com.persistit

Class Persistit

java.lang.Object

com.persistit.Persistit

public class Persistit
extends Object

Create and manage the runtime environment for a Persistit™ database. To use Persistit an application

• constructs a Persistit instance when it starts up
• calls one of the initialize() methods to set up a configuration and initialize the memory structures and background threads
• uses various method to acquire Exchange and Transaction instances to perform work,
• calls one of the close() methods to gracefully release all memory resources and shut down the background threads.

Generally an application will have no more than one Persistit instance, treating it as a singleton. However, the application is responsible for holding a reference to that instance and calling close() when finished with it. Persistit's background threads are not daemon threads, and an application that does not call close therefore will not exit normally.

Persistit takes a large variety of configuration properties. These are specified through the initalize method.

Version:

1.1

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Persistit.FatalErrorException An Exception created when Persistit detects a fatal internal error such as database corruption.

Field Summary

Fields

Modifier and Type	Field and Description
static boolean	BIG_ENDIAN Determines whether multi-byte integers will be written in little- or big-endian format.
static String	COPYRIGHT The copyright notice
static int	MAX_POOLED_EXCHANGES Maximum number of Exchanges that will be held in an internal pool.
static String	VERSION This version of Persistit

Constructor Summary

Constructors

Constructor and Description
Persistit() Construct a hollow Persistit instance.
Persistit(Configuration configuration) Construct a Persistit instance with the supplied Configuration and then initialize it.
Persistit(Properties properties) Construct a Persistit instance with a Configuration derived from the supplied Properties instance.

Method Summary

Modifier and Type	Method and Description
void	checkAllVolumes() Convenience method that performs an integrity check on all open Volumes and reports detailed results to System.out.
CheckpointManager.Checkpoint	checkpoint() Force a new Checkpoint and wait for it to be written.
void	checkSuspended() Waits until updates are no longer suspended.
void	close() Close the Persistit Journal and all Volumes.
void	close(boolean flush) Close the Persistit Journal and all Volumes.
void	copyBackPages() Copy back all pages from the journal to their host Volumes.
static String	copyright() Returns the copyright notice for this product
void	crash() Abruptly stop (using Thread.stop()) the writer and collector processes.
Volume	createTemporaryVolume() Create a temporary volume.
Volume	createTemporaryVolume(int pageSize) Create a temporary volume.
boolean	deleteVolume(String volumeName) Delete a volume currently loaded volume and remove it from the list returned by getVolumes().
long	elapsedTime() The number of milliseconds since the log was opened.
boolean	flush() Write all pending updates to the underlying OS file system.
void	force() Request OS-level file synchronization for all open files managed by Persistit.
AlertMonitor	getAlertMonitor()
long	getAvailableHeap() Available heap space at the time this Persistit instance was created.
CoderManager	getCoderManager() Returns the current CoderManager.
Configuration	getConfiguration()
CheckpointManager.Checkpoint	getCurrentCheckpoint()
long	getCurrentTimestamp()
JoinPolicy	getDefaultJoinPolicy()
SplitPolicy	getDefaultSplitPolicy()
Transaction.CommitPolicy	getDefaultTransactionCommitPolicy() This property can be configured with the configuration property "txnpolicy".
Exchange	getExchange(String volumeName, String treeName, boolean create) Returns an Exchange for the Tree specified by treeName within the Volume specified by volumeName.
Exchange	getExchange(Volume volume, String treeName, boolean create) Returns an Exchange for the specified Volume and the Tree specified by the supplied name.
com.persistit.JournalManager	getJournalManager()
Volume	getLockVolume()
LogBase	getLogBase()
Management	getManagement() Returns an implementation of the Management interface.
Object	getPersistitGuiContainer() Returns the java.awt.Container object that contains the diagnostic GUI, if it is open.
PersistitLogger	getPersistitLogger()
Properties	getProperties() Deprecated.
String	getProperty(String key) Deprecated.
RecoveryManager	getRecoveryManager()
List<Tree>	getSelectedTrees(TreeSelector selector) Select a List of Trees determined by the supplied TreeSelector.
SessionId	getSessionId() Return this thread's SessionId.
Volume	getSystemVolume() Returns the designated system volume.
Transaction	getTransaction() Get the Transaction object for the current thread.
Volume	getVolume(String name) Looks up a Volume by name or path.
List<Volume>	getVolumes() Get a List of all Volumes currently being managed by this Persistit instance.
void	initialize() Initialize Persistit using the Configuration supplied by the setConfiguration(Configuration) method or derived from properties supplied by setProperties(Properties) or setPropertiesFromFile(String).
void	initialize(Configuration configuration) Deprecated.
void	initialize(Properties properties) Deprecated.
void	initialize(String propertiesFileName) Deprecated.
boolean	isClosed() Indicates whether this instance of Persistit has been closed.
boolean	isFatal()
boolean	isInitialized() Indicates whether this instance has been initialized.
boolean	isReadRetryEnabled() Indicates whether Persistit will retry read any operation that fails due to an IOException.
boolean	isShutdownSuspended() Indicates whether Persistit will suspend its shutdown activities on invocation of close().
boolean	isUpdateSuspended() Indicates whether Persistit is suspending all updates.
Volume	loadVolume(String vstring) Look up, load and/or creates a volume based on a String-valued specification.
Volume	loadVolume(VolumeSpecification volumeSpec) Look up, load and/or creates a volume based on a VolumeSpecification.
static void	main(String[] args) Perform various utility functions.
void	releaseExchange(Exchange exchange) Releases an Exchange to the internal pool.
void	releaseExchange(Exchange exchange, boolean secure) Releases an Exchange to the internal pool.
void	setCoderManager(CoderManager coderManager) Sets the CoderManager that will supply instances of ValueCoder and KeyCoder.
void	setConfiguration(Configuration configuration) Receive the supplied Configuration which will be used to control the creation of a functional Persistit within the initialize() method.
void	setDefaultJoinPolicy(JoinPolicy policy) Replace the current default SplitPolicy.
void	setDefaultSplitPolicy(SplitPolicy policy) Replace the current default SplitPolicy.
void	setDefaultTransactionCommitPolicy(String policyName) Set the current default transaction commit property by name.
void	setDefaultTransactionCommitPolicy(Transaction.CommitPolicy policy) Set the current default transaction commit property.
void	setPersistitLogger(PersistitLogger logger) Replaces the current logger implementation.
void	setProperties(Properties properties) Sets a Configuration derived from the supplied Properties.
void	setPropertiesFromFile(String propertiesFileName) Sets a Configuration derived from Properties read from the supplied file name.
void	setSessionId(SessionId sessionId) Modify this thread's SessionId.
void	setShutdownSuspended(boolean suspended) Determines whether Persistit will suspend its shutdown activities on invocation of close().
void	setUpdateSuspended(boolean suspended) Controls whether Persistit will suspend all Threads that attempt to update any Volume.
void	setupGUI(boolean suspendShutdown) Attempts to open the diagnostic GUI that displays some useful information about Persistit's internal state.
void	shutdownGUI() Closes the diagnostic GUI if it previously has been opened.
long	startTime() The time at which the log was started.
String	substituteProperties(String text, Properties properties) Deprecated.
String	transactionReport(int max) Reports status of the max longest-running transactions, in order from oldest to youngest.
static String	version() Returns the version identifier for this version of Persistit™

Methods inherited from class java.lang.Object

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

Field Detail

VERSION

public static final String VERSION

This version of Persistit

COPYRIGHT

public static final String COPYRIGHT

The copyright notice

See Also:

Constant Field Values

BIG_ENDIAN

public static final boolean BIG_ENDIAN

Determines whether multi-byte integers will be written in little- or big-endian format. This constant is true in all current builds.

See Also:

Constant Field Values

MAX_POOLED_EXCHANGES

public static final int MAX_POOLED_EXCHANGES

Maximum number of Exchanges that will be held in an internal pool.

See Also:

Constant Field Values

Constructor Detail

Persistit

public Persistit()

Construct a hollow Persistit instance. To be useful, the instance must receive a Configuration through one of the methods setConfiguration(Configuration), setProperties(Properties) or setPropertiesFromFile(String). The instance must then be started by the initialize() method.

Persistit

public Persistit(Configuration configuration)
          throws PersistitException

Construct a Persistit instance with the supplied Configuration and then initialize it. The code

 Persistit db = new Persistit(configuration);
 

is equivalent to

 Persistit db = new Persistit();
 db.setConfiguration(configuration);
 db.intialize();
 

Parameters:

configuration - the Configuration

Throws:

PersistitException

See Also:

setConfiguration(Configuration)

Persistit

public Persistit(Properties properties)
          throws PersistitException

Construct a Persistit instance with a Configuration derived from the supplied Properties instance. The code

 Persistit db = new Persistit(properties);
 

is equivalent to

 Persistit db = new Persistit();
 db.setProperties(properties);
 db.intialize();
 

Parameters:

properties - the Properties

Throws:

PersistitException

See Also:

setProperties(Properties)

Method Detail

setConfiguration

public void setConfiguration(Configuration configuration)

Receive the supplied Configuration which will be used to control the creation of a functional Persistit within the initialize() method. The configuration may only be set once.

Parameters:

configuration -

Throws:

IllegalStateException - if the Configuration has already been set

setPropertiesFromFile

public void setPropertiesFromFile(String propertiesFileName)
                           throws PersistitException

Sets a Configuration derived from Properties read from the supplied file name.

Parameters:

propertiesFileName - path to properties file

Throws:

PersistitException - if the properties file is invalid

IllegalStateException - if the Configuration has already been set

See Also:

setConfiguration(Configuration)

setProperties

public void setProperties(Properties properties)

Sets a Configuration derived from the supplied Properties.

Parameters:

properties - the Properties from which to build a Configuration

Throws:

IllegalStateException - if the Configuration has already been set

See Also:

setConfiguration(Configuration)

initialize

public void initialize()
                throws PersistitException

Initialize Persistit using the Configuration supplied by the setConfiguration(Configuration) method or derived from properties supplied by setProperties(Properties) or setPropertiesFromFile(String).

If no configuration has been set, this method reverts to its legacy behavior which is to load a configuration from a default properties file. The name of this file is supplied by the system property com.persistit.properties. If that property is not specified, the default file path is ./persistit.properties in the current working directory. If Persistit has already been initialized, this method does nothing. This method is thread-safe; if multiple threads concurrently attempt to invoke this method, one of the threads will actually perform the initialization and the other threads will do nothing.

Note that Persistit starts non-daemon threads that will keep a JVM from exiting until close() is invoked. This is to ensure that all pending updates are written before the JVM exit.

Throws:

PersistitException

IOException

Exception

initialize

@Deprecated
public void initialize(String propertiesFileName)
                            throws PersistitException

Deprecated.

Initialize Persistit using the supplied properties file path. If Persistit has already been initialized, this method does nothing. This method is thread-safe; if multiple threads concurrently attempt to invoke this method, one of the threads will actually perform the initialization and the other threads will do nothing.

Note that Persistit starts non-daemon threads that will keep a JVM from exiting until close() is invoked. This is to ensure that all pending updates are written before the JVM exit.

This method is deprecated. Applications should instead call

 
 setPropertiesFromFile(propertiesFileName);
 initialize();
 
 

Parameters:

propertiesFileName - The path to the properties file.

Throws:

PersistitException

IOException

initialize

@Deprecated
public void initialize(Properties properties)
                            throws PersistitException

Deprecated.

Initialize Persistit using the supplied java.util.Properties instance. Applications can use this method to supply computed Properties rather than reading them from a file. If Persistit has already been initialized, this method does nothing. This method is thread-safe; if multiple threads concurrently attempt to invoke this method, one of the threads will actually perform the initialization and the other threads will do nothing.

Note that Persistit starts non-daemon threads that will keep a JVM from exiting until close() is invoked. This is to ensure that all pending updates are written before the JVM exit.

This method is deprecated. Applications should instead call

 
 setProperties(properties);
 initialize();
 
 

Parameters:

properties - The Properties instance from which to build the configuration

Throws:

PersistitException

IOException

initialize

@Deprecated
public void initialize(Configuration configuration)
                            throws PersistitException

Deprecated.

Initialize Persistit using the supplied Configuration. If Persistit has already been initialized, this method does nothing. This method is thread-safe; if multiple threads concurrently attempt to invoke this method, one of the threads will actually perform the initialization and the other threads will do nothing.

Note that Persistit starts non-daemon threads that will keep a JVM from exiting until close() is invoked. This is to ensure that all pending updates are written before the JVM exit.

This method is deprecated. Applications should instead call

 
 setConfiguration(configuration);
 initialize();
 
 

Parameters:

configuration - The Configuration from which to initialize Persistit

Throws:

PersistitException

IOException

getExchange

public Exchange getExchange(Volume volume,
                            String treeName,
                            boolean create)
                     throws PersistitException

Returns an Exchange for the specified Volume and the Tree specified by the supplied name. This method optionally creates a new Tree. If the create parameter is false and a Tree by the specified name does not exist, this constructor throws a TreeNotFoundException.

This method uses an Exchange from an internal pool if one is available; otherwise it creates a new Exchange. When the application no longer needs the Exchange returned by this method, it should return it to the pool by invoking releaseExchange(com.persistit.Exchange) so that it can be reused.

Parameters:

volume - The Volume

treeName - The tree name

create - true to create a new Tree if one by the specified name does not already exist.

Throws:

PersistitException

getExchange

public Exchange getExchange(String volumeName,
                            String treeName,
                            boolean create)
                     throws PersistitException

Returns an Exchange for the Tree specified by treeName within the Volume specified by volumeName. This method optionally creates a new Tree. If the create parameter is false and a Tree by the specified name does not exist, this constructor throws a TreeNotFoundException.

The volumeNameVolume. The name matches if either (a) the Volume has an optional alias that is equal to the supplied name, or (b) if the supplied name matches a substring of the Volume's pathname. If there is not unique match for the name you supply, this method throws a VolumeNotFoundException.

This method uses an Exchange from an internal pool if one is available; otherwise it creates a new Exchange. When the application no longer needs the Exchange returned by this method, it should return it to the pool by invoking releaseExchange(com.persistit.Exchange) so that it can be reused.

Parameters:

volumeName - The volume name that either matches the alias or a partially matches the pathname of exactly one open Volume.

treeName - The tree name

create - true to create a new Tree if one by the specified name does not already exist.

Throws:

PersistitException

releaseExchange

public void releaseExchange(Exchange exchange)

Releases an Exchange to the internal pool. A subsequent invocation of getExchange(com.persistit.Volume, java.lang.String, boolean) may reuse this Exchange. An application that gets an Exchange through the getExchange(com.persistit.Volume, java.lang.String, boolean) method should release it through this method. An attempt to release the Exchange if it is already in the pool results in an IllegalStateException.

This method clears the key and value fields. Use the releaseExchange(Exchange, boolean) method to clear all state information if this Exchange may subsequently be used by another untrusted thread.

Parameters:

exchange - The Exchange to release to the pool. If null , this method returns silently.

Throws:

IllegalStateException

releaseExchange

public void releaseExchange(Exchange exchange,
                            boolean secure)

Releases an Exchange to the internal pool. A subsequent invocation of getExchange(com.persistit.Volume, java.lang.String, boolean) may reuse this Exchange. An application that gets an Exchange through the getExchange(com.persistit.Volume, java.lang.String, boolean) method should release it through this method. An attempt to release the Exchange if it is already in the pool results in an IllegalStateException.

This method optionally clears all state information in the Exchange so that no residual information in the Exchange can be obtained by a different, untrusted thread. In a closed configuration in which there is only one application, it is faster to avoid clearing the byte arrays used in representing the state of this Exchange by passing false as the value of the secure flag.

Parameters:

exchange - The Exchange to release to the pool. If null this method returns silently.

secure - true to clear all state information; false to leave the state unchanged.

Throws:

IllegalStateException

getVolumes

public List<Volume> getVolumes()

Get a List of all Volumes currently being managed by this Persistit instance. Volumes are specified by the properties used in initializing Persistit.

Returns:

the List

getSelectedTrees

public List<Tree> getSelectedTrees(TreeSelector selector)
                            throws PersistitException

Select a List of Trees determined by the supplied TreeSelector. This method enumerates all Trees in all open Volumes and selects those which satisfy the TreeSelector. If the Volume has a Volume-only selector (no tree pattern was specified), then this method adds the Volume's directory Tree to the list.

Parameters:

selector -

Returns:

the List

Throws:

PersistitException

loadVolume

public Volume loadVolume(String vstring)
                  throws PersistitException

Look up, load and/or creates a volume based on a String-valued specification. See VolumeSpecification for the specification String format.

If a Volume has already been loaded having the same ID or name, this method returns that Volume. Otherwise it tries to open or create a volume on disk (depending on the volume specification) and returns that.

Parameters:

vstring - Volume specification string

Returns:

The Volume

Throws:

PersistitException

loadVolume

public Volume loadVolume(VolumeSpecification volumeSpec)
                  throws PersistitException

Look up, load and/or creates a volume based on a VolumeSpecification. If a Volume has already been loaded having the same ID or name, this method returns that Volume. Otherwise it tries to open or create a volume on disk (depending on the volume specification) and returns that.

Parameters:

volumeSpec - The VolumeSpecification

Returns:

The Volume

Throws:

PersistitException

createTemporaryVolume

public Volume createTemporaryVolume()
                             throws PersistitException

Create a temporary volume. A temporary volume is not durable; it should be used to hold temporary data such as intermediate sort or aggregation results that can be recreated in the event the system restarts.

The temporary volume page size is can be specified by the configuration property tmpvolpagesize. The default value is determined by the BufferPool having the largest page size.

The backing store file for a temporary volume is created in the directory specified by the configuration property tmpvoldir, or if unspecified, the system temporary directory..

Returns:

the temporary Volume.

Throws:

PersistitException

createTemporaryVolume

public Volume createTemporaryVolume(int pageSize)
                             throws PersistitException

Create a temporary volume. A temporary volume is not durable; it should be used to hold temporary data such as intermediate sort or aggregation results that can be recreated in the event the system restarts.

The backing store file for a temporary volume is created in the directory specified by the configuration property tmpvoldir, or if unspecified, the system temporary directory.

Parameters:

pageSize - The page size for the volume. Must be one of 1024, 2048, 4096, 8192 or 16384, and the volume will be usable only if there are buffers of the specified size in the BufferPool.

Returns:

the temporary Volume.

Throws:

PersistitException

deleteVolume

public boolean deleteVolume(String volumeName)
                     throws PersistitException

Delete a volume currently loaded volume and remove it from the list returned by getVolumes().

Parameters:

volumeName - the Volume to delete

Returns:

true if the volume was previously loaded and has been successfully deleted.

Throws:

PersistitException

getManagement

public Management getManagement()

Returns an implementation of the Management interface. This implementation is a singleton; the first invocation of this method will create an instance; subsequent invocations will return the same instance.

Returns:

the singleton implementation of a Management from which system management services can be obtained.

copyright

public static String copyright()

Returns the copyright notice for this product

Returns:

The copyright notice

version

public static String version()

Returns the version identifier for this version of Persistit™

Returns:

The version identifier

startTime

public long startTime()

The time at which the log was started.

Returns:

The time in milliseconds

elapsedTime

public long elapsedTime()

The number of milliseconds since the log was opened.

Returns:

The elapsed time interval in milliseconds

getConfiguration

public Configuration getConfiguration()

getProperties

@Deprecated
public Properties getProperties()

Deprecated.

getProperty

@Deprecated
public String getProperty(String key)

Deprecated.

substituteProperties

@Deprecated
public String substituteProperties(String text,
                                               Properties properties)

Deprecated.

getVolume

public Volume getVolume(String name)

Looks up a Volume by name or path. The supplied name must match only one of the open volumes. If it matches none of the volumes, or if there are multiple volumes with matching names, then this method returns null.

The supplied name can match a volume in one of two ways:

• (a) its name by exact match
• (b) its path, by matching the absolute forms of the volume's path and the supplied path.

Parameters:

name - Name that identifies a volume by matching either its alias (if it has one) or a substring of its file name.

Returns:

the Volume, or null if there is no unique open Volume that matches the supplied partialName.

getSystemVolume

public Volume getSystemVolume()
                       throws VolumeNotFoundException

Returns the designated system volume. The system volume contains the class index and other structural information. It is specified by the sysvolume property with a default value of "_system".

This method handles a configuration with exactly one volume in a special way. If the sysvolume property is unspecified and there is exactly one volume, then this method returns that volume volume as the system volume even if its name does not match the default sysvolume property. This eliminates the need to specify a system volume property for configurations having only one volume.

Returns:

the Volume

Throws:

VolumeNotFoundException - if the volume was not found

getLockVolume

public Volume getLockVolume()
                     throws PersistitException

Returns:

reserved temporary volume for locks

Throws:

PersistitException

getDefaultSplitPolicy

public SplitPolicy getDefaultSplitPolicy()

Returns:

The SplitPolicy that will by applied by default to newly created or allocated Exchanges.

getDefaultJoinPolicy

public JoinPolicy getDefaultJoinPolicy()

Returns:

The JoinPolicy that will by applied by default to newly created or allocated Exchanges.

setDefaultSplitPolicy

public void setDefaultSplitPolicy(SplitPolicy policy)

Replace the current default SplitPolicy.

Parameters:

policy - The JoinPolicy that will by applied by default to newly created or allocated Exchanges.

setDefaultJoinPolicy

public void setDefaultJoinPolicy(JoinPolicy policy)

Replace the current default SplitPolicy.

Parameters:

policy - The JoinPolicy that will by applied by default to newly created or allocated Exchanges.

isInitialized

public boolean isInitialized()

Indicates whether this instance has been initialized.

Returns:

true if this Persistit has been initialized.

isClosed

public boolean isClosed()

Indicates whether this instance of Persistit has been closed.

Returns:

true if Persistit has been closed.

isReadRetryEnabled

public boolean isReadRetryEnabled()

Indicates whether Persistit will retry read any operation that fails due to an IOException. In many cases, an IOException occurs due to transient conditions, such as a file being locked by a backup program. When this property is true, Persistit will repeatedly retry the read operation until the timeout value for the current operation expires. By default this property is true. Use the com.persistit.readretry property to disable it.

Returns:

true to retry a read operation that fails due to an IOException.

getCurrentCheckpoint

public CheckpointManager.Checkpoint getCurrentCheckpoint()

Returns:

The most recently proposed Checkpoint.

Throws:

PersistitInterruptedException

checkpoint

public CheckpointManager.Checkpoint checkpoint()
                                        throws PersistitException

Force a new Checkpoint and wait for it to be written. If Persistit is closed or not yet initialized, do nothing and return null.

Returns:

the Checkpoint allocated by this process.

Throws:

PersistitInterruptedException

PersistitException

copyBackPages

public void copyBackPages()
                   throws Exception

Copy back all pages from the journal to their host Volumes. This condenses the total number of journals as much as possible given the current activity in the system.

Throws:

Exception

isFatal

public boolean isFatal()

Returns:

whether a fatal error has occurred

transactionReport

public String transactionReport(int max)

Reports status of the max longest-running transactions, in order from oldest to youngest.

Parameters:

max -

Returns:

status of the max longest-running transactions, in order from oldest to youngest, reported as a String with one line per transaction.

close

public void close()
           throws PersistitException

Close the Persistit Journal and all Volumes. This method is equivalent to close(true).

Throws:

PersistitException

IOException

PersistitException

IOException

close

public void close(boolean flush)
           throws PersistitException

Close the Persistit Journal and all Volumes. This method does nothing and returns false if Persistit is currently not in the initialized state. This method is threadsafe; if multiple threads concurrently attempt to close Persistit, only one close operation will actually take effect.

The flush determines whether this method will pause to flush all pending updates to disk before shutting down the system. If flush is true and many updated pages need to be written, the shutdown process may take a significant amount of time. However, upon restarting the system, all updates initiated before the call to this method will be reflected in the B-Tree database. This is the normal mode of operation.

When flush is false this method returns quickly, but without writing remaining dirty pages to disk. The result after restarting Persistit will be valid, internally consistent B-Trees; however, recently applied updates may be missing.

Note that Persistit starts non-daemon threads that will keep a JVM from exiting until you close Persistit. This is to ensure that all pending updates are written before the JVM exits. Therefore the recommended pattern for initializing, using and then closing Persistit is:

   try
   {
      Persistit.initialize();
      ... do work
   }
   finally
   {
      Persisit.close();
   }
 

This pattern ensures that Persistit is closed properly and all threads terminated even if the application code throws an exception or error.

VolumeClosedException.

Parameters:

flush - true to ensure all dirty pages are written to disk before shutdown completes; false to enable fast (but incomplete) shutdown.

Throws:

PersistitException

IOException

PersistitException

IOException

crash

public void crash()

Abruptly stop (using Thread.stop()) the writer and collector processes. This method should be used only by tests.

flush

public boolean flush()
              throws PersistitException

Write all pending updates to the underlying OS file system. This operation runs asynchronously with other threads performing updates. Upon successful completion, this method ensures that all updates performed prior to calling flush() (except for those performed within as-yet uncommitted transactions) will be written; however, some updates performed by other threads subsequent to calling flush() may also be written.

Returns:

true if any file writes were performed, else false.

Throws:

PersistitException

IOException

force

public void force()
           throws PersistitException

Request OS-level file synchronization for all open files managed by Persistit. An application may call this method after flush() to ensure (within the capabilities of the host operating system) that all database updates have actually been written to disk.

Throws:

IOException

PersistitException

checkSuspended

public void checkSuspended()
                    throws PersistitInterruptedException

Waits until updates are no longer suspended. The setUpdateSuspended(boolean) method controls whether update operations are currently suspended.

Throws:

PersistitInterruptedException

getSessionId

public SessionId getSessionId()

Return this thread's SessionId. Constructs a new unique SessionId if the thread has not already been bound to one.

Returns:

Thread-private SessionId

setSessionId

public void setSessionId(SessionId sessionId)

Modify this thread's SessionId. This method is intended for server applications that may execute multiple requests, possible on different threads, within the scope of one session. Such applications much use extreme care to avoid having two threads with the same SessionId at any time.

Parameters:

sessionId -

getTransaction

public Transaction getTransaction()

Get the Transaction object for the current thread. The Transaction object lasts for the life of the thread. See Transaction for more information on how to use Persistit's transaction facilities.

Returns:

This thread Transaction object.

getDefaultTransactionCommitPolicy

public Transaction.CommitPolicy getDefaultTransactionCommitPolicy()

This property can be configured with the configuration property "txnpolicy".

Returns:

The default system commit policy.

setDefaultTransactionCommitPolicy

public void setDefaultTransactionCommitPolicy(Transaction.CommitPolicy policy)

Set the current default transaction commit property. This policy is applied to transactions that call Transaction.commit(). Note that Transaction.commit(CommitPolicy) permits control on a per-transaction basis. The supplied policy value may not be null.

Parameters:

policy - The policy.

setDefaultTransactionCommitPolicy

public void setDefaultTransactionCommitPolicy(String policyName)

Set the current default transaction commit property by name. This policy is applied to transactions that call Transaction.commit(). Note that Transaction.commit(CommitPolicy) permits control on a per-transaction basis. The supplied policy value must be one of "HARD", "GROUP" or "SOFT".

Parameters:

policyName - The policy name: "SOFT", "HARD" or "GROUP"

getCurrentTimestamp

public long getCurrentTimestamp()

Returns:

The current timestamp value

getPersistitGuiContainer

public Object getPersistitGuiContainer()

Returns the java.awt.Container object that contains the diagnostic GUI, if it is open. Otherwise this method returns null. The caller must cast the returned Object to Container. Persistit is designed to avoid loading Swing or AWT classes in the event no GUI is desired in order to minimize memory usage and startup time.

Returns:

an Object that can be cast to java.awt.Container, or null if no diagnostic UI is open.

setCoderManager

public void setCoderManager(CoderManager coderManager)

Sets the CoderManager that will supply instances of ValueCoder and KeyCoder.

Parameters:

coderManager -

getCoderManager

public CoderManager getCoderManager()

Returns the current CoderManager.

Returns:

The current CoderManager.

getLogBase

public LogBase getLogBase()

getAvailableHeap

public long getAvailableHeap()

Available heap space at the time this Persistit instance was created. Determined by the MemoryUsage.getMax() method of MemoryMXBean.getHeapMemoryUsage() at the time this Persistit instance was created, i.e., before allocation of buffer pools and other data structures.

Returns:

maximum available heap memory, in bytes

getRecoveryManager

public RecoveryManager getRecoveryManager()

getJournalManager

public com.persistit.JournalManager getJournalManager()

getAlertMonitor

public AlertMonitor getAlertMonitor()

setPersistitLogger

public void setPersistitLogger(PersistitLogger logger)

Replaces the current logger implementation.

Parameters:

logger - The new logger implementation

See Also:

DefaultPersistitLogger, com.persistit.logging.JDK14LoggingAdapter, com.persistit.logging.Log4JAdapter

getPersistitLogger

public PersistitLogger getPersistitLogger()

Returns:

The current logger.

checkAllVolumes

public void checkAllVolumes()
                     throws PersistitException

Convenience method that performs an integrity check on all open Volumes and reports detailed results to System.out.

Throws:

PersistitException

setupGUI

public void setupGUI(boolean suspendShutdown)
              throws IllegalAccessException,
                     InstantiationException,
                     ClassNotFoundException,
                     RemoteException

Attempts to open the diagnostic GUI that displays some useful information about Persistit's internal state. If the UI has already been opened, this method merely sets the shutdown suspend flag.

Parameters:

suspendShutdown - If true, sets the shutdown suspend flag. Setting this flag suspends the close() method to permit continued use of the diagnostic GUI.

Throws:

ClassNotFoundException

IllegalAccessException

InstantiationException

RemoteException

shutdownGUI

public void shutdownGUI()

Closes the diagnostic GUI if it previously has been opened. Otherwise this method does nothing.

isShutdownSuspended

public boolean isShutdownSuspended()

Indicates whether Persistit will suspend its shutdown activities on invocation of close(). This flag is intended for use by management tools that need to keep Persistit open even when the application has requested it to close so that the final state of the Persistit environment can be examined.

Returns:

true if Persistit will wait when attempting to close; false if the close operation will not be suspended.

setShutdownSuspended

public void setShutdownSuspended(boolean suspended)

Determines whether Persistit will suspend its shutdown activities on invocation of close(). This flag is intended for use by management tools that need to keep Persistit open even when the application has requested it to close so that the final state of the Persistit environment can be examined.

Parameters:

suspended - true to specify that Persistit will wait when attempting to close; otherwise false.

isUpdateSuspended

public boolean isUpdateSuspended()

Indicates whether Persistit is suspending all updates. When set, this property will cause all updates to be suspended until the property is cleared. This capability is intended primarily for diagnostic and management support.

Returns:

true if all updates are suspended; otherwise false.

setUpdateSuspended

public void setUpdateSuspended(boolean suspended)

Controls whether Persistit will suspend all Threads that attempt to update any Volume. When set, this property will cause all updates to be suspended until the property is cleared. This capability is intended primarily for diagnostic support and management support.

Parameters:

suspended - true to suspend all updates; false to enable updates.

main

public static void main(String[] args)
                 throws Exception

Perform various utility functions.

• If the cliport=nnnn argument is set, then this method starts a CLI server on the specified port.
• Otherwise if the properties=filename argument is set, this method initializes a Persistit instance using the specified properties. With an initialized instance the flags -i, -g, and -c take effect to invoke an integrity check, open the AdminUI or copy back all pages from the Journal.

Parameters:

args -

Throws:

Exception