org.basex.query.xquery.expr
Class Expr

java.lang.Object
  org.basex.query.xquery.expr.Expr

Direct Known Subclasses:

Arr, Case, Cast, Castable, CComm, CDoc, Clc, CmpG, CmpN, CmpV, Context, CPI, CText, FLWOR, ForLet, FTCont, FTNot, FTOptions, FTSelect, FTWords, Fun, If, Instance, Item, Ord, Order, Range, Satisfy, Treat, Unary, VarCall

public abstract class Expr
extends java.lang.Object

Abstract Expression.

Author:

Workgroup DBIS, University of Konstanz 2005-07, ISC License, Christian Gruen

Field Summary

Type	type Data type.

Constructor Summary

Expr()

Method Summary

java.lang.String	cls() Returns the simplified class name (for debugging).
abstract Expr	comp(XQContext ctx) Optimizes and compiles the expression tree.
boolean	d() Checks if this is a duration.
boolean	e() Returns if this is an empty sequence.
abstract Item	eval(XQContext ctx) Evaluates the expression and returns the resulting item.
boolean	i() Checks if this is an item.
abstract java.lang.String	info() Returns a string description of the expression.
boolean	n() Checks if this is a numeric item.
boolean	node() Checks if this is a node.
boolean	s() Checks if this is a string item.
int	size() Returns the sequence size or 0.
byte[]	str() Returns an atomized string.
abstract java.lang.String	toString()
boolean	u() Checks if this is an untyped item.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

type

public Type type

Data type.

Constructor Detail

Expr

public Expr()

Method Detail

cls

public final java.lang.String cls()

Returns the simplified class name (for debugging).

Returns:

class name

comp

public abstract Expr comp(XQContext ctx)
                   throws XQException

Optimizes and compiles the expression tree.

Parameters:

ctx - query context

Returns:

optimized Expression

Throws:

XQException - evaluation exception

d

public boolean d()

Checks if this is a duration.

Returns:

result of check

e

public boolean e()

Returns if this is an empty sequence.

Returns:

result of check

eval

public abstract Item eval(XQContext ctx)
                   throws XQException

Evaluates the expression and returns the resulting item.

Parameters:

ctx - query context

Returns:

resulting item

Throws:

XQException - evaluation exception

i

public boolean i()

Checks if this is an item.

Returns:

result of check

info

public abstract java.lang.String info()

Returns a string description of the expression. Contrary to the toString() method, the current expressions aren't included in the output.

Returns:

result of check

n

public boolean n()

Checks if this is a numeric item.

Returns:

result of check

node

public boolean node()

Checks if this is a node.

Returns:

result of check

s

public boolean s()

Checks if this is a string item.

Returns:

result of check

size

public int size()

Returns the sequence size or 0.

Returns:

result of check

str

public byte[] str()

Returns an atomized string.

Returns:

string representation

toString

public abstract java.lang.String toString()

Overrides:

toString in class java.lang.Object

u

public boolean u()

Checks if this is an untyped item.

Returns:

result of check