jdbcmailrepository.java

邮件服务器系统 支持SMTP POP3 是著名的Apache写 有一定的参考价值

                sr = (StreamRepository) store.select(streamConfiguration);

                if (getLogger().isDebugEnabled()) {
                    getLogger().debug("Got filestore for JdbcMailRepository: " + filestore);
                }
            }

            lock = new Lock();
            if (getLogger().isDebugEnabled()) {
                StringBuffer logBuffer =
                    new StringBuffer(128)
                            .append(this.getClass().getName())
                            .append(" created according to ")
                            .append(destination);
                getLogger().debug(logBuffer.toString());
            }
        } catch (Exception e) {
            final String message = "Failed to retrieve Store component:" + e.getMessage();
            getLogger().error(message, e);
            throw new ConfigurationException(message, e);
        }
    }

    /**
     * Initialises the JDBC repository.
     * 1) Tests the connection to the database.
     * 2) Loads SQL strings from the SQL definition file,
     *     choosing the appropriate SQL for this connection,
     *     and performing paramter substitution,
     * 3) Initialises the database with the required tables, if necessary.
     *
     * @throws Exception if an error occurs
     */
    public void initialize() throws Exception {
        StringBuffer logBuffer = null;
        if (getLogger().isDebugEnabled()) {
            getLogger().debug(this.getClass().getName() + ".initialize()");
        }

        theJDBCUtil =
            new JDBCUtil() {
                protected void delegatedLog(String logString) {
                    JDBCMailRepository.this.getLogger().warn("JDBCMailRepository: " + logString);
                }
            };
        // Get the data-source required.
        datasource = (DataSourceComponent)datasources.select(datasourceName);

        // Test the connection to the database, by getting the DatabaseMetaData.
        Connection conn = datasource.getConnection();
        PreparedStatement createStatement = null;

        try {
            // Initialise the sql strings.

            File sqlFile = null;
            try {
                sqlFile = AvalonContextUtilities.getFile(context, sqlFileName);
                sqlFileName = null;
            } catch (Exception e) {
                getLogger().fatalError(e.getMessage(), e);
                throw e;
            }

            String resourceName = "org.apache.james.mailrepository.JDBCMailRepository";

            if (getLogger().isDebugEnabled()) {
                logBuffer =
                    new StringBuffer(128)
                            .append("Reading SQL resources from file: ")
                            .append(sqlFile.getAbsolutePath())
                            .append(", section ")
                            .append(this.getClass().getName())
                            .append(".");
                getLogger().debug(logBuffer.toString());
            }

            // Build the statement parameters
            Map sqlParameters = new HashMap();
            if (tableName != null) {
                sqlParameters.put("table", tableName);
            }
            if (repositoryName != null) {
                sqlParameters.put("repository", repositoryName);
            }

            sqlQueries = new SqlResources();
            sqlQueries.init(sqlFile, this.getClass().getName(),
                            conn, sqlParameters);

            // Check if the required table exists. If not, create it.
            DatabaseMetaData dbMetaData = conn.getMetaData();
            // Need to ask in the case that identifiers are stored, ask the DatabaseMetaInfo.
            // Try UPPER, lower, and MixedCase, to see if the table is there.
            if (!(theJDBCUtil.tableExists(dbMetaData, tableName))) {
                // Users table doesn't exist - create it.
                createStatement =
                    conn.prepareStatement(sqlQueries.getSqlString("createTable", true));
                createStatement.execute();

                if (getLogger().isInfoEnabled()) {
                    logBuffer =
                        new StringBuffer(64)
                                .append("JdbcMailRepository: Created table '")
                                .append(tableName)
                                .append("'.");
                    getLogger().info(logBuffer.toString());
                }
            }
            
            checkJdbcAttributesSupport(dbMetaData);

        } finally {
            theJDBCUtil.closeJDBCStatement(createStatement);
            theJDBCUtil.closeJDBCConnection(conn);
        }
    }
    
    /** Checks whether support for JDBC Mail atributes is activated for this repository
     * and if everything is consistent.
     * Looks for both the "updateMessageAttributesSQL" and "retrieveMessageAttributesSQL"
     * statements in sqlResources and for a table column named "message_attributes".
     *
     * @param dbMetaData the database metadata to be used to look up the column
     * @throws SQLException if a fatal situation is met
     */
    protected void checkJdbcAttributesSupport(DatabaseMetaData dbMetaData) throws SQLException {
        String attributesColumnName = "message_attributes";
        boolean hasUpdateMessageAttributesSQL = false;
        boolean hasRetrieveMessageAttributesSQL = false;
        
        boolean hasMessageAttributesColumn = theJDBCUtil.columnExists(dbMetaData, tableName, attributesColumnName);
        
        StringBuffer logBuffer = new StringBuffer(64)
                                    .append("JdbcMailRepository '"
                                            + repositoryName
                                            + ", table '"
                                            + tableName
                                            + "': ");
        
        //Determine whether attributes are used and available for storing
        //Do we have updateMessageAttributesSQL?
        String updateMessageAttrSql =
            sqlQueries.getSqlString("updateMessageAttributesSQL", false);
        if (updateMessageAttrSql!=null) {
            hasUpdateMessageAttributesSQL = true;
        }
        
        //Determine whether attributes are used and retrieve them
        //Do we have retrieveAttributesSQL?
        String retrieveMessageAttrSql =
            sqlQueries.getSqlString("retrieveMessageAttributesSQL", false);
        if (retrieveMessageAttrSql!=null) {
            hasRetrieveMessageAttributesSQL = true;
        }
        
        if (hasUpdateMessageAttributesSQL && !hasRetrieveMessageAttributesSQL) {
            logBuffer.append("JDBC Mail Attributes support was activated for update but not for retrieval"
                             + "(found 'updateMessageAttributesSQL' but not 'retrieveMessageAttributesSQL'"
                             + "in table '"
                             + tableName
                             + "').");
            getLogger().fatalError(logBuffer.toString());
            throw new SQLException(logBuffer.toString());
        }
        if (!hasUpdateMessageAttributesSQL && hasRetrieveMessageAttributesSQL) {
            logBuffer.append("JDBC Mail Attributes support was activated for retrieval but not for update"
                             + "(found 'retrieveMessageAttributesSQL' but not 'updateMessageAttributesSQL'"
                             + "in table '"
                             + tableName
                             + "'.");
            getLogger().fatalError(logBuffer.toString());
            throw new SQLException(logBuffer.toString());
        }
        if (!hasMessageAttributesColumn
            && (hasUpdateMessageAttributesSQL || hasRetrieveMessageAttributesSQL)
            ) {
                logBuffer.append("JDBC Mail Attributes support was activated but column '"
                                 + attributesColumnName
                                 + "' is missing in table '"
                                 + tableName
                                 + "'.");
                getLogger().fatalError(logBuffer.toString());
                throw new SQLException(logBuffer.toString());
        }
        if (hasUpdateMessageAttributesSQL && hasRetrieveMessageAttributesSQL) {
            jdbcMailAttributesReady = true;
            if (getLogger().isInfoEnabled()) {
                logBuffer.append("JDBC Mail Attributes support ready.");
                getLogger().info(logBuffer.toString());
            }
        } else {
            jdbcMailAttributesReady = false;
            logBuffer.append("JDBC Mail Attributes support not activated. "
                             + "Missing both 'updateMessageAttributesSQL' "
                             + "and 'retrieveMessageAttributesSQL' "
                             + "statements for table '"
                             + tableName
                             + "' in sqlResources.xml. "
                             + "Will not persist in the repository '"
                             + repositoryName
                             + "'.");
            getLogger().warn(logBuffer.toString());
        }
    }

    /**
     * Releases a lock on a message identified by a key
     *
     * @param key the key of the message to be unlocked
     *
     * @return true if successfully released the lock, false otherwise
     */
    public synchronized boolean unlock(String key) {
        if (lock.unlock(key)) {
            if ((DEEP_DEBUG) && (getLogger().isDebugEnabled())) {
                StringBuffer debugBuffer =
                    new StringBuffer(256)
                            .append("Unlocked ")
                            .append(key)
                            .append(" for ")
                            .append(Thread.currentThread().getName())
                            .append(" @ ")
                            .append(new java.util.Date(System.currentTimeMillis()));
                getLogger().debug(debugBuffer.toString());
            }
//            notifyAll();
            return true;
        } else {
            return false;
        }
    }

    /**
     * Obtains a lock on a message identified by a key
     *
     * @param key the key of the message to be locked
     *
     * @return true if successfully obtained the lock, false otherwise
     */
    public synchronized boolean lock(String key) {
        if (lock.lock(key)) {
            if ((DEEP_DEBUG) && (getLogger().isDebugEnabled())) {
                StringBuffer debugBuffer =
                    new StringBuffer(256)
                            .append("Locked ")
                            .append(key)
                            .append(" for ")
                            .append(Thread.currentThread().getName())
                            .append(" @ ")
                            .append(new java.util.Date(System.currentTimeMillis()));
                getLogger().debug(debugBuffer.toString());
            }
            return true;
        } else {
            return false;
        }
    }

    /**
     * Store this message to the database.  Optionally stores the message
     * body to the filesystem and only writes the headers to the database.
     */
    public void store(MailImpl mc) throws MessagingException {
        Connection conn = null;
        try {
            conn = datasource.getConnection();

            //Need to determine whether need to insert this record, or update it.

            //Begin a transaction
            conn.setAutoCommit(false);