Package com.inductiveautomation.ignition.common.expressions

Class DocumentElementExtractor

java.lang.Object

com.inductiveautomation.ignition.common.expressions.DocumentElementExtractor

All Implemented Interfaces:

ElementExtractor<DocumentElement>

public class DocumentElementExtractor
extends Object
implements ElementExtractor<DocumentElement>

An ElementExtractor over DocumentElement trees: Documents are the map elements, DocumentArrays are the array elements, and DocumentPrimitive/ DocumentNull are the primitives, converted to plain Java values by toJava(com.inductiveautomation.ignition.common.document.DocumentElement).

Nested Class Summary

Nested classes/interfaces inherited from interface com.inductiveautomation.ignition.common.expressions.ElementExtractor

ElementExtractor.ElementNotFoundException

Field Summary

Fields

Modifier and Type	Field	Description
static final DocumentElementExtractor	INSTANCE	The stateless, shared instance.

Method Summary

Modifier and Type	Method	Description
String	arrayName()
int	arraySize(DocumentElement element)
DocumentElement	extractIndex(DocumentElement element, int index)
DocumentElement	extractKey(DocumentElement element, String key)
boolean	isArray(@Nullable DocumentElement element)
boolean	isMap(@Nullable DocumentElement element)
boolean	isNull(@Nullable DocumentElement element)
boolean	isPrimitive(@Nullable DocumentElement element)
String	mapName()
Object	toJava(DocumentElement element)

Methods inherited from class java.lang.Object

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

Field Details

INSTANCE

public static final DocumentElementExtractor INSTANCE

The stateless, shared instance.

Method Details

isMap

public boolean isMap(@Nullable DocumentElement element)

Specified by:

isMap in interface ElementExtractor<DocumentElement>

Returns:

true if element is a map: a container ElementExtractor.extractKey(T, java.lang.String) can step into; false for null.

extractKey

public DocumentElement extractKey(DocumentElement element,
 String key)

Specified by:

extractKey in interface ElementExtractor<DocumentElement>

Returns:

the value at key; null if the key is present with a null value.

mapName

public String mapName()

Specified by:

mapName in interface ElementExtractor<DocumentElement>

Returns:

the representation's name for its map type (e.g. "JsonObject"), used in type-mismatch error messages.

isArray

public boolean isArray(@Nullable DocumentElement element)

Specified by:

isArray in interface ElementExtractor<DocumentElement>

Returns:

true if element is an array: a container ElementExtractor.extractIndex(T, int) can step into; false for null.

extractIndex

public DocumentElement extractIndex(DocumentElement element,
 int index)

Specified by:

extractIndex in interface ElementExtractor<DocumentElement>

Returns:

the value at index; null if the slot holds a null value.

arraySize

public int arraySize(DocumentElement element)

Specified by:

arraySize in interface ElementExtractor<DocumentElement>

Returns:

the number of elements in element, for which ElementExtractor.isArray(T) is true.

arrayName

public String arrayName()

Specified by:

arrayName in interface ElementExtractor<DocumentElement>

Returns:

the representation's name for its array type (e.g. "JsonArray"), used in type-mismatch and out-of-bounds error messages.

isNull

public boolean isNull(@Nullable DocumentElement element)

Specified by:

isNull in interface ElementExtractor<DocumentElement>

Returns:

true if element is a Java null or the representation's own null element (e.g. JsonNull).

isPrimitive

public boolean isPrimitive(@Nullable DocumentElement element)

Specified by:

isPrimitive in interface ElementExtractor<DocumentElement>

Returns:

true if element is a leaf value — null or a primitive — that ElementExtractor.toJava(T) converts to a plain Java value; false if it is a map or array, which the evaluator returns in its native representation.

toJava

public Object toJava(DocumentElement element)

Specified by:

toJava in interface ElementExtractor<DocumentElement>

Returns:

the plain Java equivalent (e.g. String, Long, Double, Boolean) of an element for which ElementExtractor.isPrimitive(T) is true; null for the representation's null element.