Package org.apache.olingo.odata2.api.uri.expression

Interface ExpressionVisitor

public interface ExpressionVisitor

Interface ExpressionVisitor is used to traverse a $filter or $orderby expression tree. Any class instance implementing this interface can be passed to the method Visitable.accept(ExpressionVisitor) of an expression node to start the traversing. While traversing, the appropriate methods of the visitor implementation will be called.

Method Summary

Modifier and Type	Method	Description
Object	visitBinary(BinaryExpression binaryExpression, BinaryOperator operator, Object leftSide, Object rightSide)	Visits a binary expression
Object	visitFilterExpression(FilterExpression filterExpression, String expressionString, Object expression)	Visits a filter expression
Object	visitLiteral(LiteralExpression literal, EdmLiteral edmLiteral)	Visits a literal expression
Object	visitMember(MemberExpression memberExpression, Object path, Object property)	Visits a member expression (e.g.
Object	visitMethod(MethodExpression methodExpression, MethodOperator method, List<Object> parameters)	Visits a method expression
Object	visitOrder(OrderExpression orderExpression, Object filterResult, SortOrder sortOrder)	Visits a order expression
Object	visitOrderByExpression(OrderByExpression orderByExpression, String expressionString, List<Object> orders)	Visits a orderby expression
Object	visitProperty(PropertyExpression propertyExpression, String uriLiteral, EdmTyped edmProperty)	Visits a property expression
Object	visitUnary(UnaryExpression unaryExpression, UnaryOperator operator, Object operand)	Visits a unary expression

Method Detail

visitFilterExpression

Object visitFilterExpression(FilterExpression filterExpression,
                             String expressionString,
                             Object expression)

Visits a filter expression

Parameters:

filterExpression - The visited filter expression node

expressionString - The $filter expression string used to build the filter expression tree

expression - The expression node representing the first operator,method,literal or property of the expression tree

Returns:

The overall result of evaluating the whole filter expression tree

visitBinary

Object visitBinary(BinaryExpression binaryExpression,
                   BinaryOperator operator,
                   Object leftSide,
                   Object rightSide)

Visits a binary expression

Parameters:

binaryExpression - The visited binary expression node

operator - The operator used in the binary expression

leftSide - The result of visiting the left expression node

rightSide - The result of visiting the right expression node

Returns:

Returns the result from evaluating operator, leftSide and rightSide

visitOrderByExpression

Object visitOrderByExpression(OrderByExpression orderByExpression,
                              String expressionString,
                              List<Object> orders)

Visits a orderby expression

Parameters:

orderByExpression - The visited orderby expression node

expressionString - The $orderby expression string used to build the orderby expression tree

orders - The result of visiting the orders of the orderby expression

Returns:

The overall result of evaluating the orderby expression tree

visitOrder

Object visitOrder(OrderExpression orderExpression,
                  Object filterResult,
                  SortOrder sortOrder)

Visits a order expression

Parameters:

orderExpression - The visited order expression node

filterResult - The result of visiting the filter expression contained in the order

sortOrder - The sort order

Returns:

The overall result of evaluating the order

visitLiteral

Object visitLiteral(LiteralExpression literal,
                    EdmLiteral edmLiteral)

Visits a literal expression

Parameters:

literal - The visited literal expression node

edmLiteral - The detected EDM literal (value and type)

Returns:

The value of the literal

visitMethod

Object visitMethod(MethodExpression methodExpression,
                   MethodOperator method,
                   List<Object> parameters)

Visits a method expression

Parameters:

methodExpression - The visited method expression node

method - The method used in the method expression

parameters - The result of visiting the parameters of the method

Returns:

Returns the result from evaluating the method and the method parameters

visitMember

Object visitMember(MemberExpression memberExpression,
                   Object path,
                   Object property)

Visits a member expression (e.g. <path property>/<member property>)

Parameters:

memberExpression - The visited member expression node

path - The result of visiting the path property expression node (the left side of the property operator)

property - The result of visiting the member property expression node

Returns:

Returns the value of the corresponding property (which may be a single EDM value or a structured EDM value)

visitProperty

Object visitProperty(PropertyExpression propertyExpression,
                     String uriLiteral,
                     EdmTyped edmProperty)

Visits a property expression

Parameters:

propertyExpression - The visited property expression node

uriLiteral - The URI literal of the property

edmProperty - The EDM property matching the property name used in the expression String

Returns:

Returns the value of the corresponding property ( which may be a single EDM value or a structured EDM value)

visitUnary

Object visitUnary(UnaryExpression unaryExpression,
                  UnaryOperator operator,
                  Object operand)

Visits a unary expression

Parameters:

unaryExpression - The visited unary expression node

operator - The operator used in the unary expression

operand - The result of visiting the operand expression node

Returns:

Returns the result from evaluating operator and operand