package java.security.cert;

import java.io.PrintStream;
import java.io.PrintWriter;
import java.security.GeneralSecurityException;

/**
 * An exception indicating one of a variety of problems encountered when 
 * validating a certification path. <br />
 * <br />
 * A <code>CertPathValidatorException</code> provides support for wrapping
 * exceptions. The {@link #getCause getCause} method returns the throwable, 
 * if any, that caused this exception to be thrown. <br />
 * <br />
 * A <code>CertPathValidatorException</code> may also include the 
 * certification path that was being validated when the exception was thrown 
 * and the index of the certificate in the certification path that caused the 
 * exception to be thrown. Use the {@link #getCertPath getCertPath} and
 * {@link #getIndex getIndex} methods to retrieve this information.<br />
 * <br />
 * <b>Concurrent Access</b><br />
 * <br />
 * Unless otherwise specified, the methods defined in this class are not
 * thread-safe. Multiple threads that need to access a single
 * object concurrently should synchronize amongst themselves and
 * provide the necessary locking. Multiple threads each manipulating
 * separate objects need not synchronize.
 *
 * @see CertPathValidator
 **/
public class CertPathValidatorException extends GeneralSecurityException
{
    private Throwable cause;
    private CertPath certPath;
    private int index = -1;

	/**
	 * Creates a <code>CertPathValidatorException</code> with 
	 * no detail message. 
	 */
    public CertPathValidatorException()
    {
	super();
    }

	/**
	 * Creates a <code>CertPathValidatorException</code> with the given
	 * detail message. A detail message is a <code>String</code> that 
	 * describes this particular exception.
	 *
	 * @param messag the detail message
	 */
    public CertPathValidatorException(String message)
    {
	super(message);
    }

	/**
	 * Creates a <code>CertPathValidatorException</code> with the specified
	 * detail message and cause.
	 *
	 * @param msg the detail message 
	 * @param cause the cause (which is saved for later retrieval by the 
	 * {@link #getCause getCause()} method). (A <code>null</code> value is 
	 * permitted, and indicates that the cause is nonexistent or unknown.)
	 */
    public CertPathValidatorException(String message, Throwable cause)
    {
	super(message);
	this.cause = cause;
    }

	/**
	 * Creates a <code>CertPathValidatorException</code> with the specified
	 * detail message, cause, certification path, and index.
	 *
	 * @param msg the detail message (or <code>null</code> if none)
	 * @param cause the cause (or <code>null</code> if none)
	 * @param certPath the certification path that was in the process of
	 * being validated when the error was encountered
	 * @param index the index of the certificate in the certification path
	 * that caused the error (or -1 if not applicable). Note that 
	 * the list of certificates in a <code>CertPath</code> is zero based.
	 *
	 * @exception IndexOutOfBoundsException if the index is out of range
	 * <code>(index < -1 || (certPath != null && index >=
	 * certPath.getCertificates().size())</code>
	 * @exception IllegalArgumentException if <code>certPath</code> is 
	 * <code>null</code> and <code>index</code> is not -1
	 */
    public CertPathValidatorException(String message, Throwable cause, CertPath certPath, int index)
    {
	super( message );

	if ( certPath == null && index != -1 )
	    throw new IllegalArgumentException( "certPath = null and index != -1" );
	if ( index < -1 || ( certPath != null && index >= certPath.getCertificates().size() ) )
	    throw new IndexOutOfBoundsException( " index < -1 or out of bound of certPath.getCertificates()" );

	this.cause = cause;
	this.certPath = certPath;
	this.index = index;
    }

	/**
	 * Creates a <code>CertPathValidatorException</code> that wraps the 
	 * specified throwable. This allows any exception to be converted into a 
	 * <code>CertPathValidatorException</code>, while retaining information 
	 * about the wrapped exception, which may be useful for debugging. The 
	 * detail message is set to (<code>cause==null ? null : cause.toString()
	 * </code>) (which typically contains the class and detail message of 
	 * cause).
	 *
	 * @param cause the cause (which is saved for later retrieval by the 
	 * {@link #getCause getCause()} method). (A <code>null</code> value is 
	 * permitted, and indicates that the cause is nonexistent or unknown.)
	 */
    public CertPathValidatorException(Throwable cause)
    {
	this.cause = cause;
    }

	/**
	 * Returns the detail message for this 
	 * <code>CertPathValidatorException</code>.
	 *
	 * @return the detail message, or <code>null</code> if neither the message
	 * nor cause were specified
	 */
    public String getMessage()
    {
	String message = super.getMessage();

	if ( message == null && cause == null )
	    return null;

	StringBuffer s = new StringBuffer();
	if ( message != null )
	{
	    s.append( message + "\n" );
	}
	if ( cause != null )
	{
	    s.append( "Cause:\n" + cause.getMessage() + "\n" );
	}
	return s.toString();
    }

	/**
	 * Returns the certification path that was being validated when
	 * the exception was thrown.
	 *
	 * @return the <code>CertPath</code> that was being validated when
	 * the exception was thrown (or <code>null</code> if not specified)
	 */
    public CertPath getCertPath()
    {
	return certPath;
    }

	/**
	 * Returns the index of the certificate in the certification path 
	 * that caused the exception to be thrown. Note that the list of
	 * certificates in a <code>CertPath</code> is zero based. If no 
	 * index has been set, -1 is returned.
	 *
	 * @return the index that has been set, or -1 if none has been set
	 */
    public int getIndex()
    {
	return index;
    }

	/**
	 * Returns the cause of this <code>CertPathValidatorException</code> or 
	 * <code>null</code> if the cause is nonexistent or unknown.
	 *
	 * @return the cause of this throwable or <code>null</code> if the cause 
	 * is nonexistent or unknown.
	 */
    public Throwable getCause()
    {
	return cause;
    }
    
	/**
	 * Returns a string describing this exception, including a description
	 * of the internal (wrapped) cause if there is one.
	 *
	 * @return a string representation of this 
	 * <code>CertPathValidatorException</code>
	 */
    public String toString()
    {
	StringBuffer sb = new StringBuffer();
	String s = getMessage();
	if ( s != null )
	{
	    sb.append( s );
	}
	if ( getIndex() >= 0 )
	{
	    sb.append("index in certpath: " + getIndex() + "\n");
	    sb.append(getCertPath());
	}
	return sb.toString();
    }

	/**
	 * Prints a stack trace to <code>System.err</code>, including the backtrace 
	 * of the cause, if any.
	 */
    public void printStackTrace()
    {
	printStackTrace(System.err);
    }

	/**
	 * Prints a stack trace to a <code>PrintStream</code>, including the 
	 * backtrace of the cause, if any.
	 *
	 * @param ps the <code>PrintStream</code> to use for output
	 */
    public void printStackTrace(PrintStream ps)
    {
	super.printStackTrace(ps);
	if ( getCause() != null )
	{
	    getCause().printStackTrace(ps);
	}
    }

	/**
	 * Prints a stack trace to a <code>PrintWriter</code>, including the 
	 * backtrace of the cause, if any.
	 *
	 * @param pw the <code>PrintWriter</code> to use for output
	 */
    public void printStackTrace(PrintWriter pw)
    {
	super.printStackTrace(pw);
	if ( getCause() != null )
	{
	    getCause().printStackTrace(pw);
	}
    }
}

