org.apache.regexp: public class: recompile

org.apache.regexp
public class: recompile [javadoc | source]

java.lang.Object
   org.apache.regexp.recompile

'recompile' is a command line tool that pre-compiles one or more regular expressions for use with the regular expression matcher class 'RE'. For example, the command java org.apache.regexp.recompile re1 "a*b" produces output like this:


// Pre-compiled regular expression 'a*b'
private static final char[] re1Instructions =
{
0x002a, 0x0000, 0x0007, 0x0041, 0x0001, 0xfffd, 0x0061,
0x0041, 0x0001, 0x0004, 0x0062, 0x0045, 0x0000, 0x0000,
};

private static final REProgram re1 = new REProgram(re1Instructions);

By pasting this output into your code, you can construct a regular expression matcher (RE) object directly from the pre-compiled data (the character array re1), thus avoiding the overhead of compiling the expression at runtime. For example:


RE r = new RE(re1);

Also see:

RECompiler

author: < - a href="mailto:jonl@muppetlabs.com">Jonathan Locke

version: $ - Id: recompile.java 518156 2007-03-14 14:31:26Z vgritsenko $

Method from org.apache.regexp.recompile Summary:
main

Methods from java.lang.Object:
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method from org.apache.regexp.recompile Detail:
public static void main(String[] arg) { // Create a compiler object RECompiler r = new RECompiler(); // Print usage if arguments are incorrect if (arg.length < = 0 \|\| arg.length % 2 != 0) { System.out.println("Usage: recompile < patternname > < pattern >"); System.exit(0); } // Loop through arguments, compiling each for (int i = 0; i < arg.length; i += 2) { try { // Compile regular expression String name = arg[i]; String pattern = arg[i+1]; String instructions = name + "Instructions"; // Output program as a nice, formatted character array System.out.print("\n // Pre-compiled regular expression '" + pattern + "'\n" + " private static final char[] " + instructions + " = \n {"); // Compile program for pattern REProgram program = r.compile(pattern); // Number of columns in output int numColumns = 7; // Loop through program char[] p = program.getInstructions(); for (int j = 0; j < p.length; j++) { // End of column? if ((j % numColumns) == 0) { System.out.print("\n "); } // Print character as padded hex number String hex = Integer.toHexString(p[j]); while (hex.length() < 4) { hex = "0" + hex; } System.out.print("0x" + hex + ", "); } // End of program block System.out.println("\n };"); System.out.println("\n private static final REProgram " + name + " = new REProgram(" + instructions + ");"); } catch (RESyntaxException e) { System.out.println("Syntax error in expression \"" + arg[i] + "\": " + e.toString()); } catch (Exception e) { System.out.println("Unexpected exception: " + e.toString()); } catch (Error e) { System.out.println("Internal error: " + e.toString()); } } } Main application entrypoint.

Method from org.apache.regexp.recompile Detail:

 public static  void main(String[] arg) {
        // Create a compiler object
        RECompiler r = new RECompiler();
        // Print usage if arguments are incorrect
        if (arg.length < = 0 || arg.length % 2 != 0)
        {
            System.out.println("Usage: recompile < patternname > < pattern >");
            System.exit(0);
        }
        // Loop through arguments, compiling each
        for (int i = 0; i <  arg.length; i += 2)
        {
            try
            {
                // Compile regular expression
                String name         = arg[i];
                String pattern      = arg[i+1];
                String instructions = name + "Instructions";
                // Output program as a nice, formatted character array
                System.out.print("\n    // Pre-compiled regular expression '" + pattern + "'\n"
                                 + "    private static final char[] " + instructions + " = \n    {");
                // Compile program for pattern
                REProgram program = r.compile(pattern);
                // Number of columns in output
                int numColumns = 7;
                // Loop through program
                char[] p = program.getInstructions();
                for (int j = 0; j <  p.length; j++)
                {
                    // End of column?
                    if ((j % numColumns) == 0)
                    {
                        System.out.print("\n        ");
                    }
                    // Print character as padded hex number
                    String hex = Integer.toHexString(p[j]);
                    while (hex.length() <  4)
                    {
                        hex = "0" + hex;
                    }
                    System.out.print("0x" + hex + ", ");
                }
                // End of program block
                System.out.println("\n    };");
                System.out.println("\n    private static final REProgram " + name + " = new REProgram(" + instructions + ");");
            }
            catch (RESyntaxException e)
            {
                System.out.println("Syntax error in expression \"" + arg[i] + "\": " + e.toString());
            }
            catch (Exception e)
            {
                System.out.println("Unexpected exception: " + e.toString());
            }
            catch (Error e)
            {
                System.out.println("Internal error: " + e.toString());
            }
        }
}

Main application entrypoint.