com.hp.ucmdb.api.topology

Interface ConditionExpression<T,O>

All Known Subinterfaces:

ConditionExpressionBuilder<T,O>

public interface ConditionExpression<T,O>

A root of an expression tree structure.

The following permutation are generally available, but specific constraints on the type of the expression may apply:

• Leaf expression: This is the actual expression leaf. Only the leaf() method will not return null.
• Bridge expression: This is a syntactic bridge. It bridges from the parent expression (if exists) to the left() expression with no operator.
• Single element expression: This expression has a left() and an op().
• Binary expression: This expression has both left() and right() and an operator acting between them

An expression may be explored using the getter methods, or by using the ConditionExpressionVisitor.

Since:

UCMDB 9.0

Method Summary

Modifier and Type	Method and Description
boolean	isLeafExpression() Returns true if this is a leaf expression, false if this is a binary expression.
T	leaf() Returns the leaf if this is a leaf expression, or null if this is a binary expression.
Collection<T>	leaves() Returns a collection of all the leaves under this condition expression.
ConditionExpression<T,O>	left() Returns the left (first) part of a binary expression, or null if this is a leaf expression.
O	op() Returns the operand of the expression, or null if this is a leaf expression.
ConditionExpression<T,O>	right() Returns the right (second) part of a binary expression, or null if this is a leaf expression.
void	visit(ConditionExpressionVisitor<T,O> visitor) Visits the expression using an (optionally client-based) visitor.

Method Detail

left

ConditionExpression<T,O> left()

Returns the left (first) part of a binary expression, or null if this is a leaf expression.

Note: This is guaranteed not null even if the expression is a single-item expression.

right

ConditionExpression<T,O> right()

Returns the right (second) part of a binary expression, or null if this is a leaf expression.

Note: Some operations may have single item expressions, in which case this method will return null as well.

op

O op()

Returns the operand of the expression, or null if this is a leaf expression.

Note: Some expressions may have single-item operands.

isLeafExpression

boolean isLeafExpression()

Returns true if this is a leaf expression, false if this is a binary expression.

leaf

T leaf()

Returns the leaf if this is a leaf expression, or null if this is a binary expression.

leaves

Collection<T> leaves()

Returns a collection of all the leaves under this condition expression.

visit

void visit(ConditionExpressionVisitor<T,O> visitor)

Visits the expression using an (optionally client-based) visitor.

This method CAN receive client implementations of ConditionExpressionVisitor

Note: This method visits the current expression only. If traversing is needed, it is the client responsability to call the child expressions, if any are present, visit methods.

Parameters:

visitor - a client implementation of the ConditionExpressionVisitor interface.