Skip to content

refactor: deduplicate DB connection and query execution logic #85

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
sauravbhattacharya001 wants to merge 1 commit into from
Closed

refactor: deduplicate DB connection and query execution logic #85

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
271 changes: 128 additions & 143 deletions Gvisual/src/app/Network.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -8,36 +8,91 @@
import java.sql.ResultSet;

/**
* Generates graph edge-list files from meeting database records.
*
* <p>Queries the meeting table for different relationship types
* (friends, classmates, study-groups, strangers, familiar strangers)
* and writes the results as a weighted edge list file.</p>
*
* @author zalenix
*/
public class Network {

/**
*
* 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).
* Describes a single meeting query: the SQL, edge type code,
* duration threshold, count threshold, and whether the duration
* comparison is {@code >} or {@code <} / count is {@code >=} or
* other comparison.
*/
private static class MeetingQuery {
final String sql;
final String edgeCode;
final int durationThreshold;
final int countThreshold;

MeetingQuery(String sql, String edgeCode, int durationThreshold,
int countThreshold) {
this.sql = sql;
this.edgeCode = edgeCode;
this.durationThreshold = durationThreshold;
this.countThreshold = countThreshold;
}
}

// ── SQL templates ──────────────────────────────────────────────
// Each query follows the same structure: filter meetings by month,
// date, location, and duration; group by IMEI pair; filter by count;
// join with deviceID to resolve human-readable IDs.

private static final String LOCATION_MEETING_SQL =
" 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 %s AND duration %s ?) as b"
+ " GROUP BY imei1, imei2) as a, deviceID as x, deviceID as y"
+ " WHERE C %s ? AND a.imei1 = x.imei AND a.imei2 = y.imei";

private static String buildSql(String locationFilter,
String durationOp,
String countOp) {
return String.format(LOCATION_MEETING_SQL,
locationFilter, durationOp, countOp);
}

// Location filters
private static final String LOC_PUBLIC = "location = 'public'";
private static final String LOC_CLASS = "location = 'class'";
private static final String LOC_NON_CLASS =
"location NOT IN ('class', 'unknown', '')";

/**
* Connects to the database and writes out the edge-list from the
* meeting DB table, forming edges of kind: friends, classmates,
* study-groups, strangers and familiar strangers.
*
* <p>The output path is validated to prevent directory traversal —
* it must resolve to a location within the current working directory.</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
* @param date date filter
* @param dThresF friend duration threshold
* @param cThresF friend count threshold
* @param dThresFS familiar stranger duration threshold
* @param cThresFS familiar stranger count threshold
* @param dThresC classmate duration threshold
* @param cThresC classmate count threshold
* @param dThresS stranger duration threshold
* @param cThresS stranger count threshold
* @param dThresSg study group duration threshold
* @param cThresSg study group count threshold
* @throws Exception if database 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,
int dThresF, int cThresF, int dThresFS, int cThresFS,
int dThresC, int cThresC, int dThresS, int cThresS,
int dThresSg, int cThresSg) throws Exception {

// Validate output path — prevent directory traversal attacks
File outputFile = new File(path).getCanonicalFile();
Expand All @@ -50,143 +105,73 @@ 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";
// Define all queries with their parameters
MeetingQuery[] queries = {
new MeetingQuery(
buildSql(LOC_PUBLIC, ">", ">="),
"f", dThresF, cThresF),
new MeetingQuery(
buildSql(LOC_CLASS, ">", "<="),
"sg", dThresSg, cThresSg),
new MeetingQuery(
buildSql(LOC_CLASS, ">", ">="),
"c", dThresC, cThresC),
new MeetingQuery(
buildSql(LOC_NON_CLASS, "<", "<"),
"s", dThresS, cThresS),
new MeetingQuery(
buildSql(LOC_NON_CLASS, "<", ">"),
"fs", dThresFS, cThresFS),
};

try (Connection conn = Util.getAppConnection()) {

// Use StringBuilder instead of String concatenation for performance
StringBuilder sb = new StringBuilder("edges");

// --- Friends ---
try (PreparedStatement psFriend = conn.prepareStatement(friendSql, ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY)) {
psFriend.setString(1, Month);
psFriend.setString(2, Date);
psFriend.setInt(3, dThresF);
psFriend.setInt(4, CThresF);
try (ResultSet rs = psFriend.executeQuery()) {
while (rs.next()) {
double weight = rs.getInt(3) * (double) rs.getFloat(4);
sb.append("\nf ").append(rs.getString(1)).append(" ")
.append(rs.getString(2)).append(" ").append(weight);
}
}
}

// --- Study groups ---
try (PreparedStatement psStudyg = conn.prepareStatement(studygSql, ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY)) {
psStudyg.setString(1, Month);
psStudyg.setString(2, Date);
psStudyg.setInt(3, dThresSg);
psStudyg.setInt(4, CThresSg);
try (ResultSet rs = psStudyg.executeQuery()) {
while (rs.next()) {
double weight = rs.getInt(3) * (double) rs.getFloat(4);
sb.append("\nsg ").append(rs.getString(1)).append(" ")
.append(rs.getString(2)).append(" ").append(weight);
}
}
}

// --- Classmates ---
try (PreparedStatement psCmate = conn.prepareStatement(cmateSql, ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY)) {
psCmate.setString(1, Month);
psCmate.setString(2, Date);
psCmate.setInt(3, dThresC);
psCmate.setInt(4, CThresC);
try (ResultSet rs = psCmate.executeQuery()) {
while (rs.next()) {
double weight = rs.getInt(3) * (double) rs.getFloat(4);
sb.append("\nc ").append(rs.getString(1)).append(" ")
.append(rs.getString(2)).append(" ").append(weight);
}
}
}

// --- Strangers ---
try (PreparedStatement psStranger = conn.prepareStatement(strangerSql, ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY)) {
psStranger.setString(1, Month);
psStranger.setString(2, Date);
psStranger.setInt(3, dThresS);
psStranger.setInt(4, CThresS);
try (ResultSet rs = psStranger.executeQuery()) {
while (rs.next()) {
double weight = rs.getInt(3) * (double) rs.getFloat(4);
sb.append("\ns ").append(rs.getString(1)).append(" ")
.append(rs.getString(2)).append(" ").append(weight);
}
}
}

// --- Familiar strangers ---
try (PreparedStatement psFamstranger = conn.prepareStatement(famstrangerSql, ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY)) {
psFamstranger.setString(1, Month);
psFamstranger.setString(2, Date);
psFamstranger.setInt(3, dThresFS);
psFamstranger.setInt(4, CThresFS);
try (ResultSet rs = psFamstranger.executeQuery()) {
while (rs.next()) {
double weight = rs.getInt(3) * (double) rs.getFloat(4);
sb.append("\nfs ").append(rs.getString(1)).append(" ")
.append(rs.getString(2)).append(" ").append(weight);
}
}
for (MeetingQuery mq : queries) {
appendEdges(conn, sb, mq, month, date);
}

// Write output file — use validated outputFile, not raw path
if (outputFile.exists()) {
outputFile.delete();
}
try (BufferedWriter out = new BufferedWriter(new FileWriter(outputFile))) {
try (BufferedWriter out = new BufferedWriter(
new FileWriter(outputFile))) {
out.write(sb.toString());
}
}
}

/**
* Executes a single meeting query and appends matching edges to the
* StringBuilder.
*
* @param conn database connection
* @param sb output buffer
* @param mq the query descriptor
* @param month month parameter
* @param date date parameter
* @throws Exception if the query fails
*/
private static void appendEdges(Connection conn, StringBuilder sb,
MeetingQuery mq, String month, String date) throws Exception {
try (PreparedStatement ps = conn.prepareStatement(
mq.sql,
ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_READ_ONLY)) {
ps.setString(1, month);
ps.setString(2, date);
ps.setInt(3, mq.durationThreshold);
ps.setInt(4, mq.countThreshold);
try (ResultSet rs = ps.executeQuery()) {
while (rs.next()) {
double weight = rs.getInt(3) * (double) rs.getFloat(4);
sb.append('\n').append(mq.edgeCode).append(' ')
.append(rs.getString(1)).append(' ')
.append(rs.getString(2)).append(' ')
.append(weight);
}
}
}
}
}
27 changes: 15 additions & 12 deletions Gvisual/src/app/Util.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -59,27 +59,30 @@ private static String validateHost(String host) {
return host;
}

public static Connection getAppConnection() throws Exception {
/**
* Opens a JDBC connection to the specified PostgreSQL database.
*
* @param dbName the database name (e.g. "nic_apps", "nic_aziala")
* @return an open connection to the database
* @throws Exception if the driver is unavailable or the connection fails
*/
private static Connection getConnection(String dbName) throws Exception {
String host = validateHost(envOrDefault("DB_HOST", DEFAULT_HOST));
String user = requireEnv("DB_USER");
String pass = requireEnv("DB_PASS");

Class.forName("org.postgresql.Driver");
Connection conn = DriverManager.getConnection(
"jdbc:postgresql://" + host + "/nic_apps", user, pass);
System.out.println("Successfully connected to database \"nic_apps\"");
"jdbc:postgresql://" + host + "/" + dbName, user, pass);
System.out.println("Successfully connected to database \"" + dbName + "\"");
return conn;
}

public static Connection getAzialaConnection() throws Exception {
String host = validateHost(envOrDefault("DB_HOST", DEFAULT_HOST));
String user = requireEnv("DB_USER");
String pass = requireEnv("DB_PASS");
public static Connection getAppConnection() throws Exception {
return getConnection("nic_apps");
}

Class.forName("org.postgresql.Driver");
Connection conn = DriverManager.getConnection(
"jdbc:postgresql://" + host + "/nic_aziala", user, pass);
System.out.println("Successfully connected to database \"nic_aziala\"");
return conn;
public static Connection getAzialaConnection() throws Exception {
return getConnection("nic_aziala");
}
}
Loading