org.apache.wicket.Page Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of wicket-core Show documentation
Wicket is a Java web application framework that takes simplicity, separation of concerns and ease of development to a whole new level. Wicket pages can be mocked up, previewed and later revised using standard WYSIWYG HTML design tools. Dynamic content processing and form handling is all handled in Java code using a first-class component model backed by POJO data beans that can easily be persisted using your favorite technology.
There is a newer version: 10.2.0
Show newest version
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.wicket;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;

import org.apache.wicket.authorization.UnauthorizedActionException;
import org.apache.wicket.core.util.lang.WicketObjects;
import org.apache.wicket.feedback.FeedbackDelay;
import org.apache.wicket.markup.MarkupException;
import org.apache.wicket.markup.MarkupStream;
import org.apache.wicket.markup.MarkupType;
import org.apache.wicket.markup.html.WebPage;
import org.apache.wicket.markup.resolver.IComponentResolver;
import org.apache.wicket.model.IModel;
import org.apache.wicket.page.IPageManager;
import org.apache.wicket.pageStore.IPageStore;
import org.apache.wicket.request.component.IRequestablePage;
import org.apache.wicket.request.cycle.RequestCycle;
import org.apache.wicket.request.mapper.parameter.PageParameters;
import org.apache.wicket.settings.DebugSettings;
import org.apache.wicket.util.lang.Classes;
import org.apache.wicket.util.lang.Generics;
import org.apache.wicket.util.string.StringValue;
import org.apache.wicket.util.visit.IVisit;
import org.apache.wicket.util.visit.IVisitor;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


/**
 * Abstract base class for pages. As a {@link MarkupContainer} subclass, a Page can contain a
 * component hierarchy and markup in some markup language such as HTML. Users of the framework
 * should not attempt to subclass Page directly. Instead they should subclass a subclass of Page
 * that is appropriate to the markup type they are using, such as {@link WebPage} (for HTML markup).
 * 
 * Page has the following differences to {@link Component}s main concepts:
 * 

 * Identity - Page numerical identifiers start at 0 for each {@link Session} and
 * increment for each new page. This numerical identifier is used as the component identifier
 * accessible via {@link #getId()}.
 * Construction - When a page is constructed, it is automatically registerd with the
 * application's {@link IPageManager}. 

 * Pages can be constructed with any constructor like any other component, but if you wish to link
 * to a Page using a URL that is "bookmarkable" (which implies that the URL will not have any
 * session information encoded in it, and that you can call this page directly without having a
 * session first directly from your browser), you need to implement your Page with a no-arg
 * constructor or with a constructor that accepts a {@link PageParameters} argument (which wraps any
 * query string parameters for a request). In case the page has both constructors, the constructor
 * with PageParameters will be used.
 * Versioning - Pages support the browser's back button when versioning is enabled via
 * {@link #setVersioned(boolean)}. By default all pages are versioned if not configured differently
 * in {@link org.apache.wicket.settings.PageSettings#setVersionPagesByDefault(boolean)}
 * 
 * 
 * @see org.apache.wicket.markup.html.WebPage
 * @see org.apache.wicket.MarkupContainer
 * @see org.apache.wicket.model.CompoundPropertyModel
 * @see org.apache.wicket.Component
 * 
 * @author Jonathan Locke
 * @author Chris Turner
 * @author Eelco Hillenius
 * @author Johan Compagner
 * 
 */
public abstract class Page extends MarkupContainer
	implements
		IRequestablePage,
		IQueueRegion
{
	/** True if the page hierarchy has been modified in the current request. */
	private static final int FLAG_IS_DIRTY = FLAG_RESERVED3;

	/** Set to prevent marking page as dirty under certain circumstances. */
	private static final int FLAG_PREVENT_DIRTY = FLAG_RESERVED4;

	/** True if the page should try to be stateless */
	private static final int FLAG_STATELESS_HINT = FLAG_RESERVED5;

	/** Flag that indicates if the page was created using one of its bookmarkable constructors */
	private static final int FLAG_WAS_CREATED_BOOKMARKABLE = FLAG_RESERVED8;

	/** Log. */
	private static final Logger log = LoggerFactory.getLogger(Page.class);

	private static final long serialVersionUID = 1L;

	/** Used to create page-unique numbers */
	private int autoIndex;

	/** Numeric version of this page's id */
	private int numericId;

	/** Set of components that rendered if component use checking is enabled */
	private transient Set renderedComponents;

	/**
	 * Boolean if the page is stateless, so it doesn't have to be in the page map, will be set in
	 * urlFor
	 */
	private transient Boolean stateless = null;

	/** Page parameters used to construct this page */
	private final PageParameters pageParameters;

	/**
	 * @see IRequestablePage#getRenderCount()
	 */
	private int renderCount = 0;

	/**
	 * Constructor.
	 */
	protected Page()
	{
		this(null, null);
	}

	/**
	 * Constructor.
	 * 
	 * @param model
	 *            See Component
	 * @see Component#Component(String, IModel)
	 */
	protected Page(final IModel model)
	{
		this(null, model);
	}

	/**
	 * The {@link PageParameters} parameter will be stored in this page and then those parameters
	 * will be used to create stateless links to this bookmarkable page.
	 * 
	 * @param parameters
	 *            externally passed parameters
	 * @see PageParameters
	 */
	protected Page(final PageParameters parameters)
	{
		this(parameters, null);
	}

	/**
	 * Construct.
	 * 
	 * @param parameters
	 * @param model
	 */
	private Page(final PageParameters parameters, IModel model)
	{
		super(null, model);

		if (parameters == null)
		{
			pageParameters = new PageParameters();
		}
		else
		{
			pageParameters = parameters;
		}
	}

	/**
	 * The {@link PageParameters} object that was used to construct this page. This will be used in
	 * creating stateless/bookmarkable links to this page
	 * 
	 * @return {@link PageParameters} The construction page parameter
	 */
	@Override
	public PageParameters getPageParameters()
	{
		return pageParameters;
	}

	/**
	 * Adds a component to the set of rendered components.
	 * 
	 * @param component
	 *            The component that was rendered
	 */
	public final void componentRendered(final Component component)
	{
		// Inform the page that this component rendered
		if (getApplication().getDebugSettings().getComponentUseCheck())
		{
			if (renderedComponents == null)
			{
				renderedComponents = new HashSet();
			}
			if (renderedComponents.add(component) == false)
			{
				throw new MarkupException(
					"The component " +
						component +
						" was rendered already. You can render it only once during a render phase. Class relative path: " +
						component.getClassRelativePath());
			}
			log.debug("Rendered {}", component);

		}
	}

	/**
	 * Detaches any attached models referenced by this page.
	 */
	@Override
	public void detachModels()
	{
		super.detachModels();
	}

	@Override
	protected void onConfigure()
	{
		if (!isInitialized())
		{
			// initialize the page if not yet initialized
			internalInitialize();
		}
		
		super.onConfigure();
	}

	/**
	 * @see #dirty(boolean)
	 */
	public final void dirty()
	{
		dirty(false);
	}

	/** {@inheritDoc} */
	@Override
	public boolean setFreezePageId(boolean freeze)
	{
		boolean frozen = getFlag(FLAG_PREVENT_DIRTY);
		setFlag(FLAG_PREVENT_DIRTY, freeze);
		return frozen;
	}

	/**
	 * Mark this page as modified in the session. If versioning is supported then a new version of
	 * the page will be stored in {@link IPageStore page store}
	 * 
	 * @param isInitialization
	 *            a flag whether this is a page instantiation
	 */
	public void dirty(final boolean isInitialization)
	{
		checkHierarchyChange(this);

		if (getFlag(FLAG_PREVENT_DIRTY))
		{
			return;
		}

		final IPageManager pageManager = getSession().getPageManager();
		if (!getFlag(FLAG_IS_DIRTY) && (isVersioned() && pageManager.supportsVersioning() ||

		// we need to get pageId for new page instances even when the page doesn't need
		// versioning, otherwise pages override each other in the page store and back button
		// support is broken
			isInitialization))
		{
			setFlag(FLAG_IS_DIRTY, true);
			setNextAvailableId();

			if (isInitialization == false)
			{
				pageManager.touchPage(this);
			}
		}
	}
	
	@Override
	protected void onInitialize()
	{
		super.onInitialize();

		final IPageManager pageManager = getSession().getPageManager();
		pageManager.touchPage(this);
	}

	/**
	 * This method is called when a component was rendered as a part. If it is a 
	 * MarkupContainer then the rendering for that container is checked.
	 * 
	 * @param component
	 * 
	 * @see Component#renderPart()
	 */
	final void endComponentRender(Component component)
	{
		if (component instanceof MarkupContainer)
		{
			checkRendering((MarkupContainer)component);
		}
		else
		{
			renderedComponents = null;
		}
	}

	/**
	 * THIS METHOD IS NOT PART OF THE WICKET PUBLIC API. DO NOT CALL IT.
	 * 
	 * Get a page unique number, which will be increased with each call.
	 * 
	 * @return A page unique number
	 */
	public final int getAutoIndex()
	{
		return autoIndex++;
	}

	@Override
	public final String getId()
	{
		return Integer.toString(numericId);
	}

	/**
	 * 
	 * @return page class
	 */
	public final Class getPageClass()
	{
		return getClass();
	}

	/**
	 * @return Size of this page in bytes
	 */
	@Override
	public final long getSizeInBytes()
	{
		return WicketObjects.sizeof(this);
	}

	/**
	 * Returns whether the page should try to be stateless. To be stateless, getStatelessHint() of
	 * every component on page (and it's behavior) must return true and the page must be
	 * bookmarkable.
	 * 
	 * @see org.apache.wicket.Component#getStatelessHint()
	 */
	@Override
	public final boolean getStatelessHint()
	{
		return getFlag(FLAG_STATELESS_HINT);
	}

	/**
	 * @return This page's component hierarchy as a string
	 */
	public final String hierarchyAsString()
	{
		final StringBuilder buffer = new StringBuilder();
		buffer.append("Page ").append(getId());
		visitChildren(new IVisitor()
		{
			@Override
			public void component(final Component component, final IVisit visit)
			{
				int levels = 0;
				for (Component current = component; current != null; current = current.getParent())
				{
					levels++;
				}
				buffer.append(StringValue.repeat(levels, "	"))
					.append(component.getPageRelativePath())
					.append(':')
					.append(Classes.simpleName(component.getClass()));
			}
		});
		return buffer.toString();
	}

	/**
	 * Bookmarkable page can be instantiated using a bookmarkable URL.
	 * 
	 * @return Returns true if the page is bookmarkable.
	 */
	@Override
	public boolean isBookmarkable()
	{
		return getApplication().getPageFactory().isBookmarkable(getClass());
	}

	/**
	 * Override this method and return true if your page is used to display Wicket errors. This can
	 * help the framework prevent infinite failure loops.
	 * 
	 * @return True if this page is intended to display an error to the end user.
	 */
	public boolean isErrorPage()
	{
		return false;
	}

	/**
	 * Determine the "statelessness" of the page while not changing the cached value.
	 * 
	 * @return boolean value
	 */
	private boolean peekPageStateless()
	{
		Boolean old = stateless;
		Boolean res = isPageStateless();
		stateless = old;
		return res;
	}

	/**
	 * Gets whether the page is stateless. Components on stateless page must not render any stateful
	 * urls, and components on stateful page must not render any stateless urls. Stateful urls are
	 * urls, which refer to a certain (current) page instance.
	 * 
	 * @return Whether this page is stateless
	 */
	@Override
	public final boolean isPageStateless()
	{
		if (isBookmarkable() == false)
		{
			stateless = Boolean.FALSE;
			if (getStatelessHint())
			{
				log.warn("Page '" + this + "' is not stateless because it is not bookmarkable, " +
					"but the stateless hint is set to true!");
			}
		}

		if (getStatelessHint() == false)
		{
			return false;
		}

		if (stateless == null)
		{
			internalInitialize();

			if (isStateless() == false)
			{
				stateless = Boolean.FALSE;
			}
		}

		if (stateless == null)
		{
			Component statefulComponent = visitChildren(Component.class,
				new IVisitor()
				{
					@Override
					public void component(final Component component, final IVisit visit)
					{
						if (!component.isStateless())
						{
							visit.stop(component);
						}
					}
				});

			stateless = statefulComponent == null;

			if (log.isDebugEnabled() && !stateless.booleanValue() && getStatelessHint())
			{
				log.debug("Page '{}' is not stateless because of component with path '{}'.", this,
					statefulComponent.getPageRelativePath());
			}

		}

		return stateless;
	}

	/**
	 * THIS METHOD IS NOT PART OF THE WICKET PUBLIC API. DO NOT CALL.
	 * 
	 * Set the id for this Page. This method is called by PageMap when a Page is added because the
	 * id, which is assigned by PageMap, is not known until this time.
	 * 
	 * @param id
	 *            The id
	 */
	public final void setNumericId(final int id)
	{
		numericId = id;
	}

	/**
	 * Sets whether the page should try to be stateless. To be stateless, getStatelessHint() of
	 * every component on page (and it's behavior) must return true and the page must be
	 * bookmarkable.
	 * 
	 * @param value
	 *            whether the page should try to be stateless
	 */
	public final Page setStatelessHint(boolean value)
	{
		if (value && !isBookmarkable())
		{
			throw new WicketRuntimeException(
				"Can't set stateless hint to true on a page when the page is not bookmarkable, page: " +
					this);
		}
		setFlag(FLAG_STATELESS_HINT, value);
		return this;
	}

	/**
	 * This method is called when a component will be rendered as a part.
	 * 
	 * @param component
	 * 
	 * @see Component#renderPart()
	 */
	final void startComponentRender(Component component)
	{
		renderedComponents = null;
	}

	/**
	 * Get the string representation of this container.
	 * 
	 * @return String representation of this container
	 */
	@Override
	public String toString()
	{
		return "[Page class = " + getClass().getName() + ", id = " + getId() + ", render count = " +
			getRenderCount() + "]";
	}

	/**
	 * Throw an exception if not all components rendered.
	 * 
	 * @param renderedContainer
	 *            The page itself if it was a full page render or the container that was rendered
	 *            standalone
	 */
	private void checkRendering(final MarkupContainer renderedContainer)
	{
		// If the application wants component uses checked and
		// the response is not a redirect
		final DebugSettings debugSettings = getApplication().getDebugSettings();
		if (debugSettings.getComponentUseCheck())
		{
			final List unrenderedComponents = new ArrayList();
			final StringBuilder buffer = new StringBuilder();
			renderedContainer.visitChildren(new IVisitor()
			{
				@Override
				public void component(final Component component, final IVisit visit)
				{
					// If component never rendered
					if (renderedComponents == null || !renderedComponents.contains(component))
					{
						// If not an auto component ...
						if (!component.isAuto() && component.isVisibleInHierarchy())
						{
							// Increase number of unrendered components
							unrenderedComponents.add(component);

							// Add to explanatory string to buffer
							buffer.append(Integer.toString(unrenderedComponents.size()))
								.append(". ")
								.append(component.toString(true))
								.append('\n');
							String metadata = component.getMetaData(Component.CONSTRUCTED_AT_KEY);
							if (metadata != null)
							{
								buffer.append(metadata).append('\n');
							}
							metadata = component.getMetaData(Component.ADDED_AT_KEY);
							if (metadata != null)
							{
								buffer.append(metadata).append('\n');
							}
						}
						else
						{
							// if the component is not visible in hierarchy we
							// should not visit its children since they are also
							// not visible
							visit.dontGoDeeper();
						}
					}
				}
			});

			// Throw exception if any errors were found
			if (unrenderedComponents.size() > 0)
			{
				renderedComponents = null;

				List transparentContainerChildren = Generics.newArrayList();

				Iterator iterator = unrenderedComponents.iterator();
				outerWhile : while (iterator.hasNext())
				{
					Component component = iterator.next();

					// If any of the transparentContainerChildren is a parent to component, then
					// ignore it.
					for (Component transparentContainerChild : transparentContainerChildren)
					{
						MarkupContainer parent = component.getParent();
						while (parent != null)
						{
							if (parent == transparentContainerChild)
							{
								iterator.remove();
								continue outerWhile;
							}
							parent = parent.getParent();
						}
					}

					if (hasInvisibleTransparentChild(component.getParent(), component))
					{
						// If we found a transparent container that isn't visible then ignore this
						// component and only do a debug statement here.
						if (log.isDebugEnabled())
						{
							log.debug(
								"Component {} wasn't rendered but might have a transparent parent.",
								component);
						}

						transparentContainerChildren.add(component);
						iterator.remove();
						continue outerWhile;
					}
				}

				// if still > 0
				if (unrenderedComponents.size() > 0)
				{
					// Throw exception
					throw new WicketRuntimeException(
						"The component(s) below failed to render. Possible reasons could be that:\n\t1) you have added a component in code but forgot to reference it in the markup (thus the component will never be rendered),\n\t2) if your components were added in a parent container then make sure the markup for the child container includes them in .\n\n" +
							buffer.toString());
				}
			}
		}

		// Get rid of set
		renderedComponents = null;
	}

	private boolean hasInvisibleTransparentChild(final MarkupContainer root, final Component self)
	{
		for (Component sibling : root)
		{
			if ((sibling != self) && (sibling instanceof IComponentResolver) &&
				(sibling instanceof MarkupContainer))
			{
				if (!sibling.isVisible())
				{
					return true;
				}
				else
				{
					boolean rtn = hasInvisibleTransparentChild((MarkupContainer)sibling, self);
					if (rtn == true)
					{
						return true;
					}
				}
			}
		}

		return false;
	}

	/**
	 * Initializes Page by adding it to the Session and initializing it.
	 */
	@Override
	void init()
	{
		if (isBookmarkable() == false)
		{
			setStatelessHint(false);
		}

		// Set versioning of page based on default
		setVersioned(getApplication().getPageSettings().getVersionPagesByDefault());

		// All Pages are born dirty so they get clustered right away
		dirty(true);

		// this is a bit of a dirty hack, but calling dirty(true) results in isStateless called
		// which is bound to set the stateless cache to true as there are no components yet
		stateless = null;
	}

	private void setNextAvailableId()
	{
		setNumericId(getSession().nextPageId());
	}

	/**
	 * This method will be called for all components that are changed on the page So also auto
	 * components or components that are not versioned.
	 * 
	 * If the parent is given that it was a remove or add from that parent of the given component.
	 * else it was just a internal property change of that component.
	 * 
	 * @param component
	 * @param parent
	 */
	protected void componentChanged(Component component, MarkupContainer parent)
	{
		if (!component.isAuto())
		{
			dirty();
		}
	}

	/**
	 * THIS METHOD IS NOT PART OF THE WICKET PUBLIC API. DO NOT CALL OR OVERRIDE.
	 * 
	 * @see org.apache.wicket.Component#internalOnModelChanged()
	 */
	@Override
	protected final void internalOnModelChanged()
	{
		visitChildren(new IVisitor()
		{
			@Override
			public void component(final Component component, final IVisit visit)
			{
				// If form component is using form model
				if (component.sameInnermostModel(Page.this))
				{
					component.modelChanged();
				}
			}
		});
	}

	@Override
	void internalOnAfterConfigure()
	{
		super.internalOnAfterConfigure();

		// first try to check if the page can be rendered:
		if (!isRenderAllowed())
		{
			if (log.isDebugEnabled())
			{
				log.debug("Page not allowed to render: " + this);
			}
			throw new UnauthorizedActionException(this, Component.RENDER);
		}
	}

	@Override
	protected void onBeforeRender()
	{
		// Make sure it is really empty
		renderedComponents = null;

		// rendering might remove or add stateful components, so clear flag to force reevaluation
		stateless = null;

		super.onBeforeRender();

		// If any of the components on page is not stateless, we need to bind the session
		// before we start rendering components, as then jsessionid won't be appended
		// for links rendered before first stateful component
		if (getSession().isTemporary() && !peekPageStateless())
		{
			getSession().bind();
		}
	}

	@Override
	protected void onAfterRender()
	{
		super.onAfterRender();

		// Check rendering if it happened fully
		checkRendering(this);

		// clean up debug meta data if component check is on
		if (getApplication().getDebugSettings().getComponentUseCheck())
		{
			visitChildren(new IVisitor()
			{
				@Override
				public void component(final Component component, final IVisit visit)
				{
					component.setMetaData(Component.CONSTRUCTED_AT_KEY, null);
					component.setMetaData(Component.ADDED_AT_KEY, null);
				}
			});
		}

		if (!isPageStateless())
		{
			// trigger creation of the actual session in case it was deferred
			getSession().getSessionStore().getSessionId(RequestCycle.get().getRequest(), true);

			// Add/touch the response page in the session.
			getSession().getPageManager().touchPage(this);
		}

		if (getApplication().getDebugSettings().isOutputMarkupContainerClassName())
		{
			String className = Classes.name(getClass());
			getResponse().write("\n");
		}
	}

	@Override
	protected void onDetach()
	{
		if (log.isDebugEnabled())
		{
			log.debug("ending request for page " + this + ", request " + getRequest());
		}

		setFlag(FLAG_IS_DIRTY, false);

		super.onDetach();
	}

	@Override
	protected void onRender()
	{
		// Loop through the markup in this container
		MarkupStream markupStream = new MarkupStream(getMarkup());
		renderAll(markupStream, null);
	}

	/**
	 * A component was added.
	 * 
	 * @param component
	 *            The component that was added
	 */
	final void componentAdded(final Component component)
	{
		if (!component.isAuto())
		{
			dirty();
		}
	}

	/**
	 * A component's model changed.
	 * 
	 * @param component
	 *            The component whose model is about to change
	 */
	final void componentModelChanging(final Component component)
	{
		dirty();
	}

	/**
	 * A component was removed.
	 * 
	 * @param component
	 *            The component that was removed
	 */
	final void componentRemoved(final Component component)
	{
		if (!component.isAuto())
		{
			dirty();
		}
	}

	/**
	 * 
	 * @param component
	 */
	final void componentStateChanging(final Component component)
	{
		if (!component.isAuto())
		{
			dirty();
		}
	}

	/**
	 * Set page stateless
	 * 
	 * @param stateless
	 */
	void setPageStateless(Boolean stateless)
	{
		this.stateless = stateless;
	}

	@Override
	public MarkupType getMarkupType()
	{
		throw new UnsupportedOperationException(
			"Page does not support markup. This error can happen if you have extended Page directly, instead extend WebPage");
	}

	/**
	 * Gets page instance's unique identifier
	 * 
	 * @return instance unique identifier
	 */
	public PageReference getPageReference()
	{
		setStatelessHint(false);

		// make sure the page will be available on following request
		getSession().getPageManager().touchPage(this);

		return new PageReference(numericId);
	}

	@Override
	public int getPageId()
	{
		return numericId;
	}

	@Override
	public int getRenderCount()
	{
		return renderCount;
	}

	/**
	 * THIS METHOD IS NOT PART OF WICKET API. DO NOT USE!
	 *
	 * Sets the flag that determines whether or not this page was created using one of its
	 * bookmarkable constructors
	 * 
	 * @param wasCreatedBookmarkable
	 */
	public final void setWasCreatedBookmarkable(boolean wasCreatedBookmarkable)
	{
		setFlag(FLAG_WAS_CREATED_BOOKMARKABLE, wasCreatedBookmarkable);
	}

	/**
	 * Checks if this page was created using one of its bookmarkable constructors
	 * 
	 * @see org.apache.wicket.request.component.IRequestablePage#wasCreatedBookmarkable()
	 */
	@Override
	public final boolean wasCreatedBookmarkable()
	{
		return getFlag(FLAG_WAS_CREATED_BOOKMARKABLE);
	}

	@Override
	public void renderPage()
	{
		// page id is frozen during the render
		final boolean frozen = setFreezePageId(true);
		try
		{
			++renderCount;

			// delay rendering of feedbacks after all other components
			try (FeedbackDelay delay = new FeedbackDelay(getRequestCycle())) {
				beforeRender();
				
				delay.beforeRender();
			}

			markRendering(true);
			
			render();
		}
		finally
		{
			setFreezePageId(frozen);
		}
	}

	/**
	 * THIS METHOD IS NOT PART OF THE WICKET PUBLIC API. DO NOT CALL.
	 * 
	 * @param component
	 * @return if this component was render in this page
	 */
	public final boolean wasRendered(Component component)
	{
		return renderedComponents != null && renderedComponents.contains(component);
	}
}