org.nanoj.util.tinydb

Class TinyTable

java.lang.Object

org.nanoj.util.tinydb.TinyTable

All Implemented Interfaces:

Serializable

public class TinyTable
extends Object
implements Serializable

This class represents one "table" of a "tiny database"
A "table" is based on a Hashtable instance, it contains 0..N "records" associated with a "key",
It provides standard entity persistance operations : insert, find, update, delete, insert or update
A table doesn't store the record object itself but a copy, in order to avoid unwanted changes

Since:

v 1.0.3

Author:

Laurent Guerin

See Also:

Serialized Form

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	TinyTable(String tableName, Class<?> keyClass, Class<?> recordClass, String tableFile) Constructs a table

Method Summary

Methods

Modifier and Type	Method and Description
boolean	deleteRecord(Object key) Deletes the record associated with the given key If there's no record for this key nothing is deleted (it's not an error)
Object	findRecord(Object key) Finds the record associated with the given key
Class<?>	getKeyClass() Returns the class of the keys for this table
Class<?>	getRecordClass() Returns the class of the records stored in this table
String	getTableFile() Returns the filename of this table (filesystem file path)
String	getTableName() Returns the logical name of this table
void	insertOrUpdateRecord(Object key, Object record) Inserts or update the given record associated with the given key If a record exists for the key it is updated, else it is inserted
void	insertRecord(Object key, Object record) Inserts the given record associated with the given key If a record already exists for this key, a "duplicate key" exception if throwned
boolean	isLoaded() Return true if the table records have been loaded (at least on time) from the file
Hashtable<Object,Object>	loadTable() Loads (or reloads) the table records from the file
void	saveTable() Saves the table records in the file
boolean	updateRecord(Object key, Object record) Updates the record associated with the given key If there's no record for this key nothing is updated (it's not an error)

Methods inherited from class java.lang.Object

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

Constructor Detail

TinyTable

protected TinyTable(String tableName,
         Class<?> keyClass,
         Class<?> recordClass,
         String tableFile)

Constructs a table

Parameters:

tableName - the logical name of the table

keyClass - the class of the key used to identify a record

recordClass - the class of the records stored in the table

tableFile - the file where the table is physically stored

Throws:

RuntimeException - if one of the parameters is null

Method Detail

getTableName

public String getTableName()

Returns the logical name of this table

Returns:

getTableFile

public String getTableFile()

Returns the filename of this table (filesystem file path)

Returns:

getKeyClass

public Class<?> getKeyClass()

Returns the class of the keys for this table

Returns:

getRecordClass

public Class<?> getRecordClass()

Returns the class of the records stored in this table

Returns:

isLoaded

public boolean isLoaded()

Return true if the table records have been loaded (at least on time) from the file

Returns:

loadTable

public Hashtable<Object,Object> loadTable()

Loads (or reloads) the table records from the file

Returns:

the Hashtable loaded (never null)

Throws:

RuntimeException - if FileSystem I/O error

saveTable

public void saveTable()

Saves the table records in the file

Throws:

RuntimeException - if FileSystem I/O error

findRecord

public Object findRecord(Object key)

Finds the record associated with the given key

Parameters:

key - the key (must not be null )

Returns:

the record found, or null if there's no record for this key

Throws:

RuntimeException - if an error occurs

insertOrUpdateRecord

public void insertOrUpdateRecord(Object key,
                        Object record)

Inserts or update the given record associated with the given key
If a record exists for the key it is updated, else it is inserted

Parameters:

key - the key (must not be null )

record -

Throws:

RuntimeException - if an error occurs

insertRecord

public void insertRecord(Object key,
                Object record)

Inserts the given record associated with the given key
If a record already exists for this key, a "duplicate key" exception if throwned

Parameters:

key - the key (must not be null )

record -

Throws:

RuntimeException - if an error occurs or if duplicate key

updateRecord

public boolean updateRecord(Object key,
                   Object record)

Updates the record associated with the given key
If there's no record for this key nothing is updated (it's not an error)

Parameters:

key - the key (must not be null )

record -

Returns:

true if an existing record was updated, false if there's no record for the given key

Throws:

RuntimeException - if an error occurs

deleteRecord

public boolean deleteRecord(Object key)

Deletes the record associated with the given key
If there's no record for this key nothing is deleted (it's not an error)

Parameters:

key - the key (must not be null )

Returns:

true if a record was found and deleted, false if there's no record for the given key

Throws:

RuntimeException - if an error occurs