241 lines
9.9 KiB
C++
241 lines
9.9 KiB
C++
/*
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********************************************************************************
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* Copyright © {1997-1999}, International Business Machines Corporation and others. All Rights Reserved.
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********************************************************************************
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*
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* File FORMAT.H
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*
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* Modification History:
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*
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* Date Name Description
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* 02/19/97 aliu Converted from java.
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* 03/17/97 clhuang Updated per C++ implementation.
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* 03/27/97 helena Updated to pass the simple test after code review.
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********************************************************************************
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*/
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// *****************************************************************************
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// This file was generated from the java source file Format.java
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// *****************************************************************************
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#ifndef FORMAT_H
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#define FORMAT_H
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#include "unicode/utypes.h"
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#include "unicode/unistr.h"
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#include "unicode/fmtable.h"
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#include "unicode/fieldpos.h"
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#include "unicode/parsepos.h"
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/**
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* Base class for all formats. This is an abstract base class which
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* specifies the protocol for classes which convert other objects or
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* values, such as numeric values and dates, and their string
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* representations. In some cases these representations may be
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* localized or contain localized characters or strings. For example,
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* a numeric formatter such as DecimalFormat may convert a numeric
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* value such as 12345 to the string "$12,345". It may also parse
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* the string back into a numeric value. A date and time formatter
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* like SimpleDateFormat may represent a specific date, encoded
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* numerically, as a string such as "Wednesday, February 26, 1997 AD".
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* <P>
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* Many of the concrete subclasses of Format employ the notion of
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* a pattern. A pattern is a string representation of the rules which
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* govern the interconversion between values and strings. For example,
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* a DecimalFormat object may be associated with the pattern
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* "$#,##0.00;($#,##0.00)", which is a common US English format for
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* currency values, yielding strings such as "$1,234.45" for 1234.45,
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* and "($987.65)" for 987.6543. The specific syntax of a pattern
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* is defined by each subclass.
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* <P>
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* Even though many subclasses use patterns, the notion of a pattern
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* is not inherent to Format classes in general, and is not part of
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* the explicit base class protocol.
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* <P>
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* Two complex formatting classes bear mentioning. These are
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* MessageFormat and ChoiceFormat. ChoiceFormat is a subclass of
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* NumberFormat which allows the user to format different number ranges
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* as strings. For instance, 0 may be represented as "no files", 1 as
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* "one file", and any number greater than 1 as "many files".
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* MessageFormat is a formatter which utilizes other Format objects to
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* format a string containing with multiple values. For instance,
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* A MessageFormat object might produce the string "There are no files
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* on the disk MyDisk on February 27, 1997." given the arguments 0,
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* "MyDisk", and the date value of 2/27/97. See the ChoiceFormat
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* and MessageFormat headers for further information.
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* <P>
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* If formatting is unsuccessful, a failing UErrorCode is returned when
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* the Format cannot format the type of object, otherwise if there is
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* something illformed about the the Unicode replacement character
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* 0xFFFD is returned.
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* <P>
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* If there is no match when parsing, a parse failure UErrorCode is
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* retured for methods which take no ParsePosition. For the method
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* that takes a ParsePosition, the index parameter is left unchanged.
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* <P>
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* [Subclassing.] All base classes that provide static functions that
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* create objects for Locales must implement the following static:
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* <pre>
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* . public static const Locale* getAvailableLocales(long&)
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* </pre>
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*/
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class U_I18N_API Format {
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public:
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virtual ~Format();
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/**
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* Return true if the given Format objects are semantically equal.
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* Objects of different subclasses are considered unequal.
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* @stable
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*/
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virtual bool_t operator==(const Format& other) const = 0;
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/**
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* Return true if the given Format objects are not semantically
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* equal.
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* @stable
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*/
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bool_t operator!=(const Format& other) const { return !operator==(other); }
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/**
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* Clone this object polymorphically. The caller is responsible
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* for deleting the result when done.
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* @stable
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*/
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virtual Format* clone() const = 0;
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/**
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* Formats an object to produce a string.
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*
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* @param obj The object to format.
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* @param result Output parameter which will be filled in with the
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* formatted string.
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* @param status Output parameter filled in with success or failure status.
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* @return Reference to 'result' parameter.
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* @stable
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*/
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UnicodeString& format(const Formattable& obj,
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UnicodeString& result,
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UErrorCode& status) const;
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/**
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* Format an object to produce a string. This is a pure virtual method which
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* subclasses must implement. This method allows polymorphic formatting
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* of Formattable objects. If a subclass of Format receives a Formattable
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* object type it doesn't handle (e.g., if a numeric Formattable is passed
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* to a DateFormat object) then it returns a failing UErrorCode.
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*
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* @param obj The object to format.
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* @param toAppendTo Where the text is to be appended.
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* @param pos On input: an alignment field, if desired.
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* On output: the offsets of the alignment field.
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* @param status Output param filled with success/failure status.
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* @return The value passed in as toAppendTo (this allows chaining,
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* as with UnicodeString::append())
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* @stable
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*/
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virtual UnicodeString& format(const Formattable& obj,
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UnicodeString& toAppendTo,
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FieldPosition& pos,
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UErrorCode& status) const = 0;
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/**
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* Parse a string to produce an object. This is a pure virtual
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* method which subclasses must implement. This method allows
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* polymorphic parsing of strings into Formattable objects.
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* <P>
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* Before calling, set parse_pos.index to the offset you want to
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* start parsing at in the source. After calling, parse_pos.index
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* is the end of the text you parsed. If error occurs, index is
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* unchanged.
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* <P>
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* When parsing, leading whitespace is discarded (with successful
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* parse), while trailing whitespace is left as is.
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* <P>
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* Example:
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* <P>
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* Parsing "_12_xy" (where _ represents a space) for a number,
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* with index == 0 will result in the number 12, with
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* parse_pos.index updated to 3 (just before the second space).
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* Parsing a second time will result in a failing UErrorCode since
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* "xy" is not a number, and leave index at 3.
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* <P>
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* Subclasses will typically supply specific parse methods that
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* return different types of values. Since methods can't overload
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* on return types, these will typically be named "parse", while
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* this polymorphic method will always be called parseObject. Any
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* parse method that does not take a parse_pos should set status
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* to an error value when no text in the required format is at the
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* start position.
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*
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* @param source The string to be parsed into an object.
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* @param result Formattable to be set to the parse result.
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* If parse fails, return contents are undefined.
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* @param parse_pos The position to start parsing at. Upon return
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* this param is set to the position after the
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* last character successfully parsed. If the
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* source is not parsed successfully, this param
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* will remain unchanged.
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* @stable
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*/
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virtual void parseObject(const UnicodeString& source,
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Formattable& result,
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ParsePosition& parse_pos) const = 0;
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/**
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* Parses a string to produce an object. This is a convenience method
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* which calls the pure virtual parseObject() method, and returns a
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* failure UErrorCode if the ParsePosition indicates failure.
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*
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* @param source The string to be parsed into an object.
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* @param result Formattable to be set to the parse result.
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* If parse fails, return contents are undefined.
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* @param status Output param to be filled with success/failure
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* result code.
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* @stable
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*/
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void parseObject(const UnicodeString& source,
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Formattable& result,
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UErrorCode& status) const;
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/**
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* Returns a unique class ID POLYMORPHICALLY. Pure virtual method.
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* This method is to implement a simple version of RTTI, since not all
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* C++ compilers support genuine RTTI. Polymorphic operator==() and
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* clone() methods call this method.
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* <P>
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* Concrete subclasses of Format must implement getDynamicClassID()
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* and also a static method and data member:
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*
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* static UClassID getStaticClassID() { return (UClassID)&fgClassID; }
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* static char fgClassID;
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*
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* @return The class ID for this object. All objects of a
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* given class have the same class ID. Objects of
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* other classes have different class IDs.
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* @stable
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*/
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virtual UClassID getDynamicClassID() const = 0;
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protected:
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/**
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* Default constructor for subclass use only. Does nothing.
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* @stable
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*/
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Format();
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/**
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* @stable
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*/
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Format(const Format&); // Does nothing; for subclasses only
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/**
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* @stable
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*/
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Format& operator=(const Format&); // Does nothing; for subclasses
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};
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#endif // _FORMAT
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//eof
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