org.basex.query.item
Class Seq

java.lang.Object
  extended by org.basex.query.ExprInfo
      extended by org.basex.query.expr.Expr
          extended by org.basex.query.item.Item
              extended by org.basex.query.item.Seq

public class Seq
extends Item

Item sequence.

Author:
Workgroup DBIS, University of Konstanz 2005-10, ISC License, Christian Gruen

Nested Class Summary
 
Nested classes/interfaces inherited from class org.basex.query.expr.Expr
Expr.Use
 
Field Summary
static Seq EMPTY
          Empty sequence.
 Item[] val
          Item array.
 
Fields inherited from class org.basex.query.item.Item
score, type
 
Method Summary
 Item atomic(QueryContext ctx)
          Evaluates the expression and returns the resulting item or a null reference.
 int diff(Item it)
          Returns the difference between the current and the specified item.
 boolean duplicates(QueryContext ctx)
          Returns true if the expression might yield duplicates and unsorted results.
 Item ebv(QueryContext ctx)
          Checks if the iterator can be dissolved into an effective boolean value.
 boolean eq(Item it)
          Checks the items for equality.
static Item get(Item[] v, int s)
          Constructor.
 boolean i()
          Checks if this is an item.
 Iter iter()
          Returns an item iterator.
 Object java()
          Returns a Java object.
 void plan(Serializer ser)
          Recursively sends the abstract syntax of this expression to the specified serializer.
 Return returned(QueryContext ctx)
          Indicates the return type of an expression.
 void serialize(Serializer ser)
          Serializes the item.
 long size(QueryContext ctx)
          Returns the sequence size or 1.
 Item test(QueryContext ctx)
          Performs a predicate test and returns the item if test was successful.
 String toString()
           
 
Methods inherited from class org.basex.query.item.Item
bool, comp, d, dbl, dec, flt, hashCode, iter, itr, n, name, node, removable, s, score, score, str, u, uses
 
Methods inherited from class org.basex.query.expr.Expr
addText, checkCtx, checkDbl, checkItr, e, indexAccessible, indexEquivalent, remove, sameAs, v
 
Methods inherited from class org.basex.query.ExprInfo
color, info
 
Methods inherited from class java.lang.Object
equals, getClass, notify, notifyAll, wait, wait, wait
 

Field Detail

EMPTY

public static final Seq EMPTY
Empty sequence.


val

public Item[] val
Item array.

Method Detail

get

public static Item get(Item[] v,
                       int s)
Constructor.

Parameters:
v - value
s - size
Returns:
resulting item or sequence

i

public final boolean i()
Description copied from class: Expr
Checks if this is an item.

Overrides:
i in class Item
Returns:
result of check

size

public final long size(QueryContext ctx)
Description copied from class: Expr
Returns the sequence size or 1.

Overrides:
size in class Item
Parameters:
ctx - query context
Returns:
result of check

java

public Object java()
Description copied from class: Item
Returns a Java object.

Overrides:
java in class Item
Returns:
string representation

iter

public Iter iter()
Description copied from class: Item
Returns an item iterator.

Overrides:
iter in class Item
Returns:
iterator

atomic

public Item atomic(QueryContext ctx)
            throws QueryException
Description copied from class: Expr
Evaluates the expression and returns the resulting item or a null reference. If this method is not overwritten, Expr.iter(org.basex.query.QueryContext) must be implemented.

Overrides:
atomic in class Item
Parameters:
ctx - query context
Returns:
iterator
Throws:
QueryException - query exception

ebv

public Item ebv(QueryContext ctx)
         throws QueryException
Description copied from class: Expr
Checks if the iterator can be dissolved into an effective boolean value. If not, returns an error. If yes, returns the first value - which can be also be e.g. an integer, which is later evaluated as position predicate.

Overrides:
ebv in class Item
Parameters:
ctx - query context
Returns:
item
Throws:
QueryException - query exception

test

public Item test(QueryContext ctx)
          throws QueryException
Description copied from class: Expr
Performs a predicate test and returns the item if test was successful.

Overrides:
test in class Item
Parameters:
ctx - query context
Returns:
item
Throws:
QueryException - query exception

eq

public final boolean eq(Item it)
                 throws QueryException
Description copied from class: Item
Checks the items for equality.

Specified by:
eq in class Item
Parameters:
it - item to be compared
Returns:
result of check
Throws:
QueryException - query exception

diff

public final int diff(Item it)
Description copied from class: Item
Returns the difference between the current and the specified item.

Overrides:
diff in class Item
Parameters:
it - item to be compared
Returns:
difference

serialize

public final void serialize(Serializer ser)
                     throws IOException
Description copied from class: Item
Serializes the item.

Overrides:
serialize in class Item
Parameters:
ser - serializer
Throws:
IOException - I/O exception

returned

public final Return returned(QueryContext ctx)
Description copied from class: Expr
Indicates the return type of an expression. Called by the compiler to check if expressions can be reformulated. null is returned by default.

Overrides:
returned in class Item
Parameters:
ctx - query context
Returns:
result of check

duplicates

public final boolean duplicates(QueryContext ctx)
Description copied from class: Expr
Returns true if the expression might yield duplicates and unsorted results.

Overrides:
duplicates in class Item
Parameters:
ctx - query context
Returns:
result of check

plan

public final void plan(Serializer ser)
                throws IOException
Description copied from class: ExprInfo
Recursively sends the abstract syntax of this expression to the specified serializer.

Overrides:
plan in class Item
Parameters:
ser - serializer
Throws:
IOException - I/O exception

toString

public final String toString()
Overrides:
toString in class Item