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.
@Deprecated public AttributeValueExp()
Deprecated. An instance created with this constructor cannot be used in a query.
An AttributeValueExp
with a null attribute.
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
.public String getAttributeName()
Returns a string representation of the name of the attribute.
public ValueExp apply(ObjectName name) throws BadStringOperationException, BadBinaryOpValueExpException, BadAttributeValueExpException, InvalidApplicationException
Applies the AttributeValueExp
on an MBean. This method calls getAttribute(name)
and wraps the result as a ValueExp
. The value returned by getAttribute
must be a Number
, String
, or Boolean
; otherwise this method throws a BadAttributeValueExpException
, which will cause the containing query to be false for this name
.
apply
in interface ValueExp
name
- The name of the MBean on which the AttributeValueExp
will be applied.ValueExp
.BadAttributeValueExpException
InvalidApplicationException
BadStringOperationException
BadBinaryOpValueExpException
public String toString()
Returns the string representing its value.
@Deprecated public void setMBeanServer(MBeanServer s)
Deprecated. 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.
setMBeanServer
in interface ValueExp
s
- The MBean server on which the query is to be performed.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.
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