/* |
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* Copyright (c) 2000, 2008, Oracle and/or its affiliates. All rights reserved. |
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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* |
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* This code is free software; you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License version 2 only, as |
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* published by the Free Software Foundation. Oracle designates this |
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* particular file as subject to the "Classpath" exception as provided |
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* by Oracle in the LICENSE file that accompanied this code. |
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* |
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* This code is distributed in the hope that it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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* version 2 for more details (a copy is included in the LICENSE file that |
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* accompanied this code). |
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* |
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* You should have received a copy of the GNU General Public License version |
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* 2 along with this work; if not, write to the Free Software Foundation, |
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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* |
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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* or visit www.oracle.com if you need additional information or have any |
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* questions. |
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*/ |
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package javax.management.openmbean; |
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// java import |
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// |
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import java.util.Arrays; |
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import javax.management.Descriptor; |
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import javax.management.MBeanConstructorInfo; |
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import javax.management.MBeanParameterInfo; |
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/** |
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* Describes a constructor of an Open MBean. |
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* |
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* |
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* @since 1.5 |
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*/ |
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public class OpenMBeanConstructorInfoSupport |
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extends MBeanConstructorInfo |
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implements OpenMBeanConstructorInfo { |
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/* Serial version */ |
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static final long serialVersionUID = -4400441579007477003L; |
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// As this instance is immutable, |
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// these two values need only be calculated once. |
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private transient Integer myHashCode = null; |
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private transient String myToString = null; |
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/** |
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* <p>Constructs an {@code OpenMBeanConstructorInfoSupport} |
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* instance, which describes the constructor of a class of open |
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* MBeans with the specified {@code name}, {@code description} and |
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* {@code signature}.</p> |
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* |
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* <p>The {@code signature} array parameter is internally copied, |
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* so that subsequent changes to the array referenced by {@code |
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* signature} have no effect on this instance.</p> |
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* |
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* @param name cannot be a null or empty string. |
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* |
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* @param description cannot be a null or empty string. |
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* |
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* @param signature can be null or empty if there are no |
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* parameters to describe. |
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* |
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* @throws IllegalArgumentException if {@code name} or {@code |
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* description} are null or empty string. |
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* |
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* @throws ArrayStoreException If {@code signature} is not an |
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* array of instances of a subclass of {@code MBeanParameterInfo}. |
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*/ |
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public OpenMBeanConstructorInfoSupport(String name, |
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String description, |
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OpenMBeanParameterInfo[] signature) { |
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this(name, description, signature, (Descriptor) null); |
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} |
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/** |
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* <p>Constructs an {@code OpenMBeanConstructorInfoSupport} |
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* instance, which describes the constructor of a class of open |
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* MBeans with the specified {@code name}, {@code description}, |
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* {@code signature}, and {@code descriptor}.</p> |
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* |
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* <p>The {@code signature} array parameter is internally copied, |
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* so that subsequent changes to the array referenced by {@code |
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* signature} have no effect on this instance.</p> |
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* |
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* @param name cannot be a null or empty string. |
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* |
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* @param description cannot be a null or empty string. |
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* |
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* @param signature can be null or empty if there are no |
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* parameters to describe. |
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* |
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* @param descriptor The descriptor for the constructor. This may |
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* be null which is equivalent to an empty descriptor. |
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* |
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* @throws IllegalArgumentException if {@code name} or {@code |
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* description} are null or empty string. |
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* |
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* @throws ArrayStoreException If {@code signature} is not an |
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* array of instances of a subclass of {@code MBeanParameterInfo}. |
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* |
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* @since 1.6 |
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*/ |
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public OpenMBeanConstructorInfoSupport(String name, |
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String description, |
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OpenMBeanParameterInfo[] signature, |
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Descriptor descriptor) { |
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super(name, |
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description, |
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arrayCopyCast(signature), // may throw an ArrayStoreException |
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descriptor); |
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// check parameters that should not be null or empty |
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// (unfortunately it is not done in superclass :-( ! ) |
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// |
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if (name == null || name.trim().equals("")) { |
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throw new IllegalArgumentException("Argument name cannot be " + |
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"null or empty"); |
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} |
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if (description == null || description.trim().equals("")) { |
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throw new IllegalArgumentException("Argument description cannot " + |
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"be null or empty"); |
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} |
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} |
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private static MBeanParameterInfo[] |
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arrayCopyCast(OpenMBeanParameterInfo[] src) { |
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if (src == null) |
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return null; |
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MBeanParameterInfo[] dst = new MBeanParameterInfo[src.length]; |
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System.arraycopy(src, 0, dst, 0, src.length); |
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// may throw an ArrayStoreException |
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return dst; |
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} |
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/* *** Commodity methods from java.lang.Object *** */ |
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/** |
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* <p>Compares the specified {@code obj} parameter with this |
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* {@code OpenMBeanConstructorInfoSupport} instance for |
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* equality.</p> |
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* |
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* <p>Returns {@code true} if and only if all of the following |
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* statements are true: |
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* |
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* <ul> |
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* <li>{@code obj} is non null,</li> |
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* <li>{@code obj} also implements the {@code |
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* OpenMBeanConstructorInfo} interface,</li> |
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* <li>their names are equal</li> |
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* <li>their signatures are equal.</li> |
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* </ul> |
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* |
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* This ensures that this {@code equals} method works properly for |
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* {@code obj} parameters which are different implementations of |
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* the {@code OpenMBeanConstructorInfo} interface. |
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* |
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* @param obj the object to be compared for equality with this |
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* {@code OpenMBeanConstructorInfoSupport} instance; |
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* |
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* @return {@code true} if the specified object is equal to this |
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* {@code OpenMBeanConstructorInfoSupport} instance. |
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*/ |
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public boolean equals(Object obj) { |
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// if obj is null, return false |
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// |
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if (obj == null) { |
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return false; |
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} |
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// if obj is not a OpenMBeanConstructorInfo, return false |
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// |
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OpenMBeanConstructorInfo other; |
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try { |
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other = (OpenMBeanConstructorInfo) obj; |
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} catch (ClassCastException e) { |
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return false; |
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} |
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// Now, really test for equality between this |
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// OpenMBeanConstructorInfo implementation and the other: |
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// |
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// their Name should be equal |
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if ( ! this.getName().equals(other.getName()) ) { |
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return false; |
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} |
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// their Signatures should be equal |
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if ( ! Arrays.equals(this.getSignature(), other.getSignature()) ) { |
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return false; |
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} |
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// All tests for equality were successfull |
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// |
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return true; |
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} |
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/** |
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* <p>Returns the hash code value for this {@code |
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* OpenMBeanConstructorInfoSupport} instance.</p> |
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* |
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* <p>The hash code of an {@code OpenMBeanConstructorInfoSupport} |
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* instance is the sum of the hash codes of all elements of |
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* information used in {@code equals} comparisons (ie: its name |
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* and signature, where the signature hashCode is calculated by a |
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* call to {@code |
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* java.util.Arrays.asList(this.getSignature).hashCode()}).</p> |
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* |
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* <p>This ensures that {@code t1.equals(t2)} implies that {@code |
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* t1.hashCode()==t2.hashCode()} for any two {@code |
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* OpenMBeanConstructorInfoSupport} instances {@code t1} and |
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* {@code t2}, as required by the general contract of the method |
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* {@link Object#hashCode() Object.hashCode()}.</p> |
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* |
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* <p>However, note that another instance of a class implementing |
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* the {@code OpenMBeanConstructorInfo} interface may be equal to |
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* this {@code OpenMBeanConstructorInfoSupport} instance as |
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* defined by {@link #equals(java.lang.Object)}, but may have a |
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* different hash code if it is calculated differently.</p> |
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* |
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* <p>As {@code OpenMBeanConstructorInfoSupport} instances are |
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* immutable, the hash code for this instance is calculated once, |
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* on the first call to {@code hashCode}, and then the same value |
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* is returned for subsequent calls.</p> |
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* |
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* @return the hash code value for this {@code |
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* OpenMBeanConstructorInfoSupport} instance |
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*/ |
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public int hashCode() { |
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// Calculate the hash code value if it has not yet been done |
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// (ie 1st call to hashCode()) |
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// |
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if (myHashCode == null) { |
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int value = 0; |
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value += this.getName().hashCode(); |
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value += Arrays.asList(this.getSignature()).hashCode(); |
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myHashCode = Integer.valueOf(value); |
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} |
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// return always the same hash code for this instance (immutable) |
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// |
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return myHashCode.intValue(); |
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} |
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/** |
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* <p>Returns a string representation of this {@code |
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* OpenMBeanConstructorInfoSupport} instance.</p> |
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* |
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* <p>The string representation consists of the name of this class |
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* (ie {@code |
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* javax.management.openmbean.OpenMBeanConstructorInfoSupport}), |
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* the name and signature of the described constructor and the |
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* string representation of its descriptor.</p> |
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* |
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* <p>As {@code OpenMBeanConstructorInfoSupport} instances are |
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* immutable, the string representation for this instance is |
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* calculated once, on the first call to {@code toString}, and |
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* then the same value is returned for subsequent calls.</p> |
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* |
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* @return a string representation of this {@code |
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* OpenMBeanConstructorInfoSupport} instance |
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*/ |
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public String toString() { |
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// Calculate the string value if it has not yet been done (ie |
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// 1st call to toString()) |
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// |
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if (myToString == null) { |
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myToString = new StringBuilder() |
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.append(this.getClass().getName()) |
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.append("(name=") |
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.append(this.getName()) |
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.append(",signature=") |
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.append(Arrays.asList(this.getSignature()).toString()) |
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.append(",descriptor=") |
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.append(this.getDescriptor()) |
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.append(")") |
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.toString(); |
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} |
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// return always the same string representation for this |
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// instance (immutable) |
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// |
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return myToString; |
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} |
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} |