Package org.basex.query.value.seq

Class DBNodeSeq

java.lang.Object

org.basex.query.expr.ExprInfo

org.basex.query.expr.Expr

org.basex.query.value.Value

org.basex.query.value.seq.Seq

org.basex.query.value.seq.DBNodeSeq

All Implemented Interfaces:

Iterable<Item>

Direct Known Subclasses:

DBNodes

public class DBNodeSeq
extends Seq

Sequence, containing at least two nodes in distinct document order (DDO).

Author:

BaseX Team 2005-21, BSD License, Christian Gruen

Field Summary

Fields

Modifier and Type	Field	Description
protected final boolean	all	Pre values reference all documents of the database.
protected final Data	data	Data reference.
protected int[]	pres	Pre values.

Fields inherited from class org.basex.query.value.seq.Seq

size

Fields inherited from class org.basex.query.value.Value

type

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	DBNodeSeq(int[] pres, Data data, Type type, boolean all)	Constructor.

Method Summary

Modifier and Type	Method	Description
boolean	all()	Indicates if pre values reference all documents of the database.
final long	atomSize()	Computes the number of atomized items.
Value	atomValue(QueryContext qc, InputInfo ii)	Evaluates the expression and returns the atomized items.
final void	cache(boolean lazy, InputInfo ii)	Caches lazy values.
Data	data()	Returns the data reference bound to this expression.
boolean	ddo()	Indicates if this expression returns nodes in document order without duplicates.
Item	ebv(QueryContext qc, InputInfo ii)	Checks if the effective boolean value can be computed for this expression:
boolean	equals(Object obj)	This function is e.g.
static Value	get(int[] pres, Data data, Expr expr)	Creates a sequence with the specified items.
static Value	get(int[] pres, Data data, Type type, boolean all)	Creates a sequence with the specified items.
static Value	get(IntList pres, Data data, boolean docs, boolean all)	Creates a node sequence with the given data reference and pre values.
final Value	insert(long pos, Item item, QueryContext qc)	Inserts an item at the given position into this sequence and returns the resulting sequence.
DBNode	itemAt(long pos)	Returns the item at the given position in the value.
void	plan(QueryString qs)	Creates a query string.
int	pre(int index)	Returns the specified pre value.
int[]	pres()	Returns the internal pre value array.
final Value	remove(long pos, QueryContext qc)	Removes the item at the given position in this sequence and returns the resulting sequence.
Value	reverse(QueryContext qc)	Returns all items of this value in reverse order.

Methods inherited from class org.basex.query.value.seq.Seq

copyInsert, description, get, hash, initialCapacity, insertBefore, item, iter, plan, refineType, seqType, size, subSeq, subsequence, test, toErrorString, toJava

Methods inherited from class org.basex.query.value.Value

accept, checkUp, compile, copy, count, exprSize, has, inline, inlineable, isEmpty, isItem, iter, iterator, materialize, serialize, serialize, serialize, value

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

arg, args, atomItem, atomIter, data, funcType, hasFreeVars, indexAccessible, isSimple, markTailCalls, mergeEbv, optimize, simplifyFor, typeCheck, uses, vacuous, visitAll

Methods inherited from class org.basex.query.expr.ExprInfo

toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Field Details

data

protected final Data data

Data reference.

all

protected final boolean all

Pre values reference all documents of the database.

pres

protected int[] pres

Pre values.

Constructor Details

DBNodeSeq

protected DBNodeSeq(int[] pres,
 Data data,
 Type type,
 boolean all)

Constructor.

Parameters:

pres - pre values

data - data reference

type - node type

all - pre values reference all documents of the database

Method Details

data

public Data data()

Description copied from class: Expr

Returns the data reference bound to this expression. This method is currently overwritten by DBNode, DBNodeSeq, AxisPath and VarRef.

Overrides:

data in class Expr

Returns:

data reference (can be null)

ebv

public Item ebv(QueryContext qc,
 InputInfo ii)

Description copied from class: Expr

Checks if the effective boolean value can be computed for this expression:

• If it yields an empty sequence, Bln.FALSE will be returned.
• If it yields a single item, this item will be returned.
• If it yields nodes, the first node will be returned.
• Otherwise, an error will be raised.

A single numeric item may later be evaluated as positional predicate.

Parameters:

qc - query context

ii - input info (required for Seq instances, which have no input info)

Returns:

item

ddo

public boolean ddo()

Description copied from class: Expr

Indicates if this expression returns nodes in document order without duplicates.

Overrides:

ddo in class Seq

Returns:

result of check

itemAt

public DBNode itemAt(long pos)

Description copied from class: Value

Returns the item at the given position in the value. The specified value must be lie within the valid bounds.

Specified by:

itemAt in class Value

Parameters:

pos - position

Returns:

item

atomValue

public Value atomValue(QueryContext qc,
 InputInfo ii)

Description copied from class: Expr

Evaluates the expression and returns the atomized items.

Parameters:

qc - query context

ii - input info (only required by Seq instances, which have no input info)

Returns:

atomized item

pres

public int[] pres()

Returns the internal pre value array.

Returns:

pre values

pre

public int pre(int index)

Returns the specified pre value.

Parameters:

index - index of pre value

Returns:

pre value

all

public boolean all()

Indicates if pre values reference all documents of the database.

Returns:

flag

reverse

public Value reverse(QueryContext qc)

Description copied from class: Value

Returns all items of this value in reverse order.

Specified by:

reverse in class Value

Parameters:

qc - query context

Returns:

items in reverse order

equals

public boolean equals(Object obj)

Description copied from class: Expr

This function is e.g. called by:

• If.optimize(CompileContext), Switch.optimize(CompileContext), Typeswitch.optimize(CompileContext), in order to discard identical expressions.
• CmpR.mergeEbv(Expr, boolean, CompileContext) or CmpSR.mergeEbv(Expr, boolean, CompileContext), in order to merge expressions with identical input.
• CmpG.optimize(CompileContext) or CmpV.optimize(CompileContext), in order to pre-evaluate equality tests.
• CmpG.optimize(CompileContext) or Pos.get(Expr, CmpV.OpV, InputInfo, CompileContext), in order to compare the start and end value.
• PathCache, in order to find identical root values at runtime.

Overrides:

equals in class Seq

plan

public void plan(QueryString qs)

Description copied from class: ExprInfo

Creates a query string.

Overrides:

plan in class Seq

Parameters:

qs - query string builder

get

public static Value get(int[] pres,
 Data data,
 Type type,
 boolean all)

Creates a sequence with the specified items.

Parameters:

pres - pre values

data - data reference

type - node type (can be null)

all - pre values reference all documents of the database

Returns:

value

get

public static Value get(int[] pres,
 Data data,
 Expr expr)

Creates a sequence with the specified items.

Parameters:

pres - pre values

data - data reference

expr - expression (can be null)

Returns:

value

get

public static Value get(IntList pres,
 Data data,
 boolean docs,
 boolean all)

Creates a node sequence with the given data reference and pre values.

Parameters:

pres - pre values

data - data reference

docs - all values reference document nodes

all - pre values reference all documents of the database

Returns:

value

cache

public final void cache(boolean lazy,
 InputInfo ii)

Description copied from class: Value

Caches lazy values.

Specified by:

cache in class Value

Parameters:

lazy - lazy caching

ii - input info

atomSize

public final long atomSize()

Description copied from class: Value

Computes the number of atomized items.

Specified by:

atomSize in class Value

Returns:

atomized item

insert

public final Value insert(long pos,
 Item item,
 QueryContext qc)

Inserts an item at the given position into this sequence and returns the resulting sequence. Because this function will mostly be invoked recursively, the standard implementation will be called, because its runtime outweighs the possibly higher memory consumption.

Specified by:

insert in class Seq

Parameters:

pos - position at which the item should be inserted, must be between 0 and Seq.size

item - item to insert

qc - query context

Returns:

resulting value

remove

public final Value remove(long pos,
 QueryContext qc)

Removes the item at the given position in this sequence and returns the resulting sequence. Because this function will mostly be invoked recursively, the standard implementation will be called, because its runtime outweighs the possibly higher memory consumption.

Specified by:

remove in class Seq

Parameters:

pos - position of the item to remove, must be between 0 and Seq.size - 1

qc - query context

Returns:

resulting sequence