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A trace tool which produces clearly arranged logs by indenting the trace messages depending on the depth of the call stack.
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/*
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 * and open the template in the editor.
 */

package de.christofreichardt.diagnosis;

import java.lang.management.ManagementFactory;

/**
 * Outlines a method for tracing.
 * 
 * @author Christof Reichardt
 */
public class TraceMethod {
  
  final private String signature;
  private final Class clazz;
  final private long startTime = System.currentTimeMillis();
  final private long startCpuTime = ManagementFactory.getThreadMXBean().getCurrentThreadCpuTime();
  private long elapsedTime;
  private long elapsedCpuTime;
  private final String methodName;
  
  /**
   * Constructs a TraceMethod with the specified signature. 
   *
   * @param signature the signature of the TraceMethod
   */
  public TraceMethod(String signature) {
    this.signature = signature;
    this.methodName = signature;
    this.clazz = null;
  }

  /**
   * Constructs a TraceMethod with the specified signature and class.
   * 
   * @param signature the signature of the TraceMethod
   * @param clazz the class of the TraceMethod
   */
  @Deprecated
  public TraceMethod(String signature, Class clazz) {
    this.signature = signature;
    this.methodName = signature;
    this.clazz = clazz;
  }
  
  /**
   * Constructs a TraceMethod with the specified signature.
   * 
   * @param returnType the return type of the method as string representation
   * @param object the object that owns the method
   * @param methodSignature the remaining method signature (without return type) inclusive parameter as string representation
   */
  public TraceMethod(String returnType, Object object, String methodSignature) {
    this.clazz = object.getClass();
    this.signature = returnType + " " + this.clazz.getSimpleName() + "[" + System.identityHashCode(object) + "]." + methodSignature;
    this.methodName = methodSignature;
  }
  
  /**
   * Constructs a TraceMethod with the specified signature.
   * 
   * @param returnType the return type of the method as string representation
   * @param clazz the class to which that method belong
   * @param methodSignature  the remaining method signature (without return type) inclusive parameter as string representation
   */
  public TraceMethod(String returnType, Class clazz, String methodSignature) {
    this.clazz = clazz;
    this.signature = returnType + " " + this.clazz.getSimpleName() + "." + methodSignature;
    this.methodName = methodSignature;
  }

  /**
   * This is the string representation of the method signature. It is composed of the return type, the owning class
   * and the remaining method signature (method name and list of parameters).
   * 
   * @return the signature
   */
  public String getSignature() {
    return signature;
  }

  /**
   * This is the elapsed time in milliseconds since the construction of the TraceMethod until the moment the TraceMethod
   * is popped from the stack again. 
   * 
   * @return the elapsedTime
   */
  public long getElapsedTime() {
    return elapsedTime;
  }

  /**
   * This is the elapsed CPU time since the construction of the TraceMethod until the moment the TraceMethod
   * is popped from the stack again. That is only the execution time of the current thread on the CPU will be measured. 
   * Suppose the scheduler decides to switch the contect to another thread during the execution of the method. This time doesn't count. 
   * Or the method itself passes the actual work to another thread. That doesn't count either.
   * 
   * @return the elapsedCpuTime
   */
  public long getElapsedCpuTime() {
    return elapsedCpuTime;
  }

  /**
   * The class owning the method.
   * 
   * @return the clazz
   */
  public Class getClazz() {
    return clazz;
  }

  /**
   * The method name inclusive list of parameters.
   * 
   * @return the methodName
   */
  public String getMethodName() {
    return methodName;
  }
  
  /**
   * Stops the elapsed (cpu) time since creation of this TraceMethod instance.
   */
  public void stopTime() {
    this.elapsedTime = System.currentTimeMillis() - this.startTime;
    this.elapsedCpuTime = (ManagementFactory.getThreadMXBean().getCurrentThreadCpuTime() - this.startCpuTime)/1000000;
  }
}