| /* |
| * 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.io.Serializable; |
| import java.util.Iterator; |
| |
| import edu.umd.cs.findbugs.annotations.SuppressFBWarnings; |
| import freemarker.ext.util.WrapperTemplateModel; |
| |
| /** |
| * Adapts an {@link Iterator} to the corresponding {@link TemplateModel} interface(s), most importantly to |
| * {@link TemplateCollectionModel}. The resulting {@link TemplateCollectionModel} can only be iterated once. |
| * |
| * <p> |
| * Thread safety: A {@link DefaultListAdapter} is as thread-safe as the array that it wraps is. Normally you only |
| * have to consider read-only access, as the FreeMarker template language doesn't allow writing these sequences (though |
| * of course, Java methods called from the template can violate this rule). |
| * |
| * <p> |
| * This adapter is used by {@link DefaultObjectWrapper} if its {@code useAdaptersForCollections} property is |
| * {@code true}, which is the default when its {@code incompatibleImprovements} property is 2.3.22 or higher. |
| * |
| * @since 2.3.22 |
| */ |
| public class DefaultIteratorAdapter extends WrappingTemplateModel implements TemplateCollectionModel, |
| AdapterTemplateModel, WrapperTemplateModel, Serializable { |
| |
| @SuppressFBWarnings(value="SE_BAD_FIELD", justification="We hope it's Seralizable") |
| private final Iterator iterator; |
| private boolean iteratorOwnedBySomeone; |
| |
| /** |
| * Factory method for creating new adapter instances. |
| * |
| * @param iterator |
| * The iterator to adapt; can't be {@code null}. |
| */ |
| public static DefaultIteratorAdapter adapt(Iterator iterator, ObjectWrapper wrapper) { |
| return new DefaultIteratorAdapter(iterator, wrapper); |
| } |
| |
| private DefaultIteratorAdapter(Iterator iterator, ObjectWrapper wrapper) { |
| super(wrapper); |
| this.iterator = iterator; |
| } |
| |
| public Object getWrappedObject() { |
| return iterator; |
| } |
| |
| public Object getAdaptedObject(Class hint) { |
| return getWrappedObject(); |
| } |
| |
| public TemplateModelIterator iterator() throws TemplateModelException { |
| return new SimpleTemplateModelIterator(); |
| } |
| |
| /** |
| * Not thread-safe. |
| */ |
| private class SimpleTemplateModelIterator implements TemplateModelIterator { |
| |
| private boolean iteratorOwnedByMe; |
| |
| public TemplateModel next() throws TemplateModelException { |
| if (!iteratorOwnedByMe) { |
| checkNotOwner(); |
| iteratorOwnedBySomeone = true; |
| iteratorOwnedByMe = true; |
| } |
| |
| if (!iterator.hasNext()) { |
| throw new TemplateModelException("The collection has no more items."); |
| } |
| |
| Object value = iterator.next(); |
| return value instanceof TemplateModel ? (TemplateModel) value : wrap(value); |
| } |
| |
| public boolean hasNext() throws TemplateModelException { |
| // Calling hasNext may looks safe, but I have met sync. problems. |
| if (!iteratorOwnedByMe) { |
| checkNotOwner(); |
| } |
| |
| return iterator.hasNext(); |
| } |
| |
| private void checkNotOwner() throws TemplateModelException { |
| if (iteratorOwnedBySomeone) { |
| throw new TemplateModelException( |
| "This collection value wraps a java.util.Iterator, thus it can be listed only once."); |
| } |
| } |
| } |
| |
| } |