jdk/src/share/classes/java/text/FieldPosition.java
changeset 2 90ce3da70b43
child 5506 202f599c92aa
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/text/FieldPosition.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,303 @@
+/*
+ * Copyright 1996-2002 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.
+ */
+
+/*
+ * (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);
+            }
+        }
+    }
+}