utilities.QueryDatabase.java Source code

Introduction

Here is the source code for utilities.QueryDatabase.java

Source

/* QueryDatabase.java
 *
 * Copyright (C) 2014 Universidad de Sevilla
 * 
 * The use of this project is hereby constrained to the conditions of the 
 * TDG Licence, a copy of which you may download from 
 * http://www.tdg-seville.info/License.html
 * 
 */

package utilities;

import java.util.List;

import org.apache.commons.lang.StringUtils;

import utilities.internal.ConsoleReader;
import utilities.internal.CustomToStringBuilder;
import utilities.internal.DatabaseUtil;

public class QueryDatabase {

    public static void main(String[] args) throws Throwable {
        DatabaseUtil databaseUtil;
        ConsoleReader reader;
        String line;
        boolean quit;

        databaseUtil = null;

        try {
            System.out.printf("QueryDatabase 1.3%n");
            System.out.printf("-----------------%n%n");

            System.out.printf("Initialising persistence context `%s'...%n", DatabaseConfig.PersistenceUnit);
            databaseUtil = new DatabaseUtil();

            reader = new ConsoleReader();

            do {
                line = reader.readCommand();
                quit = interpretLine(databaseUtil, line);
            } while (!quit);
        } catch (Throwable oops) {
            System.out.flush();
            System.err.printf("%n%s%n", oops.getLocalizedMessage());
            //oops.printStackTrace(System.out);         
        } finally {
            databaseUtil.close();
        }
    }

    private static boolean interpretLine(DatabaseUtil databaseUtil, String line) {
        boolean result;
        String command;
        List<?> objects;
        int affected;

        result = false;
        try {
            command = StringUtils.substringBefore(line, " ");
            switch (command) {
            case "quit":
                result = true;
                break;
            case "begin":
                databaseUtil.openTransaction();
                System.out.println("Transaction started");
                break;
            case "commit":
                databaseUtil.commitTransaction();
                System.out.println("Transaction committed");
                break;
            case "rollback":
                databaseUtil.rollbackTransaction();
                System.out.println("Transaction rollbacked");
                break;
            case "update":
            case "delete":
                affected = databaseUtil.executeUpdate(line);
                System.out.printf("%d objects affected%n", affected);
                break;
            case "select":
                objects = databaseUtil.executeSelect(line);
                System.out.printf("%d objects found%n", objects.size());
                printResultList(objects);
                break;
            default:
                System.err.println("Command not understood");
            }
        } catch (Throwable oops) {
            System.err.println(oops.getMessage());
            // oops.printStackTrace(System.err);
        }

        return result;
    }

    private static void printResultList(List<?> objects) {
        String text;
        Object obj;

        for (int i = 0; i < objects.size(); i++) {
            obj = objects.get(i);
            text = CustomToStringBuilder.toString(obj);
            System.out.printf("Object #%d = %s %n", i, text);
        }
    }

}