com.yoho.core.trace.instrument.async.LazyTraceExecutor.java Source code

Introduction

Here is the source code for com.yoho.core.trace.instrument.async.LazyTraceExecutor.java

Source

/*
 * Copyright 2013-2015 the original author or authors.
 *
 * 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.yoho.core.trace.instrument.async;

import java.lang.invoke.MethodHandles;
import java.util.concurrent.Executor;

import com.yoho.core.trace.*;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.NoSuchBeanDefinitionException;
import com.yoho.core.trace.DefaultSpanNamer;
import com.yoho.core.trace.SpanNamer;
import com.yoho.core.trace.TraceKeys;
import com.yoho.core.trace.Tracer;

/**
 * {@link Executor} that wraps {@link Runnable} in a
 * {@link TraceRunnable TraceRunnable} that sets a
 * local component tag on the span.
 *
 * @author Dave Syer
 * @since 1.0.0
 */
public class LazyTraceExecutor implements Executor {

    private static final Log log = LogFactory.getLog(MethodHandles.lookup().lookupClass());

    private Tracer tracer;
    private final BeanFactory beanFactory;
    private final Executor delegate;
    private TraceKeys traceKeys;
    private SpanNamer spanNamer;

    public LazyTraceExecutor(BeanFactory beanFactory, Executor delegate) {
        this.beanFactory = beanFactory;
        this.delegate = delegate;
    }

    @Override
    public void execute(Runnable command) {
        if (this.tracer == null) {
            try {
                this.tracer = this.beanFactory.getBean(Tracer.class);
            } catch (NoSuchBeanDefinitionException e) {
                this.delegate.execute(command);
                return;
            }
        }
        this.delegate.execute(new LocalComponentTraceRunnable(this.tracer, traceKeys(), spanNamer(), command));
    }

    // due to some race conditions trace keys might not be ready yet
    private TraceKeys traceKeys() {
        if (this.traceKeys == null) {
            try {
                this.traceKeys = this.beanFactory.getBean(TraceKeys.class);
            } catch (NoSuchBeanDefinitionException e) {
                log.warn("TraceKeys bean not found - will provide a manually created instance");
                return new TraceKeys();
            }
        }
        return this.traceKeys;
    }

    // due to some race conditions trace keys might not be ready yet
    private SpanNamer spanNamer() {
        if (this.spanNamer == null) {
            try {
                this.spanNamer = this.beanFactory.getBean(SpanNamer.class);
            } catch (NoSuchBeanDefinitionException e) {
                log.warn("SpanNamer bean not found - will provide a manually created instance");
                return new DefaultSpanNamer();
            }
        }
        return this.spanNamer;
    }

}