Java tutorial
/* * * JSMin.java 2006-02-13 * * Updated 2007-08-20 with updates from jsmin.c (2007-05-22) * * Copyright (c) 2006 John Reilly (www.inconspicuous.org) * * This work is a translation from C to Java of jsmin.c published by * Douglas Crockford. Permission is hereby granted to use the Java * version under the same conditions as the jsmin.c on which it is * based. * * * * * jsmin.c 2003-04-21 * * Copyright (c) 2002 Douglas Crockford (www.crockford.com) * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * The Software shall be used for Good, not Evil. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. */ package org.nuxeo.theme.html; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.io.PushbackInputStream; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.nuxeo.common.xmap.XAnnotatedList; public class JSMin { private static final Log log = LogFactory.getLog(XAnnotatedList.class); private static final int EOF = -1; private PushbackInputStream in; private OutputStream out; private int theA; private int theB; public JSMin(InputStream in, OutputStream out) { this.in = new PushbackInputStream(in); this.out = out; } /** * isAlphanum -- return true if the character is a letter, digit, * underscore, dollar sign, or non-ASCII character. */ static boolean isAlphanum(int c) { return ((c >= 'a' && c <= 'z') || (c >= '0' && c <= '9') || (c >= 'A' && c <= 'Z') || c == '_' || c == '$' || c == '\\' || c > 126); } /** * get -- return the next character from stdin. Watch out for lookahead. If * the character is a control character, translate it to a space or * linefeed. */ int get() throws IOException { int c = in.read(); if (c >= ' ' || c == '\n' || c == EOF) { return c; } if (c == '\r') { return '\n'; } return ' '; } /** * Get the next character without getting it. */ int peek() throws IOException { int lookaheadChar = in.read(); in.unread(lookaheadChar); return lookaheadChar; } /** * next -- get the next character, excluding comments. peek() is used to see * if a '/' is followed by a '/' or '*'. */ int next() throws IOException, UnterminatedCommentException { int c = get(); if (c == '/') { switch (peek()) { case '/': for (;;) { c = get(); if (c <= '\n') { return c; } } case '*': get(); for (;;) { switch (get()) { case '*': if (peek() == '/') { get(); return ' '; } break; case EOF: throw new UnterminatedCommentException(); } } default: return c; } } return c; } /** * action -- do something! What you do is determined by the argument: 1 * Output A. Copy B to A. Get the next B. 2 Copy B to A. Get the next B. * (Delete A). 3 Get the next B. (Delete B). action treats a string as a * single character. Wow! action recognizes a regular expression if it is * preceded by ( or , or =. */ void action(int d) throws IOException, UnterminatedRegExpLiteralException, UnterminatedCommentException, UnterminatedStringLiteralException { switch (d) { case 1: out.write(theA); case 2: theA = theB; if (theA == '\'' || theA == '"') { for (;;) { out.write(theA); theA = get(); if (theA == theB) { break; } if (theA <= '\n') { throw new UnterminatedStringLiteralException(); } if (theA == '\\') { out.write(theA); theA = get(); } } } case 3: theB = next(); if (theB == '/' && (theA == '(' || theA == ',' || theA == '=' || theA == ':' || theA == '[' || theA == '!' || theA == '&' || theA == '|' || theA == '?' || theA == '{' || theA == '}' || theA == ';' || theA == '\n')) { out.write(theA); out.write(theB); for (;;) { theA = get(); if (theA == '/') { break; } else if (theA == '\\') { out.write(theA); theA = get(); } else if (theA <= '\n') { throw new UnterminatedRegExpLiteralException(); } out.write(theA); } theB = next(); } } } /** * jsmin -- Copy the input to the output, deleting the characters which are * insignificant to JavaScript. Comments will be removed. Tabs will be * replaced with spaces. Carriage returns will be replaced with linefeeds. * Most spaces and linefeeds will be removed. */ public void jsmin() throws IOException, UnterminatedRegExpLiteralException, UnterminatedCommentException, UnterminatedStringLiteralException { theA = '\n'; action(3); while (theA != EOF) { switch (theA) { case ' ': if (isAlphanum(theB)) { action(1); } else { action(2); } break; case '\n': switch (theB) { case '{': case '[': case '(': case '+': case '-': action(1); break; case ' ': action(3); break; default: if (isAlphanum(theB)) { action(1); } else { action(2); } } break; default: switch (theB) { case ' ': if (isAlphanum(theA)) { action(1); break; } action(3); break; case '\n': switch (theA) { case '}': case ']': case ')': case '+': case '-': case '"': case '\'': action(1); break; default: if (isAlphanum(theA)) { action(1); } else { action(3); } } break; default: action(1); break; } } } out.flush(); } class UnterminatedCommentException extends Exception { } class UnterminatedStringLiteralException extends Exception { } class UnterminatedRegExpLiteralException extends Exception { } public static void main(String arg[]) { try { JSMin jsmin = new JSMin(new FileInputStream(arg[0]), System.out); jsmin.jsmin(); } catch (FileNotFoundException e) { log.error(e, e); } catch (ArrayIndexOutOfBoundsException e) { log.error(e, e); } catch (IOException e) { log.error(e, e); } catch (UnterminatedRegExpLiteralException e) { log.error(e, e); } catch (UnterminatedCommentException e) { log.error(e, e); } catch (UnterminatedStringLiteralException e) { log.error(e, e); } } }