org.hsqldb
Class Server

java.lang.Object
  extended byorg.hsqldb.Server
All Implemented Interfaces:
org.hsqldb.HsqlSocketRequestHandler
Direct Known Subclasses:
WebServer

public class Server
extends java.lang.Object
implements org.hsqldb.HsqlSocketRequestHandler

The HSQLDB HSQL protocol network database server.

A Server object acts as a network database server and is one way of using the client-server mode of HSQLDB Database Engine. Instances of this class handle native HSQL protocol connections exclusively, allowing database queries to be performed efficienly across the network. Server's direct descendent, WebServer, handles HTTP protocol connections exclusively, allowing HSQL protocol to be tunneled over HTTP to avoid sandbox and firewall issues, albeit less efficiently.

There are a number of ways to configure and start a Server instance.

When started from the command line or programatically via the main(String[]) method, configuration occurs in three phases, with later phases overriding properties set by previous phases:

  1. Upon construction, a Server object is assigned a set of default properties.

  2. If it exists, properties are loaded from a file named 'server.properties' in the present working directory.

  3. The command line arguments (alternatively, the String[] passed to main()) are parsed and used to further configure the Server's properties.

From the command line, the options are as follows:

 +----------------+-------------+----------+------------------------------+
 |    OPTION      |    TYPE     | DEFAULT  |         DESCRIPTION          |
 +----------------+-------------+----------+------------------------------|
 | -?             | --          | --       | prints this message          |
 | -address       | name|number | any      | server inet address          |
 | -port          | number      | 9001/544 | port at which server listens |
 | -database.i    | [type]spec  | 0=test   | path of database i           |
 | -dbname.i      | alias       | --       | url alias for database i     |
 | -silent        | true|false  | true     | false => display all queries |
 | -trace         | true|false  | false    | display JDBC trace messages  |
 | -tls           | true|false  | false    | TLS/SSL (secure) sockets     |
 | -no_system_exit| true|false  | false    | do not issue System.exit()   |
 | -remote_open   | true|false  | false    | can open databases remotely  |
 +----------------+-------------+----------+------------------------------+
 
The database.i and dbname.i options need further explanation: From the 'server.properties' file, options can be set similarly, using a slightly different format.

Here is an example 'server.properties' file:

 server.port=9001
 server.database.0=test
 server.dbname.0=...
 ...
 server.database.n=...
 server.dbname.n=...
 server.silent=true
 
Starting with 1.7.2, Server has been refactored to become a simple JavaBean with non-blocking start() and stop() service methods. It is possible to configure a Server instance through the JavaBean API as well, but this part of the public interface is still under review and will not be finalized or documented fully until the final 1.7.2 release.

Note:

The 'no_system_exit' property is of particular interest.

If a Server instance is to run embedded in, say, an application server, such as when the jdbcDataSource or HsqlServerFactory classes are used, it is typically necessary to avoid calling System.exit() when the Server instance shuts down.

By default, 'no_system_exit' is set:

  1. true when a Server is started directly from the start() method.

  2. false when a Server is started from the main(String[]) method.

These values are natural to their context because the first case allows the JVM to exit by default on Server shutdown when a Server instance is started from a command line environment, whereas the second case prevents a typically unwanted JVM exit on Server shutdown when a Server intance is started as part of a larger framework.

Replaces original Hypersonic source of the same name.

Since:
1.7.2
Author:
fredt@users

Constructor Summary
Server()
          Creates a new Server instance handling HSQL protocol connections.
 
Method Summary
 void checkRunning(boolean running)
          Checks if this Server object is or is not running and throws if the current state does not match the specified value.
 java.lang.String getAddress()
          Retrieves, in string form, this server's host address.
 java.lang.String getDatabaseName(int index, boolean asconfigured)
          Retrieves the url alias (network name) of the i'th database that this Server hosts.
 java.lang.String getDatabasePath(int index, boolean asconfigured)
          Retrieves the HSQLDB path descriptor (uri) of the i'th Database that this Server hosts.
 java.lang.String getDatabaseType(int index)
           
 java.lang.String getDefaultWebPage()
          Retrieves the name of the web page served when no page is specified.
 java.io.PrintWriter getErrWriter()
          Retrieves the PrintWriter to which server errors are printed.
 java.lang.String getHelpString()
          Retrieves a String object describing the command line and properties options for this Server.
 java.io.PrintWriter getLogWriter()
          Retrieves the PrintWriter to which server messages are printed.
 int getPort()
          Retrieves this server's host port.
 java.lang.String getProductName()
          Retrieves this server's product name.
 java.lang.String getProductVersion()
          Retrieves the server's product version, as a String.
 java.lang.String getProtocol()
          Retrieves a string respresentaion of the network protocol this server offers, typically one of 'HTTP', HTTPS', 'HSQL' or 'HSQLS'.
 java.lang.Throwable getServerError()
          Retrieves a Throwable indicating the last server error, if any.
 java.lang.String getServerId()
          Retrieves a String identifying this Server object.
 int getState()
          Retrieves current state of this server in numerically coded form.
 java.lang.String getStateDescriptor()
          Retrieves a character sequence describing this server's current state, including the message of the last exception, if there is one and it is still in context.
 java.lang.String getWebRoot()
          Retrieves the root context (directory) from which web content is served.
 void handleConnection(java.net.Socket s)
          Assigns the specified socket to a new conection handler and starts the handler in a new Thread.
 boolean isNoSystemExit()
          Retrieves whether this server calls System.exit() when shutdown.
 boolean isRestartOnShutdown()
          Retrieves whether this server restarts on shutdown.
 boolean isSilent()
          Retrieves whether silent mode operation was requested in the server properties.
 boolean isTls()
          Retrieves whether the use of secure sockets was requested in the server properties.
 boolean isTrace()
          Retrieves whether JDBC trace messages are to go to System.out or the DriverManger PrintStream/PrintWriter, if any.
static void main(java.lang.String[] args)
          Creates and starts a new Server.
 boolean putPropertiesFromFile(java.lang.String path)
          Attempts to put properties from the file with the specified path.
 void putPropertiesFromString(java.lang.String s)
          Puts properties from the supplied string argument.
 void setAddress(java.lang.String address)
          Sets the InetAddress with which this server's ServerSocket will be constructed.
 void setDatabaseName(int index, java.lang.String name)
          Sets the external name (url alias) of the i'th hosted database.
 void setDatabasePath(int index, java.lang.String path)
          Sets the path of the hosted database.
 void setDefaultWebPage(java.lang.String file)
          Sets the name of the web page served when no page is specified.
 void setErrWriter(java.io.PrintWriter pw)
          Sets the PrintWriter to which server errors are logged.
 void setLogWriter(java.io.PrintWriter pw)
          Sets the PrintWriter to which server messages are logged.
 void setNoSystemExit(boolean noExit)
          Sets whether this server calls System.exit() when shutdown.
 void setPort(int port)
          Sets the server listen port.
 void setProperties(org.hsqldb.persist.HsqlProperties p)
          Sets server properties using the specified properties object
 void setRestartOnShutdown(boolean restart)
          Sets whether this server restarts on shutdown.
 void setSilent(boolean silent)
          Sets silent mode operation
 void setTls(boolean tls)
          Sets whether to use secure sockets
 void setTrace(boolean trace)
          Sets whether trace messages go to System.out or the DriverManger PrintStream/PrintWriter, if any.
 void setWebRoot(java.lang.String root)
          Sets the path of the root directory from which web content is served.
 void shutdown()
          External method to shut down this server.
 void signalCloseAllServerConnections()
          Closes all connections to this Server.
 int start()
          Starts this server synchronously.
 int stop()
          Stops this server asynchronously.
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

Server

public Server()
Creates a new Server instance handling HSQL protocol connections.

Method Detail

main

public static void main(java.lang.String[] args)
Creates and starts a new Server.

Allows starting a Server via the command line interface.

Parameters:
args - the command line arguments for the Server instance

checkRunning

public void checkRunning(boolean running)
                  throws java.lang.RuntimeException
Checks if this Server object is or is not running and throws if the current state does not match the specified value.

Parameters:
running - if true, ensure the server is running, else ensure the server is not running
Throws:
java.lang.RuntimeException - if the supplied value does not match the current running status

signalCloseAllServerConnections

public void signalCloseAllServerConnections()
Closes all connections to this Server.

Specified by:
signalCloseAllServerConnections in interface org.hsqldb.HsqlSocketRequestHandler

getAddress

public java.lang.String getAddress()
Retrieves, in string form, this server's host address.

Returns:
this server's host address

getDatabaseName

public java.lang.String getDatabaseName(int index,
                                        boolean asconfigured)
Retrieves the url alias (network name) of the i'th database that this Server hosts.

Parameters:
index - the index of the url alias upon which to report
asconfigured - if true, report the configured value, else the live value
Returns:
the url alias component of the i'th database that this Server hosts, or null if no such name exists.

getDatabasePath

public java.lang.String getDatabasePath(int index,
                                        boolean asconfigured)
Retrieves the HSQLDB path descriptor (uri) of the i'th Database that this Server hosts.

Parameters:
index - the index of the uri upon which to report
asconfigured - if true, report the configured value, else the live value
Returns:
the HSQLDB database path descriptor of the i'th database that this Server hosts, or null if no such path descriptor exists

getDatabaseType

public java.lang.String getDatabaseType(int index)

getDefaultWebPage

public java.lang.String getDefaultWebPage()
Retrieves the name of the web page served when no page is specified. This attribute is relevant only when server protocol is HTTP(S).

Returns:
the name of the web page served when no page is specified

getHelpString

public java.lang.String getHelpString()
Retrieves a String object describing the command line and properties options for this Server.

Returns:
the command line and properties options help for this Server

getErrWriter

public java.io.PrintWriter getErrWriter()
Retrieves the PrintWriter to which server errors are printed.

Returns:
the PrintWriter to which server errors are printed.

getLogWriter

public java.io.PrintWriter getLogWriter()
Retrieves the PrintWriter to which server messages are printed.

Returns:
the PrintWriter to which server messages are printed.

getPort

public int getPort()
Retrieves this server's host port.

Returns:
this server's host port

getProductName

public java.lang.String getProductName()
Retrieves this server's product name.

Typically, this will be something like: "HSQLDB xxx server".

Returns:
the product name of this server

getProductVersion

public java.lang.String getProductVersion()
Retrieves the server's product version, as a String.

Typically, this will be something like: "1.x.x" or "2.x.x" and so on.

Returns:
the product version of the server

getProtocol

public java.lang.String getProtocol()
Retrieves a string respresentaion of the network protocol this server offers, typically one of 'HTTP', HTTPS', 'HSQL' or 'HSQLS'.

Returns:
string respresentation of this server's protocol

getServerError

public java.lang.Throwable getServerError()
Retrieves a Throwable indicating the last server error, if any.

Returns:
a Throwable indicating the last server error

getServerId

public java.lang.String getServerId()
Retrieves a String identifying this Server object.

Returns:
a String identifying this Server object

getState

public int getState()
Retrieves current state of this server in numerically coded form.

Typically, this will be one of:

  1. ServerProperties.SERVER_STATE_ONLINE (1)
  2. ServerProperties.SERVER_STATE_OPENING (4)
  3. ServerProperties.SERVER_STATE_CLOSING (8)
  4. ServerProperties.SERVER_STATE_SHUTDOWN (16)

Returns:
this server's state code.

getStateDescriptor

public java.lang.String getStateDescriptor()
Retrieves a character sequence describing this server's current state, including the message of the last exception, if there is one and it is still in context.

Returns:
this server's state represented as a character sequence.

getWebRoot

public java.lang.String getWebRoot()
Retrieves the root context (directory) from which web content is served. This property is relevant only when the server protocol is HTTP(S). Although unlikely, it may be that in the future other contexts, such as jar urls may be supported, so that pages can be served from the contents of a jar or from the JVM class path.

Returns:
the root context (directory) from which web content is served

handleConnection

public void handleConnection(java.net.Socket s)
Assigns the specified socket to a new conection handler and starts the handler in a new Thread.

Specified by:
handleConnection in interface org.hsqldb.HsqlSocketRequestHandler
Parameters:
s - the socket to connect

isNoSystemExit

public boolean isNoSystemExit()
Retrieves whether this server calls System.exit() when shutdown.

Returns:
true if this server does not call System.exit()

isRestartOnShutdown

public boolean isRestartOnShutdown()
Retrieves whether this server restarts on shutdown.

Returns:
true this server restarts on shutdown

isSilent

public boolean isSilent()
Retrieves whether silent mode operation was requested in the server properties.

Returns:
if true, silent mode was requested, else trace messages are to be printed

isTls

public boolean isTls()
Retrieves whether the use of secure sockets was requested in the server properties.

Returns:
if true, secure sockets are requested, else not

isTrace

public boolean isTrace()
Retrieves whether JDBC trace messages are to go to System.out or the DriverManger PrintStream/PrintWriter, if any.

Returns:
true if tracing is on (JDBC trace messages to system out)

putPropertiesFromFile

public boolean putPropertiesFromFile(java.lang.String path)
Attempts to put properties from the file with the specified path. The file extension '.properties' is implicit and should not be included in the path specification.

Parameters:
path - the path of the desired properties file, without the '.properties' file extension
Returns:
true if the indicated file was read sucessfully, else false
Throws:
java.lang.RuntimeException - if this server is running

putPropertiesFromString

public void putPropertiesFromString(java.lang.String s)
Puts properties from the supplied string argument. The relevant key value pairs are the same as those for the (web)server.properties file format, except that the 'server.' prefix should not be specified.

Parameters:
s - semicolon-delimited key=value pair string, e.g. k1=v1;k2=v2;k3=v3...
Throws:
java.lang.RuntimeException - if this server is running

setAddress

public void setAddress(java.lang.String address)
                throws java.lang.RuntimeException
Sets the InetAddress with which this server's ServerSocket will be constructed. A null or empty string or the special value "0.0.0.0" can be used to bypass explicit selection, causing the ServerSocket to be constructed without specifying an InetAddress.

Parameters:
address - A string representing the desired InetAddress as would be retrieved by InetAddres.getByName(), or a null or empty string or "0.0.0.0" to signify that the server socket should be constructed using the signature that does not specify the InetAddress.
Throws:
java.lang.RuntimeException - if this server is running

setDatabaseName

public void setDatabaseName(int index,
                            java.lang.String name)
                     throws java.lang.RuntimeException
Sets the external name (url alias) of the i'th hosted database.

Parameters:
name - external name (url alias) of the i'th HSQLDB database instance this server is to host.
Throws:
java.lang.RuntimeException - if this server is running

setDatabasePath

public void setDatabasePath(int index,
                            java.lang.String path)
                     throws java.lang.RuntimeException
Sets the path of the hosted database.

Parameters:
path - The path of the i'th HSQLDB database instance this server is to host.
Throws:
java.lang.RuntimeException

setDefaultWebPage

public void setDefaultWebPage(java.lang.String file)
Sets the name of the web page served when no page is specified.

Parameters:
file - the name of the web page served when no page is specified

setPort

public void setPort(int port)
             throws java.lang.RuntimeException
Sets the server listen port.

Parameters:
port - the port at which this server listens
Throws:
java.lang.RuntimeException

setErrWriter

public void setErrWriter(java.io.PrintWriter pw)
Sets the PrintWriter to which server errors are logged.

Setting this attribute to null disables server error logging

Parameters:
pw - the PrintWriter to which server messages are logged

setLogWriter

public void setLogWriter(java.io.PrintWriter pw)
Sets the PrintWriter to which server messages are logged.

Setting this attribute to null disables server message logging

Parameters:
pw - the PrintWriter to which server messages are logged

setNoSystemExit

public void setNoSystemExit(boolean noExit)
Sets whether this server calls System.exit() when shutdown.

Parameters:
noExit - if true, System.exit() will not be called.

setRestartOnShutdown

public void setRestartOnShutdown(boolean restart)
Sets whether this server restarts on shutdown.

Parameters:
restart - if true, this server restarts on shutdown

setSilent

public void setSilent(boolean silent)
Sets silent mode operation

Parameters:
silent - if true, then silent mode, else trace messages are to be printed

setTls

public void setTls(boolean tls)
Sets whether to use secure sockets

Parameters:
tls - true for secure sockets, else false
Throws:
java.lang.RuntimeException - if this server is running

setTrace

public void setTrace(boolean trace)
Sets whether trace messages go to System.out or the DriverManger PrintStream/PrintWriter, if any.

Parameters:
trace - if true, route JDBC trace messages to System.out

setWebRoot

public void setWebRoot(java.lang.String root)
Sets the path of the root directory from which web content is served.

Parameters:
root - the root (context) directory from which web content is served

setProperties

public void setProperties(org.hsqldb.persist.HsqlProperties p)
Sets server properties using the specified properties object

Parameters:
p - The object containing properties to set

start

public int start()
Starts this server synchronously.

This method waits for current state to change from SERVER_STATE_OPENNING. In order to discover the success or failure of this operation, server state must be polled or a subclass of Server must be used that overrides the setState method to provide state change notification.

Returns:
the server state noted at entry to this method

stop

public int stop()
Stops this server asynchronously.

This method returns immediately, regardless of current state. In order to discover the success or failure of this operation, server state must be polled or a subclass of Server must be used that overrides the setState method to provide state change notification.

Returns:
the server state noted at entry to this method

shutdown

public void shutdown()
External method to shut down this server.



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