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 2005-10, ISC License, Christian Gruen

Field Summary

QueryContext

ctx Expression context.

Constructor Summary

QueryProcessor(String qu, Context cx)
Default constructor.

QueryProcessor(String qu, Nodes nodes, Context cx)
Constructor with an initial context set.

Method Summary

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

Methods inherited from class org.basex.core.Progress

abort, 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.

Constructor Detail

QueryProcessor

public QueryProcessor(String qu,
                      Context cx)

Default constructor.

Parameters:

qu - query to process

cx - database context

QueryProcessor

public QueryProcessor(String qu,
                      Nodes nodes,
                      Context cx)

Constructor with an initial context set.

Parameters:

qu - query

nodes - initial context set

cx - database context

Method Detail

parse

public void parse()
           throws QueryException

Parses the 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

query

public Result query()
             throws QueryException

Evaluates the specified query and returns the result.

Returns:

result of query

Throws:

QueryException - query exception

queryNodes

public Nodes queryNodes()
                 throws QueryException

Evaluates the specified query and returns the result nodes.

Returns:

result nodes

Throws:

QueryException - query exception

module

public void module(String ns,
                   String file)

Adds a module reference.

Parameters:

ns - module namespace

file - file name

setQuery

public void setQuery(String qu)

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

Parameters:

qu - query

close

public void close()
           throws IOException

Closes the processor.

Throws:

IOException - I/O exception

info

public String info(boolean all)

Returns query background information.

Parameters:

all - show all information

Returns:

background information

plan

public void plan(Serializer ser)
          throws Exception

Returns the query plan in the dot notation.

Parameters:

ser - serializer

Throws:

Exception - exception

tit

public String tit()

Description copied from class: Progress

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

Overrides:

tit in class Progress

Returns:

header information

det

public 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