ptdb.kernel.bl.search

Class AbstractSearcher

java.lang.Object

ptdb.kernel.bl.search.AbstractSearcher

All Implemented Interfaces:

ResultHandler

Direct Known Subclasses:

AttributeSearcher, CommandSearcher, GraphSearcher, HierarchyFetcher, NameSearcher

public abstract class AbstractSearcher
extends java.lang.Object
implements ResultHandler

The abstract parent class for all the concrete searcher classes.

The entire search module is implemented in a pipe and filter chain. Each concrete searcher in the chain is a concrete class of this AbstractSearcher class, and they are configured to search on different set of search criteria that input by the user.

The actual combination of searchers chain is configured in SearchManager.

Since:

Ptolemy II 10.0

Version:

$Id$

Author:

Alek Wang

Pt.AcceptedRating:

red (wenjiaow)

Pt.ProposedRating:

red (wenjiaow)

Field Summary

Fields

Modifier and Type	Field and Description
protected java.util.ArrayList<XMLDBModel>	_currentResults Contains the currently found results in this searcher.
protected DBConnection	_dbConnection Connection to the xml database.
protected java.util.List<XMLDBModel>	_errorModels The models contains error or cannot be parsed.
protected boolean	_isIndependent Indicate whether the searcher existing depends on the existing of other searchers.
protected ResultHandler	_nextResultHandler The next result handler to be called to pass the search results from this result handler.
protected java.util.ArrayList<XMLDBModel>	_previousResults Results found and passed by the previous searchers.

Constructor Summary

Constructors

Constructor and Description
AbstractSearcher()

Method Summary

Modifier and Type	Method and Description
protected void	_addErrorModel(XMLDBModel errorModel) In case of getting model result with error or cannot be parsed, use this method to add the error model to the stored error models list.
protected boolean	_isFirstSearcher() Check whether this searcher is the first searcher in the chain.
protected boolean	_isIndependent() Check whether this searcher is independent to exist without other searchers.
protected boolean	_isIntersectNeeded() Check with this searcher needs to intersect the results that it finds with the passed results from the other searchers.
protected boolean	_isLastSeacher() Check whether this searcher is the last searcher in the chain.
protected abstract boolean	_isSearchCriteriaSet() Checks whether the search criteria has been set in this particular searcher.
protected void	_pass() Mark the search is done in this searcher.
protected abstract void	_search() Perform the actual search.
void	handleIntermediateResults(java.util.List<XMLDBModel> intermediateResults, ResultHandler resultHandler) Handle the intermediate results that found and passed by the other searcher.
void	handleResults(java.util.ArrayList<XMLDBModel> modelResults) Handle the model results passed to this class, and handle the results according to the certain search criteria.
boolean	isPassed() Check with this searcher has been passed the searching.
boolean	isSearchCancelled() Check whether the search process has been canceled by the user.
void	noIntersect() Mark this searcher as it does not need to intersect the results it find with the results passed by other searchers.
void	passErrorModels(java.util.List<XMLDBModel> errorModels) In the case of getting some models that cannot be parsed or contains some error, use this method to pass these error models to store for error handling.
void	setConnection(DBConnection connection) Set the DB connection for this searcher.
void	setFirstSearcher() Mark this searcher as the first searcher in the chain.
void	setLastSearcher() Mark this searcher as the last searcher in the chain.
void	setNextResultHandler(ResultHandler nextResultHandler) Set the next result handler object to this searcher.
void	setPreviousSeacher(AbstractSearcher previousSearcher) Set the previous searcher that does the searching before this searcher.
void	wholeSearchDone() Notify the search result buffer that the searching is done.

Methods inherited from class java.lang.Object

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

Field Detail

_currentResults

protected java.util.ArrayList<XMLDBModel> _currentResults

Contains the currently found results in this searcher.

_dbConnection

protected DBConnection _dbConnection

Connection to the xml database.

_errorModels

protected java.util.List<XMLDBModel> _errorModels

The models contains error or cannot be parsed.

_isIndependent

protected boolean _isIndependent

Indicate whether the searcher existing depends on the existing of other searchers. For example, the HierarchyFetcher needs to be configured with other dependent searcher, otherwise it is useless.

_nextResultHandler

protected ResultHandler _nextResultHandler

The next result handler to be called to pass the search results from this result handler.

_previousResults

protected java.util.ArrayList<XMLDBModel> _previousResults

Results found and passed by the previous searchers.

Constructor Detail

AbstractSearcher

public AbstractSearcher()

Method Detail

handleIntermediateResults

public void handleIntermediateResults(java.util.List<XMLDBModel> intermediateResults,
                                      ResultHandler resultHandler)

Handle the intermediate results that found and passed by the other searcher.

The searcher normally passes the intermediate results to the next result handler.

Specified by:

handleIntermediateResults in interface ResultHandler

Parameters:

intermediateResults - The intermediate results to be handled.

resultHandler - The result handler that found and pass these results.

handleResults

public void handleResults(java.util.ArrayList<XMLDBModel> modelResults)
                   throws DBConnectionException,
                          DBExecutionException

Handle the model results passed to this class, and handle the results according to the certain search criteria. The search criteria is passed to the concrete searchers when they are constructed.

Specified by:

handleResults in interface ResultHandler

Parameters:

modelResults - The results to be handled in this searcher.

Throws:

DBConnectionException - Thrown by the DBConnectorFactory if getting the DBConnection from it, which indicates that the DBConnection cannot be obtained.

DBExecutionException - Happens in the execution of DB tasks, and is thrown by the concrete searcher if they are performing the actual searching in the database.

isSearchCancelled

public boolean isSearchCancelled()

Check whether the search process has been canceled by the user.

Specified by:

isSearchCancelled in interface ResultHandler

Returns:

true - The search has been canceled by the user.
false - The search hasn't been canceled.

isPassed

public boolean isPassed()

Check with this searcher has been passed the searching. Some of the searcher may require multiple rounds of searching in a loop, and the partial results will be passed to the next result handler during the execution loop. This method indicates whether the current searcher has finished the entire searching that it wants to do.

Returns:

true - if the searching has passed in this searcher.
false - if the searching has not passed in this searcher.

noIntersect

public void noIntersect()

Mark this searcher as it does not need to intersect the results it find with the results passed by other searchers.

passErrorModels

public void passErrorModels(java.util.List<XMLDBModel> errorModels)

In the case of getting some models that cannot be parsed or contains some error, use this method to pass these error models to store for error handling.

Specified by:

passErrorModels in interface ResultHandler

Parameters:

errorModels - The error models.

setConnection

public void setConnection(DBConnection connection)

Set the DB connection for this searcher.

Specified by:

setConnection in interface ResultHandler

Parameters:

connection - The DBConnection instance to be set in this searcher.

setFirstSearcher

public void setFirstSearcher()

Mark this searcher as the first searcher in the chain.

setLastSearcher

public void setLastSearcher()

Mark this searcher as the last searcher in the chain.

setNextResultHandler

public void setNextResultHandler(ResultHandler nextResultHandler)

Set the next result handler object to this searcher. This searcher will use the next handler to pass the results from this searcher.

Parameters:

nextResultHandler - The next ResultHandler to set to this handler.

setPreviousSeacher

public void setPreviousSeacher(AbstractSearcher previousSearcher)

Set the previous searcher that does the searching before this searcher.

Parameters:

previousSearcher - The previous searcher to set in this searcher.

wholeSearchDone

public void wholeSearchDone()
                     throws DBConnectionException

Notify the search result buffer that the searching is done. The whole search means all the system's entire search process for a given complete search criteria.

Specified by:

wholeSearchDone in interface ResultHandler

Throws:

DBConnectionException - Thrown from the database layer if the database connection cannot be obtained.

_addErrorModel

protected void _addErrorModel(XMLDBModel errorModel)

In case of getting model result with error or cannot be parsed, use this method to add the error model to the stored error models list.

Parameters:

errorModel - The error model to be added to the list.

_isFirstSearcher

protected boolean _isFirstSearcher()

Check whether this searcher is the first searcher in the chain.

Returns:

true - this searcher is the first searcher in the chain.
false - this searcher is not the first searcher in the chain.

_isIndependent

protected boolean _isIndependent()

Check whether this searcher is independent to exist without other searchers.

Returns:

true - this searcher is independent.
false - this searcher is not independent.

_isIntersectNeeded

protected boolean _isIntersectNeeded()

Check with this searcher needs to intersect the results that it finds with the passed results from the other searchers.

Returns:

true - this searcher needs to intersect the results with other searchers.
false - this searcher does not need to intersect the results with other searchers.

_isLastSeacher

protected boolean _isLastSeacher()

Check whether this searcher is the last searcher in the chain.

Returns:

true - this searcher is the last searcher in the chain.
false - this searcher is not the last searcher in the chain.

_isSearchCriteriaSet

protected abstract boolean _isSearchCriteriaSet()

Checks whether the search criteria has been set in this particular searcher.

Returns:

true - if the search criteria has been set.
false - if the search criteria has not been set.

_pass

protected void _pass()

Mark the search is done in this searcher.

See Also:

isPassed()

_search

protected abstract void _search()
                         throws DBExecutionException,
                                DBConnectionException

Perform the actual search.

Throws:

DBExecutionException - Thrown from the database layer if there is error occurring during the search.

DBConnectionException - Thrown by the DBConnectorFactory if getting the DBConnection from it, which indicates that the DBConnection cannot be obtained.