org.basex.query.xquery.item
Class Item

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

Direct Known Subclasses:

B64, Bln, Date, Hex, Node, Num, QNm, Seq, Str

public abstract class Item
extends Expr

Abstract item.

Author:

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

Field Summary

Fields inherited from class org.basex.query.xquery.expr.Expr

type

Method Summary

boolean	bool() Returns a boolean representation of the item.
Item	castErr(java.lang.Object val) Throws a cast error.
Expr	comp(XQContext ctx) Optimizes and compiles the expression tree.
double	dbl() Returns a double representation of the item.
int	diff(Item it) Returns the difference between the current and the specified item.
abstract boolean	eq(Item it) Checks the items for equality.
Item	eval(XQContext ctx) Evaluates the expression and returns the resulting item.
float	flt() Returns a float representation of the item.
boolean	i() Checks if this is an item.
java.lang.String	info() Returns a string description of the expression.
Iter	iter() Returns an iterator.
long	itr() Returns a numeric (long) representation of the item.
void	serialize(PrintOutput out, XQContext ctx, int level) Serializes the item.
void	serialize(ResultReader rr, XQContext ctx, int level) Serializes the item.
int	size() Returns the sequence size or 0.
java.lang.String	toString()

Methods inherited from class org.basex.query.xquery.expr.Expr

cls, d, e, n, node, s, str, u

Methods inherited from class java.lang.Object

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

Method Detail

bool

public boolean bool()
             throws XQException

Returns a boolean representation of the item.

Returns:

boolean value

Throws:

XQException - evaluation exception

castErr

public final Item castErr(java.lang.Object val)
                   throws XQException

Throws a cast error.

Parameters:

val - cast value

Returns:

dummy item

Throws:

XQException - evaluation exception

comp

public Expr comp(XQContext ctx)

Description copied from class: Expr

Optimizes and compiles the expression tree.

Specified by:

comp in class Expr

Parameters:

ctx - query context

Returns:

optimized Expression

dbl

public double dbl()
           throws XQException

Returns a double representation of the item.

Returns:

double value

Throws:

XQException - evaluation exception

diff

public int diff(Item it)
         throws XQException

Returns the difference between the current and the specified item.

Parameters:

it - item to be compared.

Returns:

difference

Throws:

XQException - evaluation exception

eq

public abstract boolean eq(Item it)
                    throws XQException

Checks the items for equality.

Parameters:

it - item to be compared.

Returns:

result of check

Throws:

XQException - evaluation exception

eval

public final Item eval(XQContext ctx)

Description copied from class: Expr

Evaluates the expression and returns the resulting item.

Specified by:

eval in class Expr

Parameters:

ctx - query context

Returns:

resulting item

flt

public float flt()
          throws XQException

Returns a float representation of the item.

Returns:

float value

Throws:

XQException - evaluation exception

i

public final boolean i()

Description copied from class: Expr

Checks if this is an item.

Overrides:

i in class Expr

Returns:

result of check

info

public final java.lang.String info()

Description copied from class: Expr

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

Specified by:

info in class Expr

Returns:

result of check

iter

public Iter iter()

Returns an iterator.

Returns:

result of check

itr

public long itr()
         throws XQException

Returns a numeric (long) representation of the item.

Returns:

long value

Throws:

XQException - evaluation exception

serialize

public void serialize(PrintOutput out,
                      XQContext ctx,
                      int level)
               throws XQException,
                      java.io.IOException

Serializes the item.

Parameters:

out - output stream

ctx - query context

level - current level

Throws:

java.io.IOException - I/O exception

XQException - evaluation exception

serialize

public void serialize(ResultReader rr,
                      XQContext ctx,
                      int level)
               throws org.xml.sax.SAXException

Serializes the item.

Parameters:

rr - content handler

ctx - query context

level - current level

Throws:

org.xml.sax.SAXException - SAX exception

size

public int size()

Description copied from class: Expr

Returns the sequence size or 0.

Overrides:

size in class Expr

Returns:

result of check

toString

public java.lang.String toString()

Specified by:

toString in class Expr