/* * 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; /** * Format is an abstract base class for formatting locale-sensitive * information such as dates, messages, and numbers. * *

* Format defines the programming interface for formatting * locale-sensitive objects into Strings (the * format method) and for parsing Strings back * into objects (the parseObject method). * *

* Generally, a format's parseObject method must be able to parse * any string formatted by its format method. However, there may * be exceptional cases where this is not possible. For example, a * format method might create two adjacent integer numbers with * no separator in between, and in this case the parseObject could * not tell which digits belong to which number. * *

Subclassing

* *

* The Java Platform provides three specialized subclasses of Format-- * DateFormat, MessageFormat, and * NumberFormat--for formatting dates, messages, and numbers, * respectively. *

* Concrete subclasses must implement three methods: *

    *
  1. format(Object obj, StringBuffer toAppendTo, FieldPosition pos) *
  2. formatToCharacterIterator(Object obj) *
  3. parseObject(String source, ParsePosition pos) *
* These general methods allow polymorphic parsing and formatting of objects * and are used, for example, by MessageFormat. * Subclasses often also provide additional format methods for * specific input types as well as parse methods for specific * result types. Any parse method that does not take a * ParsePosition argument should throw ParseException * when no text in the required format is at the beginning of the input text. * *

* Most subclasses will also implement the following factory methods: *

    *
  1. * getInstance for getting a useful format object appropriate * for the current locale *
  2. * getInstance(Locale) for getting a useful format * object appropriate for the specified locale *
* In addition, some subclasses may also implement other * getXxxxInstance methods for more specialized control. For * example, the NumberFormat class provides * getPercentInstance and getCurrencyInstance * methods for getting specialized number formatters. * *

* Subclasses of Format that allow programmers to create objects * for locales (with getInstance(Locale) for example) * must also implement the following class method: *

*
 * public static Locale[] getAvailableLocales()
 * 
*
* *

* 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 * item_FIELD where item identifies * the field. For examples of these constants, see ERA_FIELD and its * friends in {@link DateFormat}. * *

Synchronization

* *

* 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 *

* {@link #format(Object, StringBuffer, FieldPosition) format}(obj, * new StringBuffer(), new FieldPosition(0)).toString(); *
* * @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 pos 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 FieldPosition identifying a field * in the formatted text * @return the string buffer passed in as toAppendTo, * with formatted text appended * @exception NullPointerException if toAppendTo or * pos 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 AttributedCharacterIterator. * You can use the returned AttributedCharacterIterator * to build the resulting String, as well as to determine information * about the resulting String. *

* Each attribute key of the AttributedCharacterIterator will be of type * Field. It is up to each Format implementation * to define what the legal values are for each attribute in the * AttributedCharacterIterator, but typically the attribute * key is also used as the attribute value. *

The default implementation creates an * AttributedCharacterIterator with no attributes. Subclasses * that support fields should override this and create an * AttributedCharacterIterator 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. *

* The method attempts to parse text starting at the index given by * pos. * If parsing succeeds, then the index of pos 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 pos can be used to * indicate the starting point for the next call to this method. * If an error occurs, then the index of pos is not * changed, the error index of pos is set to the index of * the character where the error occurred, and null is returned. * * @param source A String, part of which should be parsed. * @param pos A ParsePosition object with index and error * index information as described above. * @return An Object parsed from the string. In case of * error, returns null. * @exception NullPointerException if pos 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 String whose beginning should be parsed. * @return An Object 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 AttributedCharacterIterator for the String * s. * * @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 AttributedCharacterIterator containg the * concatenated contents of the passed in * AttributedCharacterIterators. * * @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 * string and additional key/value pair key, * value. * * @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 * iterator and the additional attribute key * value. * * @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 * AttributedCharacterIterator returned * from Format.formatToCharacterIterator and as * field identifiers in FieldPosition. * * @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 Format * 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 FieldPosition or for an * AttributedCharacterIterator. *

* Delegates should NOT assume that the Format 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 attr. * * @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); } }