Computing Functions ForCollections

These functions take a collection as a parameter and perform some calculations by it.

Count	Calc count not null values in path
Max	Detect max value
Min	Detect minimal value
SubList	Returning a subarray from an incoming array
TrimTo	Removes all values from the array, starting from the beginning and ending with the given value
TrimAfter	Removes all values from the array from the given value `lastValue` to the end

Count

Calc count not null values in a path or collection.

Incoming parameters

collection path or collection where required to count the number of rows

Output

Count of rows, type : int

Examples

count(null)    ->  0       
count(2)       ->  1
count((1,1,1)) ->  3

List<String> list = new ArrayList<>();
list.add("one");
list.add("two");
list.add(null);
list.add("three");

int cnt = (int) engine.calc("count(.)", list);
assertEquals(3, cnt);

Max

Detect max value.

Incoming parameters

collection path or collection where required to find the max value or several values, among which you need to find the max value.

Output

max value

Examples

max(null)    ->  null       
max(1)       ->  1
max(1,2)     ->  2
max((1,2))   ->  2

LList<Integer> list = new ArrayList<>();
list.add(1);
list.add(2);
Object max = engine.calc("max(.)", list);
assertEquals(2, max);

Min

Detect minimal value

Incoming parameters

collection path or collection where required to find the minimal value or several values, among which you need to find the max value.

Output

max value

Examples

min(null)    ->  null       
min(1)       ->  1
min(1,2)     ->  1
min((2,1))   ->  1

LList<Integer> list = new ArrayList<>();
list.add(1);
list.add(2);
Object min= engine.calc("min(.)", list);
assertEquals(1, min);

SubList

Returning a subarray from an incoming array.
Subarray, starts with indexFrom and ends with indexTo. By default indexFrom and indexTo are included in the subarray

Syntax

subList(collection, indexFrom, indexTo)
subList(collection, indexFrom, indexTo, includeFirstValue)
subList(collection, indexFrom, indexTo, includeFirstValue, includeLastValue)

Incoming parameters

Parameter Name	Type	Require	Description	Default Value
collection	List	Yes	Incoming collection
indexFrom	int	Yes	The starting index in array which the subarray will be taken. If it less than zero, then it will be counted from the end of the array.
indexTo	String	Yes	The ending index in the array from which the subarray will be taken. If it is less than zero, then it will be counted from the end of the array.
includeFirstValue	boolean	No	Include first value to subarray	true
includeLastValue	boolean	No	Include last value to subarray	true

Output

Type: java.util.List
Subarray.

Examples

assertEquals("[2, 3, 4]",       engine.calc(new Formula("subList( (1,2,3,4,5), 1,    3   )")).toString());
assertEquals("[1, 2, 3, 4, 5]", engine.calc(new Formula("subList( (1,2,3,4,5), 0,    4   )")).toString());
assertEquals("[5]",             engine.calc(new Formula("subList( (1,2,3,4,5), 100,  4   )")).toString());
assertEquals("[2, 3, 4, 5]",    engine.calc(new Formula("subList( (1,2,3,4,5), -3,   4   )")).toString());
assertEquals("[1, 2, 3, 4, 5]", engine.calc(new Formula("subList( (1,2,3,4,5), -100, 4   )")).toString());
assertEquals("[2, 3, 4, 5]",    engine.calc(new Formula("subList( (1,2,3,4,5), 1,    40  )")).toString());
assertEquals("[1, 2]",          engine.calc(new Formula("subList( (1,2,3,4,5), 1,    0   )")).toString());
assertEquals("[2, 3, 4]",       engine.calc(new Formula("subList( (1,2,3,4,5), 1,    -1  )")).toString());
assertEquals("[1, 2]",          engine.calc(new Formula("subList( (1,2,3,4,5), 1,    -100)")).toString());
assertEquals("[]", engine.calc(new Formula("subList( null,        1,   3  )")).toString());
assertEquals("[]", engine.calc(new Formula("subList( toList(),    1,   3  )")).toString());
assertEquals("[]", engine.calc(new Formula("subList( (1,2,3,4,5), 100, 100)")).toString());

TrimTo

Removes all values from the array, starting from the beginning and ending with the given value firstValue.
The optional leaveFirstValue parameter allows you to leave the specified value firstValue in the array. By default, it is true.

Syntax

trimTo(collection, firstValue)
trimTo(collection, firstValue, leaveFirstValue)

Incoming parameters

Parameter Name	Type	Require	Description	Default Value
collection	List	Yes	Incoming collection
firstValue	Object	Yes	Value as border to trim.
leaveFirstValue	boolean	No	Leave the specified value in the array	true

Output

Type: java.util.List
Trimmed array.

Examples

assertEquals("[3, 4, 5]",       engine.calc(new Formula("trimTo( (1,2,3,4,5), 3       )")).toString());
assertEquals("[4, 5]",          engine.calc(new Formula("trimTo( (1,2,3,4,5), 3, false)")).toString());

assertEquals("[]",              engine.calc(new Formula("trimTo( (1,2,3,4,5), 6       )")).toString());
assertEquals("[1, 2, 3, 4, 5]", engine.calc(new Formula("trimTo( (1,2,3,4,5), 1       )")).toString());

assertEquals("[5]",             engine.calc(new Formula("trimTo( (1,2,3,4,5), 5       )")).toString());
assertEquals("[]",              engine.calc(new Formula("trimTo( (1,2,3,4,5), 5, false)")).toString());

assertEquals("[]",              engine.calc(new Formula("trimTo( (1,2,3,4,5), null    )")).toString());
assertEquals("[]",              engine.calc(new Formula("trimTo( null,        5       )")).toString());

TrimAfter

Removes all values from the array from the given value lastValue to the end.
The optional leaveLastValue parameter allows you to leave the specified value lastValue in the array. By default, it is true.

Syntax

trimAfter(collection, lastValue)
trimAfter(collection, lastValue, leaveLastValue)

Incoming parameters

Parameter Name	Type	Require	Description	Default Value
collection	List	Yes	Incoming collection
lastValue	Object	Yes	Value as border to trim.
leaveLastValue	boolean	No	Leave the specified value in the array	true

Output

Type: java.util.List
Trimmed array.

Examples

assertEquals("[1, 2, 3]",       engine.calc(new Formula("trimAfter( (1,2,3,4,5), 3       )")).toString());
assertEquals("[1, 2]",          engine.calc(new Formula("trimAfter( (1,2,3,4,5), 3, false)")).toString());

assertEquals("[]",              engine.calc(new Formula("trimAfter( (1,2,3,4,5), 6       )")).toString());
assertEquals("[]",              engine.calc(new Formula("trimAfter( (1,2,3,4,5), 6, false)")).toString());

assertEquals("[1]",             engine.calc(new Formula("trimAfter( (1,2,3,4,5), 1       )")).toString());
assertEquals("[]",              engine.calc(new Formula("trimAfter( (1,2,3,4,5), 1, false)")).toString());

assertEquals("[1, 2, 3, 4, 5]", engine.calc(new Formula("trimAfter( (1,2,3,4,5), 5       )")).toString());
assertEquals("[1, 2, 3, 4]",    engine.calc(new Formula("trimAfter( (1,2,3,4,5), 5, false)")).toString());

assertEquals("[]",              engine.calc(new Formula("trimAfter( (1,2,3,4,5), null    )")).toString());
assertEquals("[]",              engine.calc(new Formula("trimAfter( null,        5       )")).toString());