jidefx.utils

Class CommonUtils

java.lang.Object

jidefx.utils.CommonUtils

public class CommonUtils
extends java.lang.Object

Utils that contains methods that are not depending on JavaFX classes.

Constructor Summary

Constructors

Constructor and Description
CommonUtils()

Method Summary

Modifier and Type	Method and Description
static int	binarySearch(int[] a, int key) Perform a binary search over a sorted array for the given key.
static int	binarySearch(int[] a, int key, int start, int end) Perform a binary search over a sorted array for the given key.
static int	binarySearch(java.util.List<java.lang.Object> a, java.lang.Object key) Perform a binary search over a sorted list for the given key.
static int	binarySearch(java.lang.Object[] a, java.lang.Object key) Perform a binary search over a sorted array for the given key.
static boolean	charsEqualIgnoreCase(char a, char b)
static <T,U> java.util.Comparator<T>	comparing(java.util.Comparator<? super U> comparator, java.util.function.Function<? super T,? extends U> keyExtractor) Accepts a function that extracts an object of a type U as sort key from a type T, and returns the object that compares by the specified comparator.
static boolean	equals(java.lang.CharSequence s1, java.lang.CharSequence s2, boolean caseSensitive)
static boolean	equals(java.lang.Object o1, java.lang.Object o2) Checks if the two objects equal.
static boolean	equals(java.lang.Object o1, java.lang.Object o2, boolean considerArrayOrList) Checks if the two objects equal.
static void	ignoreException(java.lang.Exception e) Ignore the exception.
static void	printException(java.lang.Exception e) Prints out the message of the exception.
static void	throwException(java.lang.Exception e) Throws the exception.
static void	throwInvocationTargetException(java.lang.reflect.InvocationTargetException e) Throws the InvocationTargetException.
static char	toLowerCase(char a) A toLowerCase routine which is faster to process the ASCII lowercase letters then Character.toLowerCase.
static char	toUpperCase(char a) A toUpperCase routine which is faster to process the ASCII lowercase letters than Character.toUpperCase.

Methods inherited from class java.lang.Object

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

Constructor Detail

CommonUtils

public CommonUtils()

Method Detail

equals

public static boolean equals(java.lang.Object o1,
                             java.lang.Object o2)

Checks if the two objects equal. If both are null, they are equal. If o1 and o2 both are Comparable, we will use compareTo method to see if it equals 0. At last, we will use o1.equals(o2) to compare. If none of the above conditions match, we return false.

Parameters:

o1 - the first object to compare

o2 - the second object to compare

Returns:

true if the two objects are equal. Otherwise false.

equals

public static boolean equals(java.lang.Object o1,
                             java.lang.Object o2,
                             boolean considerArrayOrList)

Checks if the two objects equal. If both are the same instance, they are equal. If both are null, they are equal. If o1 and o2 both are Comparable, we will use compareTo method to see if it equals 0. If considerArrayOrList is true and o1 and o2 are both array, we will compare each element in the array. At last, we will use o1.equals(o2) to compare. If none of the above conditions match, we return false.

Parameters:

o1 - the first object to compare

o2 - the second object to compare

considerArrayOrList - If true, and if o1 and o2 are both array, we will compare each element in the array instead of just compare the two array objects.

Returns:

true if the two objects are equal. Otherwise false.

equals

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

charsEqualIgnoreCase

public static boolean charsEqualIgnoreCase(char a,
                                           char b)

toUpperCase

public static char toUpperCase(char a)

A toUpperCase routine which is faster to process the ASCII lowercase letters than Character.toUpperCase.

Parameters:

a - the character to be converted.

Returns:

the uppercase equivalent of the character, if any; otherwise, the character itself.

toLowerCase

public static char toLowerCase(char a)

A toLowerCase routine which is faster to process the ASCII lowercase letters then Character.toLowerCase.

Parameters:

a - the character to be converted.

Returns:

the lowercase equivalent of the character, if any; otherwise, the character itself.

ignoreException

public static void ignoreException(java.lang.Exception e)

Ignore the exception. This method does nothing. However it's a good practice to use this method so that we can easily find out the place that ignoring exception. In development phase, we can log a message in this method so that we can verify if it makes sense to ignore.

Parameters:

e - the exception

printException

public static void printException(java.lang.Exception e)

Prints out the message of the exception.

Parameters:

e - the exception

throwException

public static void throwException(java.lang.Exception e)

Throws the exception. If the exception is RuntimeException, just throw it. Otherwise, wrap it in RuntimeException and throw it.

Parameters:

e - the exception

throwInvocationTargetException

public static void throwInvocationTargetException(java.lang.reflect.InvocationTargetException e)

Throws the InvocationTargetException. Usually InvocationTargetException has a nested exception as target exception. If the target exception is a RuntimeException or Error, we will throw it. Otherwise, we will wrap it inside RuntimeException and throw it.

Parameters:

e - the exception

binarySearch

public static int binarySearch(java.util.List<java.lang.Object> a,
                               java.lang.Object key)

Perform a binary search over a sorted list for the given key.

Parameters:

a - the array to search

key - the key to search for

Returns:

the index of the given key if it exists in the list, otherwise -1 times the index value at the insertion point that would be used if the key were added to the list.

binarySearch

public static int binarySearch(java.lang.Object[] a,
                               java.lang.Object key)

Perform a binary search over a sorted array for the given key.

Parameters:

a - the array to search

key - the key to search for

Returns:

the index of the given key if it exists in the array, otherwise -1 times the index value at the insertion point that would be used if the key were added to the array.

binarySearch

public static int binarySearch(int[] a,
                               int key)

Perform a binary search over a sorted array for the given key.

Parameters:

a - the array to search

key - the key to search for

Returns:

the index of the given key if it exists in the array, otherwise -1 times the index value at the insertion point that would be used if the key were added to the array.

binarySearch

public static int binarySearch(int[] a,
                               int key,
                               int start,
                               int end)

Perform a binary search over a sorted array for the given key.

Parameters:

a - the array to search

key - the key to search for

start - the start index to search inclusive

end - the end index to search exclusive

Returns:

the index of the given key if it exists in the array, otherwise -1 times the index value at the insertion point that would be used if the key were added to the array.

comparing

public static <T,U> java.util.Comparator<T> comparing(java.util.Comparator<? super U> comparator,
                                                      java.util.function.Function<? super T,? extends U> keyExtractor)

Accepts a function that extracts an object of a type U as sort key from a type T, and returns the object that compares by the specified comparator. For example, if a class Element has a value which has a getter, but we only have a Comparator for the value, not for the Element. We can use this method to call Person objects to get the value, then use the existing Comparator for the value.

Type Parameters:

T - the original element type

U - the actual type for comparison

Parameters:

comparator - a comparator that can sort the value.

keyExtractor - the function used to extract the value sort key for the Comparator