Class AttributeValueExp

  • All Implemented Interfaces:
    Serializable, ValueExp

    public class AttributeValueExp
    extends Object
    implements ValueExp

    Represents attributes used as arguments to relational constraints. Instances of this class are usually obtained using Query.attr.

    An AttributeValueExp may be used anywhere a ValueExp is required.

    See Also:
    Serialized Form
    • Constructor Detail

      • AttributeValueExp

        public AttributeValueExp()
        An instance created with this constructor cannot be used in a query.
        An AttributeValueExp with a null attribute.
      • AttributeValueExp

        public AttributeValueExp​(String attr)
        Creates a new AttributeValueExp representing the specified object attribute, named attr.
        attr - the name of the attribute whose value is the value of this ValueExp.
    • Method Detail

      • getAttributeName

        public String getAttributeName()
        Returns a string representation of the name of the attribute.
        the attribute name.
      • toString

        public String toString()
        Returns the string representing its value.
        toString in class Object
        a string representation of the object.
      • setMBeanServer

        public void setMBeanServer​(MBeanServer s)
        This method has no effect. The MBean Server used to obtain an attribute value is QueryEval.getMBeanServer().
        Sets the MBean server on which the query is to be performed.
        Specified by:
        setMBeanServer in interface ValueExp
        s - The MBean server on which the query is to be performed.
      • getAttribute

        protected Object getAttribute​(ObjectName name)

        Return the value of the given attribute in the named MBean. If the attempt to access the attribute generates an exception, return null.

        The MBean Server used is the one returned by QueryEval.getMBeanServer().

        name - the name of the MBean whose attribute is to be returned.
        the value of the attribute, or null if it could not be obtained.