gr.uoa.di.madgik.searchlibrary.operatorlibrary.comparator

Class CompareTokens

java.lang.Object

gr.uoa.di.madgik.searchlibrary.operatorlibrary.comparator.CompareTokens

public class CompareTokens
extends Object

The CompareTokens class exports a single method called compare. It is designed to be used in a static context, meaning that no CompareTokens object is created. The comparisons made for string are case insensitive

Author:

UoA

Field Summary

Fields

Modifier and Type	Field and Description
static short	ASCENDING_ORDER Compare in ascending order
static short	COMPARE_EQUAL The compare operation returned equal
static short	COMPARE_GREATER The compare operation returned greater
static short	COMPARE_LOWER The compare operation returned lower
static short	DESCENDING_ORDER Compare in descending order

Constructor Summary

Constructors

Constructor and Description
CompareTokens()

Method Summary

Methods

Modifier and Type	Method and Description
static int	compare(String token1, String token2) The compare method compares two tokens.
static int	compare(String token1, String token2, ComparisonMode mode) This version of the compare method compares two tokens.
static ComparisonMode	getMode() Gets the stored mode of comparison
static ComparisonMode	getMode(String token1, String token2)
static void	setMode(ComparisonMode mode) Sets a new value to comparison mode
static Date	Str2Date(String dateStr) The Str2Date method translates a string into its corresponding date representation.
static ComparisonMode	updateMode(String token) Updates the mode of comparison according to the token parameter.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

COMPARE_EQUAL

public static final short COMPARE_EQUAL

The compare operation returned equal

See Also:

Constant Field Values

COMPARE_GREATER

public static final short COMPARE_GREATER

The compare operation returned greater

See Also:

Constant Field Values

COMPARE_LOWER

public static final short COMPARE_LOWER

The compare operation returned lower

See Also:

Constant Field Values

ASCENDING_ORDER

public static final short ASCENDING_ORDER

Compare in ascending order

See Also:

Constant Field Values

DESCENDING_ORDER

public static final short DESCENDING_ORDER

Compare in descending order

See Also:

Constant Field Values

Constructor Detail

CompareTokens

public CompareTokens()

Method Detail

Str2Date

public static Date Str2Date(String dateStr)
                     throws ParseException

The Str2Date method translates a string into its corresponding date representation. The adopted format is the US one: mm/dd/yyyy OR mm/dd/yy

Parameters:

dateStr - The date convrt

Returns:

The Date object which corresponds to the string argument

Throws:

ParseException - A parsing error occured

compare

public static int compare(String token1,
          String token2)
                   throws InvalidTokenFormatComparison

The compare method compares two tokens. If the tokens are plain strings, then it employs the compareToIgnoreCase method of the string object. If the tokens are numerics, then it translates them into longs or doubles and compares them, employing the usual operators ==, >, <. We use longs to handle integer types (short, integer, long) and doubles to handle floating point types (float, double)

Parameters:

token1 - First token to be compared

token2 - Second token to be compared

Returns:

0 if token1==token2, 1 if token1>token2, -1 if token1<token2

Throws:

InvalidTokenFormatComparison - tokens where not valid

getMode

public static ComparisonMode getMode(String token1,
                     String token2)
                              throws InvalidTokenFormatComparison

Parameters:

token1 - First token to be compared

token2 - Second token to be compared

Returns:

the mode of comparison

Throws:

InvalidTokenFormatComparison - if tokens were not valid

getMode

public static ComparisonMode getMode()
                              throws Exception

Gets the stored mode of comparison

Returns:

the mode of comparison

Throws:

Exception - if mode is not set

setMode

public static void setMode(ComparisonMode mode)

Sets a new value to comparison mode

Parameters:

mode - New comparison mode

updateMode

public static ComparisonMode updateMode(String token)
                                 throws InvalidTokenFormatComparison

Updates the mode of comparison according to the token parameter. If mode is not already initialized, it is done so according to the type of token. The most general mode of comparison is considered to be string comparison so if mode is already set to string comparison, it remains unchanged. If mode is set to string comparison and token is not of date format, mode is updated to string comparison, else it remains unchanged. Likewise, if mode is set to double comparison and token is not of numeric format, mode is updated to string comparison, else it remains unchanged. Finally, if mode is set to long integer comparison, it is updated to double comparison if token is of numeric (but not integral) type, to string comparison if token is not of numeric type or remains unchanged if token is of integral type.

Parameters:

token - token used to update mode

Returns:

the updated ComparisonMode

Throws:

InvalidTokenFormatComparison - tokens where not valid

compare

public static int compare(String token1,
          String token2,
          ComparisonMode mode)
                   throws InvalidTokenFormatComparison

This version of the compare method compares two tokens. Depending on mode, if the tokens are plain strings, it employs the compareToIgnoreCase method of the string object. If one or both of the tokens are doubles, then it translates them into doubles and compares them, employing the usual operators ==, >, <. If both of the tokens are integers, then it translates them into longs and compares them. We use longs to handle integer types (short, integer, long) and doubles to handle floating point types (float, double)

Parameters:

token1 - First token to be compared

token2 - Second token to be compared

mode - The mode of comparison, one of COMPARE_INTS, COMPARE_DOUBLES and COMPARE_STRINGS

Returns:

0 if token1==token2, 1 if token1>token2, -1 if token1<token2

Throws:

InvalidTokenFormatComparison - tokens where not valid