freemarker.template.TemplateCollectionModel Maven / Gradle / Ivy
/*
* 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;
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, nor the number of elements in it is known. As such, this is very similar to Java's
* {@link Iterable} interface (but it predates that interface, hence the unfortunate class name).
*
*
* Note that 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.
*
*
* 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.
*
*
* 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;
}