ParseExpr

java.lang.Object
- org.basex.data.ExprInfo
- - org.basex.query.expr.Expr
  - - org.basex.query.expr.ParseExpr

Direct Known Subclasses:

Arr, FTContains, FTExpr, GFLWOR, Group, Order, OrderBy, Path, Preds, Quantifier, Simple, Single, Switch, TypeSwitch, Var, VarRef
```
public abstract class ParseExpr
extends Expr
```
Abstract parse expression. All non-value expressions are derived from this class.

Author:

BaseX Team 2005-12, BSD License, Christian Gruen

Nested Class Summary
- Nested classes/interfaces inherited from class org.basex.query.expr.Expr
  Expr.Use

Field Summary

Fields
Modifier and Type Field and Description

InputInfo input
Input information.

long size
Cardinality of result; unknown if set to -1.

SeqType type
Static type.

Fields
Modifier and Type	Field and Description
`InputInfo`	`input` Input information.
`long`	`size` Cardinality of result; unknown if set to -1.
`SeqType`	`type` Static type.

Constructor Summary

Constructors
Modifier Constructor and Description

protected ParseExpr(InputInfo ii)
Constructor.

Constructors
Modifier	Constructor and Description
`protected`	`ParseExpr(InputInfo ii)` Constructor.

Method Summary

Methods
Modifier and Type	Method and Description
`boolean`	`checkBln(Expr e, QueryContext ctx)` Checks if the specified expression yields a boolean.
`void`	`checkColl(Expr e, QueryContext ctx)` Checks if the specified collation is supported.
`void`	`checkCreate(QueryContext ctx)` Checks if the current user has admin permissions.
`Value`	`checkCtx(QueryContext ctx)` Throws an exception if the context item is not set.
`double`	`checkDbl(Expr e, QueryContext ctx)` Checks if the specified expression yields a double.
`DBNode`	`checkDBNode(Item it)` Checks if the specified expression is a database node.
`byte[]`	`checkEStr(Expr e, QueryContext ctx)` Checks if the specified expression yields a string or empty sequence.
`byte[]`	`checkEStr(Item it)` Checks if the specified item is a string or an empty sequence.
`IO`	`checkIO(Expr e, QueryContext ctx)` Checks if an expression yields a valid and existing `IO` instance.
`Item`	`checkItem(Expr e, QueryContext ctx)` Checks if the specified expression yields a non-empty item.
`long`	`checkItr(Expr e, QueryContext ctx)` Checks if the specified expression is an integer.
`long`	`checkItr(Item it)` Checks if the specified item is a number.
`Map`	`checkMap(Item it)` Assures that the given (non-`null`) item is a map.
`ANode`	`checkNode(Item it)` Checks if the specified expression is a node.
`Item`	`checkNoEmpty(Item it)` Checks if the specified item is no empty sequence.
`byte[]`	`checkStr(Expr e, QueryContext ctx)` Checks if the specified expression yields a string.
`Item`	`checkType(Item it, Type t)` Checks if the specified expression is an empty sequence; if yes, throws an exception.
`Expr`	`checkUp(Expr e, QueryContext ctx)` Checks if the specified expressions is no updating expression.
`void`	`checkUp(QueryContext ctx, Expr... expr)` Tests if the specified expressions are updating or vacuous.
`void`	`checkWrite(QueryContext ctx)` Checks if the current user has write permissions.
`protected Expr`	`compBln(Expr e)` Returns a boolean equivalent for the specified expression.
`Item`	`ebv(QueryContext ctx, InputInfo ii)` Checks if the iterator can be dissolved into an effective boolean value.
`Item`	`item(QueryContext ctx, InputInfo ii)` Evaluates the expression and returns the resulting item or a `null` reference, if the expression yields an empty sequence.
`Iter`	`iter(QueryContext ctx)` Evaluates the expression and returns an iterator on the resulting items.
`protected Expr`	`optPre(Expr opt, QueryContext ctx)` Adds an optimization info for pre-evaluating the specified expression.
`Expr`	`preEval(QueryContext ctx)` Pre-evaluates the specified expression.
`long`	`size()` Returns the sequence size or 1.
`Item`	`test(QueryContext ctx, InputInfo ii)` Performs a predicate test and returns the item if test was successful.
`SeqType`	`type()` Returns the sequence type of the evaluated value.
`Value`	`value(QueryContext ctx)` Evaluates the expression and returns the resulting value.

Methods inherited from class org.basex.query.expr.Expr
addText, comp, compEbv, count, hasFreeVars, indexAccessible, indexEquivalent, isEmpty, isFunction, isItem, isVacuous, isValue, iterable, markTailCalls, removable, remove, sameAs, uses

Methods inherited from class org.basex.data.ExprInfo
description, info, plan, toString

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - input
```
public final InputInfo input
```
    Input information.
  - size
```
public long size
```
    Cardinality of result; unknown if set to -1.
  - type
```
public SeqType type
```
    Static type.
- Constructor Detail
  - ParseExpr
```
protected ParseExpr(InputInfo ii)
```
    Constructor.
    
    Parameters:
    ii - input info
- Method Detail
  - iter
```
public Iter iter(QueryContext ctx)
          throws QueryException
```
    Description copied from class: Expr
    
    Evaluates the expression and returns an iterator on the resulting items. If this method is not overwritten, Expr.item(org.basex.query.QueryContext, org.basex.util.InputInfo) must be implemented by an expression, as it may be called by this method.
    
    Specified by:
    
    iter in class Expr
    
    Parameters:
    ctx - query context
    
    Returns:
    resulting item
    
    Throws:
    
    QueryException - query exception
  - item
```
public Item item(QueryContext ctx,
        InputInfo ii)
          throws QueryException
```
    Description copied from class: Expr
    
    Evaluates the expression and returns the resulting item or a null reference, if the expression yields an empty sequence. If this method is not overwritten, Expr.iter(org.basex.query.QueryContext) must be implemented by an expression, as it may be called by this method.
    
    Specified by:
    
    item in class Expr
    
    Parameters:
    ctx - query context
    ii - input info
    
    Returns:
    iterator
    
    Throws:
    
    QueryException - query exception
  - value
```
public Value value(QueryContext ctx)
            throws QueryException
```
    Description copied from class: Expr
    
    Evaluates the expression and returns the resulting value.
    
    Specified by:
    
    value in class Expr
    
    Parameters:
    ctx - query context
    
    Returns:
    iterator
    
    Throws:
    
    QueryException - query exception
  - ebv
```
public final Item ebv(QueryContext ctx,
       InputInfo ii)
               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 numeric predicate.
    
    Specified by:
    
    ebv in class Expr
    
    Parameters:
    ctx - query context
    ii - input info
    
    Returns:
    item
    
    Throws:
    
    QueryException - query exception
  - test
```
public final Item test(QueryContext ctx,
        InputInfo ii)
                throws QueryException
```
    Description copied from class: Expr
    
    Performs a predicate test and returns the item if test was successful.
    
    Specified by:
    
    test in class Expr
    
    Parameters:
    ctx - query context
    ii - input info
    
    Returns:
    item
    
    Throws:
    
    QueryException - query exception
  - type
```
public SeqType type()
```
    Description copied from class: Expr
    
    Returns the sequence type of the evaluated value. For simplicity, some types have been summarized. E.g., all numbers are treated as integers.
    
    Specified by:
    
    type in class Expr
    
    Returns:
    result of check
  - size
```
public final long size()
```
    Description copied from class: Expr
    
    Returns the sequence size or 1.
    
    Specified by:
    
    size in class Expr
    
    Returns:
    result of check
  - preEval
```
public final Expr preEval(QueryContext ctx)
                   throws QueryException
```
    Pre-evaluates the specified expression.
    
    Parameters:
    ctx - query context
    
    Returns:
    optimized expression
    
    Throws:
    
    QueryException - query exception
  - optPre
```
protected final Expr optPre(Expr opt,
          QueryContext ctx)
```
    Adds an optimization info for pre-evaluating the specified expression.
    
    Parameters:
    opt - optimized expression
    ctx - query context
    
    Returns:
    optimized expression
  - compBln
```
protected final Expr compBln(Expr e)
```
    Returns a boolean equivalent for the specified expression. If the specified expression yields a boolean value anyway, it will be returned as is. Otherwise, it will be wrapped into a boolean function.
    
    Parameters:
    e - expression to be rewritten
    
    Returns:
    expression
  - checkUp
```
public final Expr checkUp(Expr e,
           QueryContext ctx)
                   throws QueryException
```
    Checks if the specified expressions is no updating expression.
    
    Parameters:
    e - expression
    ctx - query context
    
    Returns:
    the specified expression
    
    Throws:
    
    QueryException - query exception
  - checkUp
```
public void checkUp(QueryContext ctx,
           Expr... expr)
             throws QueryException
```
    Tests if the specified expressions are updating or vacuous.
    
    Parameters:
    ctx - query context
    expr - expression array
    
    Throws:
    
    QueryException - query exception
  - checkBln
```
public final boolean checkBln(Expr e,
               QueryContext ctx)
                       throws QueryException
```
    Checks if the specified expression yields a boolean. Returns the boolean or throws an exception.
    
    Parameters:
    e - expression to be checked
    ctx - query context
    
    Returns:
    boolean
    
    Throws:
    
    QueryException - query exception
  - checkDbl
```
public final double checkDbl(Expr e,
              QueryContext ctx)
                      throws QueryException
```
    Checks if the specified expression yields a double. Returns the double or throws an exception.
    
    Parameters:
    e - expression to be checked
    ctx - query context
    
    Returns:
    double
    
    Throws:
    
    QueryException - query exception
  - checkItr
```
public final long checkItr(Expr e,
            QueryContext ctx)
                    throws QueryException
```
    Checks if the specified expression is an integer. Returns a token representation or an exception.
    
    Parameters:
    e - expression to be checked
    ctx - query context
    
    Returns:
    integer value
    
    Throws:
    
    QueryException - query exception
  - checkItr
```
public final long checkItr(Item it)
                    throws QueryException
```
    Checks if the specified item is a number. Returns a token representation or an exception.
    
    Parameters:
    it - item to be checked
    
    Returns:
    item
    
    Throws:
    
    QueryException - query exception
  - checkNode
```
public final ANode checkNode(Item it)
                      throws QueryException
```
    Checks if the specified expression is a node. Returns the node or an exception.
    
    Parameters:
    it - item to be checked
    
    Returns:
    item
    
    Throws:
    
    QueryException - query exception
  - checkDBNode
```
public final DBNode checkDBNode(Item it)
                         throws QueryException
```
    Checks if the specified expression is a database node. Returns the node or an exception.
    
    Parameters:
    it - item to be checked
    
    Returns:
    item
    
    Throws:
    
    QueryException - query exception
  - checkColl
```
public final void checkColl(Expr e,
             QueryContext ctx)
                     throws QueryException
```
    Checks if the specified collation is supported.
    
    Parameters:
    e - expression to be checked
    ctx - query context
    
    Throws:
    
    QueryException - query exception
  - checkStr
```
public final byte[] checkStr(Expr e,
              QueryContext ctx)
                      throws QueryException
```
    Checks if the specified expression yields a string. Returns a token representation or an exception.
    
    Parameters:
    e - expression to be evaluated
    ctx - query context
    
    Returns:
    item
    
    Throws:
    
    QueryException - query exception
  - checkEStr
```
public final byte[] checkEStr(Item it)
                       throws QueryException
```
    Checks if the specified item is a string or an empty sequence. Returns a token representation or an exception.
    
    Parameters:
    it - item to be checked
    
    Returns:
    item
    
    Throws:
    
    QueryException - query exception
  - checkCtx
```
public final Value checkCtx(QueryContext ctx)
                     throws QueryException
```
    Throws an exception if the context item is not set.
    
    Parameters:
    ctx - query context
    
    Returns:
    result of check
    
    Throws:
    
    QueryException - query exception
  - checkItem
```
public final Item checkItem(Expr e,
             QueryContext ctx)
                     throws QueryException
```
    Checks if the specified expression yields a non-empty item.
    
    Parameters:
    e - expression to be evaluated
    ctx - query context
    
    Returns:
    item
    
    Throws:
    
    QueryException - query exception
  - checkType
```
public final Item checkType(Item it,
             Type t)
                     throws QueryException
```
    Checks if the specified expression is an empty sequence; if yes, throws an exception.
    
    Parameters:
    it - item to be checked
    t - type to be checked
    
    Returns:
    specified item
    
    Throws:
    
    QueryException - query exception
  - checkNoEmpty
```
public final Item checkNoEmpty(Item it)
                        throws QueryException
```
    Checks if the specified item is no empty sequence.
    
    Parameters:
    it - item to be checked
    
    Returns:
    specified item
    
    Throws:
    
    QueryException - query exception
  - checkEStr
```
public final byte[] checkEStr(Expr e,
               QueryContext ctx)
                       throws QueryException
```
    Checks if the specified expression yields a string or empty sequence. Returns a token representation or an exception.
    
    Parameters:
    e - expression to be evaluated
    ctx - query context
    
    Returns:
    item
    
    Throws:
    
    QueryException - query exception
  - checkIO
```
public final IO checkIO(Expr e,
         QueryContext ctx)
                 throws QueryException
```
    Checks if an expression yields a valid and existing IO instance. Returns the instance or an exception.
    
    Parameters:
    e - expression to be evaluated
    ctx - query context
    
    Returns:
    io instance
    
    Throws:
    
    QueryException - query exception
  - checkCreate
```
public final void checkCreate(QueryContext ctx)
                       throws QueryException
```
    Checks if the current user has admin permissions. If negative, an exception is thrown.
    
    Parameters:
    ctx - query context
    
    Throws:
    
    QueryException - query exception
  - checkWrite
```
public final void checkWrite(QueryContext ctx)
                      throws QueryException
```
    Checks if the current user has write permissions. If negative, an exception is thrown.
    
    Parameters:
    ctx - query context
    
    Throws:
    
    QueryException - query exception
  - checkMap
```
public Map checkMap(Item it)
             throws QueryException
```
    Assures that the given (non-null) item is a map.
    
    Parameters:
    it - item to check
    
    Returns:
    the map
    
    Throws:
    
    QueryException - if the item is not a map

Class ParseExpr

Nested Class Summary

Nested classes/interfaces inherited from class org.basex.query.expr.Expr

Field Summary

Constructor Summary

Method Summary

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

Methods inherited from class org.basex.data.ExprInfo

Methods inherited from class java.lang.Object

Field Detail

input

size

type

Constructor Detail

ParseExpr

Method Detail

iter

item

value

ebv

test

type

size

preEval

optPre

compBln

checkUp

checkUp

checkBln

checkDbl

checkItr

checkItr

checkNode

checkDBNode

checkColl

checkStr

checkEStr

checkCtx

checkItem

checkType

checkNoEmpty

checkEStr

checkIO

checkCreate

checkWrite

checkMap