valuebean.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 javax.servlet.http.HttpServletRequest;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.struts.action.ActionMapping;

import net.sf.irunninglog.servlet.UserContainer;
import net.sf.irunninglog.util.ConstantValues;
import net.sf.irunninglog.util.Conversions;
import net.sf.irunninglog.util.DTO;
import net.sf.irunninglog.util.Utilities;

/**
 * Abstract form bean class that acts as a value container. This class
 * should be used a the parent class for any object that will be used to
 * represent data in the application's view layer.
 *
 * <p/>
 *
 * This class provides are the <code>getValues</code> and <code>setValues</code>
 * methods.  These use the <code>DTO</code> objects to provide a way to
 * allow <code>ValueBean</code>s to interact with other layers of the
 * application.  Subclasses should override these as needed to handle any
 * new fields (values) that they define.
 *
 * @author <a href="mailto:[e-mail]">Allan Lewis</a>
 * @version $Revision: 1.2 $ $Date: 2005/06/23 03:13:54 $
 * @since iRunningLog 1.0
 * @see DTO
 */
public abstract class ValueBean extends FormBean {

    /** <code>Log</code> instance for this class. */
    private static final Log LOG = LogFactory.getLog(ValueBean.class);

    /**
     * Retrieve the value bean's values.  This will return a transfer object
     * populated with <code>String</code> representations of any values that
     * the value bean wishes to expose.  At this level, this method simply
     * instantiates and returns a transfer object.
     *
     * @return A transfer object representing the for bean's state
     */
    public DTO getValues() {
        DTO valueObject = new DTO();

        if (LOG.isDebugEnabled()) {
            LOG.debug("getValues: Values contained in this object "
                      + valueObject);
        }

        return valueObject;
    }

    /**
     * Update the value bean's values.  This will pass the supplied transfer
     * object to the value bean, which is then responsible for updating any
     * internal values based on the contents of the transfer object.  At this
     * level, this method does nothing.
     *
     * @param valueObject Value object containing the new values
     *                    to be applied to the value bean
     */
    public void setValues(DTO valueObject) {
        if (LOG.isDebugEnabled()) {
            LOG.debug("setValues: Updating the object using these values "
                      + valueObject);
        }

        if (valueObject == null) {
            LOG.error("Unable to setValues using a null DTO");
            throw new NullPointerException("Unable to setValues using a null"
                                           + " DTO");
        }
    }

    /**
     * Reset the state of a value bean.  This method can be overridden by
     * subclasses to perform any necessary logic.  This
     * method is invoked from the 3-argument <code>reset</code> method, which
     * is called from the Struts framework during request processing.
     *
     * @param mapping The mapping used to select this instance
     * @param request The servlet request we are processing
     * @param container The current user's container object
     * @see #reset(ActionMapping, HttpServletRequest)
     */
    protected void reset(ActionMapping mapping, HttpServletRequest request,
                         UserContainer container) {

        super.reset(mapping, request, container);

        if (LOG.isDebugEnabled()) {
            LOG.debug("reset: Does nothing at this level.");
        }
    }

    /**
     * Get a representation of a <code>String</code> representing a true/false
     * value and convert it into either 'Yes' or 'No'.  This method will never
     * throw an exception - any sort of failue will result in a return value
     * of 'No'.
     *
     * @param sBoolean A string containing a true/false value
     * @return 'Yes' of the string represents a true value, false otherwise
     */
    protected String getAsYesNo(String sBoolean) {
        boolean bool;
        try {
            bool = Conversions.stringToBoolean(sBoolean).booleanValue();
        } catch (Exception ex) {
            bool = false;
        }
        return bool ? ConstantValues.STRING_YES : ConstantValues.STRING_NO;
    }

    /**
     * Based on an input string, return a non-null representation.  This will
     * return ConstantValues.STRING_BLANK if the parameter string is
     * <code>null</code> - otherwise the input string will be returned.
     *
     * @param value The input string
     * @return The input value, or  a blank string if the input was
     *         <code>null</code>
     * @see ConstantValues#STRING_BLANK
     */
    protected String getValueOrBlank(String value) {
        return Utilities.isBlank(value) ? ConstantValues.STRING_BLANK : value;
    }

    /**
     * Custom toString override to provide a meaningful <code>String</code>
     * representation of this object.
     *
     * @return A <code>String</code> representation of this object
     */
    public String toString() {
        StringBuffer buff = new StringBuffer();

        buff.append(getClass());
        buff.append("[");
        buff.append("values=");
        buff.append(getValues());
        buff.append("]");

        return buff.toString();
    }

}