/*
* 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.Collection;
/**
* "collection" template language data type: a collection of values that can be enumerated, but can't be or not meant to
* be accessed by index or key. As such, this is not a super-interface of {@link TemplateSequenceModel}, and
* implementations of that interface needn't also implement this interface just because they can. They should though, if
* enumeration with this interface is significantly faster than enumeration by index. The {@code #list} directive will
* enumerate using this interface if it's available.
*
* <p>
* The enumeration should be repeatable if that's possible with reasonable effort, otherwise a second enumeration
* attempt is allowed to throw an {@link TemplateModelException}. Generally, the interface user Java code need not
* handle that kind of exception, as in practice only the template author can handle it, by not listing such collections
* twice.
*
* <p>
* Note that to wrap Java's {@link Collection}, you should implement {@link TemplateCollectionModelEx}, not just this
* interface.
*/
public interface TemplateCollectionModel extends TemplateModel {
/**
* Retrieves a template model iterator that is used to iterate over the elements in this collection.
*/
public TemplateModelIterator iterator() throws TemplateModelException;
}