Java tutorial
/* * (C) Copyright 2014, IBM Corporation * * 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 com.ibm.jaggr.core.impl.modulebuilder.less; import com.ibm.jaggr.core.IAggregator; import com.ibm.jaggr.core.NotFoundException; import com.ibm.jaggr.core.impl.modulebuilder.css.CSSModuleBuilder; import com.ibm.jaggr.core.resource.IResource; import org.apache.commons.io.IOUtils; import org.mozilla.javascript.Context; import org.mozilla.javascript.Function; import org.mozilla.javascript.JavaScriptException; import org.mozilla.javascript.Script; import org.mozilla.javascript.Scriptable; import java.io.IOException; import java.io.InputStream; import java.util.concurrent.TimeUnit; import java.util.concurrent.TimeoutException; import java.util.logging.Level; import java.util.logging.Logger; import java.util.regex.Pattern; /** * This class compiles LESS resources that are loaded by the AMD aggregator. */ public class LessModuleBuilder extends CSSModuleBuilder { static final String sourceClass = LessModuleBuilder.class.getName(); static final Logger log = Logger.getLogger(sourceClass); private static final String LESS_JS_RES = "less-rhino-1.7.0.js"; //$NON-NLS-1$ private static final String LESS_COMPILER_VAR = "lessCompiler"; //$NON-NLS-1$ private static final Pattern HANDLES_PATTERN = Pattern.compile("\\.(css)|(less)$"); //$NON-NLS-1$ private static final String compilerString = new StringBuffer().append("var ").append(LESS_COMPILER_VAR) //$NON-NLS-1$ .append(" = function(input, options) {") //$NON-NLS-1$ .append(" var result;") //$NON-NLS-1$ .append(" new less.Parser(options).parse(input, function (e, root) {") //$NON-NLS-1$ .append(" if (e) {throw e;}") //$NON-NLS-1$ .append(" result = root.toCSS(options);") //$NON-NLS-1$ .append(" });") //$NON-NLS-1$ .append(" return result;") //$NON-NLS-1$ .append("}") //$NON-NLS-1$ .toString(); Script lessJsScript = null; Script compilerScript = null; public LessModuleBuilder() { super(); init(); } // for unit tests protected LessModuleBuilder(IAggregator aggregator) { super(aggregator); init(); } protected void init() { final String sourceMethod = "init"; //$NON-NLS-1$ final boolean isTraceLogging = log.isLoggable(Level.FINER); if (isTraceLogging) { log.entering(sourceClass, sourceMethod); } Context cx = Context.enter(); try { cx.setOptimizationLevel(9); InputStream in = CSSModuleBuilder.class.getClassLoader().getResourceAsStream(LESS_JS_RES); if (in == null) { throw new NotFoundException(LESS_JS_RES); } String lessJsSource = IOUtils.toString(in); lessJsScript = cx.compileString(lessJsSource, LESS_JS_RES, 1, null); compilerScript = cx.compileString(compilerString, BLANK, 1, null); } catch (IOException e) { throw new RuntimeException(e); } finally { Context.exit(); } if (isTraceLogging) { log.exiting(sourceMethod, sourceMethod); } } /* (non-Javadoc) * @see com.ibm.jaggr.core.impl.modulebuilder.css.CSSModuleBuilder#createThreadScope(org.mozilla.javascript.Context, org.mozilla.javascript.Scriptable) */ @Override public Scriptable createThreadScope(Context cx, Scriptable protoScope) { final String sourceMethod = "createThreadScope"; //$NON-NLS-1$ final boolean isTraceLogging = log.isLoggable(Level.FINER); if (isTraceLogging) { log.entering(sourceClass, sourceMethod, new Object[] { cx, protoScope }); } Scriptable threadScope = super.createThreadScope(cx, protoScope); lessJsScript.exec(cx, threadScope); compilerScript.exec(cx, threadScope); if (isTraceLogging) { log.exiting(sourceMethod, sourceMethod, threadScope); } return threadScope; } /* (non-Javadoc) * @see com.ibm.jaggr.core.impl.modulebuilder.css.CSSModuleBuilder#postcss(java.lang.String, com.ibm.jaggr.core.resource.IResource) */ @Override protected String postcss(String css, IResource resource) throws IOException { final String sourceMethod = "postcss"; //$NON-NLS-1$ final boolean isTraceLogging = log.isLoggable(Level.FINER); if (isTraceLogging) { log.entering(sourceClass, sourceMethod, new Object[] { css, resource }); } if (resource.getURI().getPath().endsWith(".less")) { //$NON-NLS-1$ css = processLess(resource.getURI().toString(), css); } css = super.postcss(css, resource); if (isTraceLogging) { log.exiting(sourceMethod, sourceMethod, css); } return css; } protected String processLess(String filename, String css) throws IOException { final String sourceMethod = "processLess"; //$NON-NLS-1$ final boolean isTraceLogging = log.isLoggable(Level.FINER); if (isTraceLogging) { log.entering(sourceClass, sourceMethod, new Object[] { filename, css }); } Context cx = Context.enter(); Scriptable threadScope = null; try { threadScope = getThreadScopes().poll(SCOPE_POOL_TIMEOUT_SECONDS, TimeUnit.SECONDS); if (threadScope == null) { throw new TimeoutException("Timeout waiting for thread scope"); //$NON-NLS-1$ } Scriptable scope = cx.newObject(threadScope); scope.setParentScope(threadScope); Scriptable options = cx.newObject(threadScope); options.put("filename", options, filename); //$NON-NLS-1$ Function compiler = (Function) threadScope.get(LESS_COMPILER_VAR, threadScope); css = compiler.call(cx, scope, null, new Object[] { css, options }).toString(); } catch (JavaScriptException e) { // Add module info String message = "Error parsing " + filename + "\r\n" + e.getMessage(); //$NON-NLS-1$ //$NON-NLS-2$ throw new IOException(message, e); } catch (InterruptedException e) { throw new IOException(e); } catch (TimeoutException e) { throw new RuntimeException(e); } finally { if (threadScope != null) { getThreadScopes().add(threadScope); } Context.exit(); } if (isTraceLogging) { log.exiting(sourceMethod, sourceMethod, css); } return css; } /* * (non-Javadoc) * * @see com.ibm.jaggr.service.modulebuilder.IModuleBuilder#handles(java.lang.String, com.ibm.jaggr.service.resource.IResource) */ @Override public boolean handles(String mid, IResource resource) { final String sourceMethod = "handles"; //$NON-NLS-1$ final boolean isTraceLogging = log.isLoggable(Level.FINER); if (isTraceLogging) { log.entering(sourceClass, sourceMethod, new Object[] { mid, resource }); } boolean result = HANDLES_PATTERN.matcher(mid).find(); if (isTraceLogging) { log.exiting(sourceMethod, sourceMethod, result); } return result; } }