totalcross.io

Class ObjectPDBFile

java.lang.Object

totalcross.io.Stream

totalcross.io.PDBFile

totalcross.io.ObjectPDBFile

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable

public class ObjectPDBFile
extends PDBFile

An extension to PDBFile that allows storage and retrieval of objects that implement the Storable interface. Create an ObjectPDBFile and use the addObject() method on the objects you want to store. If you want a particular object you can use loadObjectAt() to load the stored details into an object or to search through all records call resetSearch() and then loop with nextObject() until it returns false. The example below shows an example of it's use with a PDBFile of identical data:

 ObjectPDBFile oc = new ObjectPDBFile("Test.DATA");
 MyObject obj = new MyObject();
 oc.resetSearch();
 while (oc.nextObject(obj))
 {
    // do something with obj
 }
 

Here's an example using unknown data. The two sections of code save a vector containing a number of Lines, Circles, and Squares (all implementing Storable) in no particular order, then loads it back in again.

   // save data
   ObjectPDBFile oc=new ObjectPDBFile("Test.DATA",ObjectPDBFile.CREATE);
   for(int i=0,size=objs.getCount();i++)
     oc.addObject((Storable)objs.get(i));
   oc.close();

   // load data
   ObjectPDBFile oc=new ObjectPDBFile("Test.DATA");
   oc.registerClass(new Line());
   oc.registerClass(new Circle());
   oc.registerClass(new Square());
   objs=new Vector();
   oc.resetSearch();
   Storable obj;
   while ((obj=oc.nextObject())!=null)
   {
     objs.add(obj);
   }
   oc.close();
 

Field Summary

Fields

Modifier and Type	Field and Description
protected ByteArrayStream	bs
protected byte[]	buf
protected Vector	classes
protected int	cnt
protected DataStream	ds

Fields inherited from class totalcross.io.PDBFile

CREATE, CREATE_EMPTY, DB_ATTR_APPINFODIRTY, DB_ATTR_BACKUP, DB_ATTR_COPY_PREVENTION, DB_ATTR_OK_TO_INSTALL_NEWER, DB_ATTR_READ_ONLY, DB_ATTR_RESET_AFTER_INSTALL, DB_ATTR_STREAM, READ_WRITE, REC_ATTR_DELETE, REC_ATTR_DIRTY, REC_ATTR_SECRET, REC_RELEASE

Fields inherited from class totalcross.io.Stream

skipBuffer

Constructor Summary

Constructors

Constructor and Description
ObjectPDBFile(java.lang.String name) Construct a new ObjectPDBFile
ObjectPDBFile(java.lang.String name, int type) Constructs a new ObjectPDBFile

Method Summary

Modifier and Type	Method and Description
void	addObject(Storable s) Add an object to this PDBFile.
void	deleteObjectAt(int i) Delete an object from the PDBFile
byte	getObjectAttribute(int i) Get attributes of an object record from the PDBFile
void	insertObjectAt(Storable s, int i) Insert an object to this PDBFile.
Storable	loadObjectAt(int i) Loads an object from the PDBFile.
void	loadObjectAt(Storable s, int i) Load an object from the PDBFile into the given storable.
Storable	nextObject() Gets the next object in the PDBFile.
boolean	nextObject(Storable s) Gets the next object in the PDBFile and places it in the given storable.
void	registerClass(Storable s) Registers this class with the PDBFile.
void	resetSearch() Resets a counter for iterating through the PDBFile.
boolean	setObjectAttribute(int i, byte a) Set attributes of an object record from the PDBFile
void	setSearchIndex(int i) Sets the search counter at the given index in the PDBFile.
int	size() Get the size of this PDBFile

Methods inherited from class totalcross.io.PDBFile

addRecord, addRecord, close, delete, deleteRecord, finalize, getAttributes, getName, getRecordAttributes, getRecordCount, getRecordOffset, getRecordPos, getRecordSize, inspectRecord, listPDBs, listPDBs, readBytes, rename, resizeRecord, searchBytes, setAttributes, setRecordAttributes, setRecordOffset, setRecordPos, skipBytes, writeBytes

Methods inherited from class totalcross.io.Stream

asInputStream, asOutputStream, asStream, asStream, wrapInputStream, wrapInputStreamToStream, write, writeBytes, writeBytes, writeBytes

Methods inherited from class java.lang.Object

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

Field Detail

classes

protected Vector classes

cnt

protected int cnt

buf

protected byte[] buf

bs

protected ByteArrayStream bs

ds

protected DataStream ds

Constructor Detail

ObjectPDBFile

public ObjectPDBFile(java.lang.String name,
                     int type)
              throws IllegalArgumentIOException,
                     FileNotFoundException,
                     IOException

Constructs a new ObjectPDBFile

Parameters:

name - the name of the PDBFile

type - the mode to open the PDBFile with

Throws:

IOException

FileNotFoundException

IllegalArgumentIOException

ObjectPDBFile

public ObjectPDBFile(java.lang.String name)
              throws IllegalArgumentIOException,
                     IOException

Construct a new ObjectPDBFile

Parameters:

name - the name of the PDBFile

Throws:

IOException

IllegalArgumentIOException

Method Detail

registerClass

public void registerClass(Storable s)

Registers this class with the PDBFile. Classes must be registered before using the loadObjectAt(int) method.

Parameters:

s - an instance of the class to register. The contents are ignored.

addObject

public void addObject(Storable s)
               throws IllegalArgumentIOException,
                      IOException

Add an object to this PDBFile.

Parameters:

s - the storable object to add

Throws:

IOException

IllegalArgumentIOException

insertObjectAt

public void insertObjectAt(Storable s,
                           int i)
                    throws IllegalArgumentIOException,
                           IOException

Insert an object to this PDBFile.

Parameters:

s - the storable object to add

i - the index where to insert

Throws:

IOException

IllegalArgumentIOException

loadObjectAt

public void loadObjectAt(Storable s,
                         int i)
                  throws IllegalArgumentIOException,
                         IOException

Load an object from the PDBFile into the given storable. Unpredictable results will occur if the object in the PDBFile is not of the same class as the storable given. Good for when you know what each record will contain.

Parameters:

s - the object to load the data into

i - the index in the PDBFile to load from

Throws:

IOException

IllegalArgumentIOException

loadObjectAt

public Storable loadObjectAt(int i)
                      throws IllegalArgumentIOException,
                             IOException

Loads an object from the PDBFile. Good for when you don't know which classes are going to be in records. Note that you must call the registerClass() with each storable class before this method will work properly.

Parameters:

i - the index in the PDBFile to load from

Returns:

the loaded object, or null if unsucessful

Throws:

IOException

IllegalArgumentIOException

deleteObjectAt

public void deleteObjectAt(int i)
                    throws IllegalArgumentIOException,
                           IOException

Delete an object from the PDBFile

Parameters:

i - the index to delete from

Throws:

IOException

IllegalArgumentIOException

setObjectAttribute

public boolean setObjectAttribute(int i,
                                  byte a)
                           throws IOException

Set attributes of an object record from the PDBFile

Parameters:

i - the index to set the attribute

a - the attribute to set, use the REC_ATTR_XXXX constants from PDBFile class

Returns:

true if sucessful, false otherwise

Throws:

IOException

getObjectAttribute

public byte getObjectAttribute(int i)
                        throws IOException

Get attributes of an object record from the PDBFile

Parameters:

i - the index to get the attribute from

Returns:

the record attributes

Throws:

IOException

size

public int size()
         throws IOException

Get the size of this PDBFile

Returns:

the number of records contained by it

Throws:

IOException

resetSearch

public void resetSearch()

Resets a counter for iterating through the PDBFile. Should be called before iterating with nextObject().

setSearchIndex

public void setSearchIndex(int i)

Sets the search counter at the given index in the PDBFile.

Parameters:

i - the index to start

nextObject

public boolean nextObject(Storable s)
                   throws IllegalArgumentIOException,
                          IOException

Gets the next object in the PDBFile and places it in the given storable.

Returns:

true if sucessful, false if the end of the PDBFile has been reached

Throws:

IOException

IllegalArgumentIOException

nextObject

public Storable nextObject()
                    throws IOException

Gets the next object in the PDBFile.

Returns:

the next object, or null on error or if the end has been reached

Throws:

IOException