| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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 org.apache.htrace.core; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| |
| import java.lang.reflect.Constructor; |
| import java.util.LinkedList; |
| import java.util.List; |
| |
| /** |
| * Builds a new Tracer object. |
| */ |
| public class TracerBuilder { |
| public final static String SPAN_RECEIVER_CLASSES_KEY = |
| "span.receiver.classes"; |
| public final static String SAMPLER_CLASSES_KEY = |
| "sampler.classes"; |
| |
| private static final Log LOG = LogFactory.getLog(TracerBuilder.class); |
| |
| private String name; |
| private HTraceConfiguration conf = HTraceConfiguration.EMPTY; |
| private ClassLoader classLoader = |
| TracerBuilder.class.getClassLoader(); |
| private TracerPool tracerPool = TracerPool.GLOBAL; |
| |
| public TracerBuilder() { |
| } |
| |
| public TracerBuilder name(String name) { |
| this.name = name; |
| return this; |
| } |
| |
| public TracerBuilder conf(HTraceConfiguration conf) { |
| this.conf = conf; |
| return this; |
| } |
| |
| public TracerBuilder tracerPool(TracerPool tracerPool) { |
| this.tracerPool = tracerPool; |
| return this; |
| } |
| |
| private void loadSamplers(List<Sampler> samplers) { |
| String classNamesStr = conf.get(SAMPLER_CLASSES_KEY, ""); |
| List<String> classNames = getClassNamesFromConf(classNamesStr); |
| StringBuilder bld = new StringBuilder(); |
| String prefix = ""; |
| for (String className : classNames) { |
| try { |
| Sampler sampler = new Sampler.Builder(conf). |
| className(className). |
| classLoader(classLoader). |
| build(); |
| samplers.add(sampler); |
| bld.append(prefix).append(className); |
| prefix = ", "; |
| } catch (Throwable e) { |
| LOG.error("Failed to create SpanReceiver of type " + className, e); |
| } |
| } |
| String resultString = bld.toString(); |
| if (resultString.isEmpty()) { |
| resultString = "no samplers"; |
| } |
| LOG.info(SAMPLER_CLASSES_KEY + " = " + classNamesStr + |
| "; loaded " + resultString); |
| } |
| |
| private void loadSpanReceivers() { |
| String classNamesStr = conf.get(SPAN_RECEIVER_CLASSES_KEY, ""); |
| List<String> classNames = getClassNamesFromConf(classNamesStr); |
| StringBuilder bld = new StringBuilder(); |
| String prefix = ""; |
| for (String className : classNames) { |
| try { |
| tracerPool.loadReceiverType(className, conf, classLoader); |
| bld.append(prefix).append(className); |
| prefix = ", "; |
| } catch (Throwable e) { |
| LOG.error("Failed to create SpanReceiver of type " + className, e); |
| } |
| } |
| String resultString = bld.toString(); |
| if (resultString.isEmpty()) { |
| resultString = "no span receivers"; |
| } |
| LOG.info(SPAN_RECEIVER_CLASSES_KEY + " = " + classNamesStr + |
| "; loaded " + resultString); |
| } |
| |
| /** |
| * Get a list of class names from the HTrace configuration. |
| * Entries which are empty will be removed. Entries which lack a package will |
| * be given the default package. |
| * |
| * @param classNamesStr A semicolon-separated string containing a list |
| * of class names. |
| * @return A list of class names. |
| */ |
| private List<String> getClassNamesFromConf(String classNamesStr) { |
| String classNames[] = classNamesStr.split(";"); |
| LinkedList<String> cleanedClassNames = new LinkedList<String>(); |
| for (String className : classNames) { |
| String cleanedClassName = className.trim(); |
| if (!cleanedClassName.isEmpty()) { |
| cleanedClassNames.add(cleanedClassName); |
| } |
| } |
| return cleanedClassNames; |
| } |
| |
| public Tracer build() { |
| if (name == null) { |
| throw new RuntimeException("You must specify a name for this Tracer."); |
| } |
| LinkedList<SpanReceiver> spanReceivers = new LinkedList<SpanReceiver>(); |
| LinkedList<Sampler> samplers = new LinkedList<Sampler>(); |
| loadSamplers(samplers); |
| String tracerId = new TracerId(conf, name).get(); |
| Tracer tracer = new Tracer(tracerId, tracerPool, |
| samplers.toArray(new Sampler[samplers.size()])); |
| tracerPool.addTracer(tracer); |
| loadSpanReceivers(); |
| return tracer; |
| } |
| } |