/*

 * Copyright 1996-2006 Sun Microsystems, Inc.  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.  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 java.io;

import java.lang.reflect.Field;

/**

 * A description of a Serializable field from a Serializable class.  An array

 * of ObjectStreamFields is used to declare the Serializable fields of a class.

 *

 * @author      Mike Warres

 * @author      Roger Riggs

 * @see ObjectStreamClass

 * @since 1.2

 */

public class ObjectStreamField

    implements Comparable<Object>

{

    /** field name */

    private final String name;

    /** canonical JVM signature of field type */

    private final String signature;

    /** field type (Object.class if unknown non-primitive type) */

    private final Class type;

    /** whether or not to (de)serialize field values as unshared */

    private final boolean unshared;

    /** corresponding reflective field object, if any */

    private final Field field;

    /** offset of field value in enclosing field group */

    private int offset = 0;

    /**

     * Create a Serializable field with the specified type.  This field should

     * be documented with a <code>serialField</code> tag.

     *

     * @param   name the name of the serializable field

     * @param   type the <code>Class</code> object of the serializable field

     */

    public ObjectStreamField(String name, Class<?> type) {

        this(name, type, false);

    }

    /**

     * Creates an ObjectStreamField representing a serializable field with the

     * given name and type.  If unshared is false, values of the represented

     * field are serialized and deserialized in the default manner--if the

     * field is non-primitive, object values are serialized and deserialized as

     * if they had been written and read by calls to writeObject and

     * readObject.  If unshared is true, values of the represented field are

     * serialized and deserialized as if they had been written and read by

     * calls to writeUnshared and readUnshared.

     *

     * @param   name field name

     * @param   type field type

     * @param   unshared if false, write/read field values in the same manner

     *          as writeObject/readObject; if true, write/read in the same

     *          manner as writeUnshared/readUnshared

     * @since   1.4

     */

    public ObjectStreamField(String name, Class<?> type, boolean unshared) {

        if (name == null) {

            throw new NullPointerException();

        }

        this.name = name;

        this.type = type;

        this.unshared = unshared;

        signature = ObjectStreamClass.getClassSignature(type).intern();

        field = null;

    }

    /**

     * Creates an ObjectStreamField representing a field with the given name,

     * signature and unshared setting.

     */

    ObjectStreamField(String name, String signature, boolean unshared) {

        if (name == null) {

            throw new NullPointerException();

        }

        this.name = name;

        this.signature = signature.intern();

        this.unshared = unshared;

        field = null;

        switch (signature.charAt(0)) {

            case 'Z': type = Boolean.TYPE; break;

            case 'B': type = Byte.TYPE; break;

            case 'C': type = Character.TYPE; break;

            case 'S': type = Short.TYPE; break;

            case 'I': type = Integer.TYPE; break;

            case 'J': type = Long.TYPE; break;

            case 'F': type = Float.TYPE; break;

            case 'D': type = Double.TYPE; break;

            case 'L':

            case '[': type = Object.class; break;

            default: throw new IllegalArgumentException("illegal signature");

        }

    }

    /**

     * Creates an ObjectStreamField representing the given field with the

     * specified unshared setting.  For compatibility with the behavior of

     * earlier serialization implementations, a "showType" parameter is

     * necessary to govern whether or not a getType() call on this

     * ObjectStreamField (if non-primitive) will return Object.class (as

     * opposed to a more specific reference type).

     */

    ObjectStreamField(Field field, boolean unshared, boolean showType) {

        this.field = field;

        this.unshared = unshared;

        name = field.getName();

        Class ftype = field.getType();

        type = (showType || ftype.isPrimitive()) ? ftype : Object.class;

        signature = ObjectStreamClass.getClassSignature(ftype).intern();

    }

    /**

     * Get the name of this field.

     *

     * @return  a <code>String</code> representing the name of the serializable

     *          field

     */

    public String getName() {

        return name;

    }

    /**

     * Get the type of the field.  If the type is non-primitive and this

     * <code>ObjectStreamField</code> was obtained from a deserialized {@link

     * ObjectStreamClass} instance, then <code>Object.class</code> is returned.

     * Otherwise, the <code>Class</code> object for the type of the field is

     * returned.

     *

     * @return  a <code>Class</code> object representing the type of the

     *          serializable field

     */

    public Class<?> getType() {

        return type;

    }

    /**

     * Returns character encoding of field type.  The encoding is as follows:

     * <blockquote><pre>

     * B            byte

     * C            char

     * D            double

     * F            float

     * I            int

     * J            long

     * L            class or interface

     * S            short

     * Z            boolean

     * [            array

     * </pre></blockquote>

     *

     * @return  the typecode of the serializable field

     */

    // REMIND: deprecate?

    public char getTypeCode() {

        return signature.charAt(0);

    }

    /**

     * Return the JVM type signature.

     *

     * @return  null if this field has a primitive type.

     */

    // REMIND: deprecate?

    public String getTypeString() {

        return isPrimitive() ? null : signature;

    }

    /**

     * Offset of field within instance data.

     *

     * @return  the offset of this field

     * @see #setOffset

     */

    // REMIND: deprecate?

    public int getOffset() {

        return offset;

    }

    /**

     * Offset within instance data.

     *

     * @param   offset the offset of the field

     * @see #getOffset

     */

    // REMIND: deprecate?

    protected void setOffset(int offset) {

        this.offset = offset;

    }

    /**

     * Return true if this field has a primitive type.

     *

     * @return  true if and only if this field corresponds to a primitive type

     */

    // REMIND: deprecate?

    public boolean isPrimitive() {

        char tcode = signature.charAt(0);

        return ((tcode != 'L') && (tcode != '['));

    }

    /**

     * Returns boolean value indicating whether or not the serializable field

     * represented by this ObjectStreamField instance is unshared.

     *

     * @since 1.4

     */

    public boolean isUnshared() {

        return unshared;

    }

    /**

     * Compare this field with another <code>ObjectStreamField</code>.  Return

     * -1 if this is smaller, 0 if equal, 1 if greater.  Types that are

     * primitives are "smaller" than object types.  If equal, the field names

     * are compared.

     */

    // REMIND: deprecate?

    public int compareTo(Object obj) {

        ObjectStreamField other = (ObjectStreamField) obj;

        boolean isPrim = isPrimitive();

        if (isPrim != other.isPrimitive()) {

            return isPrim ? -1 : 1;

        }

        return name.compareTo(other.name);

    }

    /**

     * Return a string that describes this field.

     */

    public String toString() {

        return signature + ' ' + name;

    }

    /**

     * Returns field represented by this ObjectStreamField, or null if

     * ObjectStreamField is not associated with an actual field.

     */

    Field getField() {

        return field;

    }

    /**

     * Returns JVM type signature of field (similar to getTypeString, except

     * that signature strings are returned for primitive fields as well).

     */

    String getSignature() {

        return signature;

    }

}