File	Doc	Category	Size	Date	Package
MBeanInfo.java	API Doc	Java SE 5 API	16898	Fri Aug 26 14:57:32 BST 2005	javax.management

MBeanInfo

• java.lang.Object

Fields Summary
static final long	serialVersionUID
private final String	description
private final String	className
private final MBeanAttributeInfo[]	attributes
private final MBeanOperationInfo[]	operations
private final MBeanConstructorInfo[]	constructors
private final MBeanNotificationInfo[]	notifications
private transient int	hashCode
private final transient boolean	immutable True if this class is known not to override the getters of MBeanInfo. Obviously true for MBeanInfo itself, and true for a subclass where we succeed in reflecting on the methods and discover they are not overridden. The purpose of this variable is to avoid cloning the arrays when doing operations like {@link #equals} where we know they will not be changed. If a subclass overrides a getter, we cannot access the corresponding array directly.
private static final Map	immutability Cached results of previous calls to isImmutableClass. Maps Class to Boolean. This is a WeakHashMap so that we don't prevent a class from being garbage collected just because we know whether it's immutable.

Constructors Summary

public MBeanInfo(String className, String description, MBeanAttributeInfo[] attributes, MBeanConstructorInfo[] constructors, MBeanOperationInfo[] operations, MBeanNotificationInfo[] notifications) Constructs an MBeanInfo. param className The name of the Java class of the MBean described by this MBeanInfo. This value may be any syntactically legal Java class name. It does not have to be a Java class known to the MBean server or to the MBean's ClassLoader. If it is a Java class known to the MBean's ClassLoader, it is recommended but not required that the class's public methods include those that would appear in a Standard MBean implementing the attributes and operations in this MBeanInfo. param description A human readable description of the MBean (optional). param attributes The list of exposed attributes of the MBean. This may be null with the same effect as a zero-length array. param constructors The list of public constructors of the MBean. This may be null with the same effect as a zero-length array. param operations The list of operations of the MBean. This may be null with the same effect as a zero-length array. param notifications The list of notifications emitted. This may be null with the same effect as a zero-length array. this.className = className; this.description = description; if (attributes == null) attributes = MBeanAttributeInfo.NO_ATTRIBUTES; this.attributes = attributes; if (operations == null) operations = MBeanOperationInfo.NO_OPERATIONS; this.operations = operations; if (constructors == null) constructors = MBeanConstructorInfo.NO_CONSTRUCTORS; this.constructors = constructors; if (notifications == null) notifications = MBeanNotificationInfo.NO_NOTIFICATIONS; this.notifications = notifications; this.immutable = isImmutableClass(this.getClass(), MBeanInfo.class);

Methods Summary
private static int	arrayHashCode(java.lang.Object[] array) int hash = 0; for (int i = 0; i < array.length; i++) hash ^= array[i].hashCode(); return hash;
public java.lang.Object	clone() Returns a shallow clone of this instance. The clone is obtained by simply calling super.clone(), thus calling the default native shallow cloning mechanism implemented by Object.clone(). No deeper cloning of any internal field is made. Since this class is immutable, the clone method is chiefly of interest to subclasses. try { return super.clone() ; } catch (CloneNotSupportedException e) { // should not happen as this class is cloneable return null; }
public boolean	equals(java.lang.Object o) Compare this MBeanInfo to another. Two MBeanInfo objects are equal iff they return equal values for {@link #getClassName()} and for {@link #getDescription()}, and the arrays returned by the two objects for {@link #getAttributes()}, {@link #getOperations()}, {@link #getConstructors()}, and {@link #getNotifications()} are pairwise equal. Here "equal" means {@link Object#equals(Object)}, not identity. If two MBeanInfo objects return the same values in one of their arrays but in a different order then they are not equal. param o the object to compare to. return true iff o is an MBeanInfo that is equal to this one according to the rules above. if (o == this) return true; if (!(o instanceof MBeanInfo)) return false; MBeanInfo p = (MBeanInfo) o; if (!p.getClassName().equals(getClassName()) || !p.getDescription().equals(getDescription())) return false; return (Arrays.equals(p.fastGetAttributes(), fastGetAttributes()) && Arrays.equals(p.fastGetOperations(), fastGetOperations()) && Arrays.equals(p.fastGetConstructors(), fastGetConstructors()) && Arrays.equals(p.fastGetNotifications(), fastGetNotifications()));
private javax.management.MBeanAttributeInfo[]	fastGetAttributes() if (immutable) return nonNullAttributes(); else return getAttributes();
private javax.management.MBeanConstructorInfo[]	fastGetConstructors() if (immutable) return nonNullConstructors(); else return getConstructors();
private javax.management.MBeanNotificationInfo[]	fastGetNotifications() if (immutable) return nonNullNotifications(); else return getNotifications();
private javax.management.MBeanOperationInfo[]	fastGetOperations() if (immutable) return nonNullOperations(); else return getOperations();
public javax.management.MBeanAttributeInfo[]	getAttributes() Returns the list of attributes exposed for management. Each attribute is described by an MBeanAttributeInfo object. The returned array is a shallow copy of the internal array, which means that it is a copy of the internal array of references to the MBeanAttributeInfo objects but that each referenced MBeanAttributeInfo object is not copied. return An array of MBeanAttributeInfo objects. MBeanAttributeInfo[] as = nonNullAttributes(); if (as.length == 0) return as; else return (MBeanAttributeInfo[]) as.clone();
public java.lang.String	getClassName() Returns the name of the Java class of the MBean described by this MBeanInfo. return the class name. return className;
public javax.management.MBeanConstructorInfo[]	getConstructors() Returns the list of the public constructors of the MBean. Each constructor is described by an MBeanConstructorInfo object. The returned array is a shallow copy of the internal array, which means that it is a copy of the internal array of references to the MBeanConstructorInfo objects but that each referenced MBeanConstructorInfo object is not copied. The returned list is not necessarily exhaustive. That is, the MBean may have a public constructor that is not in the list. In this case, the MBean server can construct another instance of this MBean's class using that constructor, even though it is not listed here. return An array of MBeanConstructorInfo objects. MBeanConstructorInfo[] cs = nonNullConstructors(); if (cs.length == 0) return cs; else return (MBeanConstructorInfo[]) cs.clone();
public java.lang.String	getDescription() Returns a human readable description of the MBean. return the description. return description;
public javax.management.MBeanNotificationInfo[]	getNotifications() Returns the list of the notifications emitted by the MBean. Each notification is described by an MBeanNotificationInfo object. The returned array is a shallow copy of the internal array, which means that it is a copy of the internal array of references to the MBeanNotificationInfo objects but that each referenced MBeanNotificationInfo object is not copied. return An array of MBeanNotificationInfo objects. MBeanNotificationInfo[] ns = nonNullNotifications(); if (ns.length == 0) return ns; else return (MBeanNotificationInfo[]) ns.clone();
public javax.management.MBeanOperationInfo[]	getOperations() Returns the list of operations of the MBean. Each operation is described by an MBeanOperationInfo object. The returned array is a shallow copy of the internal array, which means that it is a copy of the internal array of references to the MBeanOperationInfo objects but that each referenced MBeanOperationInfo object is not copied. return An array of MBeanOperationInfo objects. MBeanOperationInfo[] os = nonNullOperations(); if (os.length == 0) return os; else return (MBeanOperationInfo[]) os.clone();
public int	hashCode() /* Since computing the hashCode is quite expensive, we cache it. If by some terrible misfortune the computed value is 0, the caching won't work and we will recompute it every time. We don't bother synchronizing, because, at worst, n different threads will compute the same hashCode at the same time. */ if (hashCode != 0) return hashCode; hashCode = getClassName().hashCode() ^ arrayHashCode(fastGetAttributes()) ^ arrayHashCode(fastGetOperations()) ^ arrayHashCode(fastGetConstructors()) ^ arrayHashCode(fastGetNotifications()); return hashCode;
static boolean	isImmutableClass(java.lang.Class subclass, java.lang.Class immutableClass) Return true if subclass is known to preserve the immutability of immutableClass. The class immutableClass is a reference class that is known to be immutable. The subclass subclass is considered immutable if it does not override any public method of immutableClass whose name begins with "get" or "is". This is obviously not an infallible test for immutability, but it works for the public interfaces of the MBean*Info classes. if (subclass == immutableClass) return true; synchronized (immutability) { Boolean immutable = (Boolean) immutability.get(subclass); if (immutable == null) { try { PrivilegedAction immutabilityAction = new ImmutabilityAction(subclass, immutableClass); immutable = (Boolean) AccessController.doPrivileged(immutabilityAction); } catch (Exception e) { // e.g. SecurityException /* We don't know, so we assume it isn't. */ immutable = Boolean.FALSE; } immutability.put(subclass, immutable); } return immutable.booleanValue(); }
private javax.management.MBeanAttributeInfo[]	nonNullAttributes() Return the value of the attributes field, or an empty array if the field is null. This can't happen with a normally-constructed instance of this class, but can if the instance was deserialized from another implementation that allows the field to be null. It would be simpler if we enforced the class invariant that these fields cannot be null by writing a readObject() method, but that would require us to define the various array fields as non-final, which is annoying because conceptually they are indeed final. return (attributes == null) ? MBeanAttributeInfo.NO_ATTRIBUTES : attributes;
private javax.management.MBeanConstructorInfo[]	nonNullConstructors() return (constructors == null) ? MBeanConstructorInfo.NO_CONSTRUCTORS : constructors;
private javax.management.MBeanNotificationInfo[]	nonNullNotifications() return (notifications == null) ? MBeanNotificationInfo.NO_NOTIFICATIONS : notifications;
private javax.management.MBeanOperationInfo[]	nonNullOperations() return (operations == null) ? MBeanOperationInfo.NO_OPERATIONS : operations;