org.qtitools.qti.node.expression.operator
Class Index

java.lang.Object
  org.qtitools.qti.node.AbstractNode
      org.qtitools.qti.node.AbstractObject
          org.qtitools.qti.node.expression.AbstractExpression
              org.qtitools.qti.node.expression.operator.Index

All Implemented Interfaces:

java.io.Serializable, Expression, ExpressionParent, XmlNode, XmlObject, Validatable

public class Index
extends AbstractExpression

The index operator takes A sub-expression with an ordered container value and any base-type. The result is the nth value of the container. The result has the same base-type as the sub-expression but single cardinality. The first value of A container has index 1, the second 2 and so on. N must be A positive integer. If n exceeds the number of values in the container or the sub-expression is NULL then the result of the index operator is NULL.

Author:

Jiri Kajaba

See Also:

Cardinality, BaseType, Serialized Form

Field Summary

static java.lang.String	ATTR_INDEX_NAME Name of n attribute in xml schema.
static java.lang.String	CLASS_TAG Name of this class in xml schema.

Fields inherited from class org.qtitools.qti.node.expression.AbstractExpression

logger

Fields inherited from interface org.qtitools.qti.node.expression.Expression

DISPLAY_NAME

Fields inherited from interface org.qtitools.qti.node.XmlNode

INDENT, NEW_LINE, SIMPLE_NAME_INNER_SEPARATOR, SIMPLE_NAMES_SEPARATOR

Constructor Summary

Index(ExpressionParent parent)
Constructs expression.

Method Summary

protected Value	evaluateSelf(int depth) Evaluates this expression.
java.lang.String	getClassTag() Gets QTI class name of this node.
java.lang.Integer	getIndex() Gets value of n attribute.
BaseType[]	getProducedBaseTypes() Gets list of all possible produced baseTypes after evaluation (possible baseTypes of evaluated result).
BaseType[]	getRequiredBaseTypes(int index) Gets list of all acceptable baseTypes which can child expression at given position produce.
void	setIndex(java.lang.Integer index) Sets new value of n attribute.
protected ValidationResult	validateAttributes() Validates attributes of this node.

Methods inherited from class org.qtitools.qti.node.expression.AbstractExpression

evaluate, getBaseType, getCardinality, getChildren, getFirstChild, getParent, getParentRequiredBaseTypes, getParentRequiredCardinalities, getProducedCardinalities, getProducedNumericalBaseTypes, getRequiredCardinalities, getRequiredSameBaseTypes, getRequiredSameCardinalities, getSecondChild, getType, getValue, isAnyChildNull, isNull, isVariable, reset, toString, validate

Methods inherited from class org.qtitools.qti.node.AbstractObject

getParentItem, getParentResult, getParentTest, setParent

Methods inherited from class org.qtitools.qti.node.AbstractNode

attrToXmlString, bodyToXmlString, getAttributes, getFullName, getIndent, getNode, getNode, getNode, getNodeGroups, getParentRoot, getSimpleName, getSourceFile, getSourceNode, getSourceString, getSourceUrl, hasChildNodes, load, load, load, load, loadAttributes, readChild, readChildren, setParent, setSourceFile, setSourceNode, setSourceString, setSourceUrl, toXmlString, toXmlString, validateChildren

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.qtitools.qti.node.XmlObject

getParentItem, getParentResult, getParentTest, setParent

Methods inherited from interface org.qtitools.qti.node.XmlNode

getAttributes, getFullName, getNodeGroups, getParentRoot, getSimpleName, getSourceFile, getSourceNode, getSourceString, getSourceUrl, hasChildNodes, load, load, load, load, setSourceFile, setSourceNode, setSourceString, setSourceUrl, toXmlString, toXmlString

Field Detail

CLASS_TAG

public static final java.lang.String CLASS_TAG

Name of this class in xml schema.

See Also:

Constant Field Values

ATTR_INDEX_NAME

public static final java.lang.String ATTR_INDEX_NAME

Name of n attribute in xml schema.

See Also:

Constant Field Values

Constructor Detail

Index

public Index(ExpressionParent parent)

Constructs expression.

Parameters:

parent - parent of this expression

Method Detail

getClassTag

public java.lang.String getClassTag()

Description copied from interface: XmlNode

Gets QTI class name of this node.

QTI class name has very important role during loading/saving nodes.

For example: Java class name is AssessmentTest; QTI class name is assessmentTest.

Specified by:

getClassTag in interface XmlNode

Specified by:

getClassTag in class AbstractNode

Returns:

QTI class name of this node

getIndex

public java.lang.Integer getIndex()

Gets value of n attribute.

Returns:

value of n attribute

See Also:

setIndex(java.lang.Integer)

setIndex

public void setIndex(java.lang.Integer index)

Sets new value of n attribute.

Parameters:

index - new value of n attribute

See Also:

getIndex()

getRequiredBaseTypes

public BaseType[] getRequiredBaseTypes(int index)

Description copied from interface: ExpressionParent

Gets list of all acceptable baseTypes which can child expression at given position produce.

Result of this method can change in time.

Static example is expression or. Expression or accepts only boolean baseType for any index.

Dynamic example is expression match. Expression match accepts any baseType of its children. but this baseType must be same for all its children.

Specified by:

getRequiredBaseTypes in interface ExpressionParent

Overrides:

getRequiredBaseTypes in class AbstractExpression

Parameters:

index - position of child expression in this parent

Returns:

list of all acceptable baseTypes which can child expression at given position produce

getProducedBaseTypes

public BaseType[] getProducedBaseTypes()

Description copied from interface: Expression

Gets list of all possible produced baseTypes after evaluation (possible baseTypes of evaluated result). Result of this method can change in time.

Static example is expression or. Expression or can produce only boolean baseType and it cannot change.

Dynamic example is expression variable. Expression variable can produce any baseType before evaluation. After evaluation it produces baseType of its result (and it can change every evaluation call!).

Null expression, empty containers (multiple, ordered, record), or NULL values produces all baseTypes. So they are compatible with anything.

Specified by:

getProducedBaseTypes in interface Expression

Overrides:

getProducedBaseTypes in class AbstractExpression

Returns:

list of all possible produced baseTypes after evaluation

validateAttributes

protected ValidationResult validateAttributes()

Description copied from class: AbstractNode

Validates attributes of this node.

Overrides:

validateAttributes in class AbstractNode

Returns:

result of validation

evaluateSelf

protected Value evaluateSelf(int depth)

Description copied from class: AbstractExpression

Evaluates this expression. All children must be already evaluated. Contains no checks.

Specified by:

evaluateSelf in class AbstractExpression

Parameters:

depth - depth of this expression in expression tree (root's depth = 0)

Returns:

result of evaluation