| /* |
| * 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.ArrayList; |
| import java.util.List; |
| |
| /** |
| * Singleton object representing nothing, used by ?if_exists built-in. |
| * It is meant to be interpreted in the most sensible way possible in various contexts. |
| * This can be returned to avoid exceptions. |
| */ |
| |
| final class GeneralPurposeNothing |
| implements TemplateBooleanModel, TemplateScalarModel, TemplateSequenceModel, TemplateHashModelEx, TemplateMethodModelEx { |
| |
| private static final TemplateModel instance = new GeneralPurposeNothing(); |
| |
| private static final TemplateCollectionModel EMPTY_COLLECTION = new SimpleCollection(new ArrayList(0)); |
| |
| private GeneralPurposeNothing() { |
| } |
| |
| static TemplateModel getInstance() { |
| return instance; |
| } |
| |
| public String getAsString() { |
| return ""; |
| } |
| |
| public boolean getAsBoolean() { |
| return false; |
| } |
| |
| public boolean isEmpty() { |
| return true; |
| } |
| |
| public int size() { |
| return 0; |
| } |
| |
| public TemplateModel get(int i) throws TemplateModelException { |
| throw new TemplateModelException("Empty list"); |
| } |
| |
| public TemplateModel get(String key) { |
| return null; |
| } |
| |
| public Object exec(List args) { |
| return null; |
| } |
| |
| public TemplateCollectionModel keys() { |
| return EMPTY_COLLECTION; |
| } |
| |
| public TemplateCollectionModel values() { |
| return EMPTY_COLLECTION; |
| } |
| } |