/* * The Apache Software License, Version 1.1 * * Copyright (c) 1999 The Apache Software Foundation. All rights * reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. The end-user documentation included with the redistribution, if * any, must include the following acknowlegement: * "This product includes software developed by the * Apache Software Foundation (http://www.apache.org/)." * Alternately, this acknowlegement may appear in the software itself, * if and wherever such third-party acknowlegements normally appear. * * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software * Foundation" must not be used to endorse or promote products derived * from this software without prior written permission. For written * permission, please contact apache@apache.org. * * 5. Products derived from this software may not be called "Apache" * nor may "Apache" appear in their names without prior written * permission of the Apache Group. * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * ==================================================================== * * This software consists of voluntary contributions made by many * individuals on behalf of the Apache Software Foundation. For more * information on the Apache Software Foundation, please see * <http://www.apache.org/>. * */ package org.jbpm.jpdl.el.impl; import java.lang.reflect.Array; import java.util.Collection; import java.util.Map; import org.jbpm.jpdl.el.ELException; /** * * <p>The implementation of the empty operator * * @author Nathan Abramson - Art Technology Group * @version $Change: 181177 $$DateTime: 2001/06/26 08:45:09 $$Author$ **/ public class EmptyOperator extends UnaryOperator { //------------------------------------- // Singleton //------------------------------------- public static final EmptyOperator SINGLETON = new EmptyOperator (); //------------------------------------- /** * * Constructor **/ public EmptyOperator () { } //------------------------------------- // Expression methods //------------------------------------- /** * * Returns the symbol representing the operator **/ public String getOperatorSymbol () { return "empty"; } //------------------------------------- /** * * Applies the operator to the given value **/ public Object apply (Object pValue, Logger pLogger) throws ELException { // See if the value is null if (pValue == null) { return PrimitiveObjects.getBoolean (true); } // See if the value is a zero-length String else if ("".equals (pValue)) { return PrimitiveObjects.getBoolean (true); } // See if the value is a zero-length array else if (pValue.getClass ().isArray () && Array.getLength (pValue) == 0) { return PrimitiveObjects.getBoolean (true); } // See if the value is an empty Map else if (pValue instanceof Map && ((Map) pValue).isEmpty ()) { return PrimitiveObjects.getBoolean (true); } // See if the value is an empty Collection else if (pValue instanceof Collection && ((Collection) pValue).isEmpty ()) { return PrimitiveObjects.getBoolean (true); } // Otherwise, not empty else { return PrimitiveObjects.getBoolean (false); } } //------------------------------------- }