refactor: extract MeetingQueryConfig to eliminate 13-param method and 5 duplicate SQL strings

Network.generateFile() had 13 parameters and 5 near-identical SQL query
strings that only differed in location filter and comparison operators.

Changes:
- New MeetingQueryConfig class encapsulates per-relationship-type query
  differences (location filter mode, comparison direction, thresholds)
- MeetingQueryConfig.buildSql() generates the parameterised SQL from config
- New generateFile(path, month, date, List<MeetingQueryConfig>) overload
- Original 13-param method preserved as @deprecated for backward compat
- Zero behavior change: deprecated method delegates to new one

Author: sauravbhattacharya001

Gvisual/src/app/MeetingQueryConfig.java

@@ -0,0 +1,121 @@
+package app;
+
+/**
+ * Configuration for a single meeting-relationship query.
+ *
+ * <p>Each relationship type (friends, classmates, study-groups, strangers,
+ * familiar strangers) uses the same parameterised SQL pattern but differs
+ * in location filter, duration comparison direction, and count comparison
+ * direction.  This class captures those differences so that
+ * {@link Network} can iterate a list of configs instead of repeating
+ * five near-identical SQL strings.</p>
+ *
+ * @author zalenix
+ */
+public final class MeetingQueryConfig {
+
+    /** Location filter mode — determines the WHERE clause for the location column. */
+    public enum LocationFilter {
+        /** Match a single exact location value (e.g. 'public', 'class'). */
+        EXACT,
+        /** Exclude a set of location values (NOT IN). */
+        EXCLUDE
+    }
+
+    /** Comparison direction for the threshold in the outer query. */
+    public enum Comparison {
+        /** Use {@code >=} for the count threshold. */
+        GTE,
+        /** Use {@code <=} for the count threshold. */
+        LTE,
+        /** Use {@code <} for the count threshold. */
+        LT,
+        /** Use {@code >} for the count threshold. */
+        GT
+    }
+
+    private final String edgePrefix;
+    private final LocationFilter locationFilter;
+    private final String[] locationValues;
+    private final Comparison durationComparison;
+    private final Comparison countComparison;
+    private final int durationThreshold;
+    private final int countThreshold;
+
+    /**
+     * @param edgePrefix          edge type prefix written to output (e.g. "f", "sg")
+     * @param locationFilter      how to filter on the location column
+     * @param locationValues      location value(s) for the filter
+     * @param durationComparison  comparison operator for duration in the inner query
+     * @param countComparison     comparison operator for count in the outer query
+     * @param durationThreshold   duration threshold value
+     * @param countThreshold      count threshold value
+     */
+    public MeetingQueryConfig(String edgePrefix,
+                              LocationFilter locationFilter,
+                              String[] locationValues,
+                              Comparison durationComparison,
+                              Comparison countComparison,
+                              int durationThreshold,
+                              int countThreshold) {
+        this.edgePrefix = edgePrefix;
+        this.locationFilter = locationFilter;
+        this.locationValues = locationValues;
+        this.durationComparison = durationComparison;
+        this.countComparison = countComparison;
+        this.durationThreshold = durationThreshold;
+        this.countThreshold = countThreshold;
+    }
+
+    public String getEdgePrefix() { return edgePrefix; }
+    public int getDurationThreshold() { return durationThreshold; }
+    public int getCountThreshold() { return countThreshold; }
+
+    /**
+     * Builds the parameterised SQL query string for this configuration.
+     *
+     * <p>The query always expects 4 positional parameters:
+     * {@code ?1=month, ?2=date, ?3=durationThreshold, ?4=countThreshold}.</p>
+     *
+     * @return the SQL query string
+     */
+    public String buildSql() {
+        String durationOp = comparisonToSql(durationComparison);
+        String countOp = comparisonToSql(countComparison);
+        String locationClause = buildLocationClause();
+
+        return " SELECT x.id , y.id , C , d "
+                + " FROM ( SELECT imei1, imei2, count(*) as C, avg(duration) as d"
+                + "       FROM ( SELECT imei1, imei2, duration"
+                + "              FROM meeting"
+                + "              WHERE month = ? AND date = ? AND " + locationClause
+                + " AND duration " + durationOp + " ?) as b"
+                + "       GROUP BY imei1, imei2) as a, deviceID as x, deviceID as y"
+                + " WHERE C " + countOp + " ? AND a.imei1= x.imei AND a.imei2 = y.imei";
+    }
+
+    private String buildLocationClause() {
+        if (locationFilter == LocationFilter.EXACT) {
+            return "location= '" + locationValues[0] + "'";
+        } else {
+            // NOT IN ('class', 'unknown', '')
+            StringBuilder sb = new StringBuilder("location NOT IN (");
+            for (int i = 0; i < locationValues.length; i++) {
+                if (i > 0) sb.append(", ");
+                sb.append("'").append(locationValues[i]).append("'");
+            }
+            sb.append(")");
+            return sb.toString();
+        }
+    }
+
+    private static String comparisonToSql(Comparison c) {
+        switch (c) {
+            case GTE: return ">=";
+            case LTE: return "<=";
+            case LT:  return "<";
+            case GT:  return ">";
+            default:  return ">=";
+        }
+    }
+}

Gvisual/src/app/Network.java

@@ -6,39 +6,43 @@
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
+import java.util.Arrays;
+import java.util.List;
+
+import app.MeetingQueryConfig.Comparison;
+import app.MeetingQueryConfig.LocationFilter;
 
 /**
+ * Generates Edge-list files from the meeting database.
+ *
+ * <p>Connects to the PostgreSQL meeting database and produces an Edge-list
+ * file for each relationship type (friends, classmates, study-groups,
+ * strangers, familiar strangers) based on configurable duration and
+ * frequency thresholds.</p>
  *
+ * <p>The output path is validated to prevent directory traversal —
+ * it must resolve to a location within the current working directory.</p>
  *
  * @author zalenix
  */
 public class Network {
 
     /**
+     * Generates the edge-list file from the meeting database.
      *
-     * Connects to database and writes out the Edge-list from the meeting DB table, forming edges of kind:
-     * friends, classmates, study-groups, strangers and familiar strangers (depending upon parameters).
-     *
-     * <p>The output path is validated to prevent directory traversal —
-     * it must resolve to a location within the current working directory.</p>
+     * <p>Replaces the previous 13-parameter signature with a structured
+     * parameter object approach.  Each relationship type is described by
+     * a {@link MeetingQueryConfig} that encapsulates the SQL pattern
+     * differences (location filter, comparison direction, thresholds).</p>
      *
-     * @param path output file path (must be within the working directory)
-     * @param Month
-     * @param Date
-     * @param dThresF
-     * @param CThresF
-     * @param dThresFS
-     * @param CThresFS
-     * @param dThresC
-     * @param CThresC
-     * @param dThresS
-     * @param CThresS
-     * @param dThresSg
-     * @param CThresSg
-     * @throws Exception
+     * @param path   output file path (must be within the working directory)
+     * @param month  month filter (e.g. "03")
+     * @param date   date filter (e.g. "15")
+     * @param configs list of relationship query configurations
+     * @throws Exception if database access or file I/O fails
      */
-    public static void generateFile(String path, String Month, String Date, int dThresF, int CThresF, int dThresFS, int CThresFS, int dThresC, int CThresC, int dThresS, int CThresS, int dThresSg, int CThresSg) throws Exception {
-
+    public static void generateFile(String path, String month, String date,
+                                     List<MeetingQueryConfig> configs) throws Exception {
         // Validate output path — prevent directory traversal attacks
         File outputFile = new File(path).getCanonicalFile();
         File workingDir = new File(".").getCanonicalFile();
@@ -50,67 +54,14 @@ public static void generateFile(String path, String Month, String Date, int dThr
 
         System.out.println("connecting...");
 
-        // Parameterized query template for location-based meeting queries.
-        // Parameters: month, date, location, duration threshold, count threshold.
-
-        // --- Friends query ---
-        String friendSql = " SELECT x.id , y.id , C , d  "
-                + " FROM ( SELECT imei1 , imei2, count(*) as C,avg(duration) as d"
-                + "       FROM ( SELECT imei1, imei2, duration"
-                + "              FROM meeting"
-                + "              WHERE month = ? AND date = ? AND location= 'public' AND duration > ?) as b"
-                + "       GROUP BY imei1, imei2) as a, deviceID as x, deviceID as y"
-                + " WHERE C >= ? AND a.imei1= x.imei AND a.imei2 = y.imei";
-
-        // --- Study groups query ---
-        String studygSql = " SELECT x.id , y.id , C , d   "
-                + " FROM ( SELECT imei1, imei2, count(*) as C,avg(duration) as d"
-                + "       FROM ( SELECT imei1, imei2, duration"
-                + "              FROM meeting"
-                + "              WHERE month = ? AND date = ? AND location= 'class' AND duration > ?) as b"
-                + "       GROUP BY imei1, imei2) as a, deviceID as x, deviceID as y"
-                + " WHERE C <= ? AND a.imei1= x.imei AND a.imei2 = y.imei";
-
-        // --- Classmates query ---
-        String cmateSql = " SELECT x.id , y.id, C , d  "
-                + " FROM ( SELECT imei1, imei2, count(*) as C, avg(duration) as d"
-                + "       FROM ( SELECT imei1, imei2, duration"
-                + "              FROM meeting"
-                + "              WHERE month = ? AND date = ? AND location= 'class' AND duration > ?) as b"
-                + "       GROUP BY imei1, imei2) as a, deviceID as x, deviceID as y"
-                + " WHERE C >= ? AND a.imei1= x.imei AND a.imei2 = y.imei";
-
-        // --- Strangers query ---
-        // Exclude both 'class' and 'unknown' locations so only meetings with
-        // a resolved location (e.g. 'public', 'path') are considered.
-        String strangerSql = " SELECT x.id , y.id , C , d "
-                + " FROM ( SELECT imei1, imei2, count(*) as C,avg(duration) as d"
-                + "       FROM ( SELECT imei1, imei2, duration"
-                + "              FROM meeting"
-                + "              WHERE month = ? AND date = ? AND location NOT IN ('class', 'unknown', '') AND duration < ?) as b"
-                + "       GROUP BY imei1, imei2) as a, deviceID as x, deviceID as y"
-                + " WHERE C < ? AND a.imei1= x.imei AND a.imei2 = y.imei";
-
-        // --- Familiar strangers query ---
-        String famstrangerSql = " SELECT x.id , y.id , C , d  "
-                + " FROM ( SELECT imei1, imei2, count(*) as C, avg(duration) as d"
-                + "       FROM ( SELECT imei1, imei2, duration"
-                + "              FROM meeting"
-                + "              WHERE month = ? AND date = ? AND location NOT IN ('class', 'unknown', '') AND duration < ?) as b"
-                + "       GROUP BY imei1, imei2) as a , deviceID as x, deviceID as y"
-                + " WHERE C > ? AND a.imei1= x.imei AND a.imei2 = y.imei";
-
         try (Connection conn = Util.getAppConnection()) {
-
-            // Use StringBuilder instead of String concatenation for performance
             StringBuilder sb = new StringBuilder("edges");
 
-            // Execute each relationship query using the shared helper
-            appendEdges(conn, sb, friendSql,      "f",  Month, Date, dThresF,  CThresF);
-            appendEdges(conn, sb, studygSql,       "sg", Month, Date, dThresSg, CThresSg);
-            appendEdges(conn, sb, cmateSql,        "c",  Month, Date, dThresC,  CThresC);
-            appendEdges(conn, sb, strangerSql,     "s",  Month, Date, dThresS,  CThresS);
-            appendEdges(conn, sb, famstrangerSql,  "fs", Month, Date, dThresFS, CThresFS);
+            for (MeetingQueryConfig config : configs) {
+                appendEdges(conn, sb, config.buildSql(), config.getEdgePrefix(),
+                           month, date, config.getDurationThreshold(),
+                           config.getCountThreshold());
+            }
 
             // Write output file — use validated outputFile, not raw path
             if (outputFile.exists()) {
@@ -122,6 +73,45 @@ public static void generateFile(String path, String Month, String Date, int dThr
         }
     }
 
+    /**
+     * Backward-compatible overload preserving the original 13-parameter signature.
+     *
+     * <p>Delegates to {@link #generateFile(String, String, String, List)} by
+     * constructing {@link MeetingQueryConfig} instances from the raw threshold
+     * parameters.</p>
+     *
+     * @deprecated Use {@link #generateFile(String, String, String, List)} with
+     *             explicit {@link MeetingQueryConfig} objects instead.
+     */
+    @Deprecated
+    public static void generateFile(String path, String Month, String Date,
+            int dThresF, int CThresF, int dThresFS, int CThresFS,
+            int dThresC, int CThresC, int dThresS, int CThresS,
+            int dThresSg, int CThresSg) throws Exception {
+
+        String[] excludedLocations = {"class", "unknown", ""};
+
+        List<MeetingQueryConfig> configs = Arrays.asList(
+            new MeetingQueryConfig("f",  LocationFilter.EXACT,
+                new String[]{"public"}, Comparison.GT, Comparison.GTE,
+                dThresF, CThresF),
+            new MeetingQueryConfig("sg", LocationFilter.EXACT,
+                new String[]{"class"}, Comparison.GT, Comparison.LTE,
+                dThresSg, CThresSg),
+            new MeetingQueryConfig("c",  LocationFilter.EXACT,
+                new String[]{"class"}, Comparison.GT, Comparison.GTE,
+                dThresC, CThresC),
+            new MeetingQueryConfig("s",  LocationFilter.EXCLUDE,
+                excludedLocations, Comparison.LT, Comparison.LT,
+                dThresS, CThresS),
+            new MeetingQueryConfig("fs", LocationFilter.EXCLUDE,
+                excludedLocations, Comparison.LT, Comparison.GT,
+                dThresFS, CThresFS)
+        );
+
+        generateFile(path, Month, Date, configs);
+    }
+
     /**
      * Executes a parameterized meeting query and appends edges to the output buffer.
      *