| /* |
| * The Apache Software License, Version 1.1 |
| * |
| * Copyright (c) 2000-2001 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.tools.ant.types; |
| |
| |
| import java.util.Stack; |
| import org.apache.tools.ant.BuildException; |
| import org.apache.tools.ant.Project; |
| import org.apache.tools.ant.ProjectComponent; |
| |
| /** |
| * Base class for those classes that can appear inside the build file |
| * as stand alone data types. |
| * |
| * <p>This class handles the common description attribute and provides |
| * a default implementation for reference handling and checking for |
| * circular references that is appropriate for types that can not be |
| * nested inside elements of the same type (i.e. <patternset> |
| * but not <path>).</p> |
| * |
| * @author <a href="mailto:stefan.bodewig@epost.de">Stefan Bodewig</a> |
| */ |
| public abstract class DataType extends ProjectComponent { |
| /** |
| * The descriptin the user has set. |
| */ |
| protected String description = null; |
| /** |
| * Value to the refid attribute. |
| */ |
| protected Reference ref = null; |
| /** |
| * Are we sure we don't hold circular references? |
| * |
| * <p>Subclasses are responsible for setting this value to false |
| * if we'd need to investigate this condition (usually because a |
| * child element has been added that is a subclass of |
| * DataType).</p> |
| */ |
| protected boolean checked = true; |
| |
| /** |
| * Sets a description of the current data type. It will be useful |
| * in commenting what we are doing. |
| */ |
| public void setDescription( String desc ) { |
| description=desc; |
| } |
| |
| /** |
| * Return the description for the current data type. |
| */ |
| public String getDescription() { |
| return description; |
| } |
| |
| /** |
| * Has the refid attribute of this element been set? |
| */ |
| public boolean isReference() { |
| return ref != null; |
| } |
| |
| /** |
| * Set the value of the refid attribute. |
| * |
| * <p>Subclasses may need to check whether any other attributes |
| * have been set as well or child elements have been created and |
| * thus override this method. if they do the must call |
| * <code>super.setRefid</code>.</p> |
| */ |
| public void setRefid(Reference ref) { |
| this.ref = ref; |
| checked = false; |
| } |
| |
| /** |
| * Check to see whether any DataType we hold references to is |
| * included in the Stack (which holds all DataType instances that |
| * directly or indirectly reference this instance, including this |
| * instance itself). |
| * |
| * <p>If one is included, throw a BuildException created by {@link |
| * #circularReference circularReference}.</p> |
| * |
| * <p>This implementation is appropriate only for a DataType that |
| * cannot hold other DataTypes as children.</p> |
| * |
| * <p>The general contract of this method is that it shouldn't do |
| * anything if {@link #checked <code>checked</code>} is true and |
| * set it to true on exit.</p> |
| */ |
| protected void dieOnCircularReference(Stack stk, Project p) |
| throws BuildException { |
| |
| if (checked || !isReference()) { |
| return; |
| } |
| Object o = ref.getReferencedObject(p); |
| |
| if (o instanceof DataType) { |
| if (stk.contains(o)) { |
| throw circularReference(); |
| } else { |
| stk.push(o); |
| ((DataType) o).dieOnCircularReference(stk, p); |
| stk.pop(); |
| } |
| } |
| checked = true; |
| } |
| |
| /** |
| * Performs the check for circular references and returns the |
| * referenced object. |
| */ |
| protected Object getCheckedRef(Class requiredClass, String dataTypeName) { |
| if (!checked) { |
| Stack stk = new Stack(); |
| stk.push(this); |
| dieOnCircularReference(stk, getProject()); |
| } |
| |
| Object o = ref.getReferencedObject(getProject()); |
| if (!(requiredClass.isAssignableFrom(o.getClass()))) { |
| String msg = ref.getRefId()+" doesn\'t denote a " + dataTypeName; |
| throw new BuildException(msg); |
| } else { |
| return o; |
| } |
| } |
| |
| /** |
| * Creates an exception that indicates that refid has to be the |
| * only attribute if it is set. |
| */ |
| protected BuildException tooManyAttributes() { |
| return new BuildException( "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 BuildException noChildrenAllowed() { |
| return new BuildException("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 BuildException circularReference() { |
| return new BuildException("This data type contains a circular reference."); |
| } |
| } |
