Model for item lists

ccm-cms/src/main/java/org/librecms/pages/models/AbstractContentItemListItemModelBuilder.java

@@ -29,14 +29,15 @@ import javax.inject.Inject;
  * @param <T>
  * @param <M>
  */
-public abstract class AbstractContentItemListModelBuilder<T extends ContentItem, M extends AbstractContentItemListItemModel>
+public abstract class AbstractContentItemListItemModelBuilder<T extends ContentItem, M extends AbstractContentItemListItemModel>
     implements ContentItemListItemModelBuilder<T, M> {
 
     @Inject
     private GlobalizationHelper globalizationHelper;
 
     @Override
-    public M buildListItemModel(final T contentItem) {
+    @SuppressWarnings("unchecked")
+    public M buildListItemModel(final ContentItem contentItem) {
         final M model = buildModel();
         model.setDescription(
             globalizationHelper.getValueFromLocalizedString(
@@ -53,7 +54,7 @@ public abstract class AbstractContentItemListModelBuilder<T extends ContentItem,
             )
         );
 
-        addProperties(contentItem, model);
+        addProperties((T) contentItem, model);
         
         return model;
     }

ccm-cms/src/main/java/org/librecms/pages/models/ArticleListItemModelBuilder.java

@@ -28,7 +28,7 @@ import javax.enterprise.context.RequestScoped;
  */
 @RequestScoped
 public class ArticleListItemModelBuilder 
-    extends AbstractContentItemListModelBuilder<Article, ArticleListItemModel> {
+    extends AbstractContentItemListItemModelBuilder<Article, ArticleListItemModel> {
 
     @Override
     protected ArticleListItemModel buildModel() {

ccm-cms/src/main/java/org/librecms/pages/models/ContentItemListItemModelBuilder.java

@@ -28,7 +28,7 @@ import org.librecms.contentsection.ContentItem;
  */
 public interface ContentItemListItemModelBuilder<T extends ContentItem, M extends AbstractContentItemListItemModel> {
 
-    M buildListItemModel(T contentItem);
+    M buildListItemModel(ContentItem contentItem);
     
     Class<T> buildsListItemModelFor();
 

ccm-cms/src/main/java/org/librecms/pages/models/EventListItemModelBuilder.java

@@ -30,7 +30,7 @@ import javax.inject.Inject;
  * @author <a href="mailto:jens.pelzetter@googlemail.com">Jens Pelzetter</a>
  */
 public class EventListItemModelBuilder
-    extends AbstractContentItemListModelBuilder<Event, EventListItemModel> {
+    extends AbstractContentItemListItemModelBuilder<Event, EventListItemModel> {
 
     @Inject
     private GlobalizationHelper globalizationHelper;

ccm-cms/src/main/java/org/librecms/pages/models/EventModel.java

@@ -20,7 +20,6 @@ package org.librecms.pages.models;
 
 import org.libreccm.l10n.GlobalizationHelper;
 import org.librecms.contentsection.ContentItem;
-import org.librecms.contenttypes.Article;
 import org.librecms.contenttypes.Event;
 
 import java.time.ZoneId;
@@ -47,13 +46,15 @@ public class EventModel {
     private GlobalizationHelper globalizationHelper;
 
     public String getTitle() {
-        return globalizationHelper
+        return globalizationHelper.getValueFromLocalizedString(
-            .getValueFromLocalizedString(getEvent().getTitle());
+            getEvent().getTitle()
+        );
     }
 
     public String getText() {
-        return globalizationHelper
+        return globalizationHelper.getValueFromLocalizedString(
-            .getValueFromLocalizedString(getEvent().getText());
+            getEvent().getText()
+        );
     }
 
     public String getStartDateTime() {
@@ -69,13 +70,15 @@ public class EventModel {
     }
 
     public String getEventDate() {
-        return globalizationHelper
+        return globalizationHelper.getValueFromLocalizedString(
-            .getValueFromLocalizedString(getEvent().getEventDate());
+            getEvent().getEventDate()
+        );
     }
 
     public String getLocation() {
-        return globalizationHelper.
+        return globalizationHelper.getValueFromLocalizedString(
-            getValueFromLocalizedString(getEvent().getLocation());
+            getEvent().getLocation()
+        );
     }
 
     protected Event getEvent() {

ccm-cms/src/main/java/org/librecms/pages/models/ItemListModel.java

@@ -0,0 +1,412 @@
+/*
+ * Copyright (C) 2021 LibreCCM Foundation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301  USA
+ */
+package org.librecms.pages.models;
+
+import com.arsdigita.kernel.KernelConfig;
+
+import org.libreccm.categorization.Categorization;
+import org.libreccm.categorization.Category;
+import org.libreccm.configuration.ConfigurationManager;
+import org.libreccm.core.UnexpectedErrorException;
+import org.libreccm.l10n.GlobalizationHelper;
+import org.libreccm.security.Permission;
+import org.libreccm.security.PermissionChecker;
+import org.libreccm.security.Role;
+import org.libreccm.security.RoleManager;
+import org.libreccm.security.Shiro;
+import org.libreccm.security.User;
+import org.libreccm.security.UserRepository;
+import org.librecms.contentsection.ContentItem;
+import org.librecms.contentsection.ContentItemL10NManager;
+import org.librecms.contentsection.ContentItemVersion;
+import org.librecms.contentsection.privileges.ItemPrivileges;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Optional;
+import java.util.stream.Collectors;
+
+import javax.enterprise.context.RequestScoped;
+import javax.inject.Inject;
+import javax.inject.Named;
+import javax.persistence.EntityManager;
+import javax.persistence.criteria.CriteriaBuilder;
+import javax.persistence.criteria.CriteriaQuery;
+import javax.persistence.criteria.Join;
+import javax.persistence.criteria.JoinType;
+import javax.persistence.criteria.Order;
+import javax.persistence.criteria.Predicate;
+import javax.persistence.criteria.Root;
+import javax.ws.rs.WebApplicationException;
+import javax.ws.rs.core.Response;
+
+/**
+ *
+ * @author <a href="mailto:jens.pelzetter@googlemail.com">Jens Pelzetter</a>
+ */
+@RequestScoped
+@Named("CmsPagesItemListModel")
+public class ItemListModel {
+
+    @Inject
+    private CategoryModel categoryModel;
+
+    @Inject
+    private ConfigurationManager confManager;
+
+    @Inject
+    private ContentItemL10NManager itemL10NManager;
+
+    @Inject
+    private ContentItemListItemModelBuilders listItemModelBuilders;
+
+    @Inject
+    private GlobalizationHelper globalizationHelper;
+
+    @Inject
+    private EntityManager entityManager;
+
+    @Inject
+    private PermissionChecker permissionChecker;
+
+    @Inject
+    private RoleManager roleManager;
+
+    @Inject
+    private UserRepository userRepo;
+
+    @Inject
+    private Shiro shiro;
+
+    @Inject
+    private PageUrlModel pageUrlModel;
+
+    private boolean descending;
+
+    private String limitToType;
+
+    private List<String> listOrder;
+
+    private int pageSize;
+
+    private List<? extends AbstractContentItemListItemModel> itemList;
+
+    public ItemListModel() {
+        descending = false;
+        limitToType = ContentItem.class.getName();
+        listOrder = List.of(ContentItem.class.getName());
+        pageSize = 20;
+    }
+
+    public boolean isDescending() {
+        return descending;
+    }
+
+    public void setDescending(final boolean descending) {
+        this.descending = descending;
+    }
+
+    public String getLimitToType() {
+        return limitToType;
+    }
+
+    public void setLimitToType(final String limitToType) {
+        this.limitToType = limitToType;
+    }
+
+    public List<String> getListOrder() {
+        return Collections.unmodifiableList(listOrder);
+    }
+
+    public void setListOrder(final List<String> listOrder) {
+        this.listOrder = new ArrayList<>(listOrder);
+    }
+
+    public int getPageSize() {
+        return pageSize;
+    }
+
+    public void setPageSize(final int pageSize) {
+        this.pageSize = pageSize;
+    }
+
+    public int getFirstItem() {
+        return getOffset(pageSize);
+    }
+
+    public int getListSize() {
+        return getItems().size();
+    }
+
+    public List<? extends AbstractContentItemListItemModel> getItems() {
+        if (itemList == null) {
+            buildList(
+                buildLimitToType(limitToType),
+                collectCategories(categoryModel.getCategory()),
+                listOrder,
+                pageSize
+            );
+        }
+
+        return Collections.unmodifiableList(itemList);
+    }
+
+    private void buildList(
+        final Class<? extends ContentItem> limitToType,
+        final List<Category> categories,
+        final List<String> listOrder,
+        final int pageSize
+    ) {
+        final CriteriaBuilder criteriaBuilder = entityManager
+            .getCriteriaBuilder();
+        final CriteriaQuery<? extends ContentItem> criteriaQuery
+            = criteriaBuilder
+                .createQuery(limitToType);
+        final Root<? extends ContentItem> from = criteriaQuery
+            .from(limitToType);
+        final Join<? extends ContentItem, Categorization> catJoin = from
+            .join("categories");
+        final Join<? extends ContentItem, Permission> permissionsJoin = from
+            .join("permissions", JoinType.LEFT);
+
+        criteriaQuery
+            .distinct(true)
+            .where(
+                criteriaBuilder.and(
+                    catJoin.get("category").in(categories),
+                    criteriaBuilder.equal(catJoin.get("indexObject"), false),
+                    criteriaBuilder.equal(catJoin.get("type"), ""),
+                    criteriaBuilder.equal(
+                        from.get("version"), ContentItemVersion.LIVE
+                    ),
+                    buildPermissionsCheck(
+                        criteriaBuilder, from, permissionsJoin
+                    )
+                )
+            );
+
+        criteriaQuery.orderBy(
+            listOrder
+                .stream()
+                .map(order -> builderOrder(order, from, criteriaBuilder))
+                .collect(Collectors.toList())
+        );
+
+        itemList = entityManager
+            .createQuery(criteriaQuery)
+            .getResultList()
+            .stream()
+            .filter(
+                item -> itemL10NManager.hasLanguage(
+                    item, globalizationHelper.getNegotiatedLocale()
+                )
+            )
+            .skip(getOffset(pageSize))
+            .limit(pageSize)
+            .map(this::buildListItemModel)
+            .collect(Collectors.toList());
+    }
+
+    private List<Category> collectCategories(final Category category) {
+
+        if (category.getSubCategories().isEmpty()) {
+            return Collections.emptyList();
+        } else {
+            final List<Category> categories = new ArrayList<>();
+            for (final Category subCategory : category.getSubCategories()) {
+                categories.add(subCategory);
+                categories.addAll(collectCategories(subCategory));
+            }
+            return categories;
+        }
+    }
+
+    private Class<? extends ContentItem> buildLimitToType(
+        final String className
+    ) {
+        if (className == null || className.isBlank()) {
+            return ContentItem.class;
+        } else {
+            final Class<?> clazz;
+            try {
+                clazz = Class.forName(className);
+            } catch (ClassNotFoundException ex) {
+                throw new UnexpectedErrorException(ex);
+            }
+
+            if (ContentItem.class.isAssignableFrom(clazz)) {
+                @SuppressWarnings("unchecked")
+                final Class<? extends ContentItem> type
+                    = (Class<? extends ContentItem>) clazz;
+                return type;
+            } else {
+                throw new UnexpectedErrorException(String
+                    .format(
+                        "The type \"%s\" set in ItemList is not a subtype of "
+                            + "\"%s\".",
+                        clazz.getName(),
+                        ContentItem.class.getName()));
+            }
+        }
+    }
+
+    private Predicate buildPermissionsCheck(
+        final CriteriaBuilder criteriaBuilder,
+        final Root<? extends ContentItem> from,
+        final Join<? extends ContentItem, Permission> permissionsJoin
+    ) {
+        final List<Role> roles = retrieveCurrentRoles();
+
+        final boolean isSystemUser = shiro.isSystemUser();
+        final boolean isAdmin = permissionChecker.isPermitted("*");
+
+        final Predicate permissionsCheck;
+        if (roles.isEmpty()) {
+            permissionsCheck = criteriaBuilder
+                .or(
+                    criteriaBuilder.equal(criteriaBuilder.literal(true),
+                                          isSystemUser),
+                    criteriaBuilder.equal(criteriaBuilder.literal(true),
+                                          isAdmin)
+                );
+        } else {
+            permissionsCheck = criteriaBuilder
+                .or(
+                    criteriaBuilder
+                        .and(
+                            criteriaBuilder.in(permissionsJoin.get("grantee"))
+                                .value(roles),
+                            criteriaBuilder
+                                .equal(
+                                    permissionsJoin.get("grantedPrivilege"),
+                                    criteriaBuilder.selectCase()
+                                        .when(
+                                            criteriaBuilder.equal(
+                                                from.get("version"),
+                                                ContentItemVersion.DRAFT),
+                                            ItemPrivileges.PREVIEW)
+                                        .otherwise(
+                                            ItemPrivileges.VIEW_PUBLISHED))
+                        ),
+                    criteriaBuilder
+                        .equal(criteriaBuilder.literal(true),
+                               isSystemUser),
+                    criteriaBuilder
+                        .equal(criteriaBuilder.literal(true),
+                               isAdmin)
+                );
+        }
+
+        return permissionsCheck;
+    }
+
+    private List<Role> retrieveCurrentRoles() {
+        final Optional<User> user = shiro.getUser();
+        final List<Role> roles;
+        if (user.isPresent()) {
+            final User theUser = userRepo
+                .findById(user.get().getPartyId())
+                .orElseThrow(() -> new IllegalArgumentException(String
+                .format(
+                    "No user with id %d in the database. "
+                        + "Where did that ID come from?",
+                    user.get().getPartyId())));
+            roles = roleManager.findAllRolesForUser(theUser);
+        } else {
+            final Optional<User> publicUser;
+
+            final KernelConfig kernelConfig = confManager
+                .findConfiguration(KernelConfig.class);
+            final String principal = (String) shiro
+                .getPublicUser()
+                .getPrincipal();
+            if (kernelConfig.emailIsPrimaryIdentifier()) {
+                publicUser = userRepo.findByEmailAddress(principal);
+            } else {
+                publicUser = userRepo.findByName(principal);
+            }
+
+            if (publicUser.isPresent()) {
+                roles = roleManager.findAllRolesForUser(publicUser.get());
+            } else {
+                roles = Collections.emptyList();
+            }
+        }
+
+        return roles;
+    }
+
+    private Order builderOrder(
+        final String order,
+        final Root<? extends ContentItem> from,
+        final CriteriaBuilder criteriaBuilder
+    ) {
+        if (order.endsWith(" ASC")) {
+            final String colName = order
+                .substring(0, order.length() - " ASC".length());
+            return (criteriaBuilder.asc(from.get(colName)));
+        } else if (order.endsWith(" DESC")) {
+            final String colName = order
+                .substring(0, order.length() - " DESC".length());
+            return criteriaBuilder.desc(from.get(colName));
+        } else {
+            return criteriaBuilder.asc(from.get(order));
+        }
+    }
+
+    private int getOffset(final int pageSize) {
+        if (pageUrlModel.getQueryParameters().containsKey("page")) {
+            final String value = pageUrlModel.getQueryParameters().get("page");
+            if (value.matches("\\d*")) {
+                final int page = Integer.valueOf(value);
+
+                return page * pageSize;
+            } else {
+                return 0;
+            }
+        } else {
+            return 0;
+        }
+    }
+
+    private AbstractContentItemListItemModel buildListItemModel(
+        final ContentItem contentItem
+    ) {
+        final ContentItemListItemModelBuilder<?, ?> builder
+            = listItemModelBuilders.getModelBuilderFor(contentItem.getClass())
+                .orElseThrow(
+                    () -> new WebApplicationException(
+                        Response
+                            .status(Response.Status.INTERNAL_SERVER_ERROR)
+                            .entity(
+                                String.format(
+                                    "No ListItemModelBuilder for content item "
+                                        + "type %s available.",
+                                    contentItem.getClass().getName()
+                                )
+                            )
+                            .build()
+                    )
+                );
+
+        return builder.buildListItemModel(contentItem);
+    }
+
+}

ccm-cms/src/main/java/org/librecms/pages/models/MultiPartArticleListItemModel.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2021 LibreCCM Foundation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301  USA
+ */
+package org.librecms.pages.models;
+
+import org.librecms.contenttypes.MultiPartArticle;
+
+/**
+ *
+ * @author <a href="mailto:jens.pelzetter@googlemail.com">Jens Pelzetter</a>
+ */
+public class MultiPartArticleListItemModel
+    extends AbstractContentItemListItemModel {
+
+    private String summary;
+    
+    public String getSummary() {
+        return summary;
+    }
+    
+    protected void setSummary(final String summary) {
+        this.summary = summary;
+    }
+    
+    @Override
+    public String getType() {
+        return MultiPartArticle.class.getName();
+    }
+
+}

ccm-cms/src/main/java/org/librecms/pages/models/MultiPartArticleListItemModelBuilder.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2021 LibreCCM Foundation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301  USA
+ */
+package org.librecms.pages.models;
+
+import org.libreccm.l10n.GlobalizationHelper;
+import org.librecms.contenttypes.MultiPartArticle;
+
+import javax.inject.Inject;
+
+/**
+ *
+ * @author <a href="mailto:jens.pelzetter@googlemail.com">Jens Pelzetter</a>
+ */
+public class MultiPartArticleListItemModelBuilder
+    extends AbstractContentItemListItemModelBuilder<MultiPartArticle, MultiPartArticleListItemModel> {
+
+    @Inject
+    private GlobalizationHelper globalizationHelper;
+
+    @Override
+    public Class<MultiPartArticle> buildsListItemModelFor() {
+        return MultiPartArticle.class;
+    }
+
+    @Override
+    protected MultiPartArticleListItemModel buildModel() {
+        return new MultiPartArticleListItemModel();
+    }
+
+    @Override
+    protected void addProperties(
+        final MultiPartArticle article,
+        final MultiPartArticleListItemModel model
+    ) {
+        super.addProperties(article, model);
+        model.setSummary(
+            globalizationHelper.getValueFromLocalizedString(
+                article.getSummary()
+            )
+        );
+    }
+
+}

ccm-cms/src/main/java/org/librecms/pages/models/MultiPartArticleModel.java

@@ -0,0 +1,168 @@
+/*
+ * Copyright (C) 2021 LibreCCM Foundation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301  USA
+ */
+package org.librecms.pages.models;
+
+import org.libreccm.l10n.GlobalizationHelper;
+import org.librecms.contentsection.ContentItem;
+import org.librecms.contenttypes.MultiPartArticle;
+import org.librecms.contenttypes.MultiPartArticleSection;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+import javax.enterprise.context.RequestScoped;
+import javax.inject.Inject;
+import javax.inject.Named;
+import javax.ws.rs.WebApplicationException;
+import javax.ws.rs.core.Response;
+
+/**
+ *
+ * @author <a href="mailto:jens.pelzetter@googlemail.com">Jens Pelzetter</a>
+ */
+@RequestScoped
+@Named("CmsPagesMultiPartArticleModel")
+public class MultiPartArticleModel {
+
+    @Inject
+    private ContentItemModel contentItemModel;
+
+    @Inject
+    private GlobalizationHelper globalizationHelper;
+
+    @Inject
+    private PageUrlModel pageUrlModel;
+
+    public String getTitle() {
+        return globalizationHelper.getValueFromLocalizedString(
+            getMultiPartArticle().getTitle()
+        );
+    }
+
+    public String getSummary() {
+        return globalizationHelper.getValueFromLocalizedString(
+            getMultiPartArticle().getSummary()
+        );
+    }
+
+    public List<String> getSectionTitles() {
+        return getMultiPartArticle()
+            .getSections()
+            .stream()
+            .map(MultiPartArticleSection::getTitle)
+            .map(globalizationHelper::getValueFromLocalizedString)
+            .collect(Collectors.toList());
+    }
+
+    public String getCurrentSectionTitle() {
+        final int currentSection = readCurrentSection();
+        if (getMultiPartArticle().getSections().size() > currentSection) {
+            throw new WebApplicationException(
+                Response
+                    .status(Response.Status.NOT_FOUND)
+                    .entity(
+                        String.format(
+                            "MultiPartArticle %s has not section %d.",
+                            getMultiPartArticle().getDisplayName(),
+                            currentSection
+                        )
+                    )
+                    .build()
+            );
+        }
+
+        return globalizationHelper.getValueFromLocalizedString(
+            getMultiPartArticle().getSections().get(currentSection).getTitle()
+        );
+    }
+
+    public String getCurrentSectionText() {
+        final int currentSection = readCurrentSection();
+        if (getMultiPartArticle().getSections().size() > currentSection) {
+            throw new WebApplicationException(
+                Response
+                    .status(Response.Status.NOT_FOUND)
+                    .entity(
+                        String.format(
+                            "MultiPartArticle %s has not section %d.",
+                            getMultiPartArticle().getDisplayName(),
+                            currentSection
+                        )
+                    )
+                    .build()
+            );
+        }
+
+        return globalizationHelper.getValueFromLocalizedString(
+            getMultiPartArticle().getSections().get(currentSection).getText()
+        );
+    }
+
+    public List<MultiPartArticleSectionModel> getSections() {
+        return getMultiPartArticle()
+            .getSections()
+            .stream()
+            .map(this::buildSectionModel)
+            .collect(Collectors.toList());
+    }
+
+    protected MultiPartArticle getMultiPartArticle() {
+        final ContentItem contentItem = contentItemModel.getContentItem();
+        if (contentItem instanceof MultiPartArticle) {
+            return (MultiPartArticle) contentItem;
+        } else {
+            throw new WebApplicationException(
+                "Current content item is not an MultiPartArticle",
+                Response
+                    .status(Response.Status.INTERNAL_SERVER_ERROR)
+                    .entity("Current content item is not an MultiPartArticle.")
+                    .build()
+            );
+        }
+    }
+
+    private int readCurrentSection() {
+        if (pageUrlModel.getPath().matches(".*/@sections/[0-9]*$")) {
+            final String[] tokens = pageUrlModel.getPath().split("/");
+            return Integer.valueOf(tokens[tokens.length - 1]) - 1;
+        } else {
+            return 0;
+        }
+    }
+
+    private MultiPartArticleSectionModel buildSectionModel(
+        final MultiPartArticleSection fromSection
+    ) {
+        final MultiPartArticleSectionModel model
+            = new MultiPartArticleSectionModel();
+        model.setTitle(
+            globalizationHelper.getValueFromLocalizedString(
+                fromSection.getTitle()
+            )
+        );
+        model.setText(
+            globalizationHelper.getValueFromLocalizedString(
+                fromSection.getText()
+            )
+        );
+
+        return model;
+    }
+
+}

ccm-cms/src/main/java/org/librecms/pages/models/MultiPartArticleSectionModel.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2021 LibreCCM Foundation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301  USA
+ */
+package org.librecms.pages.models;
+
+/**
+ *
+ * @author <a href="mailto:jens.pelzetter@googlemail.com">Jens Pelzetter</a>
+ */
+public class MultiPartArticleSectionModel {
+
+    private String title;
+
+    private String text;
+
+    public String getTitle() {
+        return title;
+    }
+
+    protected void setTitle(final String title) {
+        this.title = title;
+    }
+
+    public String getText() {
+        return text;
+    }
+
+    protected void setText(final String text) {
+        this.text = text;
+    }
+
+}

ccm-cms/src/main/java/org/librecms/pages/models/NewsListItemModelBuilder.java

@@ -27,7 +27,7 @@ import java.time.LocalDateTime;
  * @author <a href="mailto:jens.pelzetter@googlemail.com">Jens Pelzetter</a>
  */
 public class NewsListItemModelBuilder
-    extends AbstractContentItemListModelBuilder<News, NewsListItemModel> {
+    extends AbstractContentItemListItemModelBuilder<News, NewsListItemModel> {
 
     @Override
     public Class<News> buildsListItemModelFor() {

ccm-cms/src/main/java/org/librecms/pages/models/PageUrlModel.java

@@ -0,0 +1,96 @@
+/*
+ * Copyright (C) 2021 LibreCCM Foundation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301  USA
+ */
+package org.librecms.pages.models;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+import javax.enterprise.context.RequestScoped;
+import javax.inject.Named;
+
+/**
+ * Model initalized by the Pages application containing information about the
+ * URL requested.
+ *
+ * @author <a href="mailto:jens.pelzetter@googlemail.com">Jens Pelzetter</a>
+ */
+@RequestScoped
+@Named("CmsPagesPageUrlModel")
+public class PageUrlModel {
+
+    private String protocol;
+
+    private String host;
+
+    private int port;
+
+    private String path;
+
+    private Map<String, String> queryParameters;
+
+    public String getProtocol() {
+        return protocol;
+    }
+
+    public void setProtocol(final String protocol) {
+        this.protocol = protocol;
+    }
+
+    public String getHost() {
+        return host;
+    }
+
+    public void setHost(final String host) {
+        this.host = host;
+    }
+
+    public int getPort() {
+        return port;
+    }
+
+    public void setPort(final int port) {
+        this.port = port;
+    }
+
+    public String getPath() {
+        return path;
+    }
+
+    public void setPath(final String path) {
+        this.path = path;
+    }
+
+    public PageUrlModel() {
+        queryParameters = new HashMap<>();
+    }
+
+    public Map<String, String> getQueryParameters() {
+        return Collections.unmodifiableMap(queryParameters);
+    }
+
+    public void addQueryParameter(final String key, final String value) {
+        queryParameters.put(key, value);
+    }
+
+    public void setQueryParameters(final Map<String, String> queryParameters) {
+        this.queryParameters = new HashMap<>(queryParameters);
+    }
+
+}