/*

 * 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.io.InvalidObjectException;

import java.io.ObjectStreamException;

import java.math.BigDecimal;

import java.math.BigInteger;

import java.util.Date;

import java.util.Map;

import java.util.HashMap;

// jmx import

//

import javax.management.ObjectName;

/**

 * The <code>SimpleType</code> class is the <i>open type</i> class whose instances describe

 * all <i>open data</i> values which are neither arrays,

 * It predefines all its possible instances as static fields, and has no public constructor.

 * <p>

 * Given a <code>SimpleType</code> instance describing values whose Java class name is <i>className</i>,

 * the internal fields corresponding to the name and description of this <code>SimpleType</code> instance

 * are also set to <i>className</i>.

 * In other words, its methods <code>getClassName</code>, <code>getTypeName</code> and <code>getDescription</code>

 * all return the same string value <i>className</i>.

 *

 * @since 1.5

 */

public final class SimpleType<T> extends OpenType<T> {

    /* Serial version */

    static final long serialVersionUID = 2215577471957694503L;

    // SimpleType instances.

    // IF YOU ADD A SimpleType, YOU MUST UPDATE OpenType and typeArray

    /**

     * The <code>SimpleType</code> instance describing values whose

     * Java class name is <code>java.lang.Void</code>.

     */

    public static final SimpleType<Void> VOID =

        new SimpleType<Void>(Void.class);

    /**

     * The <code>SimpleType</code> instance describing values whose

     * Java class name is <code>java.lang.Boolean</code>.

     */

    public static final SimpleType<Boolean> BOOLEAN =

        new SimpleType<Boolean>(Boolean.class);

    /**

     * The <code>SimpleType</code> instance describing values whose

     * Java class name is <code>java.lang.Character</code>.

     */

    public static final SimpleType<Character> CHARACTER =

        new SimpleType<Character>(Character.class);

    /**

     * The <code>SimpleType</code> instance describing values whose

     * Java class name is <code>java.lang.Byte</code>.

     */

    public static final SimpleType<Byte> BYTE =

        new SimpleType<Byte>(Byte.class);

    /**

     * The <code>SimpleType</code> instance describing values whose

     * Java class name is <code>java.lang.Short</code>.

     */

    public static final SimpleType<Short> SHORT =

        new SimpleType<Short>(Short.class);

    /**

     * The <code>SimpleType</code> instance describing values whose

     * Java class name is <code>java.lang.Integer</code>.

     */

    public static final SimpleType<Integer> INTEGER =

        new SimpleType<Integer>(Integer.class);

    /**

     * The <code>SimpleType</code> instance describing values whose

     * Java class name is <code>java.lang.Long</code>.

     */

    public static final SimpleType<Long> LONG =

        new SimpleType<Long>(Long.class);

    /**

     * The <code>SimpleType</code> instance describing values whose

     * Java class name is <code>java.lang.Float</code>.

     */

    public static final SimpleType<Float> FLOAT =

        new SimpleType<Float>(Float.class);

    /**

     * The <code>SimpleType</code> instance describing values whose

     * Java class name is <code>java.lang.Double</code>.

     */

    public static final SimpleType<Double> DOUBLE =

        new SimpleType<Double>(Double.class);

    /**

     * The <code>SimpleType</code> instance describing values whose

     * Java class name is <code>java.lang.String</code>.

     */

    public static final SimpleType<String> STRING =

        new SimpleType<String>(String.class);

    /**

     * The <code>SimpleType</code> instance describing values whose

     * Java class name is <code>java.math.BigDecimal</code>.

     */

    public static final SimpleType<BigDecimal> BIGDECIMAL =

        new SimpleType<BigDecimal>(BigDecimal.class);

    /**

     * The <code>SimpleType</code> instance describing values whose

     * Java class name is <code>java.math.BigInteger</code>.

     */

    public static final SimpleType<BigInteger> BIGINTEGER =

        new SimpleType<BigInteger>(BigInteger.class);

    /**

     * The <code>SimpleType</code> instance describing values whose

     * Java class name is <code>java.util.Date</code>.

     */

    public static final SimpleType<Date> DATE =

        new SimpleType<Date>(Date.class);

    /**

     * The <code>SimpleType</code> instance describing values whose

     * Java class name is <code>javax.management.ObjectName</code>.

     */

    public static final SimpleType<ObjectName> OBJECTNAME =

        new SimpleType<ObjectName>(ObjectName.class);

    private static final SimpleType<?>[] typeArray = {

        VOID, BOOLEAN, CHARACTER, BYTE, SHORT, INTEGER, LONG, FLOAT,

        DOUBLE, STRING, BIGDECIMAL, BIGINTEGER, DATE, OBJECTNAME,

    };

    private transient Integer myHashCode = null;        // As this instance is immutable, these two values

    private transient String  myToString = null;        // need only be calculated once.

    /* *** Constructor *** */

    private SimpleType(Class<T> valueClass) {

        super(valueClass.getName(), valueClass.getName(), valueClass.getName(),

              false);

    }

    /* *** SimpleType specific information methods *** */

    /**

     * Tests whether <var>obj</var> is a value for this

     * <code>SimpleType</code> instance.  <p> This method returns

     * <code>true</code> if and only if <var>obj</var> is not null and

     * <var>obj</var>'s class name is the same as the className field

     * defined for this <code>SimpleType</code> instance (ie the class

     * name returned by the {@link OpenType#getClassName()

     * getClassName} method).

     *

     * @param obj the object to be tested.

     *

     * @return <code>true</code> if <var>obj</var> is a value for this

     * <code>SimpleType</code> instance.

     */

    public boolean isValue(Object obj) {

        // if obj is null, return false

        //

        if (obj == null) {

            return false;

        }

        // Test if obj's class name is the same as for this instance

        //

        return this.getClassName().equals(obj.getClass().getName());

    }

    /* *** Methods overriden from class Object *** */

    /**

     * Compares the specified <code>obj</code> parameter with this <code>SimpleType</code> instance for equality.

     * <p>

     * Two <code>SimpleType</code> instances are equal if and only if their

     * {@link OpenType#getClassName() getClassName} methods return the same value.

     *

     * @param  obj  the object to be compared for equality with this <code>SimpleType</code> instance;

     *              if <var>obj</var> is <code>null</code> or is not an instance of the class <code>SimpleType</code>,

     *              <code>equals</code> returns <code>false</code>.

     *

     * @return  <code>true</code> if the specified object is equal to this <code>SimpleType</code> instance.

     */

    public boolean equals(Object obj) {

        /* If it weren't for readReplace(), we could replace this method

           with just:

           return (this == obj);

        */

        if (!(obj instanceof SimpleType<?>))

            return false;

        SimpleType<?> other = (SimpleType<?>) obj;

        // Test if other's className field is the same as for this instance

        //

        return this.getClassName().equals(other.getClassName());

    }

    /**

     * Returns the hash code value for this <code>SimpleType</code> instance.

     * The hash code of a <code>SimpleType</code> instance is the the hash code of

     * the string value returned by the {@link OpenType#getClassName() getClassName} method.

     * <p>

     * As <code>SimpleType</code> instances are immutable, the hash code for this instance is calculated once,

     * on the first call to <code>hashCode</code>, and then the same value is returned for subsequent calls.

     *

     * @return  the hash code value for this <code>SimpleType</code> instance

     */

    public int hashCode() {

        // Calculate the hash code value if it has not yet been done (ie 1st call to hashCode())

        //

        if (myHashCode == null) {

            myHashCode = Integer.valueOf(this.getClassName().hashCode());

        }

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

        //

        return myHashCode.intValue();

    }

    /**

     * Returns a string representation of this <code>SimpleType</code> instance.

     * <p>

     * The string representation consists of

     * the name of this class (ie <code>javax.management.openmbean.SimpleType</code>) and the type name

     * for this instance (which is the java class name of the values this <code>SimpleType</code> instance represents).

     * <p>

     * As <code>SimpleType</code> instances are immutable, the string representation for this instance is calculated once,

     * on the first call to <code>toString</code>, and then the same value is returned for subsequent calls.

     *

     * @return  a string representation of this <code>SimpleType</code> instance

     */

    public String toString() {

        // Calculate the string representation if it has not yet been done (ie 1st call to toString())

        //

        if (myToString == null) {

            myToString = this.getClass().getName()+ "(name="+ getTypeName() +")";

        }

        // return always the same string representation for this instance (immutable)

        //

        return myToString;

    }

    private static final Map<SimpleType<?>,SimpleType<?>> canonicalTypes =

        new HashMap<SimpleType<?>,SimpleType<?>>();

    static {

        for (int i = 0; i < typeArray.length; i++) {

            final SimpleType<?> type = typeArray[i];

            canonicalTypes.put(type, type);

        }

    }

    /**

     * Replace an object read from an {@link

     * java.io.ObjectInputStream} with the unique instance for that

     * value.

     *

     * @return the replacement object.

     *

     * @exception ObjectStreamException if the read object cannot be

     * resolved.

     */

    public Object readResolve() throws ObjectStreamException {

        final SimpleType<?> canonical = canonicalTypes.get(this);

        if (canonical == null) {

            // Should not happen

            throw new InvalidObjectException("Invalid SimpleType: " + this);

        }

        return canonical;

    }

}