de.stevensolleder.persistentobjectstorage

Class PersistentObjectStorage

java.lang.Object

de.stevensolleder.persistentobjectstorage.PersistentObjectStorage

public class PersistentObjectStorage
extends java.lang.Object

Constructor Summary

Constructors

Constructor and Description
PersistentObjectStorage(java.lang.String directoryName) Before you use any other method of this library you have to set a storage path.

Method Summary

Modifier and Type	Method and Description
void	firstStartFinished() If called, an empty file notFirstStart is created in the storage path.
java.lang.String	getStoragePath() Get the current set storage path as a String.
boolean	isFirstStart() Checks if the file notFirstStart exists, so you can check if the application was started once before.
static void	main(java.lang.String[] args)
<T extends java.io.Serializable> T	read(java.lang.String fileName) Reads an object of a given type from a File.
void	resetAllData() Deletes the directory where all files created with this library are stored.
boolean	resetFirstStart() Deletes the file notFirstStart in the storage path if it exists.
<T extends java.io.Serializable> void	write(T object, java.lang.String fileName) Writes an object of a given type to a File.

Methods inherited from class java.lang.Object

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

Constructor Detail

PersistentObjectStorage

public PersistentObjectStorage(java.lang.String directoryName)

Before you use any other method of this library you have to set a storage path. The storage path is always a directory with directoryName which will be created in the home path of the current user. directoryName gets trimmed.

Parameters:

directoryName - The name of the directory inside the home directory of the current user where all files are created and read with this library.

Throws:

java.lang.NullPointerException - If directoryName is null

java.lang.IllegalArgumentException - If directoryName is empty

Method Detail

getStoragePath

public java.lang.String getStoragePath()

Get the current set storage path as a String.

Returns:

Current set storage path

isFirstStart

public boolean isFirstStart()

Checks if the file notFirstStart exists, so you can check if the application was started once before.

Returns:

True if file notFirstStart doesn't exist in the storage path

firstStartFinished

public void firstStartFinished()
                        throws java.io.IOException

If called, an empty file notFirstStart is created in the storage path. From now on isFirstStart returns false.

Throws:

java.io.IOException - If an I/O error occurred

resetFirstStart

public boolean resetFirstStart()

Deletes the file notFirstStart in the storage path if it exists. From now on isFirstStart returns true.

Returns:

True if notFirstStart file existed and was successfully deleted, else false

read

public <T extends java.io.Serializable> T read(java.lang.String fileName)
                                        throws java.io.IOException,
                                               java.lang.ClassNotFoundException

Reads an object of a given type from a File.

Type Parameters:

T - The type of the object that is read

Parameters:

fileName - The name of the file an object should be read from

Returns:

Object of a given type

Throws:

java.lang.NullPointerException - If fileName is null

java.io.FileNotFoundException - If the file does not exist, is a directory rather than a regular file, or for some other reason cannot be opened for reading.

java.io.IOException - If an I/O error occurred

java.lang.ClassNotFoundException - Class of a serialized object cannot be found

java.io.InvalidClassException - Something is wrong with a class used by serialization

java.io.StreamCorruptedException - Control information in the stream is inconsistent

java.io.OptionalDataException - Primitive data was found in the stream instead of objects

java.lang.ClassCastException - If wrong class for T is given

write

public <T extends java.io.Serializable> void write(T object,
                                                   java.lang.String fileName)
                                            throws java.io.IOException

Writes an object of a given type to a File.

Type Parameters:

T - The type of the object that is written

Parameters:

object - The object of a given type that should be written

fileName - The name of the File the object should be written to

Throws:

java.lang.NullPointerException - If fileName is null

java.io.FileNotFoundException - If the file exists but is a directory rather than a regular file, does not exist but cannot be created, or cannot be opened for any other reason

java.io.InvalidClassException - Something is wrong with a class used by serialization

java.io.IOException - If an I/O error occurred

resetAllData

public void resetAllData()

Deletes the directory where all files created with this library are stored. From now on isFirstStart returns true.

main

public static void main(java.lang.String[] args)