freemarker.template.ObjectWrapper Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
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* 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;
import java.util.Map;
import java.util.ResourceBundle;
import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
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)
*/
@SuppressFBWarnings(value="IC_SUPERCLASS_USES_SUBCLASS_DURING_INITIALIZATION", justification="BC")
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. As of 2.3.22, using
* {@link DefaultObjectWrapper} with its {@code incompatibleImprovements} property set to 2.3.22 (or higher) is
* recommended instead.
*
* @deprecated Use {@link BeansWrapperBuilder#build()} instead; this instance isn't read-only
* and thus can't be trusted.
*/
@Deprecated
ObjectWrapper BEANS_WRAPPER = BeansWrapper.getDefaultInstance();
/**
* The legacy default object wrapper implementation, focusing on backward compatibility and out-of-the W3C DOM
* wrapping box extra features. See {@link DefaultObjectWrapper} for more information.
*
* @deprecated Use {@link DefaultObjectWrapperBuilder#build()} instead; this instance isn't read-only and thus can't
* be trusted.
*/
@Deprecated
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.
*/
@Deprecated
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. If it's {@code null}, the method should return {@code null}
* (however, {@link BeansWrapper}, has a legacy option for returning a null model object instead, but it's not
* a good idea).
*
* @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;
}