org.basex.query.xpath.locpath
Class Preds

java.lang.Object
  org.basex.query.xpath.locpath.Preds

public final class Preds
extends java.lang.Object

Location Steps.

Author:

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

Constructor Summary

Preds()

Method Summary

void	add(Expr expr) Adds an expression as predicate.
void	add(int min, int max) Adds a position predicate.
void	add(Pred pred) Adds a predicate.
boolean	compile(XPContext ctx) Optimizes the predicates.
void	eval(XPContext ctx, NodeBuilder nodes, NodeBuilder result) Evaluates the predicates.
Pred	get(int i) Returns a predicate.
void	remove(int s) Removes the specified step.
boolean	sameAs(Preds cmp) Returns the predicates for equality.
int	size() Returns the number of location steps.
java.lang.String	toString()
boolean	usesPos() Checks whether the predicates make use of the position parameter.
boolean	usesSetSize() Checks whether the predicates make use of the size parameter.

Methods inherited from class java.lang.Object

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

Constructor Detail

Preds

public Preds()

Method Detail

add

public void add(Expr expr)

Adds an expression as predicate.

Parameters:

expr - expression to be added

add

public void add(int min,
                int max)

Adds a position predicate.

Parameters:

min - minimum value

max - maximum value

add

public void add(Pred pred)

Adds a predicate.

Parameters:

pred - predicate to be added

compile

public boolean compile(XPContext ctx)
                throws EvalException

Optimizes the predicates.

Parameters:

ctx - query context

Returns:

false if predicate always yields false

Throws:

EvalException - evaluation exception

eval

public void eval(XPContext ctx,
                 NodeBuilder nodes,
                 NodeBuilder result)
          throws EvalException

Evaluates the predicates.

Parameters:

ctx - query context

nodes - nodes to be evaluated

result - result nodes

Throws:

EvalException - evaluation exception

get

public Pred get(int i)

Returns a predicate.

Parameters:

i - predicate offset

Returns:

predicate

remove

public void remove(int s)

Removes the specified step.

Parameters:

s - step index

sameAs

public boolean sameAs(Preds cmp)

Returns the predicates for equality.

Parameters:

cmp - predicates to be compared

Returns:

result of check

size

public int size()

Returns the number of location steps.

Returns:

number of steps

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

usesPos

public boolean usesPos()

Checks whether the predicates make use of the position parameter.

Returns:

whether position is used

usesSetSize

public boolean usesSetSize()

Checks whether the predicates make use of the size parameter.

Returns:

whether node set size is used