org.assistments.util

Class Util

java.lang.Object

org.assistments.util.Util

public class Util
extends java.lang.Object

A Util class meant to be used by GWT applications along with plain java applications

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	ALPHA_NUMERIC_STR
static java.util.List<java.lang.String>	DISABLED_LIST
static java.util.List<java.lang.String>	ENABLED_LIST
static java.lang.String	HEX_CHARS_STR
static java.lang.String	INDENT
static java.lang.String	NL Newline string for use in code that runs through the GWT compiler.
static java.lang.String	PRINTABLE_CHAR_STR
static java.util.Random	rng

Constructor Summary

Constructors

Constructor and Description
Util()

Method Summary

Modifier and Type	Method and Description
static java.lang.String	byteArrayToHexadecimalString(byte[] data)
static java.lang.String	compressWhitespace(java.lang.String str)
static boolean	equals(java.lang.String s1, java.lang.String s2) Null-safe compare of two Strings
static int	extractDbIdFromUid(java.lang.String uid)
static int	extractSectionIdFromUid(java.lang.String uid)
static void	failOnNullOrEmpty(java.lang.String name, java.lang.String value)
static java.lang.Throwable	findCauseOfClassType(java.lang.Throwable t, java.lang.Class<? extends java.lang.Exception> causeWithThisClass) Traverses the causes of an exception looking for a target type.
static java.lang.String	generateAlpaNumericString(java.util.Random rng, int length)
static java.lang.String	generateHexString(java.util.Random rng, int length)
static java.lang.String	generatePrintableCharsString(java.util.Random rng, int length)
static java.lang.String	generateString(java.util.Random rng, java.lang.String characters, int length)
static Pair<java.lang.String,java.lang.Integer>	getExceptionFileAndLine(java.lang.Throwable t)
static int	getRandom(int max) Returns a random integer such that:
static int	getRandom(int min, int max) Returns a random integer such that:
static boolean	getRandomBoolean()
static java.time.LocalDate	getRandomDate(int startYear, int endYear)
static java.time.Instant	getRandomInstant(java.lang.String timezone, int startYear, int endYear)
static java.lang.Throwable	getRootCause(java.lang.Throwable t) Returns the root cause of an exception.
static <T> java.util.Set<T>	getSetFromList(java.util.List<T> list, java.util.Comparator<T> comparator)
static java.lang.String	getSimpleClassType(java.lang.Object o)
static java.lang.String	getSimpleClassType(java.lang.Object o, boolean allowNullOrEmpty)
static java.lang.String	getSimpleClassType(java.lang.String fullName)
static java.lang.String	getSimpleClassType(java.lang.String fullName, boolean allowNullOrEmpty)
static java.lang.String	getStackTrace(java.lang.Throwable throwable, boolean htmlFormatting) Returns a String representation of a Throwable's stack trace.
static java.lang.String	getStringBetween(java.lang.String str, char start, char end) Returns the characters between the first occurrence of two delimiters
static java.lang.String	getStringBetween(java.lang.String str, java.lang.String startDelim, java.lang.String endDelim) Returns the characters between the first occurrence of two delimiters
static java.util.UUID	getUUID()
static java.lang.String	getUUIDStr()
static java.lang.String	instantToString(java.time.Instant instant)
static java.lang.String	instantToString(java.time.Instant instant, java.time.ZoneId zid)
static java.lang.String	instantToStringZulu(java.time.Instant instant)
static boolean	isDisabled(java.lang.String value)
static boolean	isEnabled(java.lang.String value)
static boolean	isEnabled(java.lang.String propertyName, java.util.Map<java.lang.String,java.lang.String> properties)
static boolean	isNullOrEmpty(java.util.List<? extends java.lang.Object> list) Returns whether a List is null or empty.
static boolean	isNullOrEmpty(java.util.Map<? extends java.lang.Object,? extends java.lang.Object> map)
static boolean	isNullOrEmpty(java.lang.String str) Returns whether a String is null or empty after removing leading and trailing white spaces.
static boolean	isValidParentheses(java.lang.String value) AS-794
static java.lang.String[]	makeStringArray(java.util.List<java.lang.String> stringList)
static java.lang.String[]	makeStringArray(java.lang.String... strings)
static java.lang.String	msToHMS(long ms)
static java.util.Map<java.lang.String,java.lang.String>	parseStringIntoMap(java.lang.String data)
static java.lang.String	preParseParameters(java.lang.String str)
static void	preventListTooSmall(java.lang.String name, java.util.List<?> value, int lowerLimit)
static void	preventNotEqual(int expected, int actual)
static void	preventNull(java.lang.String name, java.lang.Object o)
static void	preventNullOrEmpty(java.util.List<? extends java.lang.Object> list)
static void	preventNullOrEmpty(java.util.List<? extends java.lang.Object> list, java.lang.String msg)
static void	preventNullOrEmpty(java.lang.String name, java.lang.String value)
static void	preventNullOrEmpty(java.lang.String name, java.lang.String[] values)
static void	preventNumberTooBig(java.lang.String name, int value, int upperLimit)
static void	preventNumberTooSmall(java.lang.String name, int value, int lowerLimit)
static void	preventOutOfBoundNumber(java.lang.String name, int value, int lowerLimit, int upperLimit)
static java.util.Map<java.lang.String,java.util.List<java.lang.String>>	quadrupletToMap(java.lang.String value, java.lang.String listDelim, java.lang.String tripletDelim)
static java.lang.String	quoteString(java.lang.String s)
static java.lang.String	removeWhitespace(java.lang.String str)
static <E> Pair<java.util.List<E>,int[]>	scrambleList(java.util.List<E> sourceList) Returns the contents of a list in a random order.
static java.lang.String	stackTraceToString(java.lang.Throwable t)
static void	throwExceptionAfterDate(java.time.Instant instant)
static void	throwExceptionAfterDate(int year, int month, int day) Throw an exception if the current date is after the specified year,month,day
static java.util.Map<java.lang.String,Pair<java.lang.String,java.lang.String>>	tripletToMap(java.lang.String value, java.lang.String listDelim, java.lang.String tripletDelim)
static <E extends java.lang.Enum<E>> void	unexpectedEnumValue(E enumValue)
static boolean	verifySingleton(java.lang.String classType, boolean isInstantiated) Assists a class to enforce the classes intention to be a singleton.

Methods inherited from class java.lang.Object

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

Field Detail

ENABLED_LIST

public static final java.util.List<java.lang.String> ENABLED_LIST

DISABLED_LIST

public static final java.util.List<java.lang.String> DISABLED_LIST

HEX_CHARS_STR

public static final java.lang.String HEX_CHARS_STR

See Also:

Constant Field Values

ALPHA_NUMERIC_STR

public static final java.lang.String ALPHA_NUMERIC_STR

See Also:

Constant Field Values

PRINTABLE_CHAR_STR

public static final java.lang.String PRINTABLE_CHAR_STR

See Also:

Constant Field Values

rng

public static final java.util.Random rng

NL

public static final java.lang.String NL

Newline string for use in code that runs through the GWT compiler. Unfortunately the GWT compiler does not support System.getProperty() so any code using NL fails to compile. nl provides an inelegant workaround.

See Also:

NL, Constant Field Values

INDENT

public static final java.lang.String INDENT

See Also:

Constant Field Values

Constructor Detail

Util

public Util()

Method Detail

isEnabled

public static boolean isEnabled(java.lang.String value)
                         throws java.lang.IllegalArgumentException

Throws:

java.lang.IllegalArgumentException

isEnabled

public static boolean isEnabled(java.lang.String propertyName,
                                java.util.Map<java.lang.String,java.lang.String> properties)

isNullOrEmpty

public static boolean isNullOrEmpty(java.lang.String str)

Returns whether a String is null or empty after removing leading and trailing white spaces.

Parameters:

str - String to check.

Returns:

true if the String is null or empty; otherwise false

isNullOrEmpty

public static boolean isNullOrEmpty(java.util.List<? extends java.lang.Object> list)

Returns whether a List is null or empty.

Parameters:

list - List to check.

Returns:

true if list is null or empty; otherwise false

isNullOrEmpty

public static boolean isNullOrEmpty(java.util.Map<? extends java.lang.Object,? extends java.lang.Object> map)

preventNull

public static void preventNull(java.lang.String name,
                               java.lang.Object o)

preventNullOrEmpty

public static void preventNullOrEmpty(java.lang.String name,
                                      java.lang.String[] values)
                               throws java.lang.IllegalArgumentException

Throws:

java.lang.IllegalArgumentException

preventNullOrEmpty

public static void preventNullOrEmpty(java.lang.String name,
                                      java.lang.String value)
                               throws java.lang.IllegalArgumentException

Throws:

java.lang.IllegalArgumentException

preventNullOrEmpty

public static void preventNullOrEmpty(java.util.List<? extends java.lang.Object> list)
                               throws java.lang.IllegalArgumentException

Throws:

java.lang.IllegalArgumentException

preventNullOrEmpty

public static void preventNullOrEmpty(java.util.List<? extends java.lang.Object> list,
                                      java.lang.String msg)
                               throws java.lang.IllegalArgumentException

Throws:

java.lang.IllegalArgumentException

preventOutOfBoundNumber

public static void preventOutOfBoundNumber(java.lang.String name,
                                           int value,
                                           int lowerLimit,
                                           int upperLimit)
                                    throws java.lang.IllegalArgumentException

Throws:

java.lang.IllegalArgumentException

preventNumberTooSmall

public static void preventNumberTooSmall(java.lang.String name,
                                         int value,
                                         int lowerLimit)
                                  throws java.lang.IllegalArgumentException

Throws:

java.lang.IllegalArgumentException

preventNumberTooBig

public static void preventNumberTooBig(java.lang.String name,
                                       int value,
                                       int upperLimit)
                                throws java.lang.IllegalArgumentException

Throws:

java.lang.IllegalArgumentException

preventListTooSmall

public static void preventListTooSmall(java.lang.String name,
                                       java.util.List<?> value,
                                       int lowerLimit)
                                throws java.lang.IllegalArgumentException

Throws:

java.lang.IllegalArgumentException

preventNotEqual

public static void preventNotEqual(int expected,
                                   int actual)

getRandom

public static int getRandom(int max)

Returns a random integer such that:

0 <= <returned integer> < max

That is to say values of max are not returned.

Parameters:

max - Specifies to return integers less than this value.

getRandom

public static int getRandom(int min,
                            int max)

Returns a random integer such that:

min <= <returned integer> < max

That is to say values of max are not returned.

Parameters:

min -

max -

Returns:

getRandomBoolean

public static boolean getRandomBoolean()

scrambleList

public static <E> Pair<java.util.List<E>,int[]> scrambleList(java.util.List<E> sourceList)

Returns the contents of a list in a random order.

Type Parameters:

E - Any Object

Parameters:

sourceList - List of Objects to randomly order.

Returns:

A Pair containing:

1. As the first member: a randomly ordered List containing a shallow copy of the elements in sourceList.
2. As the second member: A int[] where each element corresponds, in order, to the elements in the returned List (the first member of the Pair. The value of each array element specifies the index of where in find the scrambled element in the sourceList.

For example, if sourceList contained the following elements in this order:

• 0: "one"
• 1: "two"
• 2: "three"
• 3: "four"

and scrambleList() returned them in this order:

• 0: "three"
• 1: "two"
• 2: "four"
• 3: "one"

then, the returned int[] contains:

• [0]: 2
• [1]: 1
• [2]: 3
• [3]: 0

makeStringArray

public static java.lang.String[] makeStringArray(java.lang.String... strings)

makeStringArray

public static java.lang.String[] makeStringArray(java.util.List<java.lang.String> stringList)

getStackTrace

public static java.lang.String getStackTrace(java.lang.Throwable throwable,
                                             boolean htmlFormatting)

Returns a String representation of a Throwable's stack trace. This is GWT compiler-safe.

Parameters:

throwable -

Returns:

The call stack or an empty string if none.

getExceptionFileAndLine

public static Pair<java.lang.String,java.lang.Integer> getExceptionFileAndLine(java.lang.Throwable t)

getRootCause

public static java.lang.Throwable getRootCause(java.lang.Throwable t)

Returns the root cause of an exception.

getRootCause recursively traverses an exception's cause member so long as the cause is not null and is not the current exception itself. When either of those conditions are met (there is no further cause or the current cause and it's parent exception are the same), getRootCause returns the current exception.

Parameters:

t - exception to process

Returns:

root cause of t

findCauseOfClassType

public static java.lang.Throwable findCauseOfClassType(java.lang.Throwable t,
                                                       java.lang.Class<? extends java.lang.Exception> causeWithThisClass)

Traverses the causes of an exception looking for a target type.

Parameters:

t - The exception to process

causeWithThisClass - The Class of the exception of interest.

Returns:

The exception of type causeWithThisClass, if found; otherwise null

verifySingleton

public static boolean verifySingleton(java.lang.String classType,
                                      boolean isInstantiated)
                               throws SingletonException

Assists a class to enforce the classes intention to be a singleton. The calling class should declare:

public static boolean isInstatiated;

In its constructor, the class calls this method as:

isInstatiated = verifySingleton(classType, isInstatiated);

Note: You need to be vigilant when calling verifySingleton() in super- and subclasses. For example, assume (1) B extends A and (2) B is a singleton.

If you never expect your code to instantiate A directly, then you should call verifySingleton() in A's constructor. This protects against a piece of code requesting an instance of A independently (of B). You could additionally call verifySingleton() from B, but it is not necessary.

However, if you expect your code to use B as a singleton and to use additional instances of A (other than as a superclass of B), then you must call verifySingleton() in B; but not in A.

Parameters:

classType - Class name

isInstantiated - true if the class has already been instantiated; otherwise false that the class has not yet been instantiated.

Returns:

true if the value of isInstantiated was false.

Throws:

SingletonException - when the current value of isInstantiated is true.

generateHexString

public static java.lang.String generateHexString(java.util.Random rng,
                                                 int length)

generateAlpaNumericString

public static java.lang.String generateAlpaNumericString(java.util.Random rng,
                                                         int length)

generatePrintableCharsString

public static java.lang.String generatePrintableCharsString(java.util.Random rng,
                                                            int length)

generateString

public static java.lang.String generateString(java.util.Random rng,
                                              java.lang.String characters,
                                              int length)

unexpectedEnumValue

public static <E extends java.lang.Enum<E>> void unexpectedEnumValue(E enumValue)

getSimpleClassType

public static java.lang.String getSimpleClassType(java.lang.Object o)

getSimpleClassType

public static java.lang.String getSimpleClassType(java.lang.Object o,
                                                  boolean allowNullOrEmpty)

getSimpleClassType

public static java.lang.String getSimpleClassType(java.lang.String fullName)

getSimpleClassType

public static java.lang.String getSimpleClassType(java.lang.String fullName,
                                                  boolean allowNullOrEmpty)

isDisabled

public static boolean isDisabled(java.lang.String value)

failOnNullOrEmpty

public static void failOnNullOrEmpty(java.lang.String name,
                                     java.lang.String value)

equals

public static boolean equals(java.lang.String s1,
                             java.lang.String s2)

Null-safe compare of two Strings

Parameters:

s1 - one string

s2 - the other string

Returns:

true if both are null or both are contain the same string value; otherwise false

removeWhitespace

public static java.lang.String removeWhitespace(java.lang.String str)

compressWhitespace

public static java.lang.String compressWhitespace(java.lang.String str)

getStringBetween

public static java.lang.String getStringBetween(java.lang.String str,
                                                char start,
                                                char end)

Returns the characters between the first occurrence of two delimiters

Parameters:

str - String to process

start - Starting delimiter

end - Ending delimiter

Returns:

The string extracted from between start and end or null if:

• either delimiter was not found, or
• only one of the delimiters was not found, or
• the end delimiter was found before the start delimiter

getStringBetween

public static java.lang.String getStringBetween(java.lang.String str,
                                                java.lang.String startDelim,
                                                java.lang.String endDelim)

Returns the characters between the first occurrence of two delimiters

Parameters:

str - String to process

startDelim - Starting delimiter

endDelim - Ending delimiter

Returns:

The string extracted from between start and end or null if:

• either delimiter was not found, or
• only one of the delimiters was not found, or
• the end delimiter was found before the start delimiter

isValidParentheses

public static boolean isValidParentheses(java.lang.String value)

AS-794

quoteString

public static java.lang.String quoteString(java.lang.String s)

tripletToMap

public static java.util.Map<java.lang.String,Pair<java.lang.String,java.lang.String>> tripletToMap(java.lang.String value,
                                                                                                   java.lang.String listDelim,
                                                                                                   java.lang.String tripletDelim)

quadrupletToMap

public static java.util.Map<java.lang.String,java.util.List<java.lang.String>> quadrupletToMap(java.lang.String value,
                                                                                               java.lang.String listDelim,
                                                                                               java.lang.String tripletDelim)

getSetFromList

public static <T> java.util.Set<T> getSetFromList(java.util.List<T> list,
                                                  java.util.Comparator<T> comparator)

extractDbIdFromUid

public static int extractDbIdFromUid(java.lang.String uid)

extractSectionIdFromUid

public static int extractSectionIdFromUid(java.lang.String uid)

preParseParameters

public static java.lang.String preParseParameters(java.lang.String str)

parseStringIntoMap

@GwtIncompatible
public static java.util.Map<java.lang.String,java.lang.String> parseStringIntoMap(java.lang.String data)
                                                                                             throws java.lang.IllegalArgumentException

Throws:

java.lang.IllegalArgumentException

byteArrayToHexadecimalString

@GwtIncompatible
public static java.lang.String byteArrayToHexadecimalString(byte[] data)

stackTraceToString

@GwtIncompatible
public static java.lang.String stackTraceToString(java.lang.Throwable t)

instantToString

@GwtIncompatible
public static java.lang.String instantToString(java.time.Instant instant)

instantToString

@GwtIncompatible
public static java.lang.String instantToString(java.time.Instant instant,
                                                                 java.time.ZoneId zid)

instantToStringZulu

@GwtIncompatible
public static java.lang.String instantToStringZulu(java.time.Instant instant)

msToHMS

@GwtIncompatible
public static java.lang.String msToHMS(long ms)

getRandomDate

@GwtIncompatible
public static java.time.LocalDate getRandomDate(int startYear,
                                                                  int endYear)

getRandomInstant

@GwtIncompatible
public static java.time.Instant getRandomInstant(java.lang.String timezone,
                                                                   int startYear,
                                                                   int endYear)

getUUID

@GwtIncompatible
public static java.util.UUID getUUID()

getUUIDStr

@GwtIncompatible
public static java.lang.String getUUIDStr()

throwExceptionAfterDate

@GwtIncompatible
public static void throwExceptionAfterDate(int year,
                                                             int month,
                                                             int day)

Throw an exception if the current date is after the specified year,month,day

Parameters:

year - the year you want the exception to be thrown

month - the month you want the exception to be thrown (January is 0, You can use Calendar. to make things easier)

day - the day you want the exception to be thrown

throwExceptionAfterDate

@GwtIncompatible
public static void throwExceptionAfterDate(java.time.Instant instant)