001    /*
002     * Copyright 2002-2004 the original author or authors.
003     *
004     * Licensed under the Apache License, Version 2.0 (the "License"); you may not
005     * use this file except in compliance with the License. You may obtain a copy of
006     * the License at
007     *
008     * http://www.apache.org/licenses/LICENSE-2.0
009     *
010     * Unless required by applicable law or agreed to in writing, software
011     * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
012     * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
013     * License for the specific language governing permissions and limitations under
014     * the License.
015     */
016    package org.springframework.rules.closure.support;
017    
018    
019    /**
020     * Simple implementation of AbstractClosure: makes it easy to just execute a
021     * block of code without any additional parameters.
022     */
023    public abstract class NoArgBlock extends AbstractClosure {
024    
025            /**
026             * {@inheritDoc}
027             *
028             * @return allways <code>null</code>, only code is executed.
029             */
030            public final Object call(Object argument) {
031                    handle();
032                    return null;
033            }
034    
035            /**
036             * Block of code to be executed. Implement this.
037             */
038            protected void handle() {
039                    throw new UnsupportedOperationException("You must override call() for a noArg block that returns a value, or "
040                                    + "override handle() for a noArg block that returns no value");
041            }
042    
043    }