src/java.management/share/classes/javax/management/QualifiedAttributeValueExp.java

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
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 *
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package javax.management;


/**
 * <p>Represents attributes used as arguments to relational constraints,
 * where the attribute must be in an MBean of a specified {@linkplain
 * MBeanInfo#getClassName() class}. A QualifiedAttributeValueExp may be used
 * anywhere a ValueExp is required.
 *
 * @serial include
 *
 * @since 1.5
 */
class QualifiedAttributeValueExp extends AttributeValueExp   {


    /* Serial version */
    private static final long serialVersionUID = 8832517277410933254L;

    /**
     * @serial The attribute class name
     */
    private String className;


    /**
     * Basic Constructor.
     * @deprecated see {@link AttributeValueExp#AttributeValueExp()}
     */
    @Deprecated
    public QualifiedAttributeValueExp() {
    }

    /**
     * Creates a new QualifiedAttributeValueExp representing the specified object
     * attribute, named attr with class name className.
     */
    public QualifiedAttributeValueExp(String className, String attr) {
        super(attr);
        this.className = className;
    }


    /**
     * Returns a string representation of the class name of the attribute.
     */
    public String getAttrClassName()  {
        return className;
    }

    /**
     * Applies the QualifiedAttributeValueExp to an MBean.
     *
     * @param name The name of the MBean on which the QualifiedAttributeValueExp will be applied.
     *
     * @return  The ValueExp.
     *
     * @exception BadStringOperationException
     * @exception BadBinaryOpValueExpException
     * @exception BadAttributeValueExpException
     * @exception InvalidApplicationException
     */
    @Override
    public ValueExp apply(ObjectName name) throws BadStringOperationException, BadBinaryOpValueExpException,
        BadAttributeValueExpException, InvalidApplicationException  {
        try {
            MBeanServer server = QueryEval.getMBeanServer();
            String v = server.getObjectInstance(name).getClassName();

            if (v.equals(className)) {
                return super.apply(name);
            }
            throw new InvalidApplicationException("Class name is " + v +
                                                  ", should be " + className);

        } catch (Exception e) {
            throw new InvalidApplicationException("Qualified attribute: " + e);
            /* Can happen if MBean disappears between the time we
               construct the list of MBeans to query and the time we
               evaluate the query on this MBean, or if
               getObjectInstance throws SecurityException.  */
        }
    }

    /**
     * Returns the string representing its value
     */
    @Override
    public String toString()  {
        if (className != null) {
            return className + "." + super.toString();
        } else {
            return super.toString();
        }
    }

}