File	Doc	Category	Size	Date	Package
ConnectionBaseAdapter.java	API Doc	J2ME MIDP 2.0	25864	Thu Nov 07 12:02:20 GMT 2002	com.sun.midp.io

ConnectionBaseAdapter

• java.lang.Object

Fields Summary
protected boolean	connectionOpen Flag indicating if the connection is open.
protected int	iStreams Number of input streams that were opened.
protected int	maxIStreams Maximum number of open input streams. Set this to zero to prevent openInputStream from giving out a stream in write-only mode.
protected int	oStreams Number of output streams were opened.
protected int	maxOStreams Maximum number of output streams. Set this to zero to prevent openOutputStream from giving out a stream in read-only mode.
protected int	requiredPermission The security permission required by a subclass. -1 for none.
protected String	protocol Protocol name of subclass to prefix name of resource, can be null.
private boolean	permissionChecked The subclass needs know that the permission occured.

Constructors Summary

Methods Summary
public int	available() Returns the number of bytes that can be read (or skipped over) from this input stream without blocking by the next caller of a method for this input stream. The next caller might be the same thread or another thread. This classes implementation always returns 0. It is up to subclasses to override this method. return the number of bytes that can be read from this input stream without blocking. exception IOException if an I/O error occurs. return 0;
public void	checkForPermission(java.lang.String name) Check for the required permission, if needed. param name name of resource to insert into the permission question exception IOInterruptedException if another thread interrupts the calling thread while this method is waiting to preempt the display. Scheduler scheduler; MIDletSuite midletSuite; if (permissionChecked) { return; } permissionChecked = true; if (requiredPermission == -1) { return; } scheduler = Scheduler.getScheduler(); midletSuite = scheduler.getMIDletSuite(); // there is no suite running when installing from the command line if (midletSuite != null) { if (protocol != null) { name = protocol + ":" + name; } try { midletSuite.checkForPermission(requiredPermission, name); } catch (InterruptedException ie) { throw new InterruptedIOException( "Interrupted while trying to ask the user permission"); } }
public void	close() Close the connection. exception IOException if an I/O error occurs when closing the connection. if (connectionOpen) { connectionOpen = false; closeCommon(); }
void	closeCommon() Disconnect if the connection and all the streams and the closed. exception IOException if an I/O error occurs when closing the connection. if (!connectionOpen && iStreams == 0 && oStreams == 0) { disconnect(); }
protected void	closeInputStream() Called once by each child input stream. If the input stream is marked open, it will be marked closed and the if the connection and output stream are closed the disconnect method will be called. exception IOException if the subclass throws one iStreams--; closeCommon();
protected void	closeOutputStream() Called once by each child output stream. If the output stream is marked open, it will be marked closed and the if the connection and input stream are closed the disconnect method will be called. exception IOException if the subclass throws one oStreams--; closeCommon();
protected abstract void	connect(java.lang.String name, int mode, boolean timeouts) Connect to a target. param name URL for the connection, without the protocol part param mode I/O access mode, see {@link Connector} param timeouts flag to indicate that the called wants timeout exceptions exception IllegalArgumentException If a parameter is invalid. exception ConnectionNotFoundException If the connection cannot be found. exception IOException If some other kind of I/O error occurs.
protected abstract void	disconnect() Free up the connection resources. exception IOException if an I/O error occurs.
protected void	ensureOpen() Check if the connection is open. exception IOException is thrown, if the stream is not open. if (!connectionOpen) { throw new IOException("Connection closed"); }
protected void	flush() Forces any buffered output bytes to be written out. The general contract of flush is that calling it is an indication that, if any bytes previously written that have been buffered by the connection, should immediately be written to their intended destination. The flush method of ConnectionBaseAdapter does nothing. exception IOException if an I/O error occurs.
public java.io.DataInputStream	openDataInputStream() Open and return a data input stream for a connection. return An input stream exception IOException If an I/O error occurs return new DataInputStream(openInputStream());
public java.io.DataOutputStream	openDataOutputStream() Open and return a data output stream for a connection. return An input stream exception IOException If an I/O error occurs return new DataOutputStream(openOutputStream());
public java.io.InputStream	openInputStream() Returns an input stream. return an input stream for writing bytes to this port. exception IOException if an I/O error occurs when creating the output stream. InputStream i; ensureOpen(); if (maxIStreams == 0) { throw new IOException("no more input streams available"); } i = new BaseInputStream(this); maxIStreams--; iStreams++; return i;
public java.io.OutputStream	openOutputStream() Returns an output stream. return an output stream for writing bytes to this port. exception IOException if an I/O error occurs when creating the output stream. OutputStream o; ensureOpen(); if (maxOStreams == 0) { throw new IOException("no more output streams available"); } o = new BaseOutputStream(this); maxOStreams--; oStreams++; return o;
public Connection	openPrim(java.lang.String name, int mode, boolean timeouts) Check for required permission and open a connection to a target. param name URL for the connection, without the without the protocol part param mode I/O access mode, see {@link Connector} param timeouts flag to indicate that the caller wants timeout exceptions return this Connection object exception IllegalArgumentException If a parameter is invalid. exception ConnectionNotFoundException If the connection cannot be found. exception IOException If some other kind of I/O error occurs. checkForPermission(name); switch (mode) { case Connector.READ: case Connector.WRITE: case Connector.READ_WRITE: break; default: throw new IllegalArgumentException("Illegal mode"); } connect(name, mode, timeouts); connectionOpen = true; return this;
public Connection	openPrim(SecurityToken token, java.lang.String name, int mode, boolean timeouts) Check for the required permission and open a connection to a target. This method can be used with permissions greater than the current MIDlet suite. param token security token of the calling class param name URL for the connection, without the without the protocol part param mode I/O access mode, see {@link Connector} param timeouts flag to indicate that the caller wants timeout exceptions return this Connection object exception IllegalArgumentException If a parameter is invalid. exception ConnectionNotFoundException If the connection cannot be found. exception IOException If some other kind of I/O error occurs. if (requiredPermission != -1) { token.checkIfPermissionAllowed(requiredPermission); } permissionChecked = true; return openPrim(name, mode, timeouts);
public Connection	openPrim(SecurityToken token, java.lang.String name) Check for required permission and open a connection to a target. This method can be used with permissions greater than the current MIDlet suite. Assume read/write and no timeouts. param token security token of the calling class param name URL for the connection, without the without the protocol part return this Connection object exception IllegalArgumentException If a parameter is invalid. exception ConnectionNotFoundException If the connection cannot be found. exception IOException If some other kind of I/O error occurs. return openPrim(token, name, Connector.READ_WRITE, false);
protected abstract int	readBytes(byte[] b, int off, int len) Reads up to len bytes of data from the input stream into an array of bytes, blocks until at least one byte is available. param b the buffer into which the data is read. param off the start offset in array b at which the data is written. param len the maximum number of bytes to read. return the total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached. exception IOException if an I/O error occurs.
protected void	verifyPermissionCheck() Lets a subclass know that the security check was done. Called by the connect method of subclasses that require permission. This method is needed since the security check must be put off until connection since the name of the resource must be presented to the user in the permission question. An attacker could directly construct a in a subclass of the protocol and then call its connect method. A subclass can detect this attack by calling this method. exception SecurityException if the check did not happen. if (permissionChecked) { return; } throw new SecurityException("The permission check was bypassed");
protected abstract int	writeBytes(byte[] b, int off, int len) Writes len bytes from the specified byte array starting at offset off to this output stream. Polling the native code is done here to allow for simple asynchronous native code to be written. Not all implementations work this way (they block in the native code) but the same Java code works for both. param b the data. param off the start offset in the data. param len the number of bytes to write. return number of bytes written exception IOException if an I/O error occurs. In particular, an IOException is thrown if the output stream is closed.