User: mnf999
Date: 01/08/29 16:22:01
Added: src/main/org/jboss/system ServiceCreator.java
Log:
A helper class to create an MBean from an XML snippet
Revision Changes Path
1.1 jboss/src/main/org/jboss/system/ServiceCreator.java
Index: ServiceCreator.java
===================================================================
/*
* JBoss, the OpenSource J2EE server
*
* Distributable under LGPL license.
* See terms of license at gnu.org.
*/
package org.jboss.system;
import java.lang.reflect.Constructor;
import javax.management.ObjectName;
import javax.management.MBeanServer;
import javax.management.ObjectInstance;
import javax.management.MalformedObjectNameException;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
/**
*
* A helper class for the controller
*
* @author <a href="mailto:[EMAIL PROTECTED]";>Marc Fleury</a>
* @see org.jboss.system.Service
* @version $Revision: 1.1 $
* <p><b>Revisions:</b>
* <p><b>2001/08/03 marcf </b>
* <ol>
* <li>Initial version checked in
* </ol>
*
*/
public class ServiceCreator
{
// Attributes ----------------------------------------------------
private MBeanServer server;
public ServiceCreator(MBeanServer server) {this.server = server;}
/**
* Parses the given configuration document and creates MBean
* instances in the current MBean server.
*
* @param configuration The configuration document.
*
* @throws ConfigurationException The configuration document contains
* invalid or missing syntax.
* @throws Exception Failed for some other reason.
*/
public ObjectInstance create(Element mbeanElement) throws Exception
{
ObjectName name = parseObjectName(mbeanElement);
//marcf fixme add and remove the classlaoder from the controller
ObjectName loader = new
ObjectName("ZClassLoaders:id="+name.hashCode());
MBeanClassLoader cl = new MBeanClassLoader(name);
if (!server.isRegistered(loader))
server.registerMBean(cl, loader);
// If class is given, instantiate it
String code = mbeanElement.getAttribute("code");
if (code == null)
{
throw new ConfigurationException
("missing 'code' attribute");
}
// get the constructor params/sig to use
ConstructorInfo constructor =
ConstructorInfo.create(mbeanElement);
System.out.println("About to create the bean"+name);
// Create the MBean instance
ObjectInstance instance =
server.createMBean(code,
name,
loader,
constructor.params,
constructor.signature);
System.out.println("Created the bean"+name);
return instance;
}
/**
* Provides a wrapper around the information about which constructor
* that MBeanServer should use to construct a MBean.
* Please note that only basic datatypes (type is then the same as
* you use to declare it "short", "int", "float" etc.) and any class
* having a constructor taking a single "String" as only parameter.
*
* <p>XML syntax for contructor:
* <pre>
* <constructor>
* <arg type="xxx" value="yyy"/>
* ...
* <arg type="xxx" value="yyy"/>
* </constructor>
* </pre>
*/
private static class ConstructorInfo
{
/** An empty parameters list. */
public static final Object EMPTY_PARAMS[] = {};
/** An signature list. */
public static final String EMPTY_SIGNATURE[] = {};
/** The constructor signature. */
public String[] signature = EMPTY_SIGNATURE;
/** The constructor parameters. */
public Object[] params = EMPTY_PARAMS;
/**
* Create a ConstructorInfo object for the given configuration.
*
* @param element The element to build info for.
* @return A constructor information object.
*
* @throws ConfigurationException Failed to create info object.
*/
public static ConstructorInfo create(Element element)
throws ConfigurationException
{
ConstructorInfo info = new ConstructorInfo();
NodeList list = element.getElementsByTagName("constructor");
if (list.getLength() > 1) {
throw new ConfigurationException
("only one <constructor> element may be defined");
}
else if (list.getLength() == 1) {
element = (Element)list.item(0);
// get all of the "arg" elements
list = element.getElementsByTagName("arg");
int length = list.getLength();
info.params = new Object[length];
info.signature = new String[length];
// decode the values into params & signature
for (int j=0; j<length; j++) {
Element arg = (Element)list.item(j);
//
// NOTE: should coerce value to the correct
type??
//
// Add support for primitive Data Types
String signature = arg.getAttribute("type");
String value = arg.getAttribute("value");
Object realValue = value;
if( signature != null ) {
if( signature.equals( "short" ) ) {
signature =
Short.TYPE.getName();
realValue = new Short( value );
} else
if( signature.equals( "int" ) ) {
signature =
Integer.TYPE.getName();
realValue = new Integer( value
);
} else
if( signature.equals( "long" ) ) {
signature =
Long.TYPE.getName();
realValue = new Long( value );
} else
if( signature.equals( "byte" ) ) {
signature =
Byte.TYPE.getName();
realValue = new Byte( value );
} else
if( signature.equals( "char" ) ) {
signature =
Character.TYPE.getName();
realValue = new Character(
value.charAt( 0 ) );
} else
if( signature.equals( "float" ) ) {
signature =
Float.TYPE.getName();
realValue = new Float( value );
} else
if( signature.equals( "double" ) ) {
signature =
Double.TYPE.getName();
realValue = new Double( value
);
} else
if( signature.equals( "boolean" ) ) {
signature =
Boolean.TYPE.getName();
realValue = new Boolean( value
);
}
else
{
try {
// Check if there is a
constructor with a single String as
// only parameter
Class signatureClass =
Thread.currentThread().getContextClassLoader().loadClass( signature );
Constructor
signatureConstructor =
signatureClass.getConstructor( new Class[] { String.class } );
realValue =
signatureConstructor.newInstance(
new Object[] {
value }
);
}
catch( Exception e ) {
}
}
}
info.signature[j] = signature;
info.params[j] = realValue;
}
}
return info;
}
}
/**
* Parse an object name from the given element attribute 'name'.
*
* @param element Element to parse name from.
* @return Object name.
*
* @throws ConfigurationException Missing attribute 'name'
* (thrown if 'name' is null or "").
* @throws MalformedObjectNameException
*/
private ObjectName parseObjectName(final Element element)
throws ConfigurationException, MalformedObjectNameException
{
String name = element.getAttribute("name");
if (name == null || name.trim().equals("")) {
throw new ConfigurationException
("MBean attribute 'name' must be given.");
}
return new ObjectName(name);
}
}
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