/*
 * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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/*
 * (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
 * @since 1.1
 * @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.
 *
 * @param field the field identifier
 * @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 constant 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.
 *
 * @return the field identifier
 */
 public int getField() {
 return field;
 }

 /**
 * Retrieves the index of the first character in the requested field.
 *
 * @return the begin index
 */
 public int getBeginIndex() {
 return beginIndex;
 }

 /**
 * Retrieves the index of the character following the last character in the
 * requested field.
 *
 * @return the end index
 */
 public int getEndIndex() {
 return endIndex;
 }

 /**
 * Sets the begin index. For use by subclasses of Format.
 *
 * @param bi the begin index
 * @since 1.2
 */
 public void setBeginIndex(int bi) {
 beginIndex = bi;
 }

 /**
 * Sets the end index. For use by subclasses of Format.
 *
 * @param ei the end index
 * @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);
 }
 }
 }
}