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/*
* Copyright (c) 1996, 2002, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
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* 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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/*
* (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;
/**
* FieldPosition
is a simple class used by Format
* and its subclasses to identify fields in formatted output. Fields can
* be identified in two ways:
*
* - By an integer constant, whose names typically end with
*
_FIELD
. The constants are defined in the various
* subclasses of Format
.
* - By a
Format.Field
constant, see ERA_FIELD
* and its friends in DateFormat
for an example.
*
*
* FieldPosition
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.
*
*
* One version of the format
method in the various
* Format
classes requires a FieldPosition
* object as an argument. You use this format
method
* to perform partial formatting or to get information about the
* formatted output (such as the position of a field).
*
*
* If you are interested in the positions of all attributes in the
* formatted string use the Format
method
* formatToCharacterIterator
.
*
* @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 Format
* subclasses. This is equivalent to calling
* new FieldPosition(attribute, -1)
.
*
* @param attribute Format.Field constant identifying a field
* @since 1.4
*/
public FieldPosition(Format.Field attribute)
{
this(attribute, -1);
}
/**
* Creates a FieldPosition
object for the given field.
* The field is identified by an attribute constant from one of the
* Field
subclasses as well as an integer field ID
* defined by the Format
subclasses. Format
* subclasses that are aware of Field
should give precedence
* to attribute
and ignore fieldID
if
* attribute
is not null. However, older Format
* subclasses may not be aware of Field
and rely on
* fieldID
. If the field has no corresponding integer
* constant, fieldID
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 Field
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 Format.FieldDelegate
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 Format.Field
value and
* attribute
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 Format.Field
value and
* attribute
is equal to it, or true if the receiver
* represents an inteter constant and field
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 formatted
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);
}
}
}
}