/* * JBoss, the OpenSource J2EE webOS * * Distributable under LGPL license. * See terms of license at gnu.org. */ package javax.management.modelmbean; import java.lang.reflect.Method; import java.io.IOException; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.io.ObjectStreamField; import java.io.StreamCorruptedException; import javax.management.Descriptor; import javax.management.DescriptorAccess; import javax.management.MBeanAttributeInfo; import javax.management.IntrospectionException; import org.jboss.logging.Logger; import org.jboss.mx.modelmbean.ModelMBeanConstants; import org.jboss.mx.util.Serialization; /** * Represents a Model MBean's management attribute. * * @see javax.management.MBeanAttributeInfo * * @author Juha Lindfors. * @author Adrian Brock. * @version $Revision: 1.6.4.2 $ * *

Revisions: * *

20020320 Juha Lindfors: *

* *

20020715 Adrian Brock: *

*/ public class ModelMBeanAttributeInfo extends MBeanAttributeInfo implements DescriptorAccess, Cloneable { // Attributes ---------------------------------------------------- /** * The descriptor associated with this attribute. */ private Descriptor descriptor = null; // Static -------------------------------------------------------- private static final Logger log = Logger.getLogger(ModelMBeanAttributeInfo.class); 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 Method instance representing a read method for this attribute * @param setter a Method 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...? // // TODO: We should go against the RI javadoc and create a descriptor // with the proper method mapping. [JPL] super(name, description, getter, setter); setDescriptor(createDefaultDescriptor()); } /** * Creates a new attribute info object. If a null 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 Method instance representing a read method for this attribute * @param setter a Method 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 { this(name, description, getter, setter); if (descriptor == null || !descriptor.isValid()) setDescriptor(createDefaultDescriptor()); else 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) { // JPL: As far as I can tell, the isIs boolean has no use in the Model MBean // attribute info (since attributes will map to methods through operations) // I'm setting this boolean to false, until someone complains. super(name, type, description, isReadable, isWritable, false /*isIs*/); setDescriptor(createDefaultDescriptor()); if (isIs == true) log.warn("WARNING: supplied isIS=true, set to false"); } /** * Creates a new attribute info object with a given descriptor. If a null 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) { // JPL: As far as I can tell, the isIs boolean has no use in the Model MBean // attribute info (since attributes will map to methods through operations) // I'm setting this boolean to false, until someone complains. super(name, type, description, isReadable, isWritable, false/*isIs*/); if (descriptor == null || !descriptor.isValid()) setDescriptor(createDefaultDescriptor()); else setDescriptor(descriptor); if (isIs == true) log.warn("WARNING: supplied isIS=true, set to false"); } /** * Copy constructor. * * @param inInfo 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 inDescriptor * argument is null 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()) // FIXME: give more detailed error throw new IllegalArgumentException("Invalid descriptor."); this.descriptor = inDescriptor; } // Cloneable implementation -------------------------------------- /** * Creates a copy of this object. * * @return clone of this object * @throws CloneNotSupportedException if there was a failure creating the copy */ public synchronized Object clone() throws CloneNotSupportedException { 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: 
    *
    *   ModelMBeanAttributeInfo[Name=<attribute name>,
    *   Type=<class name of the attribute type>,
    *   Access= RW | RO | WO,
    *   Descriptor=(fieldName1=fieldValue1, ... , fieldName<n>=fieldValue<n>)]
    *
    *
* * @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 with "name" field set to this * attributes name, "descriptorType" field set to "attribute" * and "currencyTimeLimit" set to -1 (always cache attributes). * * @return a default descriptor */ private Descriptor createDefaultDescriptor() { DescriptorSupport descr = new DescriptorSupport(); descr.setField(ModelMBeanConstants.NAME, super.getName()); descr.setField(ModelMBeanConstants.DESCRIPTOR_TYPE, ModelMBeanConstants.ATTRIBUTE_DESCRIPTOR); // [JPL] Setting the currencyTimeLimit to -1 for default descriptors. // This means that for attributes the resource object is never // invoked. For default descriptors this is the correct behavior // since method mapping to the resource (setMethod, getMethod) // does not exist. However, it means that if the descriptor is // changed afterwards with method mapping, the currencyTimeLimit // property should be changed as well (otherwise the methods on // the resource won't be invoked). descr.setField(ModelMBeanConstants.CURRENCY_TIME_LIMIT, "-1"); // FIXME: check the spec for all required descriptor fields! 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(); } }