org.basex.query
Class QueryProcessor

java.lang.Object
  org.basex.core.Progress
      org.basex.query.QueryProcessor

public final class QueryProcessor
extends Progress

This abstract class contains various methods which allow querying in the database. A variety of hierarchical parsers (XPath, XQuery, etc..) can be implemented on top of this class.

Author:

Workgroup DBIS, University of Konstanz 2005-09, ISC License, Christian Gruen

Field Summary

QueryContext	ctx Expression context.
java.lang.String	query Initial node set.

Constructor Summary

QueryProcessor(java.lang.String q)
Default Constructor.

QueryProcessor(java.lang.String qu, IO f)
XQuery Constructor.

QueryProcessor(java.lang.String qu, Nodes n)
XQuery Constructor.

Method Summary

void	close() Parses the specified query and returns the result.
void	compile() Compiles the query.
java.lang.String	det() Returns short information on this process.
Item	eval() Returns the result as an item.
java.lang.String	info() Returns query background information.
Iter	iter() Returns a result iterator.
void	module(java.lang.String ns, java.lang.String file) Adds a module reference.
void	parse() Parses the specified query.
void	plan(Serializer ser) Returns the query plan in the dot notation.
double	prog() Returns progress information.
Result	query() Parses the specified query and returns the result.
Nodes	queryNodes() Parses the specified query and returns the result nodes.
void	setQuery(java.lang.String qu) Sets a new query.
java.lang.String	tit() Returns short information on this process.

Methods inherited from class org.basex.core.Progress

checkStop, detail, progress, progress, stop, title

Methods inherited from class java.lang.Object

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

Field Detail

ctx

public final QueryContext ctx

Expression context.

query

public java.lang.String query

Initial node set.

Constructor Detail

QueryProcessor

public QueryProcessor(java.lang.String q)

Default Constructor.

Parameters:

q - query

QueryProcessor

public QueryProcessor(java.lang.String qu,
                      IO f)

XQuery Constructor.

Parameters:

qu - query

f - query file reference

QueryProcessor

public QueryProcessor(java.lang.String qu,
                      Nodes n)

XQuery Constructor.

Parameters:

qu - query

n - initial nodes

Method Detail

parse

public void parse()
           throws QueryException

Parses the specified query.

Throws:

QueryException - query exception

compile

public void compile()
             throws QueryException

Compiles the query.

Throws:

QueryException - query exception

iter

public Iter iter()
          throws QueryException

Returns a result iterator.

Returns:

result iterator

Throws:

QueryException - query exception

eval

public Item eval()
          throws QueryException

Returns the result as an item.

Returns:

result iterator

Throws:

QueryException - query exception

query

public Result query()
             throws QueryException

Parses the specified query and returns the result.

Returns:

result of query

Throws:

QueryException - query exception

queryNodes

public Nodes queryNodes()
                 throws QueryException

Parses the specified query and returns the result nodes.

Returns:

result of query

Throws:

QueryException - query exception

module

public void module(java.lang.String ns,
                   java.lang.String file)

Adds a module reference.

Parameters:

ns - module namespace

file - file name

setQuery

public void setQuery(java.lang.String qu)

Sets a new query. Should be called before parsing the query.

Parameters:

qu - query

close

public void close()
           throws java.io.IOException

Parses the specified query and returns the result.

Throws:

java.io.IOException - query exception

info

public java.lang.String info()

Returns query background information.

Returns:

background information

plan

public void plan(Serializer ser)
          throws java.lang.Exception

Returns the query plan in the dot notation.

Parameters:

ser - serializer

Throws:

java.lang.Exception - exception

tit

public java.lang.String tit()

Description copied from class: Progress

Returns short information on this process. Can be overwritten to give more detailed information.

Returns:

header information

det

public java.lang.String det()

Description copied from class: Progress

Returns short information on this process.

Overrides:

det in class Progress

Returns:

header information

prog

public double prog()

Description copied from class: Progress

Returns progress information. Can be overwritten to give more detailed information.

Overrides:

prog in class Progress

Returns:

header information