| ModelMBeanAttributeInfo.java |
/*
* JBoss, the OpenSource J2EE webOS
*
* Distributable under LGPL license.
* See terms of license at gnu.org.
*/
package javax.management.modelmbean;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.ObjectStreamField;
import java.io.StreamCorruptedException;
import java.lang.reflect.Method;
import javax.management.Descriptor;
import javax.management.DescriptorAccess;
import javax.management.IntrospectionException;
import javax.management.MBeanAttributeInfo;
import javax.management.RuntimeOperationsException;
import org.jboss.mx.modelmbean.ModelMBeanConstants;
import org.jboss.mx.util.Serialization;
/**
* Represents a Model MBean's management attribute.
*
* @see javax.management.MBeanAttributeInfo
*
* @author <a href="mailto:juha@jboss.org">Juha Lindfors</a>.
* @author <a href="mailto:adrian.brock@happeningtimes.com">Adrian Brock</a>.
* @author <a href="mailto:thomas.diesler@jboss.com">Thomas Diesler</a>.
* @version $Revision: 1.13.6.1 $
*
* <p><b>Revisions:</b>
*
* <p><b>20020320 Juha Lindfors:</b>
* <ul>
* <li>toString() implementation</li>
*
* <li>Changed the default descriptor to include field <tt>currencyTimeLimit</tt>
* with a value -1. Since default descriptors do not include method mapping
* this automatically caches attribute values in the Model MBean.
* </li>
* </ul>
*
* <p><b>20020715 Adrian Brock:</b>
* <ul>
* <li> Serialization
* </ul>
*/
public class ModelMBeanAttributeInfo
extends MBeanAttributeInfo
implements DescriptorAccess, Cloneable
{
// Attributes ----------------------------------------------------
/**
* The descriptor associated with this attribute.
*/
private Descriptor descriptor = null;
// Static --------------------------------------------------------
private static final long serialVersionUID;
private static final ObjectStreamField[] serialPersistentFields;
static
{
switch (Serialization.version)
{
case Serialization.V1R0:
serialVersionUID = 7098036920755973145L;
break;
default:
serialVersionUID = 6181543027787327345L;
}
serialPersistentFields = new ObjectStreamField[]
{
new ObjectStreamField("attrDescriptor", Descriptor.class)
};
}
// Constructors --------------------------------------------------
/**
* Creates a new attribute info with a default descriptor.
*
* @param name name of the attribute
* @param description human readable description string
* @param getter a <tt>Method</tt> instance representing a read method for this attribute
* @param setter a <tt>Method</tt> instance representing a write method for this attribute
*
* @throws IntrospectionException if the accessor methods are not valid for this attribute
*/
public ModelMBeanAttributeInfo(String name, String description, Method getter, Method setter)
throws IntrospectionException
{
// NOTE: This constructor provides the method mapping for
// a Model MBean attribute so the 'setMethod' and 'getMethod'
// descriptor field should be set, but the javadoc dictates a
// default descriptor...?
super(name, description, getter, setter);
setDescriptor(createDefaultDescriptor());
}
/**
* Creates a new attribute info object. If a <tt>null</tt> or
* invalid descriptor is passed as a parameter, a default descriptor will be created
* for the attribute.
*
* @param name name of the attribute
* @param description human readable description string
* @param getter a <tt>Method</tt> instance representing a read method for this attribute
* @param setter a <tt>Method</tt> instance representing a write method for this attribute
* @param descriptor a descriptor to associate with this attribute
*
* @throws IntrospectionException if the accessor methods are not valid for this attribute
*/
public ModelMBeanAttributeInfo(String name, String description, Method getter, Method setter, Descriptor descriptor)
throws IntrospectionException
{
super(name, description, getter, setter);
setDescriptor(descriptor);
}
/**
* Creates a new attribute info object with a default descriptor.
*
* @param name name of the attribute
* @param type fully qualified class name of the attribute's type
* @param description human readable description string
* @param isReadable true if attribute is readable; false otherwise
* @param isWritable true if attribute is writable; false otherwise
* @param isIs (not used for Model MBeans; false)
*/
public ModelMBeanAttributeInfo(String name, String type, String description,
boolean isReadable, boolean isWritable, boolean isIs)
{
super(name, type, description, isReadable, isWritable, isIs);
setDescriptor(createDefaultDescriptor());
}
/**
* Creates a new attribute info object with a given descriptor. If a <tt>null</tt> or invalid
* descriptor is passed as a parameter, a default descriptor will be created for the attribute.
*
* @param name name of the attribute
* @param type fully qualified class name of the attribute's type
* @param description human readable description string
* @param isReadable true if the attribute is readable; false otherwise
* @param isWritable true if the attribute is writable; false otherwise
* @param isIs (not used for Model MBeans; false)
*/
public ModelMBeanAttributeInfo(String name, String type, String description,
boolean isReadable, boolean isWritable, boolean isIs, Descriptor descriptor)
{
super(name, type, description, isReadable, isWritable, isIs);
setDescriptor(descriptor);
}
/**
* Copy constructor.
*
* @param info the attribute info to copy
*/
public ModelMBeanAttributeInfo(ModelMBeanAttributeInfo info)
{
// THS - javadoc says a default descriptor will be created but that's not
// consistent with the other *Info classes.
// I'm also assuming that getDescriptor returns a clone.
this(info.getName(), info.getType(), info.getDescription(), info.isReadable(),
info.isWritable(), info.isIs(), info.getDescriptor());
}
// DescriptorAccess implementation -------------------------------
/**
* Returns a copy of the descriptor associated with this attribute.
*
* @return a copy of this attribute's descriptor
*/
public Descriptor getDescriptor()
{
return (Descriptor)descriptor.clone();
}
/**
* Replaces the descriptor associated with this attribute. If the <tt>inDescriptor</tt>
* argument is <tt>null</tt> then the existing descriptor is replaced with a default
* descriptor.
*
* @param inDescriptor descriptor used for replacing the existing operation descriptor
* @throws IllegalArgumentException if the new descriptor is not valid
*/
public void setDescriptor(Descriptor inDescriptor)
{
if (inDescriptor == null)
inDescriptor = createDefaultDescriptor();
if (inDescriptor.isValid() && isAttributeDescriptorValid(inDescriptor))
this.descriptor = inDescriptor;
}
/**
* Validate the descriptor in the context of an attribute
*/
private boolean isAttributeDescriptorValid(Descriptor inDescriptor)
{
String name = (String)inDescriptor.getFieldValue(ModelMBeanConstants.NAME);
if (name.equals(getName()) == false)
throw new RuntimeOperationsException (new IllegalArgumentException("Invalid name, expected '" + getName() + "' but got: " + name));
String descriptorType = (String)inDescriptor.getFieldValue(ModelMBeanConstants.DESCRIPTOR_TYPE);
if (ModelMBeanConstants.ATTRIBUTE_DESCRIPTOR.equalsIgnoreCase(descriptorType) == false)
throw new RuntimeOperationsException (new IllegalArgumentException("Invalid descriptorType, for attribute '" + name + "' expected 'attribute' but got: " + descriptorType));
return true;
}
// Cloneable implementation --------------------------------------
/**
* Creates a copy of this object.
*
* @return clone of this object
*/
public synchronized Object clone()
{
ModelMBeanAttributeInfo clone = (ModelMBeanAttributeInfo)super.clone();
clone.descriptor = (Descriptor)this.descriptor.clone();
return clone;
}
// Object override -----------------------------------------------
/**
* Returns a string representation of this Model MBean attribute info object.
* The returned string is in the form: <pre>
*
* ModelMBeanAttributeInfo[Name=<attribute name>,
* Type=<class name of the attribute type>,
* Access= RW | RO | WO,
* Descriptor=(fieldName1=fieldValue1, ... , fieldName<n>=fieldValue<n>)]
*
* </pre>
*
* @return string representation of this object
*/
public String toString()
{
return "ModelMBeanAttributeInfo[" +
"Name=" + getName() +
",Type=" + getType() +
",Access=" + ((isReadable() && isWritable()) ? "RW" : (isReadable()) ? "RO" : "WO") +
",Descriptor(" + getDescriptor() + ")]";
}
// Private -------------------------------------------------------
/**
* Creates a default descriptor.
*/
private Descriptor createDefaultDescriptor()
{
DescriptorSupport descr = new DescriptorSupport();
descr.setField(ModelMBeanConstants.NAME, super.getName());
descr.setField(ModelMBeanConstants.DESCRIPTOR_TYPE, ModelMBeanConstants.ATTRIBUTE_DESCRIPTOR);
descr.setField(ModelMBeanConstants.DISPLAY_NAME, super.getName());
return descr;
}
private void readObject(ObjectInputStream ois)
throws IOException, ClassNotFoundException
{
ObjectInputStream.GetField getField = ois.readFields();
descriptor = (Descriptor) getField.get("attrDescriptor", null);
if (descriptor == null)
throw new StreamCorruptedException("Null descriptor?");
}
private void writeObject(ObjectOutputStream oos)
throws IOException
{
ObjectOutputStream.PutField putField = oos.putFields();
putField.put("attrDescriptor", descriptor);
oos.writeFields();
}
}
| ModelMBeanAttributeInfo.java |