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src/main/java/com/bib/essensbestellungsverwaltung/Database.java

@@ -13,6 +13,11 @@ import java.util.List;
 
 public class Database {
     private static final String dbLocation = "jdbc:sqlite:"+Path.of("").toAbsolutePath()+"/database.db";
+
+    /**
+     * creates new database.db if it doesn't exist
+     * @return true if a new database has been created
+     */
     protected static boolean init(){
         File db = new File(Path.of("").toAbsolutePath()+"/database.db");
         try {
@@ -21,6 +26,11 @@ public class Database {
             throw new RuntimeException(e);
         }
     }
+
+    /**
+     * connects to the database
+     * @return Connection to the database
+     */
     protected static Connection connect(){
         Connection conn = null;
         try{
@@ -31,6 +41,9 @@ public class Database {
         return conn;
     }
 
+    /**
+     * creates the initial structure of the db
+     */
     protected static void createDb(){
         String[] sql = new String[14];
         sql[0] = """
@@ -152,6 +165,9 @@ public class Database {
         }
     }
 
+    /**
+     * inserts fixed values into the database
+     */
     protected static void fillDb(){
         List<String> sqls = new ArrayList<>();
         sqls.add("""
@@ -249,6 +265,7 @@ public class Database {
 
     /**
      * inserts data into table and returns its id
+     * does not insert if the exact set already exists
      * @param table name of the database table
      * @param header String[] order should match with values
      * @param values String[] order should match with header
@@ -288,6 +305,13 @@ public class Database {
         return id;
     }
 
+    /**
+     * returns a single id that matches the given data
+     * @param table the table that contains the searched entry
+     * @param header the header of the table, order should match with values
+     * @param values the data you want the id of, order should match witch values
+     * @return one id matching the given data or -1 if no match has been found
+     */
     protected static long getSingleId(String table, String[] header, String[] values){
         long id = -1;
         try(Connection conn = connect()){
@@ -307,6 +331,9 @@ public class Database {
         return id;
     }
 
+    /**
+     * @deprecated
+     */
     protected static void printSampleQuery(){
         String sql = """
                 SELECT * FROM food_type WHERE id > ?;""";
@@ -332,6 +359,11 @@ public class Database {
         }
     }
 
+    /**
+     * deletes an entry from table with matching id
+     * @param table the table that contains the entry you want to delete
+     * @param id the id of the entry you want to delete
+     */
     protected static void delete(String table, long id){
         String sql = "DELETE FROM " + table + " WHERE id = ?;";
         try(Connection conn = connect();PreparedStatement ps = conn.prepareStatement(sql)){
@@ -434,6 +466,11 @@ public class Database {
         return sql;
     }
 
+    /**
+     * returns a list of all entries
+     * @param table the table you want
+     * @return a list of all entries as String with the fields separated by ":"
+     */
     protected static List<String> getTable(String table){
         List<String> data = new ArrayList<>();
         StringBuilder sb;
@@ -458,6 +495,13 @@ public class Database {
         return data;
     }
 
+    /**
+     * issues a select query on the database for the given table and the given values checked with LIKE
+     * @param table the table you want the data from
+     * @param header header for the WHERE portion, order should match with values
+     * @param values values for the WHERE portion, order should match with header
+     * @return a list of the matching data as String separated by ":"
+     */
     protected static List<String> select(String table,String[] header, String[] values){
         List<String> data = new ArrayList<>();
         StringBuilder sb;
@@ -483,6 +527,12 @@ public class Database {
         return data;
     }
 
+    /**
+     * returns the entry from table with the given id
+     * @param table the table you want the entry from
+     * @param id the id of the entry you want
+     * @return a list of String separated by ":"
+     */
     protected static List<String> getEntryById(String table, long id){
         List<String> data = new ArrayList<>();
         StringBuilder sb;
@@ -509,6 +559,13 @@ public class Database {
         return data;
     }
 
+    /**
+     * counts the number of matching entries
+     * @param table the table you want to count
+     * @param header the properties you want to count on
+     * @param values the values for the properties
+     * @return the number of found rows
+     */
     protected static int count(String table,String[] header,String[] values){
         String sql = queryBuilder("count",table,header,values);
         try(Connection conn = connect()) {
@@ -520,6 +577,13 @@ public class Database {
         }
     }
 
+    /**
+     * updates an entry in the database
+     * @param table the table you want to update
+     * @param header [0] is used as WHERE, everything else in SET
+     * @param values [0] is used as WHERE, everything else in SET
+     * @return number of rows affected or -1 on error
+     */
     protected static int update(String table,String[] header,String[] values){
         try(Connection conn = connect()) {
             String sql = queryBuilder("update",table,header,values);