org.cdlib.xtf.textIndexer

Class StructuredFileProxy

Object

StructuredFileProxy

All Implemented Interfaces:

StructuredStore

public class StructuredFileProxy
extends Object
implements StructuredStore

Used to put off actually creating a structured store until it is needed. Essentially, all methods are delegated to a StructuredFile that is created when the first time a method is called. The file is released after a close() or delete() operation. As an additional precaution, the store is created under a temporary file name, and only renamed to the final filename when the file is closed.

Author:

Martin Haye

Field Summary

Fields

Modifier and Type	Field and Description
private File	finalPath
private StructuredFile	realStore
private File	tmpPath

Constructor Summary

Constructors

Constructor and Description
StructuredFileProxy(File path)

Method Summary

Modifier and Type	Method and Description
void	close() Closes the store.
SubStoreWriter	createSubStore(String name) Create a new sub-store with the specified name.
void	delete() Deletes the storage completely (implies close() first)
String	getSystemId() Gets the path, URI, or other unique identifier for this store
String	getUserVersion() Gets the user version (if any) set by StructuredStore.setUserVersion(String).
SubStoreReader	openSubStore(String name) Opens a pre-existing sub-store for read (or write).
private StructuredFile	realStore()
void	setUserVersion(String ver) Sets a user-defined version number for the file.

Methods inherited from class Object

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

Field Detail

finalPath

private File finalPath

tmpPath

private File tmpPath

realStore

private StructuredFile realStore

Constructor Detail

StructuredFileProxy

public StructuredFileProxy(File path)

Method Detail

createSubStore

public SubStoreWriter createSubStore(String name)
                              throws IOException

Description copied from interface: StructuredStore

Create a new sub-store with the specified name. Returns a SubStore that has most of the interface of a RandomAccessFile, except that seeks will be relative to the sub-store start. Only one substore may be created at a time (though many others may be opened, provided they were created before.) The caller must call SubStore.close() when the file is complete, to ensure that the directory gets written.

Specified by:

createSubStore in interface StructuredStore

Parameters:

name - Name of the sub-file to create. Must not exist.

Returns:

A sub-store to write to.

Throws:

IOException

openSubStore

public SubStoreReader openSubStore(String name)
                            throws IOException

Description copied from interface: StructuredStore

Opens a pre-existing sub-store for read (or write). Returns a sub-store that has most of the interface of a RandomAccessFile, except that seeks will be relative to the sub-file start, and IO operations cannot exceed the boundaries of the sub-file. Many sub-stores may be open simultaneously; each one has an independent file pointer. Each one is light weight, so it's okay to have many open at a time.

Specified by:

openSubStore in interface StructuredStore

Parameters:

name - Name of pre-existing sub-store to open.

Throws:

IOException

close

public void close()
           throws IOException

Description copied from interface: StructuredStore

Closes the store. This should always be called, to ensure that all sub-stores have been closed and that the directory has been written.

Specified by:

close in interface StructuredStore

Throws:

IOException

delete

public void delete()
            throws IOException

Description copied from interface: StructuredStore

Deletes the storage completely (implies close() first)

Specified by:

delete in interface StructuredStore

Throws:

IOException

getSystemId

public String getSystemId()

Description copied from interface: StructuredStore

Gets the path, URI, or other unique identifier for this store

Specified by:

getSystemId in interface StructuredStore

setUserVersion

public void setUserVersion(String ver)
                    throws IOException

Description copied from interface: StructuredStore

Sets a user-defined version number for the file. It can be retrieved later with StructuredStore.getUserVersion().

Specified by:

setUserVersion in interface StructuredStore

Parameters:

ver - The version number to set.

Throws:

IOException

getUserVersion

public String getUserVersion()

Description copied from interface: StructuredStore

Gets the user version (if any) set by StructuredStore.setUserVersion(String).

Specified by:

getUserVersion in interface StructuredStore

realStore

private StructuredFile realStore()