| /* |
| * 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.ext.beans; |
| |
| import java.util.Iterator; |
| import java.util.NoSuchElementException; |
| |
| import freemarker.template.TemplateCollectionModel; |
| import freemarker.template.TemplateModel; |
| import freemarker.template.TemplateModelException; |
| import freemarker.template.TemplateModelIterator; |
| |
| /** |
| * <p>A class that adds {@link TemplateModelIterator} functionality to the |
| * {@link Iterator} interface implementers. |
| * </p> |
| * <p>It differs from the {@link freemarker.template.SimpleCollection} in that |
| * it inherits from {@link BeanModel}, and therefore you can call methods on |
| * it directly, even to the effect of calling <tt>iterator.remove()</tt> in |
| * the template.</p> <p>Using the model as a collection model is NOT |
| * thread-safe, as iterators are inherently not thread-safe. |
| * Further, you can iterate over it only once. Attempts to call the |
| * {@link #iterator()} method after it was already driven to the end once will |
| * throw an exception.</p> |
| */ |
| |
| public class IteratorModel |
| extends |
| BeanModel |
| implements |
| TemplateModelIterator, |
| TemplateCollectionModel { |
| private boolean accessed = false; |
| |
| /** |
| * Creates a new model that wraps the specified iterator object. |
| * @param iterator the iterator object to wrap into a model. |
| * @param wrapper the {@link BeansWrapper} associated with this model. |
| * Every model has to have an associated {@link BeansWrapper} instance. The |
| * model gains many attributes from its wrapper, including the caching |
| * behavior, method exposure level, method-over-item shadowing policy etc. |
| */ |
| public IteratorModel(Iterator iterator, BeansWrapper wrapper) { |
| super(iterator, wrapper); |
| } |
| |
| /** |
| * This allows the iterator to be used in a <tt><#list></tt> block. |
| * @return "this" |
| */ |
| public TemplateModelIterator iterator() throws TemplateModelException { |
| synchronized (this) { |
| if (accessed) { |
| throw new TemplateModelException( |
| "This collection is stateful and can not be iterated over the" + |
| " second time."); |
| } |
| accessed = true; |
| } |
| return this; |
| } |
| |
| /** |
| * Calls underlying {@link Iterator#hasNext()}. |
| */ |
| public boolean hasNext() { |
| return ((Iterator) object).hasNext(); |
| } |
| |
| |
| /** |
| * Calls underlying {@link Iterator#next()} and wraps the result. |
| */ |
| public TemplateModel next() |
| throws TemplateModelException { |
| try { |
| return wrap(((Iterator) object).next()); |
| } catch (NoSuchElementException e) { |
| throw new TemplateModelException( |
| "No more elements in the iterator.", e); |
| } |
| } |
| |
| /** |
| * Returns {@link Iterator#hasNext()}. Therefore, an |
| * iterator that has no more element evaluates to false, and an |
| * iterator that has further elements evaluates to true. |
| */ |
| public boolean getAsBoolean() { |
| return hasNext(); |
| } |
| } |