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package java.lang.management;
import javax.management.openmbean.CompositeData;
import java.util.concurrent.locks.*;
import sun.management.LockInfoCompositeData;
Information about a lock. A lock can be a built-in object monitor,
an ownable synchronizer, or the Condition object associated with synchronizers.
An ownable synchronizer is a synchronizer that may be exclusively owned by a thread and uses AbstractOwnableSynchronizer (or its subclass) to implement its synchronization property. ReentrantLock and the write-lock (but not the read-lock) of ReentrantReadWriteLock are two examples of ownable synchronizers provided by the platform.
MXBean Mapping
LockInfo is mapped to a CompositeData as specified in the from method. Author: Mandy Chung See Also: Since: 1.6
/**
* Information about a <em>lock</em>. A lock can be a built-in object monitor,
* an <em>ownable synchronizer</em>, or the {@link Condition Condition}
* object associated with synchronizers.
* <p>
* <a id="OwnableSynchronizer">An ownable synchronizer</a> is
* a synchronizer that may be exclusively owned by a thread and uses
* {@link AbstractOwnableSynchronizer AbstractOwnableSynchronizer}
* (or its subclass) to implement its synchronization property.
* {@link ReentrantLock ReentrantLock} and the write-lock (but not
* the read-lock) of {@link ReentrantReadWriteLock ReentrantReadWriteLock} are
* two examples of ownable synchronizers provided by the platform.
*
* <h2><a id="MappedType">MXBean Mapping</a></h2>
* {@code LockInfo} is mapped to a {@link CompositeData CompositeData}
* as specified in the {@link #from from} method.
*
* @see java.util.concurrent.locks.AbstractOwnableSynchronizer
* @see java.util.concurrent.locks.Condition
*
* @author Mandy Chung
* @since 1.6
*/
public class LockInfo {
private String className;
private int identityHashCode;
Constructs a LockInfo object. Params: - className – the fully qualified name of the class of the lock object.
- identityHashCode – the
identity hash code of the lock object.
/**
* Constructs a {@code LockInfo} object.
*
* @param className the fully qualified name of the class of the lock object.
* @param identityHashCode the {@link System#identityHashCode
* identity hash code} of the lock object.
*/
public LockInfo(String className, int identityHashCode) {
if (className == null) {
throw new NullPointerException("Parameter className cannot be null");
}
this.className = className;
this.identityHashCode = identityHashCode;
}
package-private constructors
/**
* package-private constructors
*/
LockInfo(Object lock) {
this.className = lock.getClass().getName();
this.identityHashCode = System.identityHashCode(lock);
}
Returns the fully qualified name of the class of the lock object.
Returns: the fully qualified name of the class of the lock object.
/**
* Returns the fully qualified name of the class of the lock object.
*
* @return the fully qualified name of the class of the lock object.
*/
public String getClassName() {
return className;
}
Returns the identity hash code of the lock object returned from the System.identityHashCode method. Returns: the identity hash code of the lock object.
/**
* Returns the identity hash code of the lock object
* returned from the {@link System#identityHashCode} method.
*
* @return the identity hash code of the lock object.
*/
public int getIdentityHashCode() {
return identityHashCode;
}
Returns a LockInfo object represented by the given CompositeData. The given CompositeData must contain the following attributes:
The attributes and the types the given CompositeData contains
Attribute Name
Type
className
java.lang.String
identityHashCode
java.lang.Integer
Params: - cd –
CompositeData representing a LockInfo
Throws: - IllegalArgumentException – if
cd does not represent a LockInfo with the attributes described above.
Returns: a LockInfo object represented by cd if cd is not null; null otherwise. Since: 1.8
/**
* Returns a {@code LockInfo} object represented by the
* given {@code CompositeData}.
* The given {@code CompositeData} must contain the following attributes:
* <table class="striped" style="margin-left:2em;">
* <caption style="display:none">The attributes and the types the given CompositeData contains</caption>
* <thead style="text-align:left">
* <tr>
* <th scope="col">Attribute Name</th>
* <th scope="col">Type</th>
* </tr>
* </thead>
* <tbody style="text-align:left">
* <tr>
* <th scope="row">className</th>
* <td>{@code java.lang.String}</td>
* </tr>
* <tr>
* <th scope="row">identityHashCode</th>
* <td>{@code java.lang.Integer}</td>
* </tr>
* </tbody>
* </table>
*
* @param cd {@code CompositeData} representing a {@code LockInfo}
*
* @throws IllegalArgumentException if {@code cd} does not
* represent a {@code LockInfo} with the attributes described
* above.
* @return a {@code LockInfo} object represented
* by {@code cd} if {@code cd} is not {@code null};
* {@code null} otherwise.
*
* @since 1.8
*/
public static LockInfo from(CompositeData cd) {
if (cd == null) {
return null;
}
if (cd instanceof LockInfoCompositeData) {
return ((LockInfoCompositeData) cd).getLockInfo();
} else {
return LockInfoCompositeData.toLockInfo(cd);
}
}
Returns a string representation of a lock. The returned
string representation consists of the name of the class of the
lock object, the at-sign character `@', and the unsigned
hexadecimal representation of the identity hash code
of the object. This method returns a string equals to the value of:
lock.getClass().getName() + '@' + Integer.toHexString(System.identityHashCode(lock))
where lock is the lock object. Returns: the string representation of a lock.
/**
* Returns a string representation of a lock. The returned
* string representation consists of the name of the class of the
* lock object, the at-sign character `@', and the unsigned
* hexadecimal representation of the <em>identity</em> hash code
* of the object. This method returns a string equals to the value of:
* <blockquote>
* <pre>
* lock.getClass().getName() + '@' + Integer.toHexString(System.identityHashCode(lock))
* </pre></blockquote>
* where {@code lock} is the lock object.
*
* @return the string representation of a lock.
*/
public String toString() {
return className + '@' + Integer.toHexString(identityHashCode);
}
}