prajna.structure.accessor

Class DelimitedAccessor

java.lang.Object

prajna.structure.AbstractDataAccessor<DataRecord,DataRecord>

prajna.structure.accessor.RecordAccessor

prajna.structure.accessor.DelimitedAccessor

All Implemented Interfaces:

DataAccessor<DataRecord,DataRecord>

public class DelimitedAccessor
extends RecordAccessor

Accessor designed to read data from delimited files. This class reads data from a file or other data source, splits the data according to the delimiting character, and treats each row as a single record. The first row is expected to be composed of column names.

Author:

Edward Swing

Constructor Summary

Constructors

Constructor and Description
DelimitedAccessor()

Method Summary

Methods

Modifier and Type	Method and Description
int	getCacheLimit() Get the cache limit for this accessor.
protected java.util.Set<DataRecord>	retrieveRecords(DataTemplate template) Retrieve a set of data records for a particular DataTemplate.
void	setCacheLimit(int limit) Set the cache limit for this accessor.
void	setInitParameters(java.util.Map<java.lang.String,java.lang.String> parameters) Set any initialization parameters required by this accessor.
void	setQuery(java.lang.String queryString) Set the query string used to retrieve records.

Methods inherited from class prajna.structure.accessor.RecordAccessor

addFieldHandler, addToGraph, addToTree, createReferenceNode, extendGraph, extendTree, getDataset, getFieldHandler, getGraph, getGrid, getMaxRecords, getReasoner, getStructureReasoners, getTree, setMaxRecords, setReasoner, setReasoner

Methods inherited from class prajna.structure.AbstractDataAccessor

addStructure, addTemplate, getDatasetNames, getGraphNames, getGridNames, getSpec, getStructureType, getTemplate, getTemplateNames, getTreeNames, setConfig, setConfigFile, setConfigFile

Methods inherited from class java.lang.Object

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

Constructor Detail

DelimitedAccessor

public DelimitedAccessor()

Method Detail

getCacheLimit

public int getCacheLimit()

Get the cache limit for this accessor. The cache limit specifies how many rows can be stored internally. If the number of rows in the data file exceeds this limit, then the file is re-read when data is accessed. If not set, the default value is 1000.

Returns:

the cache limit

retrieveRecords

protected java.util.Set<DataRecord> retrieveRecords(DataTemplate template)

Retrieve a set of data records for a particular DataTemplate. This method is used by the various getStructure methods.

Specified by:

retrieveRecords in class RecordAccessor

Parameters:

template - The data template specifying field mappings and descriptions

Returns:

the set of DataRecords for the template

setCacheLimit

public void setCacheLimit(int limit)

Set the cache limit for this accessor. The cache limit specifies how many rows can be stored internally. If the number of rows in the data file exceeds this limit, then the file is re-read when data is accessed.

Parameters:

limit - the cache limit

setInitParameters

public void setInitParameters(java.util.Map<java.lang.String,java.lang.String> parameters)

Set any initialization parameters required by this accessor. The parameters for the DelimitedAccessor are dataFile, which specifies a path or URL for the data file to be read, delimiter, which identifies the delimiter separating fields in the file, and cacheLimit, which specifies the maximum number of lines which can be cached.

Parameters:

parameters - a map of initialization parameters

setQuery

public void setQuery(java.lang.String queryString)

Set the query string used to retrieve records. This method should transform the query string into a format which the accessor can parse. The query string supports a query of the form field=value.

Specified by:

setQuery in class AbstractDataAccessor<DataRecord,DataRecord>

Parameters:

queryString - the query string