Package de.murmelmeister.murmelapi.database

Class Database

java.lang.Object
de.murmelmeister.murmelapi.database.Database
public final class Database extends Object
Database class to manage the database. (Thread-safe)

  • Constructor Summary

    Constructors
    Constructor
    Description
    Database()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    callUpdate(String name, Object... objects)
    Executes a database update call using a CallableStatement with the given name and parameters.
    void
    connect(String url, String user, String password)
    Connects to the database using the provided URL, username and password.
    void
    connect(String driver, String hostname, String port, String database, String username, String password)
    Establishes a connection to a database using the specified parameters.
    void
    createTable(String tableName, String value)
    Creates a new database table if it does not already exist.
    void
    disconnect()
    Closes the database connection safely by attempting to close the underlying data source if it is not already closed.
    boolean
    exists(String name, Object... objects)
    Checks whether a record exists in the database for a given stored procedure name and the provided parameters.
    UUID
    generateUniqueIdentifier(String name)
    Generates a unique identifier of type UUID that does not conflict with existing entries associated with the specified name.
    static String
    getProcedureQuery(String name, String input, String query)
    Generates a SQL query string for creating a stored procedure in the database.
    <T> T
    query(T defaultValue, String label, Class<T> type, String name, Object... objects)
    Executes a database query using a prepared statement and retrieves a result of the specified type and label.
    <T> List<T>
    queryList(List<T> defaultList, String label, Class<T> type, String name, Object... objects)
    Executes a database query using a callable statement and populates the provided list with the results.
    <V> Map<String,V>
    queryMap(Map<String,V> defaultMap, Class<V> valueType, String name, Object... objects)
    Executes a database query using a callable statement and populates the provided map with the results.
    void
    update(String sql, Object... objects)
    Executes an update on the database using the provided SQL query and parameters.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • Database

      public Database()

  • Method Details

    • connect

      public void connect(String url, String user, String password)
      Connects to the database using the provided URL, username and password. Note: It is not checked whether it is really connected!
      Parameters:
      url - The JDBC URL for the database.
      user - The username for the database.
      password - The password for the database.

    • connect

      public void connect(String driver, String hostname, String port, String database, String username, String password)
      Establishes a connection to a database using the specified parameters.
      Parameters:
      driver - The database driver to be used (e.g., "mysql", "postgresql").
      hostname - The hostname or IP address of the database server.
      port - The port number on which the database server is listening.
      database - The name of the database to connect to.
      username - The username to use for authentication.
      password - The password to use for authentication.

    • disconnect

      public void disconnect()
      Closes the database connection safely by attempting to close the underlying data source if it is not already closed. Ensures that the operation is thread-safe by acquiring a write lock before performing the closure. If an exception occurs during the closure process, a runtime exception is thrown with the error details. The lock is always released after the operation, regardless of its success.

    • update

      public void update(String sql, Object... objects)
      Executes an update on the database using the provided SQL query and parameters. This method acquires a write lock to ensure thread safety while performing the operation.
      Parameters:
      sql - The SQL query to be executed. It may contain placeholders for parameters.
      objects - The arguments to be used as parameters in the SQL query. These will replace the placeholders in the provided query.
      Throws:
      DatabaseException - if an error occurs during database updating, wrapping the SQLException.

    • callUpdate

      public void callUpdate(String name, Object... objects)
      Executes a database update call using a CallableStatement with the given name and parameters. The method acquires a write lock before performing the operation to ensure thread-safety.
      Parameters:
      name - The name of the database procedure or function to be called.
      objects - The parameters to be passed to the CallableStatement. These can be any number of objects to match the required procedure or function signature.

    • createTable

      public void createTable(String tableName, String value)
      Creates a new database table if it does not already exist.
      Parameters:
      tableName - The name of the table to be created
      value - The column definitions for the table

    • query

      public <T> T query(T defaultValue, String label, Class<T> type, String name, Object... objects)
      Executes a database query using a prepared statement and retrieves a result of the specified type and label.
      Type Parameters:
      T - The type of the result to be retrieved from the database query.
      Parameters:
      defaultValue - The default value to return in case the query does not produce a result.
      label - The label of the column in the result set to extract the value from.
      type - The class type of the expected result.
      name - The name of the stored procedure or query to execute.
      objects - The parameters to be set in the prepared statement for the query.
      Returns:
      The value retrieved from the database query result set, or the default value if no result is found.
      Throws:
      DatabaseException - If there is an error while executing the database query or processing the result.

    • queryList

      public <T> List<T> queryList(List<T> defaultList, String label, Class<T> type, String name, Object... objects)
      Executes a database query using a callable statement and populates the provided list with the results. The method operates under a read lock to ensure thread safety during data retrieval. The query is executed using the given stored procedure name and parameters.
      Type Parameters:
      T - The type of elements to be retrieved and added to the list.
      Parameters:
      defaultList - A list to populate with the query results. The elements are cast to the specified type.
      label - The label or column name from the query result set to retrieve values from.
      type - The class type of the elements to be added to the list.
      name - The name of the stored procedure to be executed.
      objects - A variable number of parameters to be passed to the stored procedure.
      Returns:
      The list provided as the input, populated with elements extracted from the query result set.
      Throws:
      DatabaseException - If a database access error occurs while querying or processing the results.

    • queryMap

      public <V> Map<String,V> queryMap(Map<String,V> defaultMap, Class<V> valueType, String name, Object... objects)
      Executes a database query using a callable statement and populates the provided map with the results. The method operates under a read lock to ensure thread safety during data retrieval. The query is executed using the given stored procedure name and parameters.
      Type Parameters:
      V - The type of values to be stored in the map.
      Parameters:
      defaultMap - A map to populate with the query results. The keys are column labels from the query result set, and the values are cast to the specified type.
      valueType - The class type of the values to be stored in the map.
      name - The name of the stored procedure to be executed.
      objects - A variable number of parameters to be passed to the stored procedure.
      Returns:
      The map populated with key-value pairs extracted from the query result set.
      Throws:
      DatabaseException - If a database access error occurs while querying or processing the results.

    • exists

      public boolean exists(String name, Object... objects)
      Checks whether a record exists in the database for a given stored procedure name and the provided parameters.
      Parameters:
      name - The name of the stored procedure to be executed for checking existence.
      objects - A variable number of objects representing the parameters to be passed to the stored procedure.
      Returns:
      true if a record exists in the database for the specified procedure and parameters, false otherwise.

    • generateUniqueIdentifier

      public UUID generateUniqueIdentifier(String name)
      Generates a unique identifier of type UUID that does not conflict with existing entries associated with the specified name. The method ensures uniqueness by repeatedly generating random UUIDs and checking if they already exist in the database through the exists method.
      Parameters:
      name - The name used to identify the context in which the unique identifier is generated. Typically refers to a database table or similar scope for uniqueness checks.
      Returns:
      A universally unique identifier (UUID) that is guaranteed to be unique in the specified context.

    • getProcedureQuery

      public static String getProcedureQuery(String name, String input, String query)
      Generates a SQL query string for creating a stored procedure in the database.
      Parameters:
      name - The name of the stored procedure.
      input - The input parameters for the stored procedure, defined as a comma-separated list of parameter names and types (e.g., "param1 INT, param2 VARCHAR(100)").
      query - The SQL statement(s) to be executed within the body of the stored procedure.
      Returns:
      A string containing the complete SQL query for creating the stored procedure, including the name, input parameters, and body.