305 lines · 10.9 KB · Java
RawDownload
/* * Copyright (c) 2000, 2008, 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. */  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. * * * @since 1.5 */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 = Integer.valueOf(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 StringBuilder()                .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;    } }