java.lang.Objectjava.text.Format
public abstract class Format
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.
The Java 2 platform provides three specialized subclasses of Format-- DateFormat, MessageFormat, and NumberFormat--for formatting dates, messages, and numbers, respectively.
Concrete subclasses must implement three methods:
Most subclasses will also implement the following factory methods:
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 DateFormat .
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.
Nested Class Summary | |
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static class |
Format.Field
Defines constants that are used as attribute keys in the AttributedCharacterIterator returned from Format.formatToCharacterIterator and as field identifiers in FieldPosition. |
Constructor Summary | |
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Format
() ![]() ![]() |
Method Summary | |
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Object |
clone
() Creates and returns a copy of this object. |
String |
format
(
Object
obj) Formats an object to produce a string. |
abstract StringBuffer |
format
(
Object
obj,
StringBuffer
toAppendTo,
FieldPosition
pos) Formats an object and appends the resulting text to a given string buffer. |
AttributedCharacterIterator |
formatToCharacterIterator
(
Object
obj) Formats an Object producing an AttributedCharacterIterator. |
Object |
parseObject
(
String
source) Parses text from the beginning of the given string to produce an object. |
abstract Object |
parseObject
(
String
source,
ParsePosition
pos) Parses text from a string to produce an object. |
Methods inherited from class java.lang. Object |
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equals , finalize , getClass , hashCode , notify , notifyAll , toString , wait , wait , wait |
Constructor Detail |
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protected
publicFormat()
Method Detail |
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public final String format(Object obj)
format (obj, new StringBuffer(), new FieldPosition(0)).toString();
public abstract StringBuffer format(Object obj, StringBuffer toAppendTo, FieldPosition pos)
public AttributedCharacterIterator formatToCharacterIterator(Object obj)
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.
public abstract Object parseObject(String source, ParsePosition pos)
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.
public Object parseObject(String source) throws ParseException
public Object clone()