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330 lines
11 KiB
Java
330 lines
11 KiB
Java
/*-
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* Copyright (C) 2002, 2017, Oracle and/or its affiliates. All rights reserved.
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*
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* This file was distributed by Oracle as part of a version of Oracle Berkeley
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* DB Java Edition made available at:
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*
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* http://www.oracle.com/technetwork/database/database-technologies/berkeleydb/downloads/index.html
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*
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* Please see the LICENSE file included in the top-level directory of the
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* appropriate version of Oracle Berkeley DB Java Edition for a copy of the
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* license and additional information.
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*/
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package jmx;
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import java.io.File;
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import java.lang.reflect.Constructor;
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import java.util.List;
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import javax.management.Attribute;
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import javax.management.AttributeList;
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import javax.management.AttributeNotFoundException;
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import javax.management.DynamicMBean;
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import javax.management.InvalidAttributeValueException;
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import javax.management.MBeanAttributeInfo;
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import javax.management.MBeanConstructorInfo;
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import javax.management.MBeanException;
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import javax.management.MBeanInfo;
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import javax.management.MBeanNotificationInfo;
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import javax.management.MBeanOperationInfo;
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import javax.management.MBeanParameterInfo;
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import com.sleepycat.je.DatabaseException;
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import com.sleepycat.je.Environment;
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import com.sleepycat.je.jmx.JEMBeanHelper;
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/**
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* JEApplicationMBean is an example of how a JE application can incorporate JE
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* monitoring into its existing MBean. It may be installed as is, or used as a
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* starting point for building a MBean which includes JE support.
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* <p>
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* JE management is divided between the JEApplicationMBean class and
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* JEMBeanHelper class. JEApplicationMBean contains an instance of
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* JEMBeanHelper, which knows about JE attributes, operations and
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* notifications. JEApplicationMBean itself has the responsibility of
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* configuring, opening and closing the JE environment along with any other
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* resources used by the application, and maintains a
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* com.sleepycat.je.Environment handle.
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* <p>
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* The approach taken for accessing the environment is an application specific
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* choice. Some of the salient considerations are:
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* <ul>
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* <li>Applications may open one or many Environment objects per process
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* against a given environment.</li>
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*
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* <li>All Environment handles reference the same underlying JE environment
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* implementation object.</li>
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* <li> The first Environment object instantiated in the process does the real
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* work of configuring and opening the environment. Follow-on instantiations of
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* Environment merely increment a reference count. Likewise,
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* Environment.close() only does real work when it's called by the last
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* Environment object in the process. </li>
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* </ul>
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* <p>
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* Another MBean approach for environment access can be seen in
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* com.sleepycat.je.jmx.JEMonitor. That MBean does not take responsibility for
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* opening and closing environments, and can only operate against already-open
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* environments.
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*/
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public class JEApplicationMBean implements DynamicMBean {
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private static final String DESCRIPTION =
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"A MBean for an application which uses JE. Provides open and close " +
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"operations which configure and open a JE environment as part of the "+
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"applications's resources. Also supports general JE monitoring.";
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private MBeanInfo mbeanInfo; // this MBean's visible interface.
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private JEMBeanHelper jeHelper; // gets JE management interface
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private Environment targetEnv; // saved environment handle
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/**
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* This MBean provides an open operation to open the JE environment.
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*/
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public static final String OP_OPEN = "openJE";
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/**
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* This MBean provides a close operation to release the JE environment.
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* Note that environments must be closed to release resources.
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*/
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public static final String OP_CLOSE = "closeJE";
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/**
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* Instantiate a JEApplicationMBean
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*
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* @param environmentHome home directory of the target JE environment.
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*/
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public JEApplicationMBean(String environmentHome) {
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File environmentDirectory = new File(environmentHome);
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jeHelper = new JEMBeanHelper(environmentDirectory, true);
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resetMBeanInfo();
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}
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/**
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* @see DynamicMBean#getAttribute
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*/
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public Object getAttribute(String attributeName)
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throws AttributeNotFoundException,
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MBeanException {
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return jeHelper.getAttribute(targetEnv, attributeName);
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}
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/**
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* @see DynamicMBean#setAttribute
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*/
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public void setAttribute(Attribute attribute)
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throws AttributeNotFoundException,
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InvalidAttributeValueException {
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jeHelper.setAttribute(targetEnv, attribute);
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}
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/**
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* @see DynamicMBean#getAttributes
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*/
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public AttributeList getAttributes(String[] attributes) {
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/* Sanity checking. */
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if (attributes == null) {
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throw new IllegalArgumentException("Attributes cannot be null");
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}
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/* Get each requested attribute. */
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AttributeList results = new AttributeList();
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for (int i = 0; i < attributes.length; i++) {
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try {
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String name = attributes[i];
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Object value = jeHelper.getAttribute(targetEnv, name);
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results.add(new Attribute(name, value));
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} catch (Exception e) {
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e.printStackTrace();
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}
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}
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return results;
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}
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/**
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* @see DynamicMBean#setAttributes
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*/
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public AttributeList setAttributes(AttributeList attributes) {
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/* Sanity checking. */
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if (attributes == null) {
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throw new IllegalArgumentException("attribute list can't be null");
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}
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/* Set each attribute specified. */
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AttributeList results = new AttributeList();
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for (int i = 0; i < attributes.size(); i++) {
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Attribute attr = (Attribute) attributes.get(i);
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try {
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/* Set new value. */
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jeHelper.setAttribute(targetEnv, attr);
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/*
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* Add the name and new value to the result list. Be sure
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* to ask the MBean for the new value, rather than simply
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* using attr.getValue(), because the new value may not
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* be same if it is modified according to the JE
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* implementation.
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*/
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String name = attr.getName();
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Object newValue = jeHelper.getAttribute(targetEnv, name);
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results.add(new Attribute(name, newValue));
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} catch (Exception e) {
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e.printStackTrace();
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}
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}
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return results;
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}
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/**
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* @see DynamicMBean#invoke
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*/
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public Object invoke(String actionName,
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Object[] params,
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String[] signature)
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throws MBeanException {
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Object result = null;
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if (actionName == null) {
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throw new IllegalArgumentException("actionName cannot be null");
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}
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if (actionName.equals(OP_OPEN)) {
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openEnvironment();
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return null;
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} else if (actionName.equals(OP_CLOSE)) {
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closeEnvironment();
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return null;
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} else {
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result = jeHelper.invoke(targetEnv, actionName, params, signature);
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}
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return result;
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}
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/**
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* @see DynamicMBean#getMBeanInfo
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*/
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public MBeanInfo getMBeanInfo() {
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return mbeanInfo;
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}
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/**
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* Create the available management interface for this environment.
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* The attributes and operations available vary according to
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* environment configuration.
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*
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*/
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private synchronized void resetMBeanInfo() {
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/*
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* Get JE attributes, operation and notification information
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* from JEMBeanHelper. An application may choose to add functionality
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* of its own when constructing the MBeanInfo.
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*/
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/* Attributes. */
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List attributeList = jeHelper.getAttributeList(targetEnv);
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MBeanAttributeInfo[] attributeInfo =
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new MBeanAttributeInfo[attributeList.size()];
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attributeList.toArray(attributeInfo);
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/* Constructors. */
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Constructor[] constructors = this.getClass().getConstructors();
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MBeanConstructorInfo[] constructorInfo =
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new MBeanConstructorInfo[constructors.length];
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for (int i = 0; i < constructors.length; i++) {
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constructorInfo[i] =
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new MBeanConstructorInfo(this.getClass().getName(),
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constructors[i]);
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}
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/* Operations. */
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/*
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* Get the list of operations available from the jeHelper. Then add
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* an open and close operation.
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*/
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List operationList = jeHelper.getOperationList(targetEnv);
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if (targetEnv == null) {
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operationList.add(
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new MBeanOperationInfo(OP_OPEN,
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"Configure and open the JE environment.",
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new MBeanParameterInfo[0], // no params
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"java.lang.Boolean",
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MBeanOperationInfo.ACTION_INFO));
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} else {
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operationList.add(
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new MBeanOperationInfo(OP_CLOSE,
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"Close the JE environment.",
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new MBeanParameterInfo[0], // no params
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"void",
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MBeanOperationInfo.ACTION_INFO));
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}
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MBeanOperationInfo[] operationInfo =
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new MBeanOperationInfo[operationList.size()];
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operationList.toArray(operationInfo);
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/* Notifications. */
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MBeanNotificationInfo[] notificationInfo =
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jeHelper.getNotificationInfo(targetEnv);
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/* Generate the MBean description. */
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mbeanInfo = new MBeanInfo(this.getClass().getName(),
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DESCRIPTION,
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attributeInfo,
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constructorInfo,
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operationInfo,
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notificationInfo);
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}
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/**
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* Open a JE environment using the configuration specified through
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* MBean attributes and recorded within the JEMBeanHelper.
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*/
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private void openEnvironment()
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throws MBeanException {
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try {
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if (targetEnv == null) {
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/*
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* The environment configuration has been set through
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* mbean attributes managed by the JEMBeanHelper.
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*/
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targetEnv =
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new Environment(jeHelper.getEnvironmentHome(),
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jeHelper.getEnvironmentOpenConfig());
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resetMBeanInfo();
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}
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} catch (DatabaseException e) {
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throw new MBeanException(e);
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}
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}
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/**
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* Release the environment handle contained within the MBean to properly
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* release resources.
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*/
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private void closeEnvironment()
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throws MBeanException {
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try {
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if (targetEnv != null) {
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targetEnv.close();
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targetEnv = null;
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resetMBeanInfo();
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}
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} catch (DatabaseException e) {
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throw new MBeanException(e);
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}
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}
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}
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