org.incava.ijdk.lang

Class ICore

java.lang.Object

org.incava.ijdk.lang.ICore

Direct Known Subclasses:

Common, IUtil

public class ICore
extends java.lang.Object

Constructor Summary

Constructors

Constructor and Description
ICore()

Method Summary

Modifier and Type	Method and Description
static <T> T	and(T... operands) Returns the last parameter, if all parameters evaluate to true (via isTrue).
static <T> T	and(T a, T b) If both parameters evaluate to true (via isTrue), then the second value is returned.
static <T> T[]	ary(T... args) Converts varargs to T[].
static <T> T	elvis(T obj, T defVal) An alias for the or method.
static Array<java.lang.Integer>	intlist(java.lang.Integer... elements) Returns an integer list, which can be empty.
static boolean	isEmpty(java.lang.Object obj) Returns whether the object is null or is a string or collection of zero length.
static boolean	isEmpty(java.lang.String str) Returns whether the string is null or of zero length.
static boolean	isFalse(java.lang.Object... objs) Returns whether the array is not null and is not of zero length.
static boolean	isFalse(java.lang.Object obj) Returns whether the object is null or is a string or collection of zero length.
static boolean	isNotNull(java.lang.Object obj) Returns whether the object is not null.
static boolean	isNull(java.lang.Object obj) Returns whether the object is null.
static boolean	isTrue(java.lang.Object... objs) Returns whether the array is not null and is not of zero length.
static boolean	isTrue(java.lang.Object obj) Returns whether the object is non-null and, if it is a collection or a string, has a length greater than zero.
static java.lang.Iterable<java.lang.Integer>	iter(int num) Returns an iterator to be executed num times.
static <T> java.lang.Iterable<T>	iter(java.lang.Iterable<T> coll) Returns an Iterable (iterator) for the collection, which can be null.
static <T> java.lang.Iterable<T>	iter(T[] ary) Returns an Iterable (iterator) for the C-style array, which can be null.
static <T> Array<T>	list(T... elements) Returns a list (a Array) initialized with the given elements.
static <KeyType,ValueType> java.util.TreeMap<KeyType,ValueType>	map() Creates an empty tree map.
static <KeyType,ValueType> java.util.TreeMap<KeyType,ValueType>	map(KeyType k1, ValueType v1) Creates a map with one key/value pair.
static <KeyType,ValueType> java.util.TreeMap<KeyType,ValueType>	map(KeyType k1, ValueType v1, KeyType k2, ValueType v2) Creates a map with two key/value pairs.
static <T> T	or(T... operands) Returns the first parameter that evaluates to true (via isTrue).
static <T> T	or(T a, T b) Returns the first parameter if it is true, and otherwise returns the default value.
static boolean	printf(java.lang.String fmt, java.lang.Object... args) Writes to standard output.
static boolean	println(java.lang.Object obj) Writes to standard output.
static boolean	puts(java.lang.Object obj) Writes to standard output.
static StringList	strlist(java.lang.String... elements) Returns an string list, which can be empty.

Methods inherited from class java.lang.Object

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

Constructor Detail

ICore

public ICore()

Method Detail

isTrue

public static boolean isTrue(java.lang.Object obj)

Returns whether the object is non-null and, if it is a collection or a string, has a length greater than zero.

Parameters:

obj - the object to check

Returns:

whether the object is true

See Also:

isEmpty(java.lang.Object), isFalse(java.lang.Object), ObjectExt.isTrue(java.lang.Object)

isTrue

public static boolean isTrue(java.lang.Object... objs)

Returns whether the array is not null and is not of zero length.

Parameters:

objs - the array

Returns:

whether the array is true

See Also:

isEmpty(java.lang.Object), isFalse(java.lang.Object)

isFalse

public static boolean isFalse(java.lang.Object obj)

Returns whether the object is null or is a string or collection of zero length.

Parameters:

obj - the object to check

Returns:

whether the object is false

See Also:

isEmpty(java.lang.Object)

isFalse

public static boolean isFalse(java.lang.Object... objs)

Returns whether the array is not null and is not of zero length.

Parameters:

objs - the array

Returns:

whether the array is false

See Also:

isEmpty(java.lang.Object)

isEmpty

public static boolean isEmpty(java.lang.Object obj)

Returns whether the object is null or is a string or collection of zero length.

Parameters:

obj - the object to check

Returns:

whether the object is empty

See Also:

isEmpty(java.lang.Object)

isEmpty

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

Returns whether the string is null or of zero length.

Parameters:

str - the string to check

Returns:

whether the string is empty

See Also:

isEmpty(java.lang.Object)

isNull

public static boolean isNull(java.lang.Object obj)

Returns whether the object is null. This method provides an alternative syntax than "if (obj == null)".

Parameters:

obj - the object to check

Returns:

whether the object is null

See Also:

isNotNull(java.lang.Object)

isNotNull

public static boolean isNotNull(java.lang.Object obj)

Returns whether the object is not null. This method provides an alternative syntax than "if (obj != null)".

Parameters:

obj - the object to check

Returns:

whether the object is not null

See Also:

isNull(java.lang.Object)

or

public static <T> T or(T a,
                       T b)

Returns the first parameter if it is true, and otherwise returns the default value. The following two statements are equivalent:

     String statusName = userName != null ? userName : "guest";
     String statusName = IUtil.or(userName, "guest");
 

This method is best for simple objects, since the default value is evaluated before the method is executed. For example, in the second block below, db.initialize() will be called.

     String status = IUtil.or(db.status(), db.initialize());
 

     String status = db.status() != null ? db.status() : db.initialize());
 

Type Parameters:

T - the type of a and b

Parameters:

a - the value returned if true

b - the value returned if a is not true, and b is true

Returns:

a if true, b if true, else null

See Also:

elvis(T, T), isTrue(java.lang.Object)

and

public static <T> T and(T a,
                        T b)

If both parameters evaluate to true (via isTrue), then the second value is returned. This results in code such as:

    String statusName = userName != null && lastName != null ? lastName : null;
    String statusName = IUtil.and(userName, lastName);
 

Type Parameters:

T - the type of a and b

Parameters:

a - the value returned if true

b - the value returned if a is not true, and b is true

Returns:

b if a and b are true, else null

See Also:

or(T, T), isTrue(java.lang.Object)

elvis

public static <T> T elvis(T obj,
                          T defVal)

An alias for the or method. So-named for the "?:" operator in Groovy.

Parameters:

obj - the object to return if true

defVal - returned if obj is not true

Returns:

obj or defVal

See Also:

or(T, T)

and

@SafeVarargs
public static <T> T and(T... operands)

Returns the last parameter, if all parameters evaluate to true (via isTrue).

Parameters:

operands - the array of type T

Returns:

the last element in operands if all are true

See Also:

or(T, T), isTrue(java.lang.Object)

or

@SafeVarargs
public static <T> T or(T... operands)

Returns the first parameter that evaluates to true (via isTrue).

Parameters:

operands - the array of type T

Returns:

the first element in operands that is true

See Also:

or(T, T), isTrue(java.lang.Object)

iter

public static <T> java.lang.Iterable<T> iter(T[] ary)

Returns an Iterable (iterator) for the C-style array, which can be null. If ary is null, an "empty" iterator will be returned.

Parameters:

ary - the array to iterate over; can be null

Returns:

an iterator for the array

iter

public static <T> java.lang.Iterable<T> iter(java.lang.Iterable<T> coll)

Returns an Iterable (iterator) for the collection, which can be null. If coll is null, an "empty" iterator will be returned.

Parameters:

coll - the collection to iterate over; can be null

Returns:

an iterator for the collection

iter

public static java.lang.Iterable<java.lang.Integer> iter(int num)

Returns an iterator to be executed num times.

Parameters:

num - the number of times to iterate

Returns:

an iterator

list

@SafeVarargs
public static <T> Array<T> list(T... elements)

Returns a list (a Array) initialized with the given elements. The list returned is of dynamic size (unlike Arrays.asList(...), which returns a fixed-size, immutable array). The following two blocks are equivalent:

     List<String> names = new Array<String>(Arrays.asList("kevin", "jacob", "isaac"));
     names.add("henry");
 

     List<String> names = list("kevin", "jacob", "isaac");
     names.add("henry");
 

Parameters:

elements - the array of type T

Returns:

the Array

strlist

public static StringList strlist(java.lang.String... elements)

Returns an string list, which can be empty. This exists as an internate to ICore.<String>list() for empty string lists.

Parameters:

elements - the elements for the new array

Returns:

the StringList

intlist

public static Array<java.lang.Integer> intlist(java.lang.Integer... elements)

Returns an integer list, which can be empty. This exists as an internate to ICore.<Integer>list() for empty integer lists.

Parameters:

elements - the elements for the new array

Returns:

the Integer array

puts

public static boolean puts(java.lang.Object obj)

Writes to standard output. Returns true, so this can be used inside conditionals.

Parameters:

obj - the object to write

Returns:

true always

printf

public static boolean printf(java.lang.String fmt,
                             java.lang.Object... args)

Writes to standard output. Returns true, so this can be used inside conditionals.

Parameters:

fmt - the format

args - the arguments for the format

Returns:

true always

println

public static boolean println(java.lang.Object obj)

Writes to standard output. Returns true, so this can be used inside conditionals.

Parameters:

obj - the object to write

Returns:

true always

map

public static <KeyType,ValueType> java.util.TreeMap<KeyType,ValueType> map()

Creates an empty tree map.

map

public static <KeyType,ValueType> java.util.TreeMap<KeyType,ValueType> map(KeyType k1,
                                                                           ValueType v1)

Creates a map with one key/value pair.

map

public static <KeyType,ValueType> java.util.TreeMap<KeyType,ValueType> map(KeyType k1,
                                                                           ValueType v1,
                                                                           KeyType k2,
                                                                           ValueType v2)

Creates a map with two key/value pairs.

ary

@SafeVarargs
public static <T> T[] ary(T... args)

Converts varargs to T[]. ary("one", 1) is shorter than new Object[] { "one", 1 }. For Object arrays (i.e., to work around the "unchecked generic array creation" warning), use Common#objary.