/*

 * 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

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 */

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 :-( ! )

        //

            throw new IllegalArgumentException("Argument name cannot be " +

                                               "null or empty");

        }

            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;

    }

}