Set data type

Value range of the Set data type

Elements of the template development can be grouped in:

• Lists (List )
• Sets (Set )
• Maps

FirstSpirit provides the data type Set for the processing/editing of values which represent an ordered set of unique elements. This data type enables a grouping of elements. Set objects are very flexible and can be extended as required.

Unlike the data types List and Map, an element within a set cannot be accessed via an index value or a key value. It is only possible to output the first, the last, all elements or a specific element of a set. If a specific element of the set is to be output, this element must be known. Unlike a list, for example, it is not possible to simply access the second element in the set. Instead, it is necessary to check whether a specific element is contained within the set; only then can this element be accessed. For this reason, elements may only exist within a set precisely once; i.e. an expression of the form: mapElement_1.equals(mapElement_2) can never return true.

The data type Set can also be looked up in the Sun API documentation:

java.util.Set

Definition

Analogous to maps, sets can also be generated via { } (curlybrackets/braces). The following syntax must be fulfilled:

SET := '{} | '{' [ EXPRESSION [',' EXPRESSION ]*] '}'

The following code example generates an empty set and assigns it to the variables "empty_set":

  $CMS_SET(empty_set, {})$

If a set is to be generated which already contains elements, the elements can be simply passed as a comma-separated list within the curly brackets. The code example generates a new, filled set "mySet":

$CMS_SET(mySet, {"one","two","three"})$

In the following code example an element is added to the set:

$CMS_VALUE(mySet.add("four"))$

Definition using the standard input components

Within the <CMS_INPUT_LIST> tags in the form area of a page or section template, input components are defined which can be subsequently used by the editors to insert the actual editorial contents into the page. The standard input components supported by FirstSpirit return different data types.

The following standard input components return an object of data type "Set":

• CMS_INPUT_CHECKBOX
• CMS_INPUT_LIST

Then, with the help of a $CMS_VALUE(...)$ instruction, methods can be applied to this object:

$CMS_VALUE(IDENTIFIER.METHOD)$

The IDENTIFIER is the identifier defined in the resultname parameter of the input component.

Access to elements in the set

The elements in the set are accessed, for example, via an iteration:

$CMS_FOR(setWrapper,mySet)$
  $CMS_VALUE(setWrapper)$
$CMS_END_FOR$

Output:
setWrapper:three
setWrapper:one
setWrapper:four
setWrapper:two

or via functions:

 $CMS_VALUE(mySet.first())$

 $CMS_VALUE(mySet.last())$

The code example returns the first or the last value of the set.

In addition, the following expression is also possible:

$CMS_VALUE(mySet.contains("one"))$

The contains method checks whether a specific element is a component of the set and returns true for the code example given above.

Methods on set objects

The table below lists all methods which can be invoked on objects of data type "Set":

add(Object)

Overview

addAll(Collection)

Overview

clear

Overview

compareTo(Comparable)

Overview

contains(Object)

Overview

containsAll(Collection)

Overview

copy

Overview

distinct(Lambda)

This method filters a collection and returns only the first occurrence relating to a lambda expression.

It can be used to eliminate or ignore duplicates of a list according to a given condition. For this reason, it can be used for glossaries or summaries, which can then serve linked, for example, as navigational element.

See page Mapping expressions (lambda).

Overview

equals(Object)

Overview

filter(String)

Overview

filter(Lambda)

If lists have several attributes per element (comparable with a dataset with several columns), the elements can be filtered by the individual attributes using the method .filter(Lambda).

See page Mapping expressions (lambda).

Overview

fold(Lambda, Map)

This method folds the collection with the given lambda expression and start value.

See page Mapping expressions (lambda).

Overview

getClass

The .getClass() (in Bean syntax: .class) method returns the class of the invoking object (cf. java.lang.Class).

Invocation:

$CMS_VALUE(myString.class)$
$CMS_VALUE(myString.getClass())$

Output:

java.lang.String

Overview

hashCode

Overview

isCase(Object)

Overview

isEmpty

The .isEmpty() (in Bean syntax: .isEmpty) method checks whether an expression or object is empty, e.g. storeElement.isEmpty(). The result of the semantic check depends on the expression or object, e.g. a character string is empty if it does not contain any characters. In the case of objects with complex values or objects, the object decides when it is empty. The data type DomElement for example always contains an empty document, thus it is never null. For this reason, checking an empty DOM editor input component by using the method .isNull()returns the value false, whereas checking the component with .isEmpty() would return the value true.

The method .isEmpty() returns a Boolean value as the check result. true is the check result if the expression or object is empty and false if not.

Overview

isNull

The .isNull() (in Bean syntax: .isNull) method checks whether an expression or object is null , e.g. storeElement.isNull(). In the case of objects with complex values or objects, the object decides when it is null. The data type DomElement for example always contains an empty document, thus it is never null. For this reason, checking an empty DOM editor input component by using the method .isNull() returns the value false, whereas checking the component with .isEmpty() would return the value true.

The method .isNull() returns a Boolean value as the check result. true is the check result if the expression or object is null and false if not.

Overview

iterator

Overview

length

Overview

map(String)

Overview

map(Lambda)

See page Mapping expressions (lambda).

Overview

max

Overview

max(Comparator)

Overview

max(Lambda)

This method delivers the maximum element concerning to the given comparator.

See page Mapping expressions (lambda).

Overview

min

Overview

min(Comparator)

Overview

min(Lambda)

This method delivers the minimum element concerning to the given comparator.

See page Mapping expressions (lambda).

Overview

plus(Collection)

Overview

print

Overview

print(Object)

Overview

remove(Object)

Overview

removeAll(Collection)

Overview

retainAll(Collection)

Overview

set(String, Object)

Overview

size

Overview

toArray

Overview

toArray(Object[])

Overview

toJson

Overview

toString

Overview

toString(String)

The individual elements, e.g. of a list, can be output as string, separated by a delimiter which can be chosen freely.

Example:

$CMS_SET(myList, ["House","Key","Window"])$
$CMS_VALUE(myList.toString("; "))$

The elements of the list myList are output, separated each by semicolon and a space character:

House; Key; Window

Overview

toString(String, String)

Overview

type

Overview

To obtain an object of the set, an entry must be directly addressed with get() or the whole set object must be run through with the CMS_FOR or CMS_RENDER function.

Example:

$CMS_SET(myVariable,"TEXT")$

$CMS_SET(myVariable,1234)$