src/main/java/freemarker/template/SimpleObjectWrapper.java

/*
 * 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 freemarker.ext.beans.BeansWrapper;

/**
 * A restricted object wrapper that will not expose arbitrary object, just those that directly correspond to the
 * {@link TemplateModel} sub-interfaces ({@code String}, {@code Map} and such). If it had to wrap other kind of objects,
 * it will throw exception. It will also block {@code ?api} calls on the values it wraps.
 */
public class SimpleObjectWrapper extends DefaultObjectWrapper {
    
    static final SimpleObjectWrapper instance = new SimpleObjectWrapper();
    
    /**
     * @deprecated Use {@link #SimpleObjectWrapper(Version)} instead.
     */
    public SimpleObjectWrapper() {
        super();
    }
    
    /**
     * @param incompatibleImprovements see in {@link BeansWrapper#BeansWrapper(Version)}.
     * 
     * @since 2.3.21
     */
    public SimpleObjectWrapper(Version incompatibleImprovements) {
        super(incompatibleImprovements);
    }
    
    /**
     * Called if a type other than the simple ones we know about is passed in. 
     * In this implementation, this just throws an exception.
     */
    protected TemplateModel handleUnknownType(Object obj) throws TemplateModelException {
        throw new TemplateModelException("SimpleObjectWrapper deliberately won't wrap this type: " 
                                         + obj.getClass().getName());
    }

    public TemplateHashModel wrapAsAPI(Object obj) throws TemplateModelException {
        throw new TemplateModelException("SimpleObjectWrapper deliberately doesn't allow ?api.");
    }
    
}