exceptioncontainerformbean.java

A Java web application, based on Struts and Hibernate, that serves as an online running log. Users m

/* @LICENSE_COPYRIGHT@ */
package net.sf.irunninglog.servlet.formbean;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import net.sf.irunninglog.util.IdGenerator;

/**
 * Form bean useful for storing an exception, along with any exception(s) that
 * caused it.  When a bean is created, the root exception is unwrapped, and
 * any exceptions are stored in an internal list.  The list of exceptions
 * is accessible via the <code>getExceptions</code> method.
 *
 * @author <a href="mailto:[e-mail]">Allan Lewis</a>
 * @version $Revision: 1.1 $ $Date: 2005/06/30 02:01:05 $
 * @since iRunningLog 1.0
 */
public final class ExceptionContainerFormBean extends FormBean {

    /** Log instance for this class. */
    private static final Log LOG =
                            LogFactory.getLog(ExceptionContainerFormBean.class);

    /** List of exceptions contained in this container. */
    private List mExceptions;

    /**
     * Create a new exception container.
     */
    public ExceptionContainerFormBean() {
        super();

        mExceptions = new ArrayList();
    }

    /**
     * Create a new exception container to hold a given exception.
     *
     * @param ex The exception for this container
     */
    public ExceptionContainerFormBean(Exception ex) {
        this();
        setException(ex);
    }

    /**
     * Set the exception that this container represents.  This will clear
     * out any previous exception and unwrap the parameter exception, storing
     * the exception and any nested exceptions.
     *
     * @param ex The exception to store in this container
     */
    public void setException(Exception ex) {
        mExceptions.clear();

        Throwable exception = ex;
        while (exception != null) {
            if (LOG.isDebugEnabled()) {
                LOG.debug("Adding an exception with this class to the container"
                          + exception.getClass());
            }

            mExceptions.add(exception);
            exception = exception.getCause();
        }
    }

    /**
     * Get the list of exceptions contained in this container.
     *
     * @return The list of exceptions, with the root exception in the first
     *         position in the list
     */
    public List getExceptions() {
        return Collections.unmodifiableList(mExceptions);
    }

    /**
     * Get the string that identifies this container.  Constructed using the
     * bean's hash code along with a value from <code>IdGenerator</code>.
     *
     * @return The exception container's identifier
     * @see IdGenerator
     */
    public String getId() {
        return String.valueOf(hashCode()) + IdGenerator.generateId();
    }

    /**
     * Get the list of exceptions contained in this container.
     *
     * @return The list of exceptions, with the root exception in the first
     *         position in the list
     */
    public String toString() {
        StringBuffer buff = new StringBuffer();

        buff.append("ExceptionContainer[");
        buff.append("exceptions={");

        for (Iterator i = mExceptions.iterator(); i.hasNext();) {
            buff.append(i.next().getClass().getName());

            if (i.hasNext()) {
                buff.append(", ");
            }
        }

        buff.append("}");
        buff.append("]");

        return buff.toString();
    }

}