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 * 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.ImmutableDescriptor;

import javax.management.MBeanOperationInfo;

import javax.management.MBeanParameterInfo;

/**

 * Describes an operation of an Open MBean.

 *

 *

 * @since 1.5

 */

public class OpenMBeanOperationInfoSupport

    extends MBeanOperationInfo

    implements OpenMBeanOperationInfo {

    /* Serial version */

    static final long serialVersionUID = 4996859732565369366L;

    /**

     * @serial The <i>open type</i> of the values returned by the operation

     *         described by this {@link OpenMBeanOperationInfo} instance

     *

     */

    private OpenType<?> returnOpenType;

    // 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 OpenMBeanOperationInfoSupport}

     * instance, which describes the operation of a class of open

     * MBeans, with the specified {@code name}, {@code description},

     * {@code signature}, {@code returnOpenType} and {@code

     * impact}.</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 returnOpenType cannot be null: use {@code

     * SimpleType.VOID} for operations that return nothing.

     *

     * @param impact must be one of {@code ACTION}, {@code

     * ACTION_INFO}, {@code INFO}, or {@code UNKNOWN}.

     *

     * @throws IllegalArgumentException if {@code name} or {@code

     * description} are null or empty string, or {@code

     * returnOpenType} is null, or {@code impact} is not one of {@code

     * ACTION}, {@code ACTION_INFO}, {@code INFO}, or {@code UNKNOWN}.

     *

     * @throws ArrayStoreException If {@code signature} is not an

     * array of instances of a subclass of {@code MBeanParameterInfo}.

     */

    public OpenMBeanOperationInfoSupport(String name,

                                         String description,

                                         OpenMBeanParameterInfo[] signature,

                                         OpenType<?> returnOpenType,

                                         int impact) {

        this(name, description, signature, returnOpenType, impact,

             (Descriptor) null);

    }

    /**

     * <p>Constructs an {@code OpenMBeanOperationInfoSupport}

     * instance, which describes the operation of a class of open

     * MBeans, with the specified {@code name}, {@code description},

     * {@code signature}, {@code returnOpenType}, {@code

     * impact}, 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 returnOpenType cannot be null: use {@code

     * SimpleType.VOID} for operations that return nothing.

     *

     * @param impact must be one of {@code ACTION}, {@code

     * ACTION_INFO}, {@code INFO}, or {@code UNKNOWN}.

     *

     * @param descriptor The descriptor for the operation.  This may

     * be null, which is equivalent to an empty descriptor.

     *

     * @throws IllegalArgumentException if {@code name} or {@code

     * description} are null or empty string, or {@code

     * returnOpenType} is null, or {@code impact} is not one of {@code

     * ACTION}, {@code ACTION_INFO}, {@code INFO}, or {@code UNKNOWN}.

     *

     * @throws ArrayStoreException If {@code signature} is not an

     * array of instances of a subclass of {@code MBeanParameterInfo}.

     *

     * @since 1.6

     */

    public OpenMBeanOperationInfoSupport(String name,

                                         String description,

                                         OpenMBeanParameterInfo[] signature,

                                         OpenType<?> returnOpenType,

                                         int impact,

                                         Descriptor descriptor) {

        super(name,

              description,

              arrayCopyCast(signature),

              // must prevent NPE here - we will throw IAE later on if

              // returnOpenType is null

              (returnOpenType == null) ? null : returnOpenType.getClassName(),

              impact,

              ImmutableDescriptor.union(descriptor,

                // must prevent NPE here - we will throw IAE later on if

                // returnOpenType is null

                (returnOpenType==null) ? null :returnOpenType.getDescriptor()));

        // 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");

        }

        if (returnOpenType == null) {

            throw new IllegalArgumentException("Argument returnOpenType " +

                                               "cannot be null");

        }

        if (impact != ACTION && impact != ACTION_INFO && impact != INFO &&

                impact != UNKNOWN) {

            throw new IllegalArgumentException("Argument impact can only be " +

                                               "one of ACTION, ACTION_INFO, " +

                                               "INFO, or UNKNOWN: " + impact);

        }

        this.returnOpenType = returnOpenType;

    }

    // Converts an array of OpenMBeanParameterInfo objects extending

    // MBeanParameterInfo into an array of MBeanParameterInfo.

    //

    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;

    }

    // Converts an array of MBeanParameterInfo objects implementing

    // OpenMBeanParameterInfo into an array of OpenMBeanParameterInfo.

    //

    private static OpenMBeanParameterInfo[]

            arrayCopyCast(MBeanParameterInfo[] src) {

        if (src == null)

            return null;

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

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

        // may throw an ArrayStoreException

        return dst;

    }

    // [JF]: should we add constructor with java.lang.reflect.Method

    // method parameter ?  would need to add consistency check between

    // OpenType<?> returnOpenType and method.getReturnType().

    /**

     * Returns the <i>open type</i> of the values returned by the

     * operation described by this {@code OpenMBeanOperationInfo}

     * instance.

     */

    public OpenType<?> getReturnOpenType() {

        return returnOpenType;

    }

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

    /**

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

     * {@code OpenMBeanOperationInfoSupport} 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

     * OpenMBeanOperationInfo} interface,</li>

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

     * <li>their signatures are equal</li>

     * <li>their return open types are equal</li>

     * <li>their impacts are equal</li>

     * </ul>

     *

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

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

     * the {@code OpenMBeanOperationInfo} interface.

     *

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

     * {@code OpenMBeanOperationInfoSupport} instance;

     *

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

     * {@code OpenMBeanOperationInfoSupport} instance.

     */

    public boolean equals(Object obj) {

        // if obj is null, return false

        //

        if (obj == null) {

            return false;

        }

        // if obj is not a OpenMBeanOperationInfo, return false

        //

        OpenMBeanOperationInfo other;

        try {

            other = (OpenMBeanOperationInfo) obj;

        } catch (ClassCastException e) {

            return false;

        }

        // Now, really test for equality between this

        // OpenMBeanOperationInfo 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;

        }

        // their return open types should be equal

        if ( ! this.getReturnOpenType().equals(other.getReturnOpenType()) ) {

            return false;

        }

        // their impacts should be equal

        if ( this.getImpact() != other.getImpact() ) {

            return false;

        }

        // All tests for equality were successfull

        //

        return true;

    }

    /**

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

     * OpenMBeanOperationInfoSupport} instance.</p>

     *

     * <p>The hash code of an {@code OpenMBeanOperationInfoSupport}

     * instance is the sum of the hash codes of all elements of

     * information used in {@code equals} comparisons (ie: its name,

     * return open type, impact 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

     * OpenMBeanOperationInfoSupport} 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 OpenMBeanOperationInfo} interface may be equal to

     * this {@code OpenMBeanOperationInfoSupport} 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 OpenMBeanOperationInfoSupport} 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

     * OpenMBeanOperationInfoSupport} 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();

            value += this.getReturnOpenType().hashCode();

            value += this.getImpact();

            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

     * OpenMBeanOperationInfoSupport} instance.</p>

     *

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

     * (ie {@code

     * javax.management.openmbean.OpenMBeanOperationInfoSupport}), and

     * the name, signature, return open type and impact of the

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

     *

     * <p>As {@code OpenMBeanOperationInfoSupport} 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

     * OpenMBeanOperationInfoSupport} 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 StringBuilder()

                .append(this.getClass().getName())

                .append("(name=")

                .append(this.getName())

                .append(",signature=")

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

                .append(",return=")

                .append(this.getReturnOpenType().toString())

                .append(",impact=")

                .append(this.getImpact())

                .append(",descriptor=")

                .append(this.getDescriptor())

                .append(")")

                .toString();

        }

        // return always the same string representation for this

        // instance (immutable)

        //

        return myToString;

    }

    /**

     * An object serialized in a version of the API before Descriptors were

     * added to this class will have an empty or null Descriptor.

     * For consistency with our

     * behavior in this version, we must replace the object with one

     * where the Descriptors reflect the same value of returned openType.

     **/

    private Object readResolve() {

        if (getDescriptor().getFieldNames().length == 0) {

            // This constructor will construct the expected default Descriptor.

            //

            return new OpenMBeanOperationInfoSupport(

                    name, description, arrayCopyCast(getSignature()),

                    returnOpenType, getImpact());

        } else

            return this;

    }

}