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 retrieving
 * certificates and CRLs from a <code>CertStore</code>.<br />
 * <br />
 * A <code>CertStoreException</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 />
 * <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 CertStore
 **/
public class CertStoreException extends GeneralSecurityException
{
    private Throwable cause;

	/**
	 * Creates a <code>CertStoreException</code> with <code>null</code> as
	 * its detail message. 
	 */
    public CertStoreException()
    {
	super();
    }

	/**
	 * Creates a <code>CertStoreException</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 CertStoreException(String message)
    {
	super(message);
    }

	/**
	 * Creates a <code>CertStoreException</code> with the specified detail
	 * message and cause.
	 *
	 * @param messag 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 CertStoreException(String message, Throwable cause)
    {
	super(message);
	this.cause = cause;
    }

	/**
	 * Creates a <code>CertStoreException</code> that wraps the specified
	 * throwable. This allows any exception to be converted into a
	 * <code>CertStoreException</code>, while retaining information about the
	 * cause, 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 CertStoreException(Throwable cause)
    {
	this.cause = cause;
    }

	/**
	 * Returns the detail message for this <code>CertStoreException</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() );
	}
	return s.toString();
    }

	/**
	 * Returns the cause of this <code>CertStoreException</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>CertStoreException</code>
	 */
    public String toString()
    {
	String message = getMessage();
	if ( message == null )
	    return "";

	return message;
    }

	/**
	 * 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 ( cause != null ) {
	    cause.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) {
	if ( cause != null ) {
	    cause.printStackTrace(pw);
	}
	super.printStackTrace(pw);
	if ( cause != null ) {
	    cause.printStackTrace(pw);
	}
    }
}

