashMap<>();
if (model instanceof TemplateHashModelEx2) {
KeyValuePairIterator kvps = ((TemplateHashModelEx2) model).keyValuePairIterator();
while (kvps.hasNext()) {
KeyValuePair kvp = kvps.next();
map.put(
unwrap(kvp.getKey(), nullModel, permissive),
unwrap(kvp.getValue(), nullModel, permissive));
}
} else {
TemplateModelIterator keys = hash.keys().iterator();
while (keys.hasNext()) {
String key = (String) unwrap(keys.next(), nullModel, permissive);
map.put(key, unwrap(hash.get(key), nullModel, permissive));
}
}
return map;
}
if (permissive) {
return model;
}
throw new TemplateModelException("Cannot deep-unwrap model of type " + model.getClass().getName());
}
}