/*
* @(#)OpenMBeanConstructorInfoSupport.java 3.28 06/03/15
*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package javax.management.openmbean;
// java import
//
import java.util.Arrays;
import javax.management.Descriptor;
import javax.management.MBeanConstructorInfo;
import javax.management.MBeanParameterInfo;
/**
* Describes a constructor of an Open MBean.
*
* @version 3.28 06/03/15
* @author Sun Microsystems, Inc.
*
* @since 1.5
* @since.unbundled JMX 1.1
*/
public class OpenMBeanConstructorInfoSupport
extends MBeanConstructorInfo
implements OpenMBeanConstructorInfo {
/* Serial version */
static final long serialVersionUID = -4400441579007477003L;
// As this instance is immutable,
// these two values need only be calculated once.
private transient Integer myHashCode = null;
private transient String myToString = null;
/**
* <p>Constructs an {@code OpenMBeanConstructorInfoSupport}
* instance, which describes the constructor of a class of open
* MBeans with the specified {@code name}, {@code description} and
* {@code signature}.</p>
*
* <p>The {@code signature} array parameter is internally copied,
* so that subsequent changes to the array referenced by {@code
* signature} have no effect on this instance.</p>
*
* @param name cannot be a null or empty string.
*
* @param description cannot be a null or empty string.
*
* @param signature can be null or empty if there are no
* parameters to describe.
*
* @throws IllegalArgumentException if {@code name} or {@code
* description} are null or empty string.
*
* @throws ArrayStoreException If {@code signature} is not an
* array of instances of a subclass of {@code MBeanParameterInfo}.
*/
public OpenMBeanConstructorInfoSupport(String name,
String description,
OpenMBeanParameterInfo[] signature) {
this(name, description, signature, (Descriptor) null);
}
/**
* <p>Constructs an {@code OpenMBeanConstructorInfoSupport}
* instance, which describes the constructor of a class of open
* MBeans with the specified {@code name}, {@code description},
* {@code signature}, and {@code descriptor}.</p>
*
* <p>The {@code signature} array parameter is internally copied,
* so that subsequent changes to the array referenced by {@code
* signature} have no effect on this instance.</p>
*
* @param name cannot be a null or empty string.
*
* @param description cannot be a null or empty string.
*
* @param signature can be null or empty if there are no
* parameters to describe.
*
* @param descriptor The descriptor for the constructor. This may
* be null which is equivalent to an empty descriptor.
*
* @throws IllegalArgumentException if {@code name} or {@code
* description} are null or empty string.
*
* @throws ArrayStoreException If {@code signature} is not an
* array of instances of a subclass of {@code MBeanParameterInfo}.
*
* @since 1.6
*/
public OpenMBeanConstructorInfoSupport(String name,
String description,
OpenMBeanParameterInfo[] signature,
Descriptor descriptor) {
super(name,
description,
arrayCopyCast(signature), // may throw an ArrayStoreException
descriptor);
// check parameters that should not be null or empty
// (unfortunately it is not done in superclass :-( ! )
//
if (name == null || name.trim().equals("")) {
throw new IllegalArgumentException("Argument name cannot be " +
"null or empty");
}
if (description == null || description.trim().equals("")) {
throw new IllegalArgumentException("Argument description cannot " +
"be null or empty");
}
}
private static MBeanParameterInfo[]
arrayCopyCast(OpenMBeanParameterInfo[] src) {
if (src == null)
return null;
MBeanParameterInfo[] dst = new MBeanParameterInfo[src.length];
System.arraycopy(src, 0, dst, 0, src.length);
// may throw an ArrayStoreException
return dst;
}
/* *** Commodity methods from java.lang.Object *** */
/**
* <p>Compares the specified {@code obj} parameter with this
* {@code OpenMBeanConstructorInfoSupport} instance for
* equality.</p>
*
* <p>Returns {@code true} if and only if all of the following
* statements are true:
*
* <ul>
* <li>{@code obj} is non null,</li>
* <li>{@code obj} also implements the {@code
* OpenMBeanConstructorInfo} interface,</li>
* <li>their names are equal</li>
* <li>their signatures are equal.</li>
* </ul>
*
* This ensures that this {@code equals} method works properly for
* {@code obj} parameters which are different implementations of
* the {@code OpenMBeanConstructorInfo} interface.
*
* @param obj the object to be compared for equality with this
* {@code OpenMBeanConstructorInfoSupport} instance;
*
* @return {@code true} if the specified object is equal to this
* {@code OpenMBeanConstructorInfoSupport} instance.
*/
public boolean equals(Object obj) {
// if obj is null, return false
//
if (obj == null) {
return false;
}
// if obj is not a OpenMBeanConstructorInfo, return false
//
OpenMBeanConstructorInfo other;
try {
other = (OpenMBeanConstructorInfo) obj;
} catch (ClassCastException e) {
return false;
}
// Now, really test for equality between this
// OpenMBeanConstructorInfo implementation and the other:
//
// their Name should be equal
if ( ! this.getName().equals(other.getName()) ) {
return false;
}
// their Signatures should be equal
if ( ! Arrays.equals(this.getSignature(), other.getSignature()) ) {
return false;
}
// All tests for equality were successfull
//
return true;
}
/**
* <p>Returns the hash code value for this {@code
* OpenMBeanConstructorInfoSupport} instance.</p>
*
* <p>The hash code of an {@code OpenMBeanConstructorInfoSupport}
* instance is the sum of the hash codes of all elements of
* information used in {@code equals} comparisons (ie: its name
* and signature, where the signature hashCode is calculated by a
* call to {@code
* java.util.Arrays.asList(this.getSignature).hashCode()}).</p>
*
* <p>This ensures that {@code t1.equals(t2)} implies that {@code
* t1.hashCode()==t2.hashCode()} for any two {@code
* OpenMBeanConstructorInfoSupport} instances {@code t1} and
* {@code t2}, as required by the general contract of the method
* {@link Object#hashCode() Object.hashCode()}.</p>
*
* <p>However, note that another instance of a class implementing
* the {@code OpenMBeanConstructorInfo} interface may be equal to
* this {@code OpenMBeanConstructorInfoSupport} instance as
* defined by {@link #equals(java.lang.Object)}, but may have a
* different hash code if it is calculated differently.</p>
*
* <p>As {@code OpenMBeanConstructorInfoSupport} instances are
* immutable, the hash code for this instance is calculated once,
* on the first call to {@code hashCode}, and then the same value
* is returned for subsequent calls.</p>
*
* @return the hash code value for this {@code
* OpenMBeanConstructorInfoSupport} instance
*/
public int hashCode() {
// Calculate the hash code value if it has not yet been done
// (ie 1st call to hashCode())
//
if (myHashCode == null) {
int value = 0;
value += this.getName().hashCode();
value += Arrays.asList(this.getSignature()).hashCode();
myHashCode = new Integer(value);
}
// return always the same hash code for this instance (immutable)
//
return myHashCode.intValue();
}
/**
* <p>Returns a string representation of this {@code
* OpenMBeanConstructorInfoSupport} instance.</p>
*
* <p>The string representation consists of the name of this class
* (ie {@code
* javax.management.openmbean.OpenMBeanConstructorInfoSupport}),
* the name and signature of the described constructor and the
* string representation of its descriptor.</p>
*
* <p>As {@code OpenMBeanConstructorInfoSupport} instances are
* immutable, the string representation for this instance is
* calculated once, on the first call to {@code toString}, and
* then the same value is returned for subsequent calls.</p>
*
* @return a string representation of this {@code
* OpenMBeanConstructorInfoSupport} instance
*/
public String toString() {
// Calculate the string value if it has not yet been done (ie
// 1st call to toString())
//
if (myToString == null) {
myToString = new StringBuffer()
.append(this.getClass().getName())
.append("(name=")
.append(this.getName())
.append(",signature=")
.append(Arrays.asList(this.getSignature()).toString())
.append(",descriptor=")
.append(this.getDescriptor())
.append(")")
.toString();
}
// return always the same string representation for this
// instance (immutable)
//
return myToString;
}
}
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