pooledconnection.java

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/*
 * @(#)PooledConnection.java 1.41 06/08/21
 */
package mfkvit;

import java.sql.*;
import java.util.Map;

/**
 * <p>Title: PooledConnection</p>
 *
 * <p>Description: This class contains a <code>java.sql.Connection</code>
 * instance object. The class will do the function as same as
 * <code>java.sql.Connection</code> class' using connection pool tech. Now the
 * version for <code>java.sql.Connection</code> interface is JDK1.41 </p>
 *
 * @author Qian YANG
 * @version 1.0
 */
public class PooledConnection implements Connection {

    private static final boolean STATUS_FREE = true;
    private static final boolean STATUS_IN_USE = false;

    private static final String WARNING_MSG_CONNECTION_ALREADY_CLOSE =
            "The connection is already been closed!";

    /**
     * Uses for ConnectionPool if the connection is free or not
     */
    private boolean freeOrNot = STATUS_IN_USE;

    /**
     * real connection object connected to database
     */
    private Connection conn = null;

    /**
     * current connection when to be in use
     */
    private long startUsingTimeMillis = 0;

    public PooledConnection(String driverName, String dbUrl, String user,
                            String password) throws
            SQLException {
        try {
            Class.forName(driverName);
        } catch(ClassNotFoundException cnfe) {
            System.out.println("Naming space not found for " + driverName);
            cnfe.printStackTrace();
        }
        this.conn = DriverManager.getConnection(dbUrl, user, password);
        freeOrNot = STATUS_FREE;
    }

    /**
     * Set the connection object's status. It will record the timemillis when
     * the connection is being using automatically.
     */
    public void setBeUsing() {
        freeOrNot = STATUS_IN_USE;
        startUsingTimeMillis = System.currentTimeMillis();
    }

    /**
     * Returns the timemillis for current connection's using time.
     *
     * @return long
     */
    public long getUsingTimeMillis() {
        if (isFree()) {
            return -1L;
        }
        return System.currentTimeMillis() - startUsingTimeMillis;
    }

    /**
     * Retrieves whether this connection is free or being using.
     *
     * @return <code>true</code> if this <code>Connection</code> object is
     *   closed; <code>false</code> if it is still open
     */
    private boolean isFree() {
        return freeOrNot;
    }

    /**
     * Set current connection free instead of releasing the real connection to
     * database.
     */
    public void close() throws SQLException {
        freeOrNot = STATUS_FREE;
    }

    /**
     * Retrieves whether this connection is free or being using.
     *
     * @return <code>true</code> if this <code>Connection</code> object is
     *   closed; <code>false</code> if it is still open
     */
    public boolean isClosed() {
        return isFree();
    }

    /**
     * Release the connection.
     *
     * @throws SQLException
     */
    public void releaseConnection() throws SQLException {
        if (isFree()) {
            conn.close();
        }
    }

    public int getHoldability() throws SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        return conn.getHoldability();
    }

    public int getTransactionIsolation() throws SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        return conn.getTransactionIsolation();
    }

    public void clearWarnings() throws SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        conn.clearWarnings();
    }

    public void commit() throws SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        conn.commit();
    }

    public void rollback() throws SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        conn.rollback();
    }

    public boolean getAutoCommit() throws SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        return conn.getAutoCommit();
    }

    public boolean isReadOnly() throws SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        return conn.isReadOnly();
    }

    public void setHoldability(int holdability) throws SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        conn.setHoldability(holdability);
    }

    public void setTransactionIsolation(int level) throws SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        conn.setTransactionIsolation(level);
    }

    public void setAutoCommit(boolean autoCommit) throws SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        conn.setAutoCommit(autoCommit);
    }

    public void setReadOnly(boolean readOnly) throws SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        conn.setReadOnly(readOnly);
    }

    public String getCatalog() throws SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        return conn.getCatalog();
    }

    public void setCatalog(String catalog) throws SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        conn.setCatalog(catalog);
    }

    public DatabaseMetaData getMetaData() throws SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        return conn.getMetaData();
    }

    public SQLWarning getWarnings() throws SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        return conn.getWarnings();
    }

    public Savepoint setSavepoint() throws SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        return conn.setSavepoint();
    }

    public void releaseSavepoint(Savepoint savepoint) throws SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        conn.releaseSavepoint(savepoint);
    }

    public void rollback(Savepoint savepoint) throws SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        conn.rollback(savepoint);
    }

    public Statement createStatement() throws SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        return conn.createStatement();
    }

    public Statement createStatement(int resultSetType,
                                     int resultSetConcurrency) throws
            SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        return conn.createStatement(resultSetType, resultSetConcurrency);
    }

    public Statement createStatement(int resultSetType,
                                     int resultSetConcurrency,
                                     int resultSetHoldability) throws
            SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        return conn.createStatement(resultSetType, resultSetConcurrency,
                                    resultSetHoldability);
    }

    public Map getTypeMap() throws SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        return conn.getTypeMap();
    }

    public void setTypeMap(Map map) throws SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        conn.setTypeMap(map);
    }

    public String nativeSQL(String sql) throws SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        return conn.nativeSQL(sql);
    }

    public CallableStatement prepareCall(String sql) throws SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        return conn.prepareCall(sql);
    }

    public CallableStatement prepareCall(String sql, int resultSetType,
                                         int resultSetConcurrency) throws
            SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        return conn.prepareCall(sql, resultSetType, resultSetConcurrency);
    }

    public CallableStatement prepareCall(String sql, int resultSetType,
                                         int resultSetConcurrency,
                                         int resultSetHoldability) throws
            SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        return conn.prepareCall(sql, resultSetType, resultSetConcurrency,
                                resultSetHoldability);
    }

    public PreparedStatement prepareStatement(String sql) throws SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        return conn.prepareStatement(sql);
    }

    public PreparedStatement prepareStatement(String sql, int autoGeneratedKeys) throws
            SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        return conn.prepareStatement(sql, autoGeneratedKeys);
    }

    public PreparedStatement prepareStatement(String sql, int resultSetType,
                                              int resultSetConcurrency) throws
            SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        return conn.prepareStatement(sql, resultSetType, resultSetConcurrency);
    }

    public PreparedStatement prepareStatement(String sql, int resultSetType,
                                              int resultSetConcurrency,
                                              int resultSetHoldability) throws
            SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        return conn.prepareStatement(sql, resultSetType, resultSetConcurrency,
                                     resultSetHoldability);
    }

    public PreparedStatement prepareStatement(String sql, int[] columnIndexes) throws
            SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        return conn.prepareStatement(sql, columnIndexes);
    }

    public Savepoint setSavepoint(String name) throws SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        return conn.setSavepoint(name);
    }

    public PreparedStatement prepareStatement(String sql, String[] columnNames) throws
            SQLException {
        if (isFree()) {
            throw new SQLWarning(WARNING_MSG_CONNECTION_ALREADY_CLOSE);
        }
        return conn.prepareStatement(sql, columnNames);
    }
}