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/*
* 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;
import java.util.List;
import java.util.Map;
import java.util.ResourceBundle;
import freemarker.ext.beans.BeansWrapper;
import freemarker.ext.beans.BeansWrapperBuilder;
import freemarker.ext.util.WrapperTemplateModel;
/**
* Maps Java objects to the type-system of FreeMarker Template Language (see the {@link TemplateModel}
* interfaces). Thus this is what decides what parts of the Java objects will be accessible in the templates and how.
*
* For example, with a {@link BeansWrapper} both the items of {@link Map} and the JavaBean properties (the getters)
* of an object are accessible in template uniformly with the {@code myObject.foo} syntax, where "foo" is the map key or
* the property name. This is because both kind of object is wrapped by {@link BeansWrapper} into a
* {@link TemplateHashModel} implementation that will call {@link Map#get(Object)} or the getter method, transparently
* to the template language.
*
* @see Configuration#setObjectWrapper(ObjectWrapper)
*/
public interface ObjectWrapper {
/**
* An {@link ObjectWrapper} that exposes the object methods and JavaBeans properties as hash elements, and has
* custom handling for Java {@link Map}-s, {@link ResourceBundle}-s, etc. It doesn't treat
* {@link org.w3c.dom.Node}-s and Jython objects specially, however.
*
* @deprecated Use {@link BeansWrapperBuilder#build()} instead; this instance isn't read-only
* and thus can't be trusted.
*/
ObjectWrapper BEANS_WRAPPER = BeansWrapper.getDefaultInstance();
/**
* The default object wrapper implementation, focusing on backward compatibility and out-of-the box extra features.
* Extends {@link BeansWrapper} with the special handling of {@link org.w3c.dom.Node}-s (for XML processing) and
* Jython objects. However, for backward compatibility, it also somewhat downgrades {@link BeansWrapper} by using
* {@link SimpleHash} for {@link Map}-s, {@link SimpleSequence} for {@link List}-s and collections/arrays.
* Furthermore it uses {@link SimpleScalar}, {@link SimpleNumber} to wrap {@link String}-s and {@link Number}-s,
* although this is not considered to be harmful.
*
* @deprecated Use {@link BeansWrapperBuilder#build()} instead; this instance isn't
* read-only and thus can't be trusted.
*/
ObjectWrapper DEFAULT_WRAPPER = DefaultObjectWrapper.instance;
/**
* Object wrapper that uses {@code SimpleXXX} wrappers only.
* It behaves like the {@link #DEFAULT_WRAPPER}, but for objects
* that it does not know how to wrap as a {@code SimpleXXX} it
* throws an exception. It makes no use of reflection-based
* exposure of anything, which may makes it a good candidate for security-restricted applications.
*
* @deprecated No replacement as it was seldom if ever used by anyone; this instance isn't
* read-only and thus can't be trusted.
*/
ObjectWrapper SIMPLE_WRAPPER = SimpleObjectWrapper.instance;
/**
* Makes a {@link TemplateModel} out of a non-{@link TemplateModel} object, usually by "wrapping" it into a
* {@link TemplateModel} implementation that delegates to the original object.
*
* @param obj The object to wrap into a {@link TemplateModel}. If it already implements {@link TemplateModel},
* it should just return the object as is.
*
* @return a {@link TemplateModel} wrapper of the object passed in. To support un-wrapping, you may consider the
* return value to implement {@link WrapperTemplateModel} and {@link AdapterTemplateModel}.
* The default expectation is that the {@link TemplateModel} isn't less thread safe than the wrapped object.
* If the {@link ObjectWrapper} returns less thread safe objects, that should be clearly documented, as it
* restricts how it can be used, like, then it can't be used to wrap "shared variables"
* ({@link Configuration#setSharedVaribles(Map)}).
*/
TemplateModel wrap(Object obj) throws TemplateModelException;
}