/**
 * An exception that gets thrown by failed persistence operations.
 * It allows you to chain exceptions so you can see what really
 * caused the persistence to fail.
 */
package imaginary.persist;

public class PersistenceException extends Exception {
    // the exception that caused the persistence to fail
    private Exception cause;

    /**
     * Constructs an exception without cause or reason.
     */
    public PersistenceException() {
        this("An exception for no reason whatsoever.", null);
    }

    /**
     * Constructs a new exception for the specified reason.
     * @param reason the reason the operation failed
     */
    public PersistenceException(String reason) {
        this(reason, null);
    }

    /**
     * Constructs a new exception caused by the specified exception.
     * @param e the exception causing the operation to fail
     */
    public PersistenceException(Exception e) {
        this("A persisitence exception caused by: " + e.getMessage(), e);
    }

    /**
     * Constructs a new exception with both a cause and reason.
     * @param reason the reason for the exception
     * @param e the cause
     */
    public PersistenceException(String reason, Exception e) {
        super(reason);
        cause = e;
    }

    /**
     * @return the exception that caused the persistence operation to fail
     */
    public Exception getCause() {
        return cause;
    }
}