CorePageInstanceLinkGenerator.java

package fr.openwide.core.wicket.more.link.descriptor.impl;

import java.util.Collection;

import org.apache.wicket.Component;
import org.apache.wicket.Page;
import org.apache.wicket.RestartResponseAtInterceptPageException;
import org.apache.wicket.RestartResponseException;
import org.apache.wicket.Session;
import org.apache.wicket.behavior.AttributeAppender;
import org.apache.wicket.core.request.handler.PageProvider;
import org.apache.wicket.core.request.handler.RenderPageRequestHandler;
import org.apache.wicket.model.IModel;
import org.apache.wicket.request.Url;
import org.apache.wicket.request.cycle.RequestCycle;
import org.apache.wicket.request.flow.RedirectToUrlException;

import com.google.common.base.Function;
import com.google.common.base.Joiner;
import com.google.common.collect.Collections2;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Lists;

import fr.openwide.core.wicket.more.link.descriptor.AbstractDynamicBookmarkableLink;
import fr.openwide.core.wicket.more.link.descriptor.LinkInvalidTargetRuntimeException;
import fr.openwide.core.wicket.more.link.descriptor.generator.ILinkGenerator;
import fr.openwide.core.wicket.more.link.descriptor.generator.IPageLinkGenerator;
import fr.openwide.core.wicket.more.link.descriptor.parameter.injector.LinkParameterInjectionRuntimeException;
import fr.openwide.core.wicket.more.link.descriptor.parameter.validator.LinkParameterValidationRuntimeException;
import fr.openwide.core.wicket.more.markup.html.template.model.NavigationMenuItem;
import fr.openwide.core.wicket.more.util.model.Models;

public class CorePageInstanceLinkGenerator implements IPageLinkGenerator {
	
	private static final long serialVersionUID = -1568375367568280290L;

	private static final String ANCHOR_ROOT = "#";
	
	private static final GetNameFromClassModelFunction GET_NAME_FROM_CLASS_MODEL_FUNCTION = new GetNameFromClassModelFunction();
	
	private final IModel<? extends Page> pageInstanceModel;
	
	private boolean bypassPermissions = false;
	
	private final Collection<IModel<? extends Class<? extends Page>>> expectedPageClassModels;
	
	public CorePageInstanceLinkGenerator(IModel<? extends Page> pageInstanceModel, Collection<IModel<? extends Class<? extends Page>>> expectedPageClassModels) {
		this.pageInstanceModel = pageInstanceModel;
		this.expectedPageClassModels = expectedPageClassModels;
	}
	
	@Override
	public IPageLinkGenerator wrap(Component component) {
		Collection<IModel<? extends Class<? extends Page>>> wrapedPageClassModels = Lists.newArrayList();
		for (IModel<? extends Class<? extends Page>> expectedPageClassModel : expectedPageClassModels) {
			wrapedPageClassModels.add(Models.wrap(expectedPageClassModel, component));
		}
		return new CorePageInstanceLinkGenerator(
				Models.wrap(pageInstanceModel, component),
				wrapedPageClassModels
		);
	}
	
	protected Class<? extends Page> getValidExpectedPageClass(Page pageInstance) {
		if (expectedPageClassModels.isEmpty()) {
			return pageInstance.getClass();
		}
		for (IModel<? extends Class<? extends Page>> expectedPageClassModel : expectedPageClassModels) {
			Class<? extends Page> expectedPageClass = expectedPageClassModel.getObject();
			if (expectedPageClass != null && expectedPageClass.isAssignableFrom(pageInstance.getClass())) {
				return expectedPageClass;
			}
		}
		return null;
	}

	protected Page getValidPageInstance() throws LinkInvalidTargetRuntimeException {
		Page pageInstance = pageInstanceModel.getObject();
		if (pageInstance == null) {
			throw new LinkInvalidTargetRuntimeException("The target page instance was null");
		}
		
		Class<? extends Page> validPageClass = getValidExpectedPageClass(pageInstance);
		
		if (validPageClass == null) {
			throw new LinkInvalidTargetRuntimeException("The target page instance '" + pageInstance + "' had unexpected type :"
					+ " got " + pageInstance.getClass().getName() + ", "
					+ "expected one of " + Joiner.on(", ").join(Collections2.transform(expectedPageClassModels, GET_NAME_FROM_CLASS_MODEL_FUNCTION)));
		}
		
		if (! bypassPermissions) {
			if (!Session.get().getAuthorizationStrategy().isActionAuthorized(pageInstance, Page.RENDER)) {
				throw new LinkInvalidTargetRuntimeException("The rendering of the target page instance '" + pageInstance
						+ "' was not authorized.");
			}
		}
		
		return pageInstance;
	}
	
	@Override
	public boolean isAccessible() {
		Page pageInstance = pageInstanceModel.getObject();
		if (pageInstance == null) {
			return false;
		}
		Class<? extends Page> validPageClass = getValidExpectedPageClass(pageInstance);
		if (validPageClass == null) {
			return false;
		}
		return Session.get().getAuthorizationStrategy().isActionAuthorized(pageInstance, Page.RENDER);
	}
	
	@Override
	public ILinkGenerator chain(ILinkGenerator other) {
		if (other instanceof IPageLinkGenerator) {
			return chain((IPageLinkGenerator) other);
		}
		return new ChainedLinkGeneratorImpl(ImmutableList.of(this, other));
	}
	
	@Override
	public IPageLinkGenerator chain(IPageLinkGenerator other) {
		return new ChainedPageLinkGeneratorImpl(ImmutableList.of(this, other));
	}
	
	@Override
	public String url() throws LinkInvalidTargetRuntimeException {
		return url(RequestCycle.get());
	}
	
	@Override
	public String url(RequestCycle requestCycle) throws LinkInvalidTargetRuntimeException {
		return requestCycle.urlFor(
						new RenderPageRequestHandler(new PageProvider(getValidPageInstance()))
				).toString();
	}

	@Override
	public String fullUrl() throws LinkInvalidTargetRuntimeException {
		return fullUrl(RequestCycle.get());
	}

	@Override
	public String fullUrl(RequestCycle requestCycle) throws LinkInvalidTargetRuntimeException {
		return requestCycle.getUrlRenderer().renderFullUrl(Url.parse(url(requestCycle)));
	}

	@Override
	public AbstractDynamicBookmarkableLink link(String wicketId) {
		return new DynamicBookmarkablePageInstanceLink(wicketId, this);
	}
	
	@Override
	public AbstractDynamicBookmarkableLink link(String wicketId, String anchor) {
		AbstractDynamicBookmarkableLink link = link(wicketId);
		link.add(new AttributeAppender("href", ANCHOR_ROOT + anchor));
		
		return link;
	}

	@Override
	public void setResponsePage() throws LinkInvalidTargetRuntimeException, LinkParameterValidationRuntimeException, LinkParameterInjectionRuntimeException {
		RequestCycle.get().setResponsePage(getValidPageInstance());
	}

	@Override
	public RestartResponseException newRestartResponseException() throws LinkInvalidTargetRuntimeException {
		return new RestartResponseException(getValidPageInstance());
	}

	@Override
	public RestartResponseAtInterceptPageException newRestartResponseAtInterceptPageException()
			throws LinkInvalidTargetRuntimeException {
		return new RestartResponseAtInterceptPageException(getValidPageInstance());
	}

	@Override
	public RedirectToUrlException newRedirectToUrlException() throws LinkInvalidTargetRuntimeException {
		return new RedirectToUrlException(fullUrl());
	}

	@Override
	public RedirectToUrlException newRedirectToUrlException(String anchor) throws LinkInvalidTargetRuntimeException {
		return new RedirectToUrlException(fullUrl() + ANCHOR_ROOT + anchor);
	}

	@Override
	public NavigationMenuItem navigationMenuItem(IModel<String> labelModel) throws LinkInvalidTargetRuntimeException {
		return navigationMenuItem(labelModel, Lists.<NavigationMenuItem>newArrayListWithExpectedSize(0));
	}

	@Override
	public NavigationMenuItem navigationMenuItem(IModel<String> labelModel, Collection<NavigationMenuItem> subMenuItems)
			throws LinkInvalidTargetRuntimeException {
		return new NavigationMenuItem(labelModel, this, subMenuItems);
	}

	@Override
	public boolean isActive(Class<? extends Page> selectedPage) {
		throw new IllegalStateException("We may not call isActive on a page instance link.");
	}

	@Override
	public void detach() {
		pageInstanceModel.detach();
		
		for (IModel<? extends Class<? extends Page>> expectedPageClassModel : expectedPageClassModels) {
			expectedPageClassModel.detach();
		}
	}
	
	private static class GetNameFromClassModelFunction implements Function<IModel<? extends Class<?>>, String> {
		@Override
		public String apply(IModel<? extends Class<?>> input) {
			if (input.getObject() != null) {
				return input.getObject().getName();
			}
			return null;
		}
	}

	@Override
	public PageProvider newPageProvider() {
		return new PageProvider(getValidPageInstance());
	}
	
	/**
	 * @see IPageLinkGenerator#bypassPermissions()
	 */
	@Deprecated
	@Override
	public IPageLinkGenerator bypassPermissions() {
		bypassPermissions = true;
		return this;
	}

}