Java tutorial
/* * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package it.wingstech.csslesser; import java.io.BufferedWriter; import java.io.File; import java.io.FileWriter; import java.io.IOException; import java.io.InputStreamReader; import java.net.URL; import java.util.ArrayList; import java.util.List; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.mozilla.javascript.Context; import org.mozilla.javascript.Function; import org.mozilla.javascript.JavaScriptException; import org.mozilla.javascript.NativeArray; import org.mozilla.javascript.Scriptable; import org.mozilla.javascript.ScriptableObject; import org.mozilla.javascript.tools.shell.Global; /** * @author Rostislav Hristov * @author Uriah Carpenter */ public class LessEngine { private final Log logger = LogFactory.getLog(getClass()); private Scriptable scope; private Function cs; private Function cf; public LessEngine() { try { logger.debug("Initializing LESS Engine."); URL browser = getClass().getClassLoader().getResource("META-INF/browser.js"); URL less = getClass().getClassLoader().getResource("META-INF/less-1.1.4.js"); URL engine = getClass().getClassLoader().getResource("META-INF/engine.js"); Context cx = Context.enter(); logger.warn("Using implementation version: " + cx.getImplementationVersion()); cx.setOptimizationLevel(9); Global global = new Global(); global.init(cx); scope = cx.initStandardObjects(global); cx.evaluateReader(scope, new InputStreamReader(browser.openConnection().getInputStream()), browser.getFile(), 1, null); cx.evaluateReader(scope, new InputStreamReader(less.openConnection().getInputStream()), less.getFile(), 1, null); cx.evaluateReader(scope, new InputStreamReader(engine.openConnection().getInputStream()), engine.getFile(), 1, null); cs = (Function) scope.get("compileString", scope); cf = (Function) scope.get("compileFile", scope); Context.exit(); } catch (Exception e) { logger.error("LESS Engine intialization failed.", e); } } public String compile(String input) throws LessException { try { long time = System.currentTimeMillis(); String result = call(cs, new Object[] { input }); logger.debug("The compilation of '" + input + "' took " + (System.currentTimeMillis() - time) + " ms."); return result; } catch (Exception e) { throw parseLessException(e); } } public String compile(URL input) throws LessException { try { long time = System.currentTimeMillis(); logger.debug("Compiling URL: " + input.getProtocol() + ":" + input.getFile()); String result = call(cf, new Object[] { input.getProtocol() + ":" + input.getFile(), getClass().getClassLoader() }); logger.debug("The compilation of '" + input + "' took " + (System.currentTimeMillis() - time) + " ms."); return result; } catch (Exception e) { throw parseLessException(e); } } public String compile(File input) throws LessException { try { long time = System.currentTimeMillis(); logger.debug("Compiling File: " + "file:" + input.getAbsolutePath()); String result = call(cf, new Object[] { "file:" + input.getAbsolutePath(), getClass().getClassLoader() }); logger.debug("The compilation of '" + input + "' took " + (System.currentTimeMillis() - time) + " ms."); return result; } catch (Exception e) { throw parseLessException(e); } } public void compile(File input, File output) throws LessException, IOException { try { String content = compile(input); if (!output.exists()) { output.createNewFile(); } BufferedWriter bw = new BufferedWriter(new FileWriter(output)); bw.write(content); bw.close(); } catch (Exception e) { throw parseLessException(e); } } private synchronized String call(Function fn, Object[] args) { return (String) Context.call(null, fn, scope, scope, args); } private LessException parseLessException(Exception root) throws LessException { logger.debug("Parsing LESS Exception", root); if (root instanceof JavaScriptException) { Scriptable value = (Scriptable) ((JavaScriptException) root).getValue(); boolean hasName = ScriptableObject.hasProperty(value, "name"); boolean hasType = ScriptableObject.hasProperty(value, "type"); if (hasName || hasType) { String errorType = "Error"; if (hasName) { String type = (String) ScriptableObject.getProperty(value, "name"); if ("ParseError".equals(type)) { errorType = "Parse Error"; } else { errorType = type + " Error"; } } else if (hasType) { Object prop = ScriptableObject.getProperty(value, "type"); if (prop instanceof String) { errorType = (String) prop + " Error"; } } String message = (String) ScriptableObject.getProperty(value, "message"); String filename = ""; if (ScriptableObject.hasProperty(value, "filename")) { filename = (String) ScriptableObject.getProperty(value, "filename"); } int line = -1; if (ScriptableObject.hasProperty(value, "line")) { line = ((Double) ScriptableObject.getProperty(value, "line")).intValue(); } int column = -1; if (ScriptableObject.hasProperty(value, "column")) { column = ((Double) ScriptableObject.getProperty(value, "column")).intValue(); } List<String> extractList = new ArrayList<String>(); if (ScriptableObject.hasProperty(value, "extract")) { NativeArray extract = (NativeArray) ScriptableObject.getProperty(value, "extract"); for (int i = 0; i < extract.getLength(); i++) { if (extract.get(i, extract) instanceof String) { extractList.add(((String) extract.get(i, extract)).replace("\t", " ")); } } } throw new LessException(message, errorType, filename, line, column, extractList); } } throw new LessException(root); } }