Java Reference
In-Depth Information
The
millisToDecideToPopup
property represents the number of milliseconds that the
monitor waits before deciding if it needs to display the pop-up window. If the
progress
property
hasn't changed yet, the monitor waits for another increment of this time period before checking
again. When the
ProgressMonitor
checks and the
progress
property has changed, it estimates
whether the task will be completed in the number of milliseconds in the
millisToPopup
property.
If the
ProgressMonitor
thinks the monitored task will complete on time, the pop-up window is
never displayed. Otherwise, the pop-up will display after
millisToPopup
milliseconds have
passed from the time the task started.
■
Caution
Although technically possible, it isn't a good practice to move the
minimum
and
maximum
properties
after the pop-up has appeared. This could result in the progress bar increasing and decreasing in an erratic
manner. The same behavior happens if you move the progress setting in a nonlinear fashion.
Customizing a ProgressMonitor Look and Feel
Changing the look and feel of
ProgressMonitor
requires changing the appearance of both the
JProgressBar
and the
JLabel
, as well as the
JOptionPane
the
ProgressMonitor
uses.
The
ProgressMonitor
has one
UIResource
-related property:
•
ProgressMonitor.progressText
of type
String
ProgressMonitorInputStream Class
The
ProgressMonitorInputStream
class represents an input stream filter that uses a
ProgressMonitor
to check the progress of the reading of an input stream. If the reading is
taking too long to complete, a
ProgressMonitor
appears, and the user can select the Cancel
button in the pop-up window, causing the reading to be interrupted and the input stream to
throw an
InterruptedIOException
.
Creating a ProgressMonitorInputStream
Like other filtering streams, the
ProgressMonitorInputStream
is created with a reference
to the stream it needs to filter. Besides a reference to this filter, the single constructor for
ProgressMonitorInputStream
requires two arguments for its
ProgressMonitor
: a parent compo-
nent and a message. As seen here, the constructor takes the
ProgressMonitor
arguments first:
public ProgressMonitorInputStream(
Component parentComponent, Object message, InputStream inputStream)
As with the
JOptionPane
and
ProgressMonitor
, the message argument is an
Object
, not a
String
, so you can display an array of components or strings on multiple lines. The following
code creates one
ProgressMonitorInputStream
.
