/*
 * Copyright (c) 2005, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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package javax.management;


/**
 * This class is used by the query building mechanism for isInstanceOf expressions.
 * @serial include
 *
 * @since 1.6
 */
class InstanceOfQueryExp extends QueryEval implements QueryExp {

 /* Serial version */
 private static final long serialVersionUID = -1081892073854801359L;

 /**
 * @serial The {@link StringValueExp} returning the name of the class
 * of which selected MBeans should be instances.
 */
 private StringValueExp classNameValue;

 /**
 * Creates a new InstanceOfExp with a specific class name.
 * @param classNameValue The {@link StringValueExp} returning the name of
 * the class of which selected MBeans should be instances.
 */
 // We are using StringValueExp here to be consistent with other queries,
 // although we should actually either use a simple string (the classname)
 // or a ValueExp - which would allow more complex queries - like for
 // instance evaluating the class name from an AttributeValueExp.
 // As it stands - using StringValueExp instead of a simple constant string
 // doesn't serve any useful purpose besides offering a consistent
 // look & feel.
 public InstanceOfQueryExp(StringValueExp classNameValue) {
 if (classNameValue == null) {
 throw new IllegalArgumentException("Null class name.");
 }

 this.classNameValue = classNameValue;
 }

 /**
 * Returns the class name.
 * @returns The {@link StringValueExp} returning the name of
 * the class of which selected MBeans should be instances.
 */
 public StringValueExp getClassNameValue() {
 return classNameValue;
 }

 /**
 * Applies the InstanceOf on a MBean.
 *
 * @param name The name of the MBean on which the InstanceOf will be applied.
 *
 * @return True if the MBean specified by the name is instance of the class.
 * @exception BadAttributeValueExpException
 * @exception InvalidApplicationException
 * @exception BadStringOperationException
 * @exception BadBinaryOpValueExpException
 */
 public boolean apply(ObjectName name)
 throws BadStringOperationException,
 BadBinaryOpValueExpException,
 BadAttributeValueExpException,
 InvalidApplicationException {

 // Get the class name value
 final StringValueExp val;
 try {
 val = (StringValueExp) classNameValue.apply(name);
 } catch (ClassCastException x) {
 // Should not happen - unless someone wrongly implemented
 // StringValueExp.apply().
 final BadStringOperationException y =
 new BadStringOperationException(x.toString());
 y.initCause(x);
 throw y;
 }

 // Test whether the MBean is an instance of that class.
 try {
 return getMBeanServer().isInstanceOf(name, val.getValue());
 } catch (InstanceNotFoundException infe) {
 return false;
 }
 }

 /**
 * Returns a string representation of this InstanceOfQueryExp.
 * @return a string representation of this InstanceOfQueryExp.
 */
 public String toString() {
 return "InstanceOf " + classNameValue.toString();
 }
}