/*
* @(#)OpenMBeanConstructorInfoSupport.java 3.22 03/12/19
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package javax.management.openmbean;
// java import
//
import java.io.Serializable;
import java.util.Arrays;
// jmx import
//
import javax.management.MBeanConstructorInfo;
import javax.management.MBeanParameterInfo;
/**
* Describes a constructor of an Open MBean.
*
* @version 3.22 03/12/19
* @author Sun Microsystems, Inc.
*
* @since 1.5
* @since.unbundled JMX 1.1
*/
public class OpenMBeanConstructorInfoSupport
extends MBeanConstructorInfo
implements OpenMBeanConstructorInfo, Serializable {
/* Serial version */
static final long serialVersionUID = -4400441579007477003L;
private transient Integer myHashCode = null; // As this instance is immutable, these two values
private transient String myToString = null; // need only be calculated once.
/**
* Constructs an <tt>OpenMBeanConstructorInfoSupport</tt> instance, which describes the constructor
* of a class of open MBeans with the specified <var>name</var>, <var>description</var> and <var>signature</var>.
* <p>
* The <var>signature</var> array parameter is internally copied, so that subsequent changes
* to the array referenced by <var>signature</var> have no effect on this instance.
*
* @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 <var>name</var> or <var>description</var> are null or empty string.
*
* @throws ArrayStoreException If <var>signature</var> is not an array of instances of a subclass of <tt>MBeanParameterInfo</tt>.
*/
public OpenMBeanConstructorInfoSupport(String name,
String description,
OpenMBeanParameterInfo[] signature) {
super(name,
description,
( signature == null ? null : arrayCopyCast(signature) )); // may throw an ArrayStoreException
// 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) throws ArrayStoreException {
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 *** */
/**
* Compares the specified <var>obj</var> parameter with this <code>OpenMBeanConstructorInfoSupport</code> instance for equality.
* <p>
* Returns <tt>true</tt> if and only if all of the following statements are true:
* <ul>
* <li><var>obj</var> is non null,</li>
* <li><var>obj</var> also implements the <code>OpenMBeanConstructorInfo</code> interface,</li>
* <li>their names are equal</li>
* <li>their signatures are equal.</li>
* </ul>
* This ensures that this <tt>equals</tt> method works properly for <var>obj</var> parameters which are
* different implementations of the <code>OpenMBeanConstructorInfo</code> interface.
* <br>
* @param obj the object to be compared for equality with this <code>OpenMBeanConstructorInfoSupport</code> instance;
*
* @return <code>true</code> if the specified object is equal to this <code>OpenMBeanConstructorInfoSupport</code> 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;
}
/**
* Returns the hash code value for this <code>OpenMBeanConstructorInfoSupport</code> instance.
* <p>
* The hash code of an <code>OpenMBeanConstructorInfoSupport</code> instance is the sum of the hash codes
* of all elements of information used in <code>equals</code> comparisons
* (ie: its name and signature, where the signature hashCode is calculated by a call to
* <tt>java.util.Arrays.asList(this.getSignature).hashCode()</tt>).
* <p>
* This ensures that <code> t1.equals(t2) </code> implies that <code> t1.hashCode()==t2.hashCode() </code>
* for any two <code>OpenMBeanConstructorInfoSupport</code> instances <code>t1</code> and <code>t2</code>,
* as required by the general contract of the method
* {@link Object#hashCode() Object.hashCode()}.
* <p>
* However, note that another instance of a class implementing the <code>OpenMBeanConstructorInfo</code> interface
* may be equal to this <code>OpenMBeanConstructorInfoSupport</code> instance as defined by {@link #equals(java.lang.Object)},
* but may have a different hash code if it is calculated differently.
* <p>
* As <code>OpenMBeanConstructorInfoSupport</code> instances are immutable, the hash code for this instance is calculated once,
* on the first call to <code>hashCode</code>, and then the same value is returned for subsequent calls.
*
* @return the hash code value for this <code>OpenMBeanConstructorInfoSupport</code> 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();
}
/**
* Returns a string representation of this <code>OpenMBeanConstructorInfoSupport</code> instance.
* <p>
* The string representation consists of the name of this class (ie <code>javax.management.openmbean.OpenMBeanConstructorInfoSupport</code>),
* and of the name and signature of the described constructor.
* <p>
* As <code>OpenMBeanConstructorInfoSupport</code> instances are immutable,
* the string representation for this instance is calculated once,
* on the first call to <code>toString</code>, and then the same value is returned for subsequent calls.
*
* @return a string representation of this <code>OpenMBeanConstructorInfoSupport</code> instance
*/
public String toString() {
// Calculate the hash code 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(")")
.toString();
}
// return always the same string representation for this instance (immutable)
//
return myToString;
}
}
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