//
// Copyright (C) 2007 United States Government as represented by the
// Administrator of the National Aeronautics and Space Administration
// (NASA).  All Rights Reserved.
// 
// This software is distributed under the NASA Open Source Agreement
// (NOSA), version 1.3.  The NOSA has been approved by the Open Source
// Initiative.  See the file NOSA-1.3-JPF at the top of the distribution
// directory tree for the complete NOSA document.
// 
// THE SUBJECT SOFTWARE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY OF ANY
// KIND, EITHER EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT
// LIMITED TO, ANY WARRANTY THAT THE SUBJECT SOFTWARE WILL CONFORM TO
// SPECIFICATIONS, ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR
// A PARTICULAR PURPOSE, OR FREEDOM FROM INFRINGEMENT, ANY WARRANTY THAT
// THE SUBJECT SOFTWARE WILL BE ERROR FREE, OR ANY WARRANTY THAT
// DOCUMENTATION, IF PROVIDED, WILL CONFORM TO THE SUBJECT SOFTWARE.
//

package java.lang;

import java.io.PrintStream;
import java.io.PrintWriter;

/**
 * barebones model class for java.lang.Throwable
 * 
 * the main reason for having one is to defer the stacktrace creation, which
 * we don't want if all an application does is intercepting a gazillion of
 * exceptions like NoSuchMethodException
 */
public class Throwable {

  int[] snapshot; // this is an internal array of { globalMethodId, pcOffset } pairs
  
  protected Throwable cause; // in case this is a wrapper exception (like InvocationTargetException)
  
  protected String detailMessage; // where we keep the context specific info
    
  protected StackTraceElement[] stackTrace; // only set on demand, if getStackTrace() is called
  
  public Throwable() {
    try {                                            // Use Class.forName() instead of new StackTraceElement() since the latter creates garbage.
      Class.forName("java.lang.StackTraceElement");  // Force this class to load here instead of in createStackTrace().
    } catch (ClassNotFoundException e) {
      throw new NoClassDefFoundError("java.lang.StackTraceElement");
    }
     
    fillInStackTrace();
  }

  public Throwable (String msg) {
    this();
    detailMessage = msg;
    cause = this;
  }

  public Throwable (String msg, Throwable xCause) {
    this();
    detailMessage = msg;
    cause = xCause;
  }

  public Throwable (Throwable xCause) {
    this();
    
    cause = xCause;
    if (cause != null){
      detailMessage = xCause.toString();
    }
  }

  public String getMessage() {
    return detailMessage;
  }
  
  public String getLocalizedMessage() {
    return detailMessage;
  }

  public Throwable getCause() {
    if (cause == this){
      return null;  // quirky
    } else {
      return cause;
    }
  }

  // this sets 'snapshot' from the native side
  public native Throwable fillInStackTrace();
  
  // and this turns 'snapshot' into an array of StackTraceElement objects
  private native StackTraceElement[] createStackTrace();
  
  public StackTraceElement[] getStackTrace() {
    if (stackTrace == null){
      stackTrace = createStackTrace();
    }
    
    return stackTrace;
  }
  
  public void setStackTrace (StackTraceElement[] st) {
    stackTrace = st;
  }

  public synchronized Throwable initCause (Throwable xCause) {
    if (xCause == this){
      throw new IllegalArgumentException("self-causation not permitted");
    }
    
    if (cause != this){
      throw new IllegalStateException("cannot overwrite cause");
    }
    
    cause = xCause;
    
    return this;
  }

  public native String toString();
  
  public native void printStackTrace ();
  
  // <2do> and lots more of printStackTraces..

  private native String getStackTraceAsString();
  
  public void printStackTrace (PrintStream ps){
    String s = getStackTraceAsString();
    ps.print(s);
  }
  
  public void printStackTrace (PrintWriter pw){
    String s = getStackTraceAsString();
    pw.print(s);    
  }
  
  int getStackTraceDepth(){
    return (snapshot.length / 2); // snapshot stores the methodId and pc for each StackFrame 
  }
}