<html><head><title>javax.management.openmbean package</title><!--Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. This code is free software; you can redistribute it and/or modify itunder the terms of the GNU General Public License version 2 only, aspublished by the Free Software Foundation.  Oracle designates thisparticular file as subject to the "Classpath" exception as providedby Oracle in the LICENSE file that accompanied this code. This code is distributed in the hope that it will be useful, but WITHOUTANY WARRANTY; without even the implied warranty of MERCHANTABILITY orFITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public Licenseversion 2 for more details (a copy is included in the LICENSE file thataccompanied this code). You should have received a copy of the GNU General Public License version2 along with this work; if not, write to the Free Software Foundation,Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USAor visit www.oracle.com if you need additional information or have anyquestions.--></head><body bgcolor="white">     <p>Provides the open data types and Open MBean descriptor classes.      An <em>Open MBean</em> is an MBean where the types of attributes      and of operation parameters and return values are built using a      small set of predefined Java classes.  Open MBeans facilitate      operation with remote management programs that do not necessarily      have access to application-specific types, including non-Java      programs.</p>     <p>Every MBean has an {@link javax.management.MBeanInfo      MBeanInfo} with information about the MBean itself, and its      attributes, operations, constructors, and notifications.  In an      Open MBean, this <code>MBeanInfo</code> implements the {@link      javax.management.openmbean.OpenMBeanInfo OpenMBeanInfo}      interface, usually by being an instance of {@link      javax.management.openmbean.OpenMBeanInfoSupport      OpenMBeanInfoSupport}.</p>     <p>The attribute information returned by {@link      javax.management.MBeanInfo#getAttributes()      MBeanInfo.getAttributes} for an Open MBean is an array of      objects implementing {@link      javax.management.openmbean.OpenMBeanAttributeInfo      OpenMBeanAttributeInfo}, usually instances of {@link      javax.management.openmbean.OpenMBeanAttributeInfoSupport      OpenMBeanAttributeInfoSupport}.  In addition to the usual      information about attributes, an      <code>OpenMBeanAttributeInfo</code> specifies the {@link      javax.management.openmbean.OpenType OpenType} of the attribute.      The possible <code>OpenType</code> values are predefined, which      is what ensures that remote managers will understand them.</p>     <p>Similar remarks apply to the parameter types of operations and      constructors, and to the return types of operations.</p>     <p>There is a distinction between an attribute's Java language      type, as returned by {@link      javax.management.MBeanAttributeInfo#getType() getType()}, and      its <code>OpenType</code>, as returned by {@link      javax.management.openmbean.OpenMBeanAttributeInfo#getOpenType()      getOpenType()}.  For example, if the Java language type is      <code>java.lang.String</code>, the <code>OpenType</code> will be      {@link javax.management.openmbean.SimpleType#STRING      SimpleType.String}.  If the Java language type is {@link      javax.management.openmbean.CompositeData}, the      <code>OpenType</code> will be a {@link      javax.management.openmbean.CompositeType CompositeType} that      describes the items in the <code>CompositeData</code> instances      for the attribute.</p>     <h2><a name="constraints">Default values and constraints</a></h2>     <p>In Open MBeans, attributes and parameters can have default values      and/or constraints associated with them in the {@code      OpenMBeanAttributeInfo} or {@code OpenMBeanParameterInfo}.      There are two ways to specify these constraints.  Either the      values are directly specified as parameters to one of the      constructors of {@code OpenMBeanAttributeInfoSupport} or      {@code OpenMBeanParameterInfoSupport}, for example      {@link      javax.management.openmbean.OpenMBeanParameterInfoSupport#OpenMBeanParameterInfoSupport(      String, String, OpenType, Object, Object[])}; or the values are      specified in a {@link javax.management.Descriptor Descriptor} given      as a parameter to one of the constructors.</p>     <p>When a {@code Descriptor} is used, the fields of interest are      these:</p>     <ul>       <li>{@code defaultValue} defines the value returned by	{@link javax.management.openmbean.OpenMBeanParameterInfo#getDefaultValue()	getDefaultValue()};       <li>{@code minValue} defines the value returned by {@link	javax.management.openmbean.OpenMBeanParameterInfo#getMinValue() getMinValue()};       <li>{@code maxValue} defines the value returned by {@link	javax.management.openmbean.OpenMBeanParameterInfo#getMaxValue() getMaxValue()};       <li>{@code legalValues} defines the values returned by {@link	javax.management.openmbean.OpenMBeanParameterInfo#getLegalValues() getLegalValues()}.     </ul>     <p>For {@code defaultValue}, {@code minValue}, and {@code      maxValue}, the associated value must either be of the Java type      corresponding to {@code openType}, or be a string that can be      converted into that type.  The conversion uses the static method      {@code valueOf(String)} if it finds one; otherwise a constructor      with a single {@code String} parameter if it finds one; otherwise      it fails.</p>     <p>For {@code legalValues}, the associated value must be either      an array or a {@code Set}, and the elements of the array or set      must be convertible as described for {@code defaultValue} etc.</p>     <p>The following conditions must be met for these fields:</p>     <ul>      <li>the values must be of the appropriate type, or be strings	that can be converted to the appropriate type as explained	above;       <li>if {@code legalValues} is present then neither {@code	minValue} nor {@code maxValue} must be present;       <li>if {@code defaultValue} is present then it must satisfy the	constraints defined by {@code legalValues}, {@code minValue}, or	{@code maxValue} when any of these is also present;       <li>if {@code minValue} and {@code maxValue} are both present	then {@code minValue} must not be greater than {@code maxValue}.    </ul>     @see <a href="{@docRoot}/../technotes/guides/jmx/">      Java Platform documentation on JMX technology</a>,    in particular the     <a href="{@docRoot}/../technotes/guides/jmx/JMX_1_4_specification.pdf">      JMX Specification, version 1.4</a>     @since 1.5 </BODY></HTML>