| /* |
| * The Apache Software License, Version 1.1 |
| * |
| * Copyright (c) 2001 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", "Ant", 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.apache.ant.core.types; |
| |
| import org.apache.ant.core.execution.*; |
| import java.io.*; |
| |
| /** |
| * A DataType is an element which can register a named value in the |
| * ExecutionFrame's context. |
| * |
| * @author <a href="mailto:conor@apache.org">Conor MacNeill</a> |
| */ |
| public abstract class DataType extends AbstractTask { |
| private String reference = null; |
| private Object referencedObject = null; |
| |
| public void execute() throws ExecutionException { |
| validate(); |
| } |
| |
| protected void validate() throws ExecutionException { |
| } |
| |
| /** |
| * Creates an exception that indicates that refid has to be the |
| * only attribute if it is set. |
| */ |
| protected ExecutionException tooManyAttributes() { |
| return new ExecutionException("You must not specify more than one attribute" + |
| " when using refid" ); |
| } |
| |
| /** |
| * Creates an exception that indicates that this XML element must |
| * not have child elements if the refid attribute is set. |
| */ |
| protected ExecutionException noChildrenAllowed() { |
| return new ExecutionException("You must not specify nested elements when using refid"); |
| } |
| |
| /** |
| * Creates an exception that indicates the user has generated a |
| * loop of data types referencing each other. |
| */ |
| protected ExecutionException circularReference() { |
| return new ExecutionException("This data type contains a circular reference."); |
| } |
| |
| /** |
| * Makes this instance in effect a reference to another DataType |
| * instance. |
| */ |
| public void setRefid(String reference) throws ExecutionException { |
| this.reference = reference; |
| Object referencedObject = getTaskContext().getDataValue(reference); |
| |
| if (referencedObject == null) { |
| throw new ExecutionException("Unable to locate the reference specified by refid '" + |
| getReference() + "'"); |
| } |
| |
| if (!this.getClass().isAssignableFrom(referencedObject.getClass())) { |
| throw new ExecutionException("The object referenced by refid '" + |
| getReference() + "' is not compatible with this element "); |
| } |
| } |
| |
| /** |
| * Has the refid attribute of this element been set? |
| */ |
| public boolean isReference() { |
| return referencedObject != null; |
| } |
| |
| |
| protected Object getReferencedObject() throws ExecutionException { |
| if (!isReference()) { |
| throw new ExecutionException("You cannot get a referenced value from a data type " + |
| "which does not have the refid attribute"); |
| } |
| |
| return referencedObject; |
| } |
| |
| protected String getReference() { |
| return reference; |
| } |
| } |