/*

 * 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.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package javax.management.openmbean;

// java import

//

import java.util.Arrays;

import java.util.HashSet;

import javax.management.Descriptor;

import javax.management.MBeanAttributeInfo;

import javax.management.MBeanConstructorInfo;

import javax.management.MBeanInfo;

import javax.management.MBeanNotificationInfo;

import javax.management.MBeanOperationInfo;

/**

 * The {@code OpenMBeanInfoSupport} class describes the management

 * information of an <i>open MBean</i>: it is a subclass of {@link

 * javax.management.MBeanInfo}, and it implements the {@link

 * OpenMBeanInfo} interface.  Note that an <i>open MBean</i> is

 * recognized as such if its {@code getMBeanInfo()} method returns an

 * instance of a class which implements the OpenMBeanInfo interface,

 * typically {@code OpenMBeanInfoSupport}.

 *

 *

 * @since 1.5

 */

public class OpenMBeanInfoSupport

    extends MBeanInfo

    implements OpenMBeanInfo {

    /* Serial version */

    static final long serialVersionUID = 4349395935420511492L;

    // 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 OpenMBeanInfoSupport} instance, which

     * describes a class of open MBeans with the specified {@code

     * className}, {@code description}, {@code openAttributes}, {@code

     * openConstructors} , {@code openOperations} and {@code

     * notifications}.</p>

     *

     * <p>The {@code openAttributes}, {@code openConstructors},

     * {@code openOperations} and {@code notifications}

     * array parameters are internally copied, so that subsequent changes

     * to the arrays referenced by these parameters have no effect on this

     * instance.</p>

     *

     * @param className The fully qualified Java class name of the

     * open MBean described by this <CODE>OpenMBeanInfoSupport</CODE>

     * instance.

     *

     * @param description A human readable description of the open

     * MBean described by this <CODE>OpenMBeanInfoSupport</CODE>

     * instance.

     *

     * @param openAttributes The list of exposed attributes of the

     * described open MBean; Must be an array of instances of a

     * subclass of {@code MBeanAttributeInfo}, typically {@code

     * OpenMBeanAttributeInfoSupport}.

     *

     * @param openConstructors The list of exposed public constructors

     * of the described open MBean; Must be an array of instances of a

     * subclass of {@code MBeanConstructorInfo}, typically {@code

     * OpenMBeanConstructorInfoSupport}.

     *

     * @param openOperations The list of exposed operations of the

     * described open MBean.  Must be an array of instances of a

     * subclass of {@code MBeanOperationInfo}, typically {@code

     * OpenMBeanOperationInfoSupport}.

     *

     * @param notifications The list of notifications emitted by the

     * described open MBean.

     *

     * @throws ArrayStoreException If {@code openAttributes}, {@code

     * openConstructors} or {@code openOperations} is not an array of

     * instances of a subclass of {@code MBeanAttributeInfo}, {@code

     * MBeanConstructorInfo} or {@code MBeanOperationInfo}

     * respectively.

     */

    public OpenMBeanInfoSupport(String className,

                                String description,

                                OpenMBeanAttributeInfo[] openAttributes,

                                OpenMBeanConstructorInfo[] openConstructors,

                                OpenMBeanOperationInfo[] openOperations,

                                MBeanNotificationInfo[] notifications) {

        this(className, description,

             openAttributes, openConstructors, openOperations, notifications,

             (Descriptor) null);

    }

    /**

     * <p>Constructs an {@code OpenMBeanInfoSupport} instance, which

     * describes a class of open MBeans with the specified {@code

     * className}, {@code description}, {@code openAttributes}, {@code

     * openConstructors} , {@code openOperations}, {@code

     * notifications}, and {@code descriptor}.</p>

     *

     * <p>The {@code openAttributes}, {@code openConstructors}, {@code

     * openOperations} and {@code notifications} array parameters are

     * internally copied, so that subsequent changes to the arrays

     * referenced by these parameters have no effect on this

     * instance.</p>

     *

     * @param className The fully qualified Java class name of the

     * open MBean described by this <CODE>OpenMBeanInfoSupport</CODE>

     * instance.

     *

     * @param description A human readable description of the open

     * MBean described by this <CODE>OpenMBeanInfoSupport</CODE>

     * instance.

     *

     * @param openAttributes The list of exposed attributes of the

     * described open MBean; Must be an array of instances of a

     * subclass of {@code MBeanAttributeInfo}, typically {@code

     * OpenMBeanAttributeInfoSupport}.

     *

     * @param openConstructors The list of exposed public constructors

     * of the described open MBean; Must be an array of instances of a

     * subclass of {@code MBeanConstructorInfo}, typically {@code

     * OpenMBeanConstructorInfoSupport}.

     *

     * @param openOperations The list of exposed operations of the

     * described open MBean.  Must be an array of instances of a

     * subclass of {@code MBeanOperationInfo}, typically {@code

     * OpenMBeanOperationInfoSupport}.

     *

     * @param notifications The list of notifications emitted by the

     * described open MBean.

     *

     * @param descriptor The descriptor for the MBean.  This may be null

     * which is equivalent to an empty descriptor.

     *

     * @throws ArrayStoreException If {@code openAttributes}, {@code

     * openConstructors} or {@code openOperations} is not an array of

     * instances of a subclass of {@code MBeanAttributeInfo}, {@code

     * MBeanConstructorInfo} or {@code MBeanOperationInfo}

     * respectively.

     *

     * @since 1.6

     */

    public OpenMBeanInfoSupport(String className,

                                String description,

                                OpenMBeanAttributeInfo[] openAttributes,

                                OpenMBeanConstructorInfo[] openConstructors,

                                OpenMBeanOperationInfo[] openOperations,

                                MBeanNotificationInfo[] notifications,

                                Descriptor descriptor) {

        super(className,

              description,

              attributeArray(openAttributes),

              constructorArray(openConstructors),

              operationArray(openOperations),

              (notifications == null) ? null : notifications.clone(),

              descriptor);

    }

    private static MBeanAttributeInfo[]

            attributeArray(OpenMBeanAttributeInfo[] src) {

        if (src == null)

            return null;

        MBeanAttributeInfo[] dst = new MBeanAttributeInfo[src.length];

        System.arraycopy(src, 0, dst, 0, src.length);

        // may throw an ArrayStoreException

        return dst;

    }

    private static MBeanConstructorInfo[]

            constructorArray(OpenMBeanConstructorInfo[] src) {

        if (src == null)

            return null;

        MBeanConstructorInfo[] dst = new MBeanConstructorInfo[src.length];

        System.arraycopy(src, 0, dst, 0, src.length);

        // may throw an ArrayStoreException

        return dst;

    }

    private static MBeanOperationInfo[]

            operationArray(OpenMBeanOperationInfo[] src) {

        if (src == null)

            return null;

        MBeanOperationInfo[] dst = new MBeanOperationInfo[src.length];

        System.arraycopy(src, 0, dst, 0, src.length);

        return dst;

    }

    /* ***  Commodity methods from java.lang.Object  *** */

    /**

     * <p>Compares the specified {@code obj} parameter with this

     * {@code OpenMBeanInfoSupport} 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 OpenMBeanInfo}

     * interface,</li>

     * <li>their class names are equal</li>

     * <li>their infos on attributes, constructors, operations and

     * notifications are equal</li>

     * </ul>

     *

     * This ensures that this {@code equals} method works properly for

     * {@code obj} parameters which are different implementations of

     * the {@code OpenMBeanInfo} interface.

     *

     * @param obj the object to be compared for equality with this

     * {@code OpenMBeanInfoSupport} instance;

     *

     * @return {@code true} if the specified object is equal to this

     * {@code OpenMBeanInfoSupport} instance.

     */

    public boolean equals(Object obj) {

        // if obj is null, return false

        //

        if (obj == null) {

            return false;

        }

        // if obj is not a OpenMBeanInfo, return false

        //

        OpenMBeanInfo other;

        try {

            other = (OpenMBeanInfo) obj;

        } catch (ClassCastException e) {

            return false;

        }

        // Now, really test for equality between this OpenMBeanInfo

        // implementation and the other:

        //

        // their MBean className should be equal

        if ( ! this.getClassName().equals(other.getClassName()) )

            return false;

        // their infos on attributes should be equal (order not

        // significant => equality between sets, not arrays or lists)

        if (!sameArrayContents(this.getAttributes(), other.getAttributes()))

            return false;

        // their infos on constructors should be equal (order not

        // significant => equality between sets, not arrays or lists)

        if (!sameArrayContents(this.getConstructors(), other.getConstructors()))

            return false;

        // their infos on operations should be equal (order not

        // significant => equality between sets, not arrays or lists)

        if (!sameArrayContents(this.getOperations(), other.getOperations()))

            return false;

        // their infos on notifications should be equal (order not

        // significant => equality between sets, not arrays or lists)

        if (!sameArrayContents(this.getNotifications(), other.getNotifications()))

            return false;

        // All tests for equality were successful

        //

        return true;

    }

    private static <T> boolean sameArrayContents(T[] a1, T[] a2) {

        return (new HashSet<T>(Arrays.asList(a1))

                .equals(new HashSet<T>(Arrays.asList(a2))));

    }

    /**

     * <p>Returns the hash code value for this {@code

     * OpenMBeanInfoSupport} instance.</p>

     *

     * <p>The hash code of an {@code OpenMBeanInfoSupport} instance is

     * the sum of the hash codes of all elements of information used

     * in {@code equals} comparisons (ie: its class name, and its

     * infos on attributes, constructors, operations and

     * notifications, where the hashCode of each of these arrays is

     * calculated by a call to {@code new

     * java.util.HashSet(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

     * OpenMBeanInfoSupport} 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 OpenMBeanInfo} interface may be equal to this {@code

     * OpenMBeanInfoSupport} 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 OpenMBeanInfoSupport} 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

     * OpenMBeanInfoSupport} 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.getClassName().hashCode();

            value += arraySetHash(this.getAttributes());

            value += arraySetHash(this.getConstructors());

            value += arraySetHash(this.getOperations());

            value += arraySetHash(this.getNotifications());

            myHashCode = Integer.valueOf(value);

        }

        // return always the same hash code for this instance (immutable)

        //

        return myHashCode.intValue();

    }

    private static <T> int arraySetHash(T[] a) {

        return new HashSet<T>(Arrays.asList(a)).hashCode();

    }

    /**

     * <p>Returns a string representation of this {@code

     * OpenMBeanInfoSupport} instance.</p>

     *

     * <p>The string representation consists of the name of this class

     * (ie {@code javax.management.openmbean.OpenMBeanInfoSupport}),

     * the MBean class name, the string representation of infos on

     * attributes, constructors, operations and notifications of the

     * described MBean and the string representation of the descriptor.</p>

     *

     * <p>As {@code OpenMBeanInfoSupport} 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

     * OpenMBeanInfoSupport} 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("(mbean_class_name=")

                .append(this.getClassName())

                .append(",attributes=")

                .append(Arrays.asList(this.getAttributes()).toString())

                .append(",constructors=")

                .append(Arrays.asList(this.getConstructors()).toString())

                .append(",operations=")

                .append(Arrays.asList(this.getOperations()).toString())

                .append(",notifications=")

                .append(Arrays.asList(this.getNotifications()).toString())

                .append(",descriptor=")

                .append(this.getDescriptor())

                .append(")")

                .toString();

        }

        // return always the same string representation for this

        // instance (immutable)

        //

        return myToString;

    }

}