/*

  * Copyright (c) 1996, 2002, 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.

  */

 /*

  * (C) Copyright Taligent, Inc. 1996 - All Rights Reserved

  * (C) Copyright IBM Corp. 1996 - All Rights Reserved

  *

  *   The original version of this source code and documentation is copyrighted

  * and owned by Taligent, Inc., a wholly-owned subsidiary of IBM. These

  * materials are provided under terms of a License Agreement between Taligent

  * and Sun. This technology is protected by multiple US and International

  * patents. This notice and attribution to Taligent may not be removed.

  *   Taligent is a registered trademark of Taligent, Inc.

  *

  */

 package java.text;

 /**

  * <code>FieldPosition</code> is a simple class used by <code>Format</code>

  * and its subclasses to identify fields in formatted output. Fields can

  * be identified in two ways:

  * <ul>

  *  <li>By an integer constant, whose names typically end with

  *      <code>_FIELD</code>. The constants are defined in the various

  *      subclasses of <code>Format</code>.

  *  <li>By a <code>Format.Field</code> constant, see <code>ERA_FIELD</code>

  *      and its friends in <code>DateFormat</code> for an example.

  * </ul>

  * <p>

  * <code>FieldPosition</code> keeps track of the position of the

  * field within the formatted output with two indices: the index

  * of the first character of the field and the index of the last

  * character of the field.

  *

  * <p>

  * One version of the <code>format</code> method in the various

  * <code>Format</code> classes requires a <code>FieldPosition</code>

  * object as an argument. You use this <code>format</code> method

  * to perform partial formatting or to get information about the

  * formatted output (such as the position of a field).

  *

  * <p>

  * If you are interested in the positions of all attributes in the

  * formatted string use the <code>Format</code> method

  * <code>formatToCharacterIterator</code>.

  *

  * @author      Mark Davis

  * @see         java.text.Format

  */

 public class FieldPosition {

     /**

      * Input: Desired field to determine start and end offsets for.

      * The meaning depends on the subclass of Format.

      */

     int field = 0;

     /**

      * Output: End offset of field in text.

      * If the field does not occur in the text, 0 is returned.

      */

     int endIndex = 0;

     /**

      * Output: Start offset of field in text.

      * If the field does not occur in the text, 0 is returned.

      */

     int beginIndex = 0;

     /**

      * Desired field this FieldPosition is for.

      */

     private Format.Field attribute;

     /**

      * Creates a FieldPosition object for the given field.  Fields are

      * identified by constants, whose names typically end with _FIELD,

      * in the various subclasses of Format.

      *

      * @see java.text.NumberFormat#INTEGER_FIELD

      * @see java.text.NumberFormat#FRACTION_FIELD

      * @see java.text.DateFormat#YEAR_FIELD

      * @see java.text.DateFormat#MONTH_FIELD

      */

     public FieldPosition(int field) {

         this.field = field;

     }

     /**

      * Creates a FieldPosition object for the given field constant. Fields are

      * identified by constants defined in the various <code>Format</code>

      * subclasses. This is equivalent to calling

      * <code>new FieldPosition(attribute, -1)</code>.

      *

      * @param attribute Format.Field constant identifying a field

      * @since 1.4

      */

     public FieldPosition(Format.Field attribute) {

         this(attribute, -1);

     }

     /**

      * Creates a <code>FieldPosition</code> object for the given field.

      * The field is identified by an attribute constant from one of the

      * <code>Field</code> subclasses as well as an integer field ID

      * defined by the <code>Format</code> subclasses. <code>Format</code>

      * subclasses that are aware of <code>Field</code> should give precedence

      * to <code>attribute</code> and ignore <code>fieldID</code> if

      * <code>attribute</code> is not null. However, older <code>Format</code>

      * subclasses may not be aware of <code>Field</code> and rely on

      * <code>fieldID</code>. If the field has no corresponding integer

      * constant, <code>fieldID</code> should be -1.

      *

      * @param attribute Format.Field constant identifying a field

      * @param fieldID integer constantce identifying a field

      * @since 1.4

      */

     public FieldPosition(Format.Field attribute, int fieldID) {

         this.attribute = attribute;

         this.field = fieldID;

     }

     /**

      * Returns the field identifier as an attribute constant

      * from one of the <code>Field</code> subclasses. May return null if

      * the field is specified only by an integer field ID.

      *

      * @return Identifier for the field

      * @since 1.4

      */

     public Format.Field getFieldAttribute() {

         return attribute;

     }

     /**

      * Retrieves the field identifier.

      */

     public int getField() {

         return field;

     }

     /**

      * Retrieves the index of the first character in the requested field.

      */

     public int getBeginIndex() {

         return beginIndex;

     }

     /**

      * Retrieves the index of the character following the last character in the

      * requested field.

      */

     public int getEndIndex() {

         return endIndex;

     }

     /**

      * Sets the begin index.  For use by subclasses of Format.

      * @since 1.2

      */

     public void setBeginIndex(int bi) {

         beginIndex = bi;

     }

     /**

      * Sets the end index.  For use by subclasses of Format.

      * @since 1.2

      */

     public void setEndIndex(int ei) {

         endIndex = ei;

     }

     /**

      * Returns a <code>Format.FieldDelegate</code> instance that is associated

      * with the FieldPosition. When the delegate is notified of the same

      * field the FieldPosition is associated with, the begin/end will be

      * adjusted.

      */

     Format.FieldDelegate getFieldDelegate() {

         return new Delegate();

     }

     /**

      * Overrides equals

      */

     public boolean equals(Object obj)

     {

         if (obj == null) return false;

         if (!(obj instanceof FieldPosition))

             return false;

         FieldPosition other = (FieldPosition) obj;

         if (attribute == null) {

             if (other.attribute != null) {

                 return false;

             }

         }

         else if (!attribute.equals(other.attribute)) {

             return false;

         }

         return (beginIndex == other.beginIndex

             && endIndex == other.endIndex

             && field == other.field);

     }

     /**

      * Returns a hash code for this FieldPosition.

      * @return a hash code value for this object

      */

     public int hashCode() {

         return (field << 24) | (beginIndex << 16) | endIndex;

     }

     /**

      * Return a string representation of this FieldPosition.

      * @return  a string representation of this object

      */

     public String toString() {

         return getClass().getName() +

             "[field=" + field + ",attribute=" + attribute +

             ",beginIndex=" + beginIndex +

             ",endIndex=" + endIndex + ']';

     }

     /**

      * Return true if the receiver wants a <code>Format.Field</code> value and

      * <code>attribute</code> is equal to it.

      */

     private boolean matchesField(Format.Field attribute) {

         if (this.attribute != null) {

             return this.attribute.equals(attribute);

         }

         return false;

     }

     /**

      * Return true if the receiver wants a <code>Format.Field</code> value and

      * <code>attribute</code> is equal to it, or true if the receiver

      * represents an inteter constant and <code>field</code> equals it.

      */

     private boolean matchesField(Format.Field attribute, int field) {

         if (this.attribute != null) {

             return this.attribute.equals(attribute);

         }

         return (field == this.field);

     }

     /**

      * An implementation of FieldDelegate that will adjust the begin/end

      * of the FieldPosition if the arguments match the field of

      * the FieldPosition.

      */

     private class Delegate implements Format.FieldDelegate {

         /**

          * Indicates whether the field has been  encountered before. If this

          * is true, and <code>formatted</code> is invoked, the begin/end

          * are not updated.

          */

         private boolean encounteredField;

         public void formatted(Format.Field attr, Object value, int start,

                               int end, StringBuffer buffer) {

             if (!encounteredField && matchesField(attr)) {

                 setBeginIndex(start);

                 setEndIndex(end);

                 encounteredField = (start != end);

             }

         }

         public void formatted(int fieldID, Format.Field attr, Object value,

                               int start, int end, StringBuffer buffer) {

             if (!encounteredField && matchesField(attr, fieldID)) {

                 setBeginIndex(start);

                 setEndIndex(end);

                 encounteredField = (start != end);

             }

         }

     }

 }