stringresourcemodel.java

Wicket一个开发Java Web应用程序框架。它使得开发web应用程序变得容易而轻松。 Wicket利用一个POJO data beans组件使得它可以与任何持久层技术相结合。

	 * <p>
	 * The relative component parameter should generally be supplied, as without it resources can
	 * not be obtained from resource bundles that are held relative to a particular component or
	 * page. However, for application that use only global resources then this parameter may be
	 * null.
	 * <p>
	 * The model parameter is also optional and only needs to be supplied if value substitutions are
	 * to take place on either the resource key or the actual resource strings.
	 * <p>
	 * The parameters parameter is also optional and is used for substitutions.
	 * 
	 * @param resourceKey
	 *            The resource key for this string resource
	 * @param component
	 *            The component that the resource is relative to
	 * @param model
	 *            The model to use for property substitutions
	 * @param parameters
	 *            The parameters to substitute using a Java MessageFormat object
	 */
	public StringResourceModel(final String resourceKey, final Component component,
		final IModel model, final Object[] parameters)
	{
		this(resourceKey, component, model, parameters, null);
	}

	/**
	 * Creates a new string resource model using the supplied parameters.
	 * <p>
	 * The relative component parameter should generally be supplied, as without it resources can
	 * not be obtained from resource bundles that are held relative to a particular component or
	 * page. However, for application that use only global resources then this parameter may be
	 * null.
	 * <p>
	 * The model parameter is also optional and only needs to be supplied if value substitutions are
	 * to take place on either the resource key or the actual resource strings.
	 * <p>
	 * The parameters parameter is also optional and is used for substitutions.
	 * 
	 * @param resourceKey
	 *            The resource key for this string resource
	 * @param component
	 *            The component that the resource is relative to
	 * @param model
	 *            The model to use for property substitutions
	 * @param parameters
	 *            The parameters to substitute using a Java MessageFormat object
	 * @param defaultValue
	 *            The default value if the resource key is not found.
	 */
	public StringResourceModel(final String resourceKey, final Component component,
		final IModel model, final Object[] parameters, final String defaultValue)
	{
		if (resourceKey == null)
		{
			throw new IllegalArgumentException("Resource key must not be null");
		}
		this.resourceKey = resourceKey;
		this.component = component;
		this.model = model;
		this.parameters = parameters;
		this.defaultValue = defaultValue;
	}

	/**
	 * Gets the localizer that is being used by this string resource model.
	 * 
	 * @return The localizer
	 */
	public Localizer getLocalizer()
	{
		return localizer;
	}

	/**
	 * Gets the string currently represented by this string resource model. The string that is
	 * returned may vary for each call to this method depending on the values contained in the model
	 * and an the parameters that were passed when this string resource model was created.
	 * 
	 * @return The string
	 */
	public final String getString()
	{
		// Make sure we have a localizer before commencing
		if (getLocalizer() == null)
		{
			if (component != null)
			{
				setLocalizer(component.getLocalizer());
			}
			else
			{
				throw new IllegalStateException("No localizer has been set");
			}
		}

		// Get the string resource, doing any property substitutions as part
		// of the get operation
		String value = localizer.getString(getResourceKey(), component, model, defaultValue);
		if (value == null)
		{
			value = defaultValue;
		}

		if (value != null)
		{
			// Substitute any parameters if necessary
			Object[] parameters = getParameters();
			if (parameters != null)
			{
				// Build the real parameters
				Object[] realParams = new Object[parameters.length];
				for (int i = 0; i < parameters.length; i++)
				{
					if (parameters[i] instanceof IModel)
					{
						realParams[i] = ((IModel)parameters[i]).getObject();
					}
					else if (model != null && parameters[i] instanceof String)
					{
						realParams[i] = PropertyVariableInterpolator.interpolate(
							(String)parameters[i], model.getObject());
					}
					else
					{
						realParams[i] = parameters[i];
					}
				}

				// escape single quotes for MessageFormat
				value = Strings.replaceAll(value, "'", "''").toString();
				// Apply the parameters
				final MessageFormat format = new MessageFormat(value, component != null
					? component.getLocale() : locale);				
				value = format.format(realParams);
			}
		}

		// Return the string resource
		return value;
	}

	/**
	 * Sets the localizer that is being used by this string resource model. This method is provided
	 * to allow the default application localizer to be overridden if required.
	 * 
	 * @param localizer
	 *            The localizer to use
	 */
	public void setLocalizer(final Localizer localizer)
	{
		this.localizer = localizer;
	}

	/**
	 * This method just returns debug information, so it won't return the localized string. Please
	 * use getString() for that.
	 * 
	 * @return The string for this model object
	 */
	public String toString()
	{
		StringBuffer sb = new StringBuffer("StringResourceModel[");
		sb.append("key:");
		sb.append(resourceKey);
		sb.append(",default:");
		sb.append(defaultValue);
		sb.append(",params:");
		if (parameters != null)
		{
			sb.append(Arrays.asList(parameters));
		}
		sb.append("]");
		return sb.toString();
	}

	/**
	 * Gets the Java MessageFormat substitution parameters.
	 * 
	 * @return The substitution parameters
	 */
	protected Object[] getParameters()
	{
		return parameters;
	}

	/**
	 * Gets the resource key for this string resource. If the resource key contains property
	 * expressions and the model is not null then the returned value is the actual resource key with
	 * all substitutions undertaken.
	 * 
	 * @return The (possibly substituted) resource key
	 */
	protected final String getResourceKey()
	{
		if (model != null)
		{
			return PropertyVariableInterpolator.interpolate(resourceKey, model.getObject());
		}
		else
		{
			return resourceKey;
		}
	}

	/**
	 * Gets the string that this string resource model currently represents. The string is returned
	 * as an object to allow it to be used generically within components.
	 * 
	 */
	protected Object load()
	{
		// Initialize information that we need to work successfully
		final Session session = Session.get();
		if (session != null)
		{
			localizer = Application.get().getResourceSettings().getLocalizer();
			locale = session.getLocale();
		}
		else
		{
			throw new WicketRuntimeException(
				"Cannot attach a string resource model without a Session context because that is required to get a Localizer");
		}
		return getString();
	}

	/**
	 * Detaches from the given session
	 */
	protected final void onDetach()
	{
		// Detach any model
		if (model != null)
		{
			model.detach();
		}

		// Null out references
		localizer = null;
		locale = null;
	}
}