craigmcc 01/08/04 16:46:30
Modified: digester/src/java/org/apache/commons/digester Digester.java
Added: digester/src/java/org/apache/commons/digester
FactoryCreateRule.java ObjectCreationFactory.java
Log:
Add a new standard Rule implementation that lets you specify a factory
class that uses the XML attributes of the matched element to create and
configure the ultimate object that is then pushed onto the stack (at
element start) and then popped (at element end), similar to
ObjectCreateRule.
I extended Robert's original implementation to allow for the case where
your ObjectCreationFactory class might itself have a zero-args
constructor, and where you might want to dynamically select the name of
the factory class in the XML document being parsed. In addition, I added
convenience rule registration methods into Digester to match the available
FactoryCreateRule constructors.
Submitted by: Robert Burrell Donkin
Revision Changes Path
1.11 +51 -4
jakarta-commons/digester/src/java/org/apache/commons/digester/Digester.java
Index: Digester.java
===================================================================
RCS file:
/home/cvs/jakarta-commons/digester/src/java/org/apache/commons/digester/Digester.java,v
retrieving revision 1.10
retrieving revision 1.11
diff -u -r1.10 -r1.11
--- Digester.java 2001/08/04 23:14:57 1.10
+++ Digester.java 2001/08/04 23:46:29 1.11
@@ -1,7 +1,7 @@
/*
- * $Header:
/home/cvs/jakarta-commons/digester/src/java/org/apache/commons/digester/Digester.java,v
1.10 2001/08/04 23:14:57 craigmcc Exp $
- * $Revision: 1.10 $
- * $Date: 2001/08/04 23:14:57 $
+ * $Header:
/home/cvs/jakarta-commons/digester/src/java/org/apache/commons/digester/Digester.java,v
1.11 2001/08/04 23:46:29 craigmcc Exp $
+ * $Revision: 1.11 $
+ * $Date: 2001/08/04 23:46:29 $
*
* ====================================================================
*
@@ -106,7 +106,7 @@
*
* @author Craig McClanahan
* @author Scott Sanders
- * @version $Revision: 1.10 $ $Date: 2001/08/04 23:14:57 $
+ * @version $Revision: 1.11 $ $Date: 2001/08/04 23:46:29 $
*/
public class Digester extends DefaultHandler {
@@ -1114,6 +1114,53 @@
addRule(pattern,
new CallParamRule(this, paramIndex, attributeName));
+
+ }
+
+
+ /**
+ * Add a "factory create" rule for the specified parameters.
+ *
+ * @param pattern Element matching pattern
+ * @param className Java class name of the object creation factory class
+ */
+ public void addFactoryCreate(String pattern, String className) {
+
+ addRule(pattern,
+ new FactoryCreateRule(this, className));
+
+ }
+
+
+ /**
+ * Add a "factory create" rule for the specified parameters.
+ *
+ * @param pattern Element matching pattern
+ * @param className Java class name of the object creation factory class
+ * @param attributeName Attribute name which, if present, overrides the
+ * value specified by <code>className</code>
+ */
+ public void addFactoryCreate(String pattern, String className,
+ String attributeName) {
+
+ addRule(pattern,
+ new FactoryCreateRule(this, className, attributeName));
+
+ }
+
+
+ /**
+ * Add a "factory create" rule for the specified parameters.
+ *
+ * @param pattern Element matching pattern
+ * @param creationFactory Previously instantiated ObjectCreationFactory
+ * to be utilized
+ */
+ public void addFactoryCreate(String pattern,
+ ObjectCreationFactory creationFactory) {
+
+ addRule(pattern,
+ new FactoryCreateRule(this, creationFactory));
}
1.1
jakarta-commons/digester/src/java/org/apache/commons/digester/FactoryCreateRule.java
Index: FactoryCreateRule.java
===================================================================
/*
* ====================================================================
*
* The Apache Software License, Version 1.1
*
* Copyright (c) 1999-2001 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", "Commons", 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 [EMAIL PROTECTED]
*
* 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.commons.digester;
import java.lang.ClassLoader;
import org.xml.sax.Attributes;
/**
* <p>Rule implementation that uses an {@link ObjectCreationFactory} to create
* a new object which it pushes onto the object stack. When the element is
* complete, the object will be popped.</p>
*
* <p>This rule is intended in situations where the element's attributes are
* needed before the object can be created. A common senario is for the
* ObjectCreationFactory implementation to use the attributes as parameters
* in a call to either a factory method or to a non-empty constructor.
*
* @author Robert Burrell Donkin
* @version $Revision: 1.1 $ $Date: 2001/08/04 23:46:29 $
*/
public class FactoryCreateRule extends Rule {
// ----------------------------------------------------------- Constructors
/**
* Construct a factory create rule that will use the specified
* class name to create an {@link ObjectCreationFactory} which will
* then be used to create an object and push it on the stack.
*
* @param digester The associated Digester
* @param className Java class name of the object creation factory class
*/
public FactoryCreateRule(Digester digester, String className) {
this(digester, className, null);
}
/**
* Construct a factory create rule that will use the specified
* class name (possibly overridden by the specified attribute if present)
* to create an {@link ObjectCreationFactory}, which will then be used
* to instantiate an object instance and push it onto the stack.
*
* @param digester The associated Digester
* @param className Default Java class name of the factory class
* @param attributeName Attribute name which, if present, contains an
* override of the class name of the object creation factory to create.
*/
public FactoryCreateRule(Digester digester,
String className, String attributeName) {
super(digester);
this.className = className;
this.attributeName = attributeName;
}
/**
* Construct a factory create rule using the given, already instantiated,
* {@link ObjectCreationFactory}.
*
* @param digester The associated Digester
* @param creationFactory called on to create the object.
*/
public FactoryCreateRule(Digester digester,
ObjectCreationFactory creationFactory) {
super(digester);
this.creationFactory = creationFactory;
}
// ----------------------------------------------------- Instance Variables
/**
* The attribute containing an override class name if it is present.
*/
protected String attributeName = null;
/**
* The Java class name of the ObjectCreationFactory to be created.
* This class must have a no-arguments constructor.
*/
protected String className = null;
/**
* The object creation factory we will use to instantiate objects
* as required based on the attributes specified in the matched XML
* element.
*/
protected ObjectCreationFactory creationFactory = null;
// --------------------------------------------------------- Public Methods
/**
* Process the beginning of this element.
*
* @param attributes The attribute list of this element
*/
public void begin(Attributes attributes) throws Exception {
Object instance = getFactory(attributes).createObject(attributes);
if (digester.getDebug() >= 1)
digester.log("New " + instance.getClass().getName());
digester.push(instance);
}
/**
* Process the end of this element.
*/
public void end() throws Exception {
Object top = digester.pop();
if (digester.getDebug() >= 1)
digester.log("Pop " + top.getClass().getName());
}
/**
* Clean up after parsing is complete.
*/
public void finish() throws Exception {
creationFactory = null;
}
// ------------------------------------------------------ Protected Methods
/**
* Return an instance of our associated object creation factory,
* creating one if necessary.
*
* @param attributes Attributes passed to our factory creation element
*
* @exception Exception if any error occurs
*/
protected ObjectCreationFactory getFactory(Attributes attributes)
throws Exception {
if (creationFactory == null) {
String realClassName = className;
if (attributeName != null) {
String value = attributes.getValue(attributeName);
if (value != null)
realClassName = value;
}
if (digester.getDebug() >= 1)
digester.log("New factory " + realClassName);
Class clazz = digester.getClassLoader().loadClass(realClassName);
creationFactory = (ObjectCreationFactory)
clazz.newInstance();
}
return (creationFactory);
}
}
1.1
jakarta-commons/digester/src/java/org/apache/commons/digester/ObjectCreationFactory.java
Index: ObjectCreationFactory.java
===================================================================
/*
* ====================================================================
*
* The Apache Software License, Version 1.1
*
* Copyright (c) 1999-2001 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", "Commons", 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 [EMAIL PROTECTED]
*
* 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.commons.digester;
import java.lang.ClassLoader;
import org.xml.sax.Attributes;
/**
* <p> Interface for use with {@link FactoryCreateRule}.
*
* @author Robert Burrell Donkin
* @version $Revision: 1.1 $ $Date: 2001/08/04 23:46:29 $
*/
public interface ObjectCreationFactory
{
/**
* <p>Factory method called by {@link FactoryCreateRule} to supply an
* object based on the element's attributes.
*
* @param attributes the element's attributes
*/
Object createObject(Attributes attributes);
}
