Early stages of a simulation project, when this program runs, its supposed to read in a file such as the one below, then it should process each neuron and synapse through the program. There are two types of synapse, unnamed synapses and named ones. Synapse X above is a named synapse connecting neurons A and B. Unnamed synapses have a single dash in the name field. Neuron and synapse names be non-numeric. Any synapse that is named may be the target of a secondary synapse. The synapse B X above is a secondary synapse that connects neuron B to (primary) synapse X. A synapse can be named or unnamed has two subclasses: Primary and Secondary.
My question: This code is part of a semester project, the first few parts were not difficult, but I'm unsure about subclasses. How do I scan in the synapse line and determine which belongs in subclass Primary and which ones belong in Secondary? Should I do something to the InitializeNetwork method or do I need something somewhere else?
Sample Input File:*
neuron A 1.0 0.95
neuron B 1.0 0.0
synapse X A B 1.2 0.5
synapse - B A 0.3 -0.5
synapse - B X 0.3 0.5
The code I have so far:
import java.io.File;
import java.io.FileNotFoundException;
import java.util.LinkedList;
import java.util.Scanner;
// Utility classes
/** Error reporting methods
*/
class Errors {
static void fatal( String message ) {
System.err.println( "Fatal error: " + message );
System.exit( 1 );
}
static void warning( String message ) {
System.err.println( "Error: " + message );
}
}
/** Input scanning support methods
*/
class ScanSupport {
/** Force there to be a line end here, complain if not
*/
static void lineEnd( Scanner sc, String message ) {
String skip = sc.nextLine();
if (!"".equals( skip )) {
// Bug: do we want to allow comments here
Errors.warning( message + " -- expected a newline" );
}
// Bug: what if sc.nextLine() was illegal (illegal state)
}
/** Get the next float, or complain if there isn't one
*/
static String nextName( Scanner sc, String message ) {
if (sc.hasNext( "[a-zA-Z]\\w*" )) {
return sc.next();
} else {
Errors.warning( message + " -- expected a name" );
return null;
}
}
/** Get the next float, or complain if there isn't one
*/
static float nextFloat( Scanner sc, String message ) {
if (sc.hasNextFloat()) {
return sc.nextFloat();
} else {
Errors.warning( message + " -- expected a number" );
return 99.99f;
}
}
}
// Simulation classes
/** Neurons are the vertices in the neuron network
* @see Synapse
*/
class Neuron {
String name; // name of this neuron
private float threshold; // voltage at which the neuron fires
private float voltage; // voltage at the given time
private float time; // (see above)
private LinkedList <Synapse> synapses; // the outputs of this neuron
public class IllegalNameException extends Exception {}
// initializer
public Neuron( Scanner sc ) throws IllegalNameException {
// scan and process one neuron
name = ScanSupport.nextName( sc, "Neuron ??" );
if (name == null) {
sc.nextLine();
throw new IllegalNameException();
}
if (NeuronNetwork.findNeuron( name ) != null) {
Errors.warning(
"Neuron " + name + " -- duplicate declaration"
);
sc.nextLine();
throw new IllegalNameException();
}
threshold = ScanSupport.nextFloat( sc, "Neuron " + name );
voltage = ScanSupport.nextFloat( sc, "Neuron " + name );
time = 0.0f;
ScanSupport.lineEnd( sc, "Neuron " + name );
}
// other methods
public String toString() {
return (
"Neuron " +
name +
" " +
threshold +
" " +
voltage
);
}
}
/** Synapses join neurons
* @see Neuron
*/
class Synapse {
Neuron source;
Neuron destination;
Float delay;
Float strength;
// name is source destination
public Synapse( Scanner sc ) {
// scan and process one synapse
String sourceName = ScanSupport.nextName( sc, "Synapse ??" );
String dstName = ScanSupport.nextName( sc,
"Synapse " +
( sourceName != null ? sourceName : "??" ) +
" ??"
);
delay = ScanSupport.nextFloat( sc,
"Synapse " +
( sourceName != null ? sourceName : "??" ) +
" " +
( dstName != null ? dstName : "??" ) +
" ??"
);
strength = ScanSupport.nextFloat( sc,
"Synapse " +
( sourceName != null ? sourceName : "??" ) +
" " +
( dstName != null ? dstName : "??" ) +
" " + delay + " ??"
);
ScanSupport.lineEnd( sc,
"Synapse " +
( sourceName != null ? sourceName : "??" ) +
" " +
( dstName != null ? dstName : "??" ) +
delay + " " + strength
);
// check correctness of fields
source = NeuronNetwork.findNeuron( sourceName );
if (source == null) {
Errors.warning(
"Synapse " +
( sourceName != null ? sourceName : "??" ) +
" " +
( dstName != null ? dstName : "??" ) +
" -- no such source"
);
}
destination = NeuronNetwork.findNeuron( dstName );
if (destination == null) {
Errors.warning(
"Synapse " +
( sourceName != null ? sourceName : "??" ) +
" " +
( dstName != null ? dstName : "??" ) +
" -- no such destination"
);
}
if (delay < 0.0f) {
Errors.warning(
"Synapse " +
( sourceName != null ? sourceName : "??" ) +
" " +
( dstName != null ? dstName : "??" ) +
" " + delay + " " + strength +
" -- illegal negative delay"
);
delay = 99.99f;
}
}
// other methods
public String toString() {
return (
"Synapse " +
( source != null ? source.name : "---" ) +
" " +
( destination != null ? destination.name : "---" ) +
" " + delay + " " + strength
);
}
}
/** NeuronNetwork is the main class that builds the whole model
* @see Neuron
* @see Synapse
*/
public class NeuronNetwork {
// the sets of all neurons and all synapses
static LinkedList <Neuron> neurons
= new LinkedList <Neuron> ();
static LinkedList <Synapse> synapses
= new LinkedList <Synapse> ();
/** Look up s in neurons, find that Neuron if it exists
* return null if not.
*/
public static Neuron findNeuron( String s ) {
for (Neuron n: neurons) {
if (n.name.equals(s)) {
return n;
}
}
return null;
}
/** Initialize the neuron network by scanning its description
*/
static void initializeNetwork( Scanner sc ) {
while (sc.hasNext()) {
String command = sc.next();
if ("neuron".equals( command )) {
try {
neurons.add( new Neuron( sc ) );
} catch (Neuron.IllegalNameException e) {
// no action required
}
} else if ("synapse".equals( command )) {
synapses.add( new Synapse( sc ) );
} else {
Errors.warning( command + " -- what is that" );
sc.nextLine();
}
}
}
/** Print out the neuron network from the data structure
*/
static void printNetwork() {
for (Neuron n:neurons) {
System.out.println( n.toString() );
}
for (Synapse s:synapses) {
System.out.println( s.toString() );
}
}
/** Main program
* @see initializeNetwork
*/
public static void main(String[] args) {
try {
if (args.length < 1) {
Errors.fatal( "-- missing file name" );
}
if (args.length > 1) {
Errors.fatal( "-- too many arguments" );
}
initializeNetwork( new Scanner(new File(args[0])) );
} catch (FileNotFoundException e) {
Errors.fatal( "" + args[0] + " -- file not found" );
}
printNetwork();
}
}
