JDK8/Java8源码在线阅读
/*
* Copyright (c) 2000, 2013, 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 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,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/*
* @author IBM Corp.
*
* Copyright IBM Corp. 1999-2000. All rights reserved.
*/
package javax.management;
import java.io.Serializable;
// Javadoc imports:
import java.lang.management.MemoryUsage;
import java.util.Arrays;
import java.util.Locale;
import java.util.ResourceBundle;
import javax.management.openmbean.CompositeData;
import javax.management.openmbean.OpenMBeanAttributeInfoSupport;
import javax.management.openmbean.OpenMBeanOperationInfoSupport;
import javax.management.openmbean.OpenMBeanParameterInfoSupport;
import javax.management.openmbean.OpenType;
/**
* <p>Additional metadata for a JMX element. A {@code Descriptor}
* is associated with a {@link MBeanInfo}, {@link MBeanAttributeInfo}, etc.
* It consists of a collection of fields. A field is a name and an
* associated value.</p>
*
* <p>Field names are not case-sensitive. The names {@code descriptorType},
* {@code descriptortype}, and {@code DESCRIPTORTYPE} are all equivalent.
* However, the case that was used when the field was first set is preserved
* in the result of the {@link #getFields} and {@link #getFieldNames}
* methods.</p>
*
* <p>Not all field names and values are predefined.
* New fields can be defined and added by any program.</p>
*
* <p>A descriptor can be mutable or immutable.
* An immutable descriptor, once created, never changes.
* The <code>Descriptor</code> methods that could modify the contents
* of the descriptor will throw an exception
* for an immutable descriptor. Immutable descriptors are usually
* instances of {@link ImmutableDescriptor} or a subclass. Mutable
* descriptors are usually instances of
* {@link javax.management.modelmbean.DescriptorSupport} or a subclass.
*
* <p>Certain fields are used by the JMX implementation. This means
* either that the presence of the field may change the behavior of
* the JMX API or that the field may be set in descriptors returned by
* the JMX API. These fields appear in <i>italics</i> in the table
* below, and each one has a corresponding constant in the {@link JMX}
* class. For example, the field {@code defaultValue} is represented
* by the constant {@link JMX#DEFAULT_VALUE_FIELD}.</p>
*
* <p>Certain other fields have conventional meanings described in the
* table below but they are not required to be understood or set by
* the JMX implementation.</p>
*
* <p>Field names defined by the JMX specification in this and all
* future versions will never contain a period (.). Users can safely
* create their own fields by including a period in the name and be
* sure that these names will not collide with any future version of
* the JMX API. It is recommended to follow the Java package naming
* convention to avoid collisions between field names from different
* origins. For example, a field created by {@code example.com} might
* have the name {@code com.example.interestLevel}.</p>
*
* <p>Note that the values in the {@code defaultValue}, {@code
* legalValues}, {@code maxValue}, and {@code minValue} fields should
* be consistent with the type returned by the {@code getType()}
* method for the associated {@code MBeanAttributeInfo} or {@code
* MBeanParameterInfo}. For MXBeans, this means that they should be
* of the mapped Java type, called <em>opendata</em>(J) in the <a
* href="MXBean.html#mapping-rules">MXBean type mapping rules</a>.</p>
*
* <table border="1" cellpadding="5" summary="Descriptor Fields">
*
* <tr><th>Name</th><th>Type</th><th>Used in</th><th>Meaning</th></tr>
*
* <tr id="defaultValue"><td><i>defaultValue</i><td>Object</td>
* <td>MBeanAttributeInfo<br>MBeanParameterInfo</td>
*
* <td>Default value for an attribute or parameter. See
* {@link javax.management.openmbean}.</td>
*
* <tr><td>deprecated</td><td>String</td><td>Any</td>
*
* <td>An indication that this element of the information model is no
* longer recommended for use. A set of MBeans defined by an
* application is collectively called an <em>information model</em>.
* The convention is for the value of this field to contain a string
* that is the version of the model in which the element was first
* deprecated, followed by a space, followed by an explanation of the
* deprecation, for example {@code "1.3 Replaced by the Capacity
* attribute"}.</td>
*
* <tr><td id="descriptionResourceBundleBaseName">descriptionResource<br>
* BundleBaseName</td><td>String</td><td>Any</td>
*
* <td>The base name for the {@link ResourceBundle} in which the key given in
* the {@code descriptionResourceKey} field can be found, for example
* {@code "com.example.myapp.MBeanResources"}. The meaning of this
* field is defined by this specification but the field is not set or
* used by the JMX API itself.</td>
*
* <tr><td id="descriptionResourceKey">descriptionResourceKey</td>
* <td>String</td><td>Any</td>
*
* <td>A resource key for the description of this element. In
* conjunction with the {@code descriptionResourceBundleBaseName},
* this can be used to find a localized version of the description.
* The meaning of this field is defined by this specification but the
* field is not set or used by the JMX API itself.</td>
*
* <tr><td>enabled</td><td>String</td>
* <td>MBeanAttributeInfo<br>MBeanNotificationInfo<br>MBeanOperationInfo</td>
*
* <td>The string {@code "true"} or {@code "false"} according as this
* item is enabled. When an attribute or operation is not enabled, it
* exists but cannot currently be accessed. A user interface might
* present it as a greyed-out item. For example, an attribute might
* only be meaningful after the {@code start()} method of an MBean has
* been called, and is otherwise disabled. Likewise, a notification
* might be disabled if it cannot currently be emitted but could be in
* other circumstances.</td>
*
* <tr id="exceptions"><td>exceptions<td>String[]</td>
* <td>MBeanAttributeInfo, MBeanConstructorInfo, MBeanOperationInfo</td>
*
* <td>The class names of the exceptions that can be thrown when invoking a
* constructor or operation, or getting an attribute. The meaning of this field
* is defined by this specification but the field is not set or used by the
* JMX API itself. Exceptions thrown when
* setting an attribute are specified by the field
* <a href="#setExceptions">{@code setExceptions}</a>.
*
* <tr id="immutableInfo"><td><i>immutableInfo</i><td>String</td>
* <td>MBeanInfo</td>
*
* <td>The string {@code "true"} or {@code "false"} according as this
* MBean's MBeanInfo is <em>immutable</em>. When this field is true,
* the MBeanInfo for the given MBean is guaranteed not to change over
* the lifetime of the MBean. Hence, a client can read it once and
* cache the read value. When this field is false or absent, there is
* no such guarantee, although that does not mean that the MBeanInfo
* will necessarily change. See also the <a
* href="MBeanInfo.html#info-changed">{@code "jmx.mbean.info.changed"}</a>
* notification.</td>
*
* <tr id="infoTimeout"><td>infoTimeout</td><td>String<br>Long</td><td>MBeanInfo</td>
*
* <td>The time in milli-seconds that the MBeanInfo can reasonably be
* expected to be unchanged. The value can be a {@code Long} or a
* decimal string. This provides a hint from a DynamicMBean or any
* MBean that does not define {@code immutableInfo} as {@code true}
* that the MBeanInfo is not likely to change within this period and
* therefore can be cached. When this field is missing or has the
* value zero, it is not recommended to cache the MBeanInfo unless it
* has the {@code immutableInfo} set to {@code true} or it has <a
* href="MBeanInfo.html#info-changed">{@code "jmx.mbean.info.changed"}</a> in
* its {@link MBeanNotificationInfo} array.</td></tr>
*
* <tr id="interfaceClassName"><td><i>interfaceClassName</i></td>
* <td>String</td><td>MBeanInfo</td>
*
* <td>The Java interface name for a Standard MBean or MXBean, as
* returned by {@link Class#getName()}. A Standard MBean or MXBean
* registered directly in the MBean Server or created using the {@link
* StandardMBean} class will have this field in its MBeanInfo
* Descriptor.</td>
*
* <tr id="legalValues"><td><i>legalValues</i></td>
* <td>{@literal Set<?>}</td><td>MBeanAttributeInfo<br>MBeanParameterInfo</td>
*
* <td>Legal values for an attribute or parameter. See
* {@link javax.management.openmbean}.</td>
*
* <tr id="locale"><td>locale</td>
* <td>String</td><td>Any</td>
*
* <td>The {@linkplain Locale locale} of the description in this
* {@code MBeanInfo}, {@code MBeanAttributeInfo}, etc, as returned
* by {@link Locale#toString()}.</td>
*
* <tr id="maxValue"><td><i>maxValue</i><td>Object</td>
* <td>MBeanAttributeInfo<br>MBeanParameterInfo</td>
*
* <td>Maximum legal value for an attribute or parameter. See
* {@link javax.management.openmbean}.</td>
*
* <tr id="metricType"><td>metricType</td><td>String</td>
* <td>MBeanAttributeInfo<br>MBeanOperationInfo</td>
*
* <td>The type of a metric, one of the strings "counter" or "gauge".
* A metric is a measurement exported by an MBean, usually an
* attribute but sometimes the result of an operation. A metric that
* is a <em>counter</em> has a value that never decreases except by
* being reset to a starting value. Counter metrics are almost always
* non-negative integers. An example might be the number of requests
* received. A metric that is a <em>gauge</em> has a numeric value
* that can increase or decrease. Examples might be the number of
* open connections or a cache hit rate or a temperature reading.
*
* <tr id="minValue"><td><i>minValue</i><td>Object</td>
* <td>MBeanAttributeInfo<br>MBeanParameterInfo</td>
*
* <td>Minimum legal value for an attribute or parameter. See
* {@link javax.management.openmbean}.</td>
*
* <tr id="mxbean"><td><i>mxbean</i><td>String</td>
* <td>MBeanInfo</td>
*
* <td>The string {@code "true"} or {@code "false"} according as this
* MBean is an {@link MXBean}. A Standard MBean or MXBean registered
* directly with the MBean Server or created using the {@link
* StandardMBean} class will have this field in its MBeanInfo
* Descriptor.</td>
*
* <tr id="openType"><td><i>openType</i><td>{@link OpenType}</td>
* <td>MBeanAttributeInfo<br>MBeanOperationInfo<br>MBeanParameterInfo</td>
*
* <td><p>The Open Type of this element. In the case of {@code
* MBeanAttributeInfo} and {@code MBeanParameterInfo}, this is the
* Open Type of the attribute or parameter. In the case of {@code
* MBeanOperationInfo}, it is the Open Type of the return value. This
* field is set in the Descriptor for all instances of {@link
* OpenMBeanAttributeInfoSupport}, {@link
* OpenMBeanOperationInfoSupport}, and {@link
* OpenMBeanParameterInfoSupport}. It is also set for attributes,
* operations, and parameters of MXBeans.</p>
*
* <p>This field can be set for an {@code MBeanNotificationInfo}, in
* which case it indicates the Open Type that the {@link
* Notification#getUserData() user data} will have.</td>
*
* <tr id="originalType"><td><i>originalType</i><td>String</td>
* <td>MBeanAttributeInfo<br>MBeanOperationInfo<br>MBeanParameterInfo</td>
*
* <td><p>The original Java type of this element as it appeared in the
* {@link MXBean} interface method that produced this {@code
* MBeanAttributeInfo} (etc). For example, a method<br> <code>public
* </code> {@link MemoryUsage}<code> getHeapMemoryUsage();</code><br>
* in an MXBean interface defines an attribute called {@code
* HeapMemoryUsage} of type {@link CompositeData}. The {@code
* originalType} field in the Descriptor for this attribute will have
* the value {@code "java.lang.management.MemoryUsage"}.
*
* <p>The format of this string is described in the section <a
* href="MXBean.html#type-names">Type Names</a> of the MXBean
* specification.</p>
*
* <tr id="setExceptions"><td><i>setExceptions</i><td>String[]</td>
* <td>MBeanAttributeInfo</td>
*
* <td>The class names of the exceptions that can be thrown when setting
* an attribute. The meaning of this field
* is defined by this specification but the field is not set or used by the
* JMX API itself. Exceptions thrown when getting an attribute are specified
* by the field <a href="#exceptions">{@code exceptions}</a>.
*
* <tr><td>severity</td><td>String<br>Integer</td>
* <td>MBeanNotificationInfo</td>
*
* <td>The severity of this notification. It can be 0 to mean
* unknown severity or a value from 1 to 6 representing decreasing
* levels of severity. It can be represented as a decimal string or
* an {@code Integer}.</td>
*
* <tr><td>since</td><td>String</td><td>Any</td>
*
* <td>The version of the information model in which this element
* was introduced. A set of MBeans defined by an application is
* collectively called an <em>information model</em>. The
* application may also define versions of this model, and use the
* {@code "since"} field to record the version in which an element
* first appeared.</td>
*
* <tr><td>units</td><td>String</td>
* <td>MBeanAttributeInfo<br>MBeanParameterInfo<br>MBeanOperationInfo</td>
*
* <td>The units in which an attribute, parameter, or operation return
* value is measured, for example {@code "bytes"} or {@code
* "seconds"}.</td>
*
* </table>
*
* <p>Some additional fields are defined by Model MBeans. See the
* information for <a href="modelmbean/ModelMBeanInfo.html#descriptor"><!--
* -->{@code ModelMBeanInfo}</a>,
* <a href="modelmbean/ModelMBeanAttributeInfo.html#descriptor"><!--
* -->{@code ModelMBeanAttributeInfo}</a>,
* <a href="modelmbean/ModelMBeanConstructorInfo.html#descriptor"><!--
* -->{@code ModelMBeanConstructorInfo}</a>,
* <a href="modelmbean/ModelMBeanNotificationInfo.html#descriptor"><!--
* -->{@code ModelMBeanNotificationInfo}</a>, and
* <a href="modelmbean/ModelMBeanOperationInfo.html#descriptor"><!--
* -->{@code ModelMBeanOperationInfo}</a>, as
* well as the chapter "Model MBeans" of the <a
* href="http://www.oracle.com/technetwork/java/javase/tech/javamanagement-140525.html">JMX
* Specification</a>. The following table summarizes these fields. Note
* that when the Type in this table is Number, a String that is the decimal
* representation of a Long can also be used.</p>
*
* <p>Nothing prevents the use of these fields in MBeans that are not Model
* MBeans. The <a href="#displayName">displayName</a>, <a href="#severity"><!--
* -->severity</a>, and <a href="#visibility">visibility</a> fields are of
* interest outside Model MBeans, for example. But only Model MBeans have
* a predefined behavior for these fields.</p>
*
* <table border="1" cellpadding="5" summary="ModelMBean Fields">
*
* <tr><th>Name</th><th>Type</th><th>Used in</th><th>Meaning</th></tr>
*
* <tr><td>class</td><td>String</td><td>ModelMBeanOperationInfo</td>
* <td>Class where method is defined (fully qualified).</td></tr>
*
* <tr><td>currencyTimeLimit</td><td>Number</td>
* <td>ModelMBeanInfo<br>ModelMBeanAttributeInfo<br>ModelMBeanOperationInfo</td>
* <td>How long cached value is valid: <0 never, =0 always,
* >0 seconds.</td></tr>
*
* <tr><td>default</td><td>Object</td><td>ModelMBeanAttributeInfo</td>
* <td>Default value for attribute.</td></tr>
*
* <tr><td>descriptorType</td><td>String</td><td>Any</td>
* <td>Type of descriptor, "mbean", "attribute", "constructor", "operation",
* or "notification".</td></tr>
*
* <tr id="displayName"><td>displayName</td><td>String</td><td>Any</td>
* <td>Human readable name of this item.</td></tr>
*
* <tr><td>export</td><td>String</td><td>ModelMBeanInfo</td>
* <td>Name to be used to export/expose this MBean so that it is
* findable by other JMX Agents.</td></tr>
*
* <tr><td>getMethod</td><td>String</td><td>ModelMBeanAttributeInfo</td>
* <td>Name of operation descriptor for get method.</td></tr>
*
* <tr><td>lastUpdatedTimeStamp</td><td>Number</td>
* <td>ModelMBeanAttributeInfo<br>ModelMBeanOperationInfo</td>
* <td>When <a href="#value-field">value</a> was set.</td></tr>
*
* <tr><td>log</td><td>String</td><td>ModelMBeanInfo<br>ModelMBeanNotificationInfo</td>
* <td>t or T: log all notifications, f or F: log no notifications.</td></tr>
*
* <tr><td>logFile</td><td>String</td><td>ModelMBeanInfo<br>ModelMBeanNotificationInfo</td>
* <td>Fully qualified filename to log events to.</td></tr>
*
* <tr><td>messageID</td><td>String</td><td>ModelMBeanNotificationInfo</td>
* <td>Unique key for message text (to allow translation, analysis).</td></tr>
*
* <tr><td>messageText</td><td>String</td><td>ModelMBeanNotificationInfo</td>
* <td>Text of notification.</td></tr>
*
* <tr><td>name</td><td>String</td><td>Any</td>
* <td>Name of this item.</td></tr>
*
* <tr><td>persistFile</td><td>String</td><td>ModelMBeanInfo</td>
* <td>File name into which the MBean should be persisted.</td></tr>
*
* <tr><td>persistLocation</td><td>String</td><td>ModelMBeanInfo</td>
* <td>The fully qualified directory name where the MBean should be
* persisted (if appropriate).</td></tr>
*
* <tr><td>persistPeriod</td><td>Number</td>
* <td>ModelMBeanInfo<br>ModelMBeanAttributeInfo</td>
* <td>Frequency of persist cycle in seconds. Used when persistPolicy is
* "OnTimer" or "NoMoreOftenThan".</td></tr>
*
* <tr><td>persistPolicy</td><td>String</td>
* <td>ModelMBeanInfo<br>ModelMBeanAttributeInfo</td>
* <td>One of: OnUpdate|OnTimer|NoMoreOftenThan|OnUnregister|Always|Never.
* See the section "MBean Descriptor Fields" in the JMX specification
* document.</td></tr>
*
* <tr><td>presentationString</td><td>String</td><td>Any</td>
* <td>XML formatted string to allow presentation of data.</td></tr>
*
* <tr><td>protocolMap</td><td>Descriptor</td><td>ModelMBeanAttributeInfo</td>
* <td>See the section "Protocol Map Support" in the JMX specification
* document. Mappings must be appropriate for the attribute and entries
* can be updated or augmented at runtime.</td></tr>
*
* <tr><td>role</td><td>String</td>
* <td>ModelMBeanConstructorInfo<br>ModelMBeanOperationInfo</td>
* <td>One of "constructor", "operation", "getter", or "setter".</td></tr>
*
* <tr><td>setMethod</td><td>String</td><td>ModelMBeanAttributeInfo</td>
* <td>Name of operation descriptor for set method.</td></tr>
*
* <tr id="severity"><td>severity</td><td>Number</td>
* <td>ModelMBeanNotificationInfo</td>
* <td>0-6 where 0: unknown; 1: non-recoverable;
* 2: critical, failure; 3: major, severe;
* 4: minor, marginal, error; 5: warning;
* 6: normal, cleared, informative</td></tr>
*
* <tr><td>targetObject</td><td>Object</td><td>ModelMBeanOperationInfo</td>
* <td>Object on which to execute this method.</td></tr>
*
* <tr><td>targetType</td><td>String</td><td>ModelMBeanOperationInfo</td>
* <td>type of object reference for targetObject. Can be:
* ObjectReference | Handle | EJBHandle | IOR | RMIReference.</td></tr>
*
* <tr id="value-field"><td>value</td><td>Object</td>
* <td>ModelMBeanAttributeInfo<br>ModelMBeanOperationInfo</td>
* <td>Current (cached) value for attribute or operation.</td></tr>
*
* <tr id="visibility"><td>visibility</td><td>Number</td><td>Any</td>
* <td>1-4 where 1: always visible, 4: rarely visible.</td></tr>
*
* </table>
*
* @since 1.5
*/
public interface Descriptor extends Serializable, Cloneable
{
/**
* Returns the value for a specific field name, or null if no value
* is present for that name.
*
* @param fieldName the field name.
*
* @return the corresponding value, or null if the field is not present.
*
* @exception RuntimeOperationsException if the field name is illegal.
*/
public Object getFieldValue(String fieldName)
throws RuntimeOperationsException;
/**
* <p>Sets the value for a specific field name. This will
* modify an existing field or add a new field.</p>
*
* <p>The field value will be validated before it is set.
* If it is not valid, then an exception will be thrown.
* The meaning of validity is dependent on the descriptor
* implementation.</p>
*
* @param fieldName The field name to be set. Cannot be null or empty.
* @param fieldValue The field value to be set for the field
* name. Can be null if that is a valid value for the field.
*
* @exception RuntimeOperationsException if the field name or field value
* is illegal (wrapped exception is {@link IllegalArgumentException}); or
* if the descriptor is immutable (wrapped exception is
* {@link UnsupportedOperationException}).
*/
public void setField(String fieldName, Object fieldValue)
throws RuntimeOperationsException;
/**
* Returns all of the fields contained in this descriptor as a string array.
*
* @return String array of fields in the format <i>fieldName=fieldValue</i>
* <br>If the value of a field is not a String, then the toString() method
* will be called on it and the returned value, enclosed in parentheses,
* used as the value for the field in the returned array. If the value
* of a field is null, then the value of the field in the returned array
* will be empty. If the descriptor is empty, you will get
* an empty array.
*
* @see #setFields
*/
public String[] getFields();
/**
* Returns all the field names in the descriptor.
*
* @return String array of field names. If the descriptor is empty,
* you will get an empty array.
*/
public String[] getFieldNames();
/**
* Returns all the field values in the descriptor as an array of Objects. The
* returned values are in the same order as the {@code fieldNames} String array parameter.
*
* @param fieldNames String array of the names of the fields that
* the values should be returned for. If the array is empty then
* an empty array will be returned. If the array is null then all
* values will be returned, as if the parameter were the array
* returned by {@link #getFieldNames()}. If a field name in the
* array does not exist, including the case where it is null or
* the empty string, then null is returned for the matching array
* element being returned.
*
* @return Object array of field values. If the list of {@code fieldNames}
* is empty, you will get an empty array.
*/
public Object[] getFieldValues(String... fieldNames);
/**
* Removes a field from the descriptor.
*
* @param fieldName String name of the field to be removed.
* If the field name is illegal or the field is not found,
* no exception is thrown.
*
* @exception RuntimeOperationsException if a field of the given name
* exists and the descriptor is immutable. The wrapped exception will
* be an {@link UnsupportedOperationException}.
*/
public void removeField(String fieldName);
/**
* <p>Sets all fields in the field names array to the new value with
* the same index in the field values array. Array sizes must match.</p>
*
* <p>The field value will be validated before it is set.
* If it is not valid, then an exception will be thrown.
* If the arrays are empty, then no change will take effect.</p>
*
* @param fieldNames String array of field names. The array and array
* elements cannot be null.
* @param fieldValues Object array of the corresponding field values.
* The array cannot be null. Elements of the array can be null.
*
* @throws RuntimeOperationsException if the change fails for any reason.
* Wrapped exception is {@link IllegalArgumentException} if
* {@code fieldNames} or {@code fieldValues} is null, or if
* the arrays are of different lengths, or if there is an
* illegal value in one of them.
* Wrapped exception is {@link UnsupportedOperationException}
* if the descriptor is immutable, and the call would change
* its contents.
*
* @see #getFields
*/
public void setFields(String[] fieldNames, Object[] fieldValues)
throws RuntimeOperationsException;
/**
* <p>Returns a descriptor which is equal to this descriptor.
* Changes to the returned descriptor will have no effect on this
* descriptor, and vice versa. If this descriptor is immutable,
/**代码未完, 请加载全部代码(NowJava.com).**/
关注时代Java
关注时代Java