Java Glossary
Last updated by Roedy Green
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T
- T-Bone
- Allows you to connect JavaBeans across multiple hosts. See Lotus
Infobus.
- T1
- an expensive dedicated phone line that can transmit 1,554,000
bits per second. In contrast an ADSL line that also runs over a
copper pair is about 500,000 bits per second. An ordinary V.90
modem is 56,000 bits per second.
- T3
- an very expensive dedicated phone line that can transmit 45,000,000
bits per second.
- tabbed dialog
- A dialog with tabs the user to bring up cards to view. The closest the
Java AWT has to this function is the CardLayout method.
- TCP/IP
- Transmission Control
Protocol/Internet Protocol. The protocol
that Internet uses to transfer packets. It allows interleaving
many streams of information on the same connection. It can also
be used as a LAN protocol. Other special-purpose Internet
protocols are piggybacked on top of it. TCP/IP in turn is
piggybacked on top of IP. See UDP, IP, IPv6, datagram, DHCP.
- Tea Set
- ISofts commercial set of about 25 JavaBeans including Grid, Tabbed
Folder, Graph, multi column list, text edit controls, buttons, Form, ComboBox,
and Slider.
- TELNET
- The Internet protocol to log in to a remote computer indirectly through
a chain of telecommunications links. The net effect is as if your computer
were a character based terminal directly attached to the remote computer.
You often log in with the id of "guest" or "anonymous", which
will give you low privilege.
- Tempest
- a commercial product for handling distributed objects.
- template
- See genericity
- template method
- See design patterns.
- temporary files
- Unlike C, Java does not have methods for generating unique temporary
filenames. I have written a getTempFile method. View
Source.
- Tengah
- WebLogic's replacement for RMI. See RMI.
- ter
- similar to "bis". Means new, improved and revised.
- text
- the text inside a component, e.g. the label on a button, the text in
a textarea or textfield. See also label.
- TextArea
- multiline display of text on the screen. Sometimes you permit the user
to edit it. See also TextField.
- textbox
- Textboxes in Javanese are referred to as TextAreas for multiline and
TextFields for single line.
- TextComponent
- generic term for either a TextArea or a TextField.
- TextEdit
- A text editor written in Java.
- Source code included.
- Allows JavaBeans to be plugged into the editor.
- Supports large (megabyte) text files.
- User selectable font and tab size.
- Supports copy/paste and find/replace.
- Supports unlimited undo/redo.
- Bypasses TextArea and uses a custom TextCanvas.
- TextField
- single line display of text on the screen. Sometimes you permit the
user to edit it. See also TextArea.
- this
- For any instance method, there is a hidden first parameter, a pointer
to the object automatically generated by the Java compiler. You can refer
to this parameter by the word "this" inside your class. However,
if you mention instance variables without any associated pointer, "this"
is automatically assumed. "this" is most useful in little accessor
functions where you have a parameter with the same name as an instance
variable. this.x refers to the instance variable. Plain x refers to the
parameter.
- thread
- Even trivial Java apps are designed to run on multi-cpu
machines with execution streams running in parallel. Each stream
is called a thread. Each thread, by default, gets one
megabyte of virtual RAM reserved for it, just in case it
wants to grow. So 2000 threads would require 2 gig of virtual
RAM, -- which all by itself would fill the largest possible
32-bit virtual RAM space in a Wintel machine. You can configure
this the stack space per thread on the java.exe command line. See
Java.exe, CSP, CJT, synchronized.
- three tier
- A true three tier database access means you have application code running
in both the client and the server. The client and server application code
exchange transactions. The application code running on the server accesses
the SQL database. dbAnywhere is a quasi-three tier database access. It
runs on a server and allows clients to speak the JDBC dialect of SQL and
translates the requests into native SQL dialects and hands them off to
the SQL server. There is no application specific code on the server. see
dbAnywhere, WebLogic.
- Timezone
- The names for timezones used in Java comes from a list maintained at
NIH by Arthur David Olson. For reasons only he understands, Pacific
Standard Time is called America/Los_Angeles. See Wassup.
- tip of the iceberg
- A class that depends on (uses) all the other classes. So before
this class can be considered up-to-date, all its dependencies must be
recompiled too (potentially), causing a cascade of compilation. It
is the visible tip of the compilation iceberg.
- TLA
- Three Letter Acronym.
- TLD
- The most common domains end in .com which means
commercial. This suffix is called the TLD (Top
Level Domain). Other common ones are .org
organisation, .edu educational institution,
.gov government, .net network, and
.mil military. See domain name.
- TLIB
- Burton Systems Software's second generation version control system.
See PVCS.
- TLS
- Transport Layer Security protocol used
communicate over an encrypted connection, and to authenticate none, one or
both of the participants. It is the successor to SSL. The actual strength
(number of bits is the key) of the encryption is decided by the site
itself not by the browser as in SSL. See HTTPS. See SSL, HTTPS.
- Together/J
- A tool to design and edit, keeping the source tidy. see beautifier.
- token
- When you break a string up into "words", each chunk is called
a token. In parsing source Java code a token would be a name, keyword or
an operator. java.util.StringTokenizer lets you define your own simple rules
for what counts as a new token. For more advanced tokenising you need a
tool like LEX.
- toolkit
- Interface to the native mode GUI. Methods for finding out details of
the particular machine your program is running on.
- TowerJ
- A heavy duty optimising compiler for Java. It starts with
class files and produces native code.
- transparent
- a communications channel that can send any arbitrary message through unmolested.
It reserves no characters or bit patterns for its own control uses. The
channel may still have control facilities. It would just implement them
such that they could never be confused with message traffic. For example
control information might only be inserted in a wrapper around each little
packet of data transmitted.
- transparent backgrounds
- Java applets are not capable of making their backgrounds
transparent. The closest you can come to this ideal is painting the
background the same colour or the same pattern as the browser background.
This of course does not arrange for the seams to align.
- Transvirtual
- The makers of the Kaffe clean room JVM that runs on a variety of
processors including embedded environments. The principles are Peter C.
Mehlitz, famous for his work developing a faster alternative to the AWT
the BISS-AWT, and Tim Wilkinson creator of Kaffe. I met them both at the
Colorado conference. They are both brilliant men.
- trellis
- When two V.32 bis modems talk to each other at 14,400 BPS they make 128
different possible sounds to each other. The sounds are various combinations
of phase shifts, and amplitude (loudness) levels of the basic carrier tone.
The modem changes the sound 2400 times a second (hence 2400 baud). You
could imagine a diagram of the possible sounds arrayed like a lattice or
trellis of intersections of phase and amplitude.
- trigger
- In the JDK 1.1, a component triggers other objects to
react by informing its registered listeners that an event
occured. In SQL, you can write procedures that are
automatically invoked before or after a given row is
updated, inserted or deleted. See fire, event
- T Spaces
- IBM's answer to Jini for connecting together embedded Java systems.
- tuples
- a language feature of Sather that Java does not have. Java functions
can return only a single value. However, Java methods may return an object
that has more than one field.
- Tutorials
- Here are a set of tutorials you can use to learn Java and the various
standard library classes. Make sure you have the
essential documentation too.
- Two's Complement Arithmetic
- Java internally uses (or emulates) two's complement arithmetic.
Positive numbers are stored in binary. That means that for example
the number 13 would be written 0x0d = 00001101 = 1*8 + 1*4 + 0*2 +
1*1. The high order bit is called the sign bit. For signed
quantities such as byte, short int and long, when that high order bit
is a 1, we consider the number negative. To represent a negative
number we first invert each bit, then add 1. We would write -13 this
way: 0x0d -> 00001101 -> 11110010 -> 11110011 -> 0xf3. Whenever you
do any operation on a byte, it is first sign extended to an int. So
so 13 -> 0x0d -> 00001101 -> 00000000000000000000000000001101 ->
0x0000000d and -13 -> 0xf3 -> 11110010 ->
11111111111111111111111111110010 -> 0xfffffff3. When you do arithmetic
the results can be too big to represent. The arithmetic is done modulo
2 to the 32nd power, which is a fancy way of saying the high order bits
of the result are discarded. The overflow may turn on
the high order bit, making the result look negative.
- type
- When you declare a variable you specify its type, e.g. int, char, Dog,
Dalmatian. This information lets the compiler generate the appropriate
specific machine code. E.g. + for strings means concatenation, where it
means addition for ints.