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A Java library for splitting text into constituent words. This can be tricky for non-trivial examples, therefore the jTokenizer package was designed to combine a set of tokenizers that range from basic whitespace tokenizers to more complex ones that deal intuitively with natural language. http://www.andy-roberts.net/coding/jt…
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jTokenizer - v.2.0 - README Andrew Roberts (16-Jul-2006) http://www.andy-roberts.net/coding/jtokenizer/ Overview ======== Tokenizing strings into its constituent words/tokens can prove tricky for non-trivial examples. In particular, when dealing with natural language, you must take into consideration punctuation too in order to isolate the words. The jTokenizer package was designed to combine a set of tokenizers that range from basic whitespace tokenizers to more complex ones that deal intuitively with natural language. Each of the tokenizers adopt a similar structure to java.util.StringTokenizer in terms of how to instantiate the classes and extract the tokens. This means they are simple to use. What's new in 2.0? ==================== * A new GUI front-end to the jTokenizer library. You can type in, copy and paste, or even load a text file into the application. You must select your tokenizer of choice (and any options of interest) and then hit the Tokenize button. Your results will be displayed as soon as they are processed and you have the option to save the results to file, if you choose. The GUI is particularly useful for experimenting with tokenization methods in a teaching environment (such as an NLP course). It will also be of interest to those wishing to use the jTokenizer library but don't have the Java programming experience to utilise the code directly. NB There have been no changes to the core tokenizer libraries and the API remain fully compatible with prior versions. Features ======== jTokenizer comprises of six tokenizers that all extend from an abstract Tokenizer class: * WhiteSpaceTokenizer - this splits a string on all occurrences of whitespace, which include spaces, newlines, tabs and linefeeds. * StringTokenizer - this is basically the same as java.util.StringTokenizer with some extra methods (and extends from Tokenizer). Its default behaviour is to act as a WhiteSpaceTokenizer, however, you can specify a set of characters that are to be used to indicate word delimiters. * RegexTokenizer - this tokenizer is much more flexible as you can use regular expressions to define a what a token is. So, "\\w+" means whenever it matches one or more letters, it will consider that a word. By default, it uses a regular expression equivalent to a whitespace tokenizer. * RegexSeparatorTokenizer - this can be thought of as an advanced StringTokenizer. Whereas StringTokenizer is limited to defining delimiters as a set of individual characters, RegexSeparatorTokenizer can utilise regular expressions for a richer and more flexible approach. * BreakIteratorTokenizer - the most sophisticated of the four, although should only be used on natural language strings to isolate words. It also comes with built-in rules about how to find words, knowing how to disregard punctuation, etc. * SentenceTokenizer - this also uses a BreakIterater like the above, but tuned towards finding sentence boundaries. The "tokens" in this tokenizer are in fact individual sentences. Installation ============ The jTokenizer package doesn't need installing as such. You simply have to download it to your computer, and then make sure that the Java compiler and virtual machine can "find" it. To uncompress the file, there are many utilities. On Windows, a popular utility is WinZip. On most platforms, there are command-line tools, such as 'unzip' that can also be used. It contains the following: ./README.txt ./jTokenizer-2.0.jar ./lib/swing-layout-1.0.jar (additional library required for the GUI if Java version is less than v6.0) Important note: In order to use jTokenizer, you need to have the Java Runtime Environment installed. It requires Java 5.0 or above. To obtain Java (or update to the latest version) goto http://www.java.com and it will automatically detect the version that you need to download and install. Running the jTokenizer GUI ========================== On Windows: When you install the Java Runtime, it normally associates .jar files with a jar-runner program. Therefore, just double-clicking the jTokenizer-2.0.jar file and the GUI should load promptly. On all platforms: At the command-line. change to the directory with the jar file and type: java -jar jTokenizer-2.0.jar Using the jTokenizer library in your programs ============================================= The package is bundled together a JAR file, with is a Java archive containing all the classes. JAR is actually compressed using the well known zip algorithms. The advantage of using JARs are that you can keep lots of related classes together in a single file, rather than having to uncompress them. All Java needs to know is where the JAR file is, and there are a couple of ways of achieving this. Imagine you have a class that uses a tokenizer from this package called ClassThatTokenizes.java. To compile and run: 1. Specifying at the command-line javac -classpath /path/to/jTokenizer-2.0.jar ClassThatTokenizes.java java -classpath /path/to/jTokenizer-2.0.jar ClassThatTokenizes NB in Windows, the path would be more like c:\path\to\jTokenizer-2.0.jar 2. Setting the CLASSPATH environment variable. In Linux: export CLASSPATH=$CLASSPATH:/path/to/jTokenizer-2.0.jar (for bash) setenv CLASSPATH $CLASSPATH:/path/to/jTokenizer-2.0.jar (for csh) javac ClassThatTokenizes.java java ClassThatTokenizes In Windows: set CLASSPATH=%CLASSPATH%;c:\path\to\jTokenizer-2.0.jar NB you can set the CLASSPATH via Control Panel/System/Advanced/Environment Variables