/* * Copyright (c) 1996, 2005, 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, 1997 - All Rights Reserved * (C) Copyright IBM Corp. 1996 - 1998 - 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; import java.io.Serializable; /** * <code>Format</code> is an abstract base class for formatting locale-sensitive * information such as dates, messages, and numbers. * * <p> * <code>Format</code> defines the programming interface for formatting * locale-sensitive objects into <code>String</code>s (the * <code>format</code> method) and for parsing <code>String</code>s back * into objects (the <code>parseObject</code> method). * * <p> * Generally, a format's <code>parseObject</code> method must be able to parse * any string formatted by its <code>format</code> method. However, there may * be exceptional cases where this is not possible. For example, a * <code>format</code> method might create two adjacent integer numbers with * no separator in between, and in this case the <code>parseObject</code> could * not tell which digits belong to which number. * * <h4>Subclassing</h4> * * <p> * The Java Platform provides three specialized subclasses of <code>Format</code>-- * <code>DateFormat</code>, <code>MessageFormat</code>, and * <code>NumberFormat</code>--for formatting dates, messages, and numbers, * respectively. * <p> * Concrete subclasses must implement three methods: * <ol> * <li> <code>format(Object obj, StringBuffer toAppendTo, FieldPosition pos)</code> * <li> <code>formatToCharacterIterator(Object obj)</code> * <li> <code>parseObject(String source, ParsePosition pos)</code> * </ol> * These general methods allow polymorphic parsing and formatting of objects * and are used, for example, by <code>MessageFormat</code>. * Subclasses often also provide additional <code>format</code> methods for * specific input types as well as <code>parse</code> methods for specific * result types. Any <code>parse</code> method that does not take a * <code>ParsePosition</code> argument should throw <code>ParseException</code> * when no text in the required format is at the beginning of the input text. * * <p> * Most subclasses will also implement the following factory methods: * <ol> * <li> * <code>getInstance</code> for getting a useful format object appropriate * for the current locale * <li> * <code>getInstance(Locale)</code> for getting a useful format * object appropriate for the specified locale * </ol> * In addition, some subclasses may also implement other * <code>getXxxxInstance</code> methods for more specialized control. For * example, the <code>NumberFormat</code> class provides * <code>getPercentInstance</code> and <code>getCurrencyInstance</code> * methods for getting specialized number formatters. * * <p> * Subclasses of <code>Format</code> that allow programmers to create objects * for locales (with <code>getInstance(Locale)</code> for example) * must also implement the following class method: * <blockquote> * <pre> * public static Locale[] getAvailableLocales() * </pre> * </blockquote> * * <p> * And finally subclasses may define a set of constants to identify the various * fields in the formatted output. These constants are used to create a FieldPosition * object which identifies what information is contained in the field and its * position in the formatted result. These constants should be named * <code><em>item</em>_FIELD</code> where <code><em>item</em></code> identifies * the field. For examples of these constants, see <code>ERA_FIELD</code> and its * friends in {@link DateFormat}. * * <h4><a name="synchronization">Synchronization</a></h4> * * <p> * Formats are generally not synchronized. * It is recommended to create separate format instances for each thread. * If multiple threads access a format concurrently, it must be synchronized * externally. * * @see          java.text.ParsePosition * @see          java.text.FieldPosition * @see          java.text.NumberFormat * @see          java.text.DateFormat * @see          java.text.MessageFormat * @author       Mark Davis */public abstract class Format implements Serializable, Cloneable {     private static final long serialVersionUID = -299282585814624189L;     /**     * Sole constructor.  (For invocation by subclass constructors, typically     * implicit.)     */    protected Format() {    }     /**     * Formats an object to produce a string. This is equivalent to     * <blockquote>     * {@link #format(Object, StringBuffer, FieldPosition) format}<code>(obj,     *         new StringBuffer(), new FieldPosition(0)).toString();</code>     * </blockquote>     *     * @param obj    The object to format     * @return       Formatted string.     * @exception IllegalArgumentException if the Format cannot format the given     *            object     */    public final String format (Object obj) {        return format(obj, new StringBuffer(), new FieldPosition(0)).toString();    }     /**     * Formats an object and appends the resulting text to a given string     * buffer.     * If the <code>pos</code> argument identifies a field used by the format,     * then its indices are set to the beginning and end of the first such     * field encountered.     *     * @param obj    The object to format     * @param toAppendTo    where the text is to be appended     * @param pos    A <code>FieldPosition</code> identifying a field     *               in the formatted text     * @return       the string buffer passed in as <code>toAppendTo</code>,     *               with formatted text appended     * @exception NullPointerException if <code>toAppendTo</code> or     *            <code>pos</code> is null     * @exception IllegalArgumentException if the Format cannot format the given     *            object     */    public abstract StringBuffer format(Object obj,                    StringBuffer toAppendTo,                    FieldPosition pos);     /**     * Formats an Object producing an <code>AttributedCharacterIterator</code>.     * You can use the returned <code>AttributedCharacterIterator</code>     * to build the resulting String, as well as to determine information     * about the resulting String.     * <p>     * Each attribute key of the AttributedCharacterIterator will be of type     * <code>Field</code>. It is up to each <code>Format</code> implementation     * to define what the legal values are for each attribute in the     * <code>AttributedCharacterIterator</code>, but typically the attribute     * key is also used as the attribute value.     * <p>The default implementation creates an     * <code>AttributedCharacterIterator</code> with no attributes. Subclasses     * that support fields should override this and create an     * <code>AttributedCharacterIterator</code> with meaningful attributes.     *     * @exception NullPointerException if obj is null.     * @exception IllegalArgumentException when the Format cannot format the     *            given object.     * @param obj The object to format     * @return AttributedCharacterIterator describing the formatted value.     * @since 1.4     */    public AttributedCharacterIterator formatToCharacterIterator(Object obj) {        return createAttributedCharacterIterator(format(obj));    }     /**     * Parses text from a string to produce an object.     * <p>     * The method attempts to parse text starting at the index given by     * <code>pos</code>.     * If parsing succeeds, then the index of <code>pos</code> is updated     * to the index after the last character used (parsing does not necessarily     * use all characters up to the end of the string), and the parsed     * object is returned. The updated <code>pos</code> can be used to     * indicate the starting point for the next call to this method.     * If an error occurs, then the index of <code>pos</code> is not     * changed, the error index of <code>pos</code> is set to the index of     * the character where the error occurred, and null is returned.     *     * @param source A <code>String</code>, part of which should be parsed.     * @param pos A <code>ParsePosition</code> object with index and error     *            index information as described above.     * @return An <code>Object</code> parsed from the string. In case of     *         error, returns null.     * @exception NullPointerException if <code>pos</code> is null.     */    public abstract Object parseObject (String source, ParsePosition pos);     /**     * Parses text from the beginning of the given string to produce an object.     * The method may not use the entire text of the given string.     *     * @param source A <code>String</code> whose beginning should be parsed.     * @return An <code>Object</code> parsed from the string.     * @exception ParseException if the beginning of the specified string     *            cannot be parsed.     */    public Object parseObject(String source) throws ParseException {        ParsePosition pos = new ParsePosition(0);        Object result = parseObject(source, pos);        if (pos.index == 0) {            throw new ParseException("Format.parseObject(String) failed",                pos.errorIndex);        }        return result;    }     /**     * Creates and returns a copy of this object.     *     * @return a clone of this instance.     */    public Object clone() {        try {            return super.clone();        } catch (CloneNotSupportedException e) {            // will never happen            return null;        }    }     //    // Convenience methods for creating AttributedCharacterIterators from    // different parameters.    //     /**     * Creates an <code>AttributedCharacterIterator</code> for the String     * <code>s</code>.     *     * @param s String to create AttributedCharacterIterator from     * @return AttributedCharacterIterator wrapping s     */    AttributedCharacterIterator createAttributedCharacterIterator(String s) {        AttributedString as = new AttributedString(s);         return as.getIterator();    }     /**     * Creates an <code>AttributedCharacterIterator</code> containg the     * concatenated contents of the passed in     * <code>AttributedCharacterIterator</code>s.     *     * @param iterators AttributedCharacterIterators used to create resulting     *                  AttributedCharacterIterators     * @return AttributedCharacterIterator wrapping passed in     *         AttributedCharacterIterators     */    AttributedCharacterIterator createAttributedCharacterIterator(                       AttributedCharacterIterator[] iterators) {        AttributedString as = new AttributedString(iterators);         return as.getIterator();    }     /**     * Returns an AttributedCharacterIterator with the String     * <code>string</code> and additional key/value pair <code>key</code>,     * <code>value</code>.     *     * @param string String to create AttributedCharacterIterator from     * @param key Key for AttributedCharacterIterator     * @param value Value associated with key in AttributedCharacterIterator     * @return AttributedCharacterIterator wrapping args     */    AttributedCharacterIterator createAttributedCharacterIterator(                      String string, AttributedCharacterIterator.Attribute key,                      Object value) {        AttributedString as = new AttributedString(string);         as.addAttribute(key, value);        return as.getIterator();    }     /**     * Creates an AttributedCharacterIterator with the contents of     * <code>iterator</code> and the additional attribute <code>key</code>     * <code>value</code>.     *     * @param iterator Initial AttributedCharacterIterator to add arg to     * @param key Key for AttributedCharacterIterator     * @param value Value associated with key in AttributedCharacterIterator     * @return AttributedCharacterIterator wrapping args     */    AttributedCharacterIterator createAttributedCharacterIterator(              AttributedCharacterIterator iterator,              AttributedCharacterIterator.Attribute key, Object value) {        AttributedString as = new AttributedString(iterator);         as.addAttribute(key, value);        return as.getIterator();    }      /**     * Defines constants that are used as attribute keys in the     * <code>AttributedCharacterIterator</code> returned     * from <code>Format.formatToCharacterIterator</code> and as     * field identifiers in <code>FieldPosition</code>.     *     * @since 1.4     */    public static class Field extends AttributedCharacterIterator.Attribute {         // Proclaim serial compatibility with 1.4 FCS        private static final long serialVersionUID = 276966692217360283L;         /**         * Creates a Field with the specified name.         *         * @param name Name of the attribute         */        protected Field(String name) {            super(name);        }    }      /**     * FieldDelegate is notified by the various <code>Format</code>     * implementations as they are formatting the Objects. This allows for     * storage of the individual sections of the formatted String for     * later use, such as in a <code>FieldPosition</code> or for an     * <code>AttributedCharacterIterator</code>.     * <p>     * Delegates should NOT assume that the <code>Format</code> will notify     * the delegate of fields in any particular order.     *     * @see FieldPosition.Delegate     * @see CharacterIteratorFieldDelegate     */    interface FieldDelegate {        /**         * Notified when a particular region of the String is formatted. This         * method will be invoked if there is no corresponding integer field id         * matching <code>attr</code>.         *         * @param attr Identifies the field matched         * @param value Value associated with the field         * @param start Beginning location of the field, will be >= 0         * @param end End of the field, will be >= start and <= buffer.length()         * @param buffer Contains current formatted value, receiver should         *        NOT modify it.         */        public void formatted(Format.Field attr, Object value, int start,                              int end, StringBuffer buffer);         /**         * Notified when a particular region of the String is formatted.         *         * @param fieldID Identifies the field by integer         * @param attr Identifies the field matched         * @param value Value associated with the field         * @param start Beginning location of the field, will be >= 0         * @param end End of the field, will be >= start and <= buffer.length()         * @param buffer Contains current formatted value, receiver should         *        NOT modify it.         */        public void formatted(int fieldID, Format.Field attr, Object value,                              int start, int end, StringBuffer buffer);    }}