File	Doc	Category	Size	Date	Package
DBM.java	API Doc	Example	3702	Sat Jun 24 20:10:14 BST 2000	None

DBM

• java.lang.Object

Fields Summary
protected static boolean	inuse Since you can only have one DBM database in use at a time due to implementation restrictions, we enforce this rule with a class-wide boolean.
protected String	fileName Save the filename for messages, etc.
protected ByteArrayOutputStream	bo

Constructors Summary
public DBM(String file) Construct a DBM given its filename synchronized(this) { if (inuse) throw new IllegalArgumentException( "Only one DBM object at a time per Java Machine"); inuse = true; } fileName = file; int retCode = dbminit(fileName); if (retCode < 0) throw new IllegalArgumentException( "dbminit failed, code = " + retCode);

Methods Summary
protected void	checkInUse() if (!inuse) throw new IllegalStateException("Method called when DBM not open");
public void	close() Public wrapper for close method. this.dbmclose(); inuse = false;
protected native int	dbmclose()
protected native byte[]	dbmfetch(byte[] key)
protected native int	dbminit(java.lang.String file)
protected native int	dbmstore(byte[] key, byte[] content)
protected native int	delete(java.lang.Object key)
public java.lang.Object	fetch(java.lang.Object key) Fetch using Objects checkInUse(); byte[] datum = dbmfetch(toByteArray(key)); return toObject(datum);
public byte[]	fetch(byte[] key) Fetch using byte arrays checkInUse(); return dbmfetch(key);
public native byte[]	firstkey()
public java.lang.Object	firstkeyObject() return toObject(firstkey());
public native byte[]	nextkey(byte[] key)
public java.lang.Object	nextkey(java.lang.Object key) byte[] ba = nextkey(toByteArray(key)); if (ba == null) return null; return toObject(ba);
public void	store(byte[] key, byte[] value) Store using byte arrays checkInUse(); dbmstore(key, value);
public void	store(java.lang.Object key, java.lang.Object value) Store using Objects checkInUse(); dbmstore(toByteArray(key), toByteArray(value));
protected byte[]	toByteArray(java.lang.Object o) serialize an Object to byte array. if (bo == null) bo = new ByteArrayOutputStream(1024); bo.reset(); ObjectOutputStream os = new ObjectOutputStream(bo); os.writeObject(o); os.close(); return bo.toByteArray();
protected java.lang.Object	toObject(byte[] b) un-serialize an Object from a byte array. Object o; ByteArrayInputStream bi = new ByteArrayInputStream(b); ObjectInputStream os = new ObjectInputStream(bi); try { o = os.readObject(); } catch (ClassNotFoundException ex) { // Convert ClassNotFoundException to I/O error throw new IOException(ex.getMessage()); } os.close(); return o;
public java.lang.String	toString() return "DBM@" + hashCode() + "[" + fileName + "]";