component.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。

		return getMetaData(MARKUP_ID_KEY);
	}

	private final int nextAutoIndex()
	{
		Page page = findPage();
		if (page == null)
		{
			throw new WicketRuntimeException(
				"This component is not (yet) coupled to a page. It has to be able "
					+ "to find the page it is supposed to operate in before you can call "
					+ "this method (Component#getMarkupId)");
		}

		return page.getAutoIndex();
	}

	/**
	 * Retrieves id by which this component is represented within the markup. This is either the id
	 * attribute set explicitly via a call to {@link #setMarkupId(String)}, id attribute defined in
	 * the markup, or an automatically generated id - in that order.
	 * <p>
	 * If no id is set and <code>createIfDoesNotExist</code> is false, this method will return
	 * null. Otherwise it will generate an id value that will be unique in the page. This is the
	 * preferred way as there is no chance of id collision.
	 * <p>
	 * Note: This method should only be called after the component or its parent have been added to
	 * the page.
	 * 
	 * @param createIfDoesNotExist
	 *            When there is no existing markup id, determines whether it should be generated or
	 *            whether <code>null</code> should be returned.
	 * 
	 * @return markup id of the component
	 */

	public String getMarkupId(boolean createIfDoesNotExist)
	{
		Object storedMarkupId = getMarkupIdImpl();

		if (storedMarkupId instanceof String)
		{
			return (String)storedMarkupId;
		}

		if (storedMarkupId == null && createIfDoesNotExist == false)
		{
			return null;
		}

		final int generatedMarkupId = storedMarkupId instanceof Integer
			? ((Integer)storedMarkupId).intValue() : nextAutoIndex();

		if (storedMarkupId == null)
		{
			setMarkupIdImpl(new Integer(generatedMarkupId));
		}

		// try to read from markup
		// TODO getting the id from markup doesn't work everywhere yet.
		// unfortunately, we have to drop this until we have a good solution
		// for issue http://issues.apache.org/jira/browse/WICKET-694
		// markupId = getMarkupAttributes().getString("id");

		String markupId = RequestContext.get().encodeMarkupId(getId() + generatedMarkupId);
		// make sure id is compliant with w3c requirements (starts with a
		// letter)
		char c = markupId.charAt(0);
		if (!Character.isLetter(c))
		{
			markupId = "id" + markupId;
		}

		// escape some noncompliant characters
		markupId = Strings.replaceAll(markupId, "_", "__").toString();
		markupId = markupId.replace('.', '_');
		markupId = markupId.replace('-', '_');

		return markupId;
	}

	/**
	 * Retrieves id by which this component is represented within the markup. This is either the id
	 * attribute set explicitly via a call to {@link #setMarkupId(String)}, id attribute defined in
	 * the markup, or an automatically generated id - in that order.
	 * <p>
	 * If no explicit id is set this function will generate an id value that will be unique in the
	 * page. This is the preferred way as there is no chance of id collision.
	 * <p>
	 * Note: This method should only be called after the component or its parent have been added to
	 * the page.
	 * 
	 * @return markup id of the component
	 */
	public String getMarkupId()
	{
		return getMarkupId(true);
	}

	/**
	 * Gets metadata for this component using the given key.
	 * 
	 * @param key
	 *            The key for the data
	 * @return The metadata or null of no metadata was found for the given key
	 * @see MetaDataKey
	 */
	public final Serializable getMetaData(final MetaDataKey key)
	{
		return key.get(getMetaData());
	}

	private MetaDataEntry[] getMetaData()
	{
		MetaDataEntry[] metaData = null;

		// index where we should expect the entry
		int index = getFlag(FLAG_MODEL_SET) ? 1 : 0;

		int length = data_length();

		if (index < length)
		{
			Object object = data_get(index);
			if (object instanceof MetaDataEntry[])
			{
				metaData = (MetaDataEntry[])object;
			}
			else if (object instanceof MetaDataEntry)
			{
				metaData = new MetaDataEntry[] { (MetaDataEntry)object };
			}
		}

		return metaData;
	}

	/**
	 * Gets the model. It returns the object that wraps the backing model.
	 * 
	 * @return The model
	 */
	public final IModel getModel()
	{
		IModel model = getModelImpl();
		// If model is null
		if (model == null)
		{
			// give subclass a chance to lazy-init model
			model = initModel();
			setModelImpl(model);
		}

		return model;
	}

	/**
	 * Gets the backing model object; this is shorthand for getModel().getObject().
	 * 
	 * @return The backing model object
	 */
	public final Object getModelObject()
	{
		final IModel model = getModel();
		if (model != null)
		{
			// Get model value for this component.
			return model.getObject();
		}
		else
		{
			return null;
		}
	}

	/**
	 * Gets a model object as a string. Depending on the "escape model strings" flag of the
	 * component, the string is either HTML escaped or not. "HTML escaped" meaning that only HTML
	 * sensitive chars are escaped but not all none-ascii chars. Proper HTML encoding should be used
	 * instead. In case you really need a fully escaped model string you may call
	 * {@link Strings#escapeMarkup(String, boolean, boolean)} on the model string returned.
	 * 
	 * @see Strings#escapeMarkup(String, boolean, boolean)
	 * @see #getEscapeModelStrings()
	 * 
	 * @return Model object for this component as a string
	 */
	public final String getModelObjectAsString()
	{
		return getModelObjectAsString(getModelObject());
	}

	/**
	 * Gets a model object as a string. Depending on the "escape model strings" flag of the
	 * component, the string is either HTML escaped or not. "HTML escaped" meaning that only HTML
	 * sensitive chars are escaped but not all none-ascii chars. Proper HTML encoding should be used
	 * instead. In case you really need a fully escaped model string you may call
	 * {@link Strings#escapeMarkup(String, boolean, boolean)} on the model string returned.
	 * 
	 * @see Strings#escapeMarkup(String, boolean, boolean)
	 * @see #getEscapeModelStrings()
	 * 
	 * @param modelObject
	 *            Model object to convert to string
	 * @return The string
	 */
	public final String getModelObjectAsString(final Object modelObject)
	{
		if (modelObject != null)
		{
			// Get converter
			final IConverter converter = getConverter(modelObject.getClass());

			// Model string from property
			final String modelString = converter.convertToString(modelObject, getLocale());

			if (modelString != null)
			{
				// If we should escape the markup
				if (getFlag(FLAG_ESCAPE_MODEL_STRINGS))
				{
					// Escape HTML sensitive characters only. Not all none-ascii chars
					return Strings.escapeMarkup(modelString, false, false).toString();
				}
				return modelString;
			}
		}
		return "";
	}

	/**
	 * Gets whether or not component will output id attribute into the markup. id attribute will be
	 * set to the value returned from {@link Component#getMarkupId()}.
	 * 
	 * @return whether or not component will output id attribute into the markup
	 */
	public final boolean getOutputMarkupId()
	{
		return getFlag(FLAG_OUTPUT_MARKUP_ID);
	}

	/**
	 * Gets whether or not an invisible component will render a placeholder tag.
	 * 
	 * @return true if a placeholder tag should be rendered
	 */
	public final boolean getOutputMarkupPlaceholderTag()
	{
		return getFlag(FLAG_PLACEHOLDER);
	}

	/**
	 * Gets the page holding this component.
	 * 
	 * @return The page holding this component
	 * @throws IllegalStateException
	 *             Thrown if component is not yet attached to a Page.
	 */
	public final Page getPage()
	{
		// Search for nearest Page
		final Page page = findPage();

		// If no Page was found
		if (page == null)
		{
			// Give up with a nice exception
			throw new IllegalStateException("No Page found for component " + this);
		}

		return page;
	}

	/**
	 * @return The page factory for the session that this component is in
	 */
	public final IPageFactory getPageFactory()
	{
		return getSession().getPageFactory();
	}

	/**
	 * Gets the path to this component relative to the page it is in.
	 * 
	 * @return The path to this component relative to the page it is in
	 */
	public final String getPageRelativePath()
	{
		return Strings.afterFirstPathComponent(getPath(), PATH_SEPARATOR);
	}

	/**
	 * Gets any parent container, or null if there is none.
	 * 
	 * @return Any parent container, or null if there is none
	 */
	public final MarkupContainer getParent()
	{
		return parent;
	}

	/**
	 * Gets this component's path.
	 * 
	 * @return Colon separated path to this component in the component hierarchy
	 */
	public final String getPath()
	{
		final PrependingStringBuffer buffer = new PrependingStringBuffer(32);
		for (Component c = this; c != null; c = c.getParent())
		{
			if (buffer.length() > 0)
			{
				buffer.prepend(PATH_SEPARATOR);
			}
			buffer.prepend(c.getId());
		}
		return buffer.toString();
	}

	/**
	 * If false the component's tag will be printed as well as its body (which is default). If true
	 * only the body will be printed, but not the component's tag.
	 * 
	 * @return If true, the component tag will not be printed
	 */
	public final boolean getRenderBodyOnly()
	{
		return getFlag(FLAG_RENDER_BODY_ONLY);
	}

	/**
	 * @return The request for this component's active request cycle
	 */
	public final Request getRequest()
	{
		RequestCycle requestCycle = getRequestCycle();
		if (requestCycle == null)
		{
			// Happens often with WicketTester when one forgets to call
			// createRequestCycle()
			throw new WicketRuntimeException("No RequestCycle is currently set!");
		}
		return requestCycle.getRequest();
	}

	/**
	 * Gets the active request cycle for this component
	 * 
	 * @return The request cycle
	 */
	public final RequestCycle getRequestCycle()
	{
		return RequestCycle.get();
	}

	/**
	 * @return The response for this component's active request cycle
	 */
	public final Response getResponse()
	{
		return getRequestCycle().getResponse();
	}

	/**
	 * Gets the current Session object.
	 * 
	 * @return The Session that this component is in
	 */
	public Session getSession()
	{
		return Session.get();
	}

	/**
	 * @return Size of this Component in bytes
	 */
	public long getSizeInBytes()
	{
		final MarkupContainer originalParent = parent;
		parent = null;
		long size = -1;
		try
		{
			size = Objects.sizeof(this);
		}
		catch (Exception e)
		{
			log.error("Exception getting size for component " + this, e);
		}
		parent = originalParent;
		return size;
	}

	/**
	 * @param key
	 *            Key of string resource in property file
	 * @return The String
	 * @see Localizer
	 */
	public final String getString(final String key)
	{
		return getString(key, null);
	}

	/**
	 * @param key
	 *            The resource key
	 * @param model
	 *            The model
	 * @return The formatted string
	 * @see Localizer
	 */
	public final String getString(final String key, final IModel model)
	{
		return getLocalizer().getString(key, this, model);
	}

	/**
	 * @param key
	 *            The resource key
	 * @param model
	 *            The model
	 * @param defaultValue
	 *            A default value if the string cannot be found
	 * @return The formatted string
	 * @see Localizer
	 */
	public final String getString(final String key, final IModel model, final String defaultValue)
	{
		return getLocalizer().getString(key, this, model, defaultValue);
	}

	/**
	 * Gets the style of this component (see {@link org.apache.wicket.Session}).
	 * 
	 * @return The style of this component.
	 * 
	 * @see org.apache.wicket.Session
	 * @see org.apache.wicket.Session#getStyle()
	 */
	public final String getStyle()
	{
		String variation = getVariation();
		String style = getSession().getStyle();
		if (variation != null && !"".equals(variation))
		{
			if (style != null && !"".equals(style))
			{
				style = variation + "_" + style;
			}
			else
			{
				style = variation;
			}
		}
		return style;