edu.washington.NVisF.dataIO
Class BinaryDataFileReader

java.lang.Object
  |
  +--edu.washington.NVisF.dataIO.DataReader
        |
        +--edu.washington.NVisF.dataIO.BinaryDataFileReader

Direct Known Subclasses:

SandPileReader, SSFileReader, TipsyFileReader

public abstract class BinaryDataFileReader

extends DataReader

BinaryDataFileReader extends DataReader to support readers of binary data files, providing simple implementations of the connection and meta-info methods. A subclass only needs to provide one initConnection() method (which usually reads the data from file into memory, and must create the TypeInfo object) and the data access methods.

Constructor Summary

BinaryDataFileReader()

Method Summary

void	closeConnection() does whatever work is needed to close the connection
abstract int	getCount(java.lang.String predicate) returns the number of objects that satisfy the given predicate.
abstract float[]	getScalar(java.lang.String predicate, java.lang.String dataField) returns an array of floats containing the specified scalar field element for all data objects that satisfy the given predicate.
TypeInfo	getTypeInfo() retrieves a description of the data available from this source as a TypeInfo object.
abstract float[][]	getVector(java.lang.String predicate, java.lang.String dataField) returns an array of arrays containing the specified vector field element for all data objects that satisfy the given predicate.
abstract void	initConnection(java.io.InputStream in)
void	initConnection(java.lang.String source) initiates a connection to the data source represented by the given String.
void	initConnection(java.net.URL source) initiates a connection to the data source represented by the given URL.
boolean	isConnectionOpen() tests whether an active connection exists
abstract void	loadData(java.lang.String predicate, java.lang.String[] dataFields) instructs this DataReader to gather and store the requested data for later access.

Methods inherited from class java.lang.Object

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

Constructor Detail

BinaryDataFileReader

public BinaryDataFileReader()

Method Detail

isConnectionOpen

public boolean isConnectionOpen()

Description copied from class: DataReader

tests whether an active connection exists

Overrides:

isConnectionOpen in class DataReader

Following copied from class: edu.washington.NVisF.dataIO.DataReader

Returns:

true if a connection is active; false otherwise

initConnection

public void initConnection(java.lang.String source)
                    throws OpenConnectionException,
                           SourceNotFoundException,
                           DataIOException

Description copied from class: DataReader

initiates a connection to the data source represented by the given String.

Overrides:

initConnection in class DataReader

Following copied from class: edu.washington.NVisF.dataIO.DataReader

Parameters:

source - a string specifying the location of the data source

Throws:

OpenConnectionException - if a connection is already established

SourceNotFoundException - if the specified resource could not be found

DataIOException - if the attempt to open the connection fails

initConnection

public void initConnection(java.net.URL source)
                    throws OpenConnectionException,
                           SourceNotFoundException,
                           DataIOException

Description copied from class: DataReader

initiates a connection to the data source represented by the given URL.

Overrides:

initConnection in class DataReader

Following copied from class: edu.washington.NVisF.dataIO.DataReader

Parameters:

source - a URL specifying the location of the data source

Throws:

OpenConnectionException - if a connection is already established

SourceNotFoundException - if the specified resource could not be found

DataIOException - if the attempt to open the connection fails

initConnection

public abstract void initConnection(java.io.InputStream in)
                             throws DataIOException

closeConnection

public void closeConnection()
                     throws NoConnectionException,
                            DataIOException

Description copied from class: DataReader

does whatever work is needed to close the connection

Overrides:

closeConnection in class DataReader

Following copied from class: edu.washington.NVisF.dataIO.DataReader

Throws:

NoConnectionException - if there is no active connection

DataIOException - if the attempt to close the connection fails

getTypeInfo

public TypeInfo getTypeInfo()
                     throws NoConnectionException

Description copied from class: DataReader

retrieves a description of the data available from this source as a TypeInfo object.

Overrides:

getTypeInfo in class DataReader

Following copied from class: edu.washington.NVisF.dataIO.DataReader

Returns:

a TypeInfo object containing meta-data information

Throws:

NoConnectionException - if there is no ative connection

See Also:

TypeInfo

getCount

public abstract int getCount(java.lang.String predicate)
                      throws java.text.ParseException,
                             NoConnectionException,
                             DataIOException

Description copied from class: DataReader

returns the number of objects that satisfy the given predicate. Note that in the current version, the only predicates supported are simply the name of a data object.

Overrides:

getCount in class DataReader

Following copied from class: edu.washington.NVisF.dataIO.DataReader

Parameters:

predicate - a string in the query language that identifies the desired objects

Returns:

int the number of objects

Throws:

java.text.ParseException - if the predicate cannot be parsed

NoConnectionException - if there is no active connection

DataIOException - if an unexpected error occurs

loadData

public abstract void loadData(java.lang.String predicate,
                              java.lang.String[] dataFields)
                       throws java.text.ParseException,
                              NoConnectionException,
                              DataIOException

Description copied from class: DataReader

instructs this DataReader to gather and store the requested data for later access. The first argument identifies what objects to get data for, and the second identifies what fields to retrieve. If the second argument is null, then all fields are retrieved. Using this method may significantly speed up later calls to getData for this predicate. Note that in the current version, the only predicates supported are simply the name of a data object. This method is not guaranteed to be implemented by all subclasses. The default implementation is to do nothing.

Overrides:

loadData in class DataReader

Following copied from class: edu.washington.NVisF.dataIO.DataReader

Parameters:

predicate - a string in the query language that identifies the desired objects

fields - an array of strings giving the names of the desired fields

Throws:

java.text.ParseException - if the predicate cannot be parsed

NoConnectionException - if there is no active connection

DataIOException - if an unexpected error occurs

See Also:

DataReader.getScalar(java.lang.String, java.lang.String), DataReader.getVector(java.lang.String, java.lang.String)

getScalar

public abstract float[] getScalar(java.lang.String predicate,
                                  java.lang.String dataField)
                           throws java.text.ParseException,
                                  NoConnectionException,
                                  DataIOException

Description copied from class: DataReader

returns an array of floats containing the specified scalar field element for all data objects that satisfy the given predicate. The first argument is a string in the query language specifying the desired objects, while the second is a string giving the name of the field to return. Note that in the current version, the only predicates supported are simply the name of a data object, and data for all objects of that type are returned. This method is not guaranteed to be implemented by all subclasses. The default implementation throws a DataIOException identifying the non-implementing class. A null value is returned if the requested data object type does not exist, or if the requested data field is not defined as a scalar field element for that data object type.

Overrides:

getScalar in class DataReader

Following copied from class: edu.washington.NVisF.dataIO.DataReader

Parameters:

predicate - a string in the query language that identifies the desired objects

dataField - a string specifying the scalar field to be returned

Returns:

float[] containing the array of scalars, or null if no matches were found

Throws:

java.text.ParseException - if the predicate cannot be parsed

NoConnectionException - if there is no active connection

DataIOException - if an unexpected error occurs

See Also:

DataReader.loadData(java.lang.String, java.lang.String[])

getVector

public abstract float[][] getVector(java.lang.String predicate,
                                    java.lang.String dataField)
                             throws java.text.ParseException,
                                    NoConnectionException,
                                    DataIOException

Description copied from class: DataReader

returns an array of arrays containing the specified vector field element for all data objects that satisfy the given predicate. That is, the desired vector is represented as an array of floats (usually 3, for a 3-D system), and the return type is an array of these arrays with length N, where N is the number of matching data objects. The first argument is a string in the query language specifying the desired objects, while the second is a string giving the name of the field to return. Note that in the current version, the only predicates supported are simply the name of a data object, and data for all objects of that type are returned. This method is not guaranteed to be implemented by all subclasses. The default implementation throws a DataIOException identifying the non-implementing class. A null value is returned if the requested data object type does not exist, or if the requested data field is not defined as a vector field element for that data object type.

Overrides:

getVector in class DataReader

Following copied from class: edu.washington.NVisF.dataIO.DataReader

Parameters:

predicate - a string in the query language that identifies the desired objects

dataField - a string specifying the vector field to be returned

Returns:

float[][] containing the array of vectors, or null if no matches were found

Throws:

java.text.ParseException - if the predicate cannot be parsed

NoConnectionException - if there is no active connection

DataIOException - if an unexpected error occurs

See Also:

DataReader.loadData(java.lang.String, java.lang.String[])