java source code of EntryUtils

/*
 * Copyright (C) 2009 Google Inc.
 *
 * Licensed 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 com.google.sites.liberation.util;

import static com.google.sites.liberation.util.EntryType.COMMENT;
import static com.google.sites.liberation.util.EntryType.LIST_ITEM;
import static com.google.sites.liberation.util.EntryType.LIST_PAGE;
import static com.google.sites.liberation.util.EntryType.getType;

import com.google.common.collect.Maps;
import com.google.gdata.data.ILink;
import com.google.gdata.data.Link;
import com.google.gdata.data.TextConstruct;
import com.google.gdata.data.XhtmlTextConstruct;
import com.google.gdata.data.sites.BaseContentEntry;
import com.google.gdata.data.sites.BasePageEntry;
import com.google.gdata.data.sites.CommentEntry;
import com.google.gdata.data.sites.ListItemEntry;
import com.google.gdata.data.sites.ListPageEntry;
import com.google.gdata.data.sites.SitesLink;
import com.google.gdata.data.spreadsheet.Column;
import com.google.gdata.data.spreadsheet.Data;
import com.google.gdata.data.spreadsheet.Field;
import com.google.gdata.data.threading.InReplyTo;
import com.google.gdata.util.XmlBlob;

import java.util.Comparator;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * Provides utility methods for dealing with BaseContentEntry's.
 * 
 * @author [email protected] (Benjamin Simon)
 */
public class EntryUtils {

  private static final Logger LOGGER = Logger.getLogger(
      EntryUtils.class.getCanonicalName());  
  
  /**
   * Returns the id given by the given entry's parent link, or null if it has
   * no parent link.
   */
  public static String getParentId(BaseContentEntry<?> entry) {
    Link link = entry.getLink(SitesLink.Rel.PARENT, ILink.Type.ATOM);
    if (link == null) {
      return null;
    }
    return link.getHref();
  }
  
  /**
   * Sets the parent link of the given entry to the given id
   */
  public static void setParentId(BaseContentEntry<?> entry, String id) {
    entry.addLink(SitesLink.Rel.PARENT, ILink.Type.ATOM, id);
  }
  
  /**
   * Sets all parent-related fields in the given entry for the given parent. 
   */
  public static void setParent(BaseContentEntry<?> entry, 
      BasePageEntry<?> parent) {
    entry.addLink(SitesLink.Rel.PARENT, ILink.Type.ATOM, parent.getId());
    if (getType(entry) == COMMENT) {
      InReplyTo inReplyTo = new InReplyTo();
      inReplyTo.setHref(
          parent.getLink(ILink.Rel.ALTERNATE, "text/html").getHref()); 
      inReplyTo.setRef(parent.getId());
      // TODO(gk5885): remove extra cast for
      // http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6302214
      ((CommentEntry) (BaseContentEntry) entry).setInReplyTo(inReplyTo);
    } else if (getType(entry) == LIST_ITEM) {
      if (getType(parent) != LIST_PAGE) {
        throw new IllegalStateException("List items can only be descendents of " 
            + "list pages!");
      }
      // TODO(gk5885): remove extra casts for
      // http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6302214
      ListItemEntry listItem = (ListItemEntry) (BaseContentEntry) entry;
      ListPageEntry listPage = (ListPageEntry) (BasePageEntry) parent;
      Data data = listPage.getData();
      Map<String, String> names = Maps.newHashMap();
      for (Column column : data.getColumns()) {
        names.put(column.getIndex(), column.getName());
      }
      for (Field field : listItem.getFields()) {
        String name = names.get(field.getIndex());
        field.setName(name);
      }
    }
  }
  
  /**
   * Returns the given entry's xhtml content as a String.
   */
  public static String getXhtmlContent(BaseContentEntry<?> entry) {
    try {
      String content = ((XhtmlTextConstruct)(entry.getTextContent()
          .getContent())).getXhtml().getBlob();
      //This is due to a bug in the GData client: http://b/issue?id=2044419
      while (content.contains("]]>")) {
        content = content.replace("]]>", "]]&gt;");
      }
      //This is due to a bug in the Sites client: http://b/issue?id=1993403
      int startIndex = content.indexOf("<iframe");
      while (startIndex != -1) {
        int endIndex = content.indexOf(">", startIndex);
        if (content.charAt(endIndex - 1) == '/') {
          content = content.substring(0, endIndex - 1) + "></iframe" 
              + content.substring(endIndex);
        }
        startIndex = content.indexOf("<iframe", endIndex);
      }
      return content;
    } catch(IllegalStateException e) {
      LOGGER.log(Level.WARNING, "Invalid Content", e);
      return "";
    } catch(ClassCastException e) {
      LOGGER.log(Level.WARNING, "Invalid Content", e);
      return "";
    } catch(NullPointerException e) {
      LOGGER.log(Level.WARNING, "Invalid Content", e);
      return "";
    }
  }
  
  /**
   * Sets the content of the given entry to the given String.
   */
  public static void setContent(BaseContentEntry<?> entry, String content) {
    XmlBlob blob = new XmlBlob();
    blob.setBlob(content);
    TextConstruct textConstruct = new XhtmlTextConstruct(blob);
    entry.setContent(textConstruct);
  }
  
  /**
   * Returns a new Comparator that orders BaseContentEntry's based on
   * their updated times (earlier updated times come first).
   */
  public static Comparator<BaseContentEntry<?>> getUpdatedComparator() {
    return new UpdatedComparator(true);
  }
  
  /**
   * Returns a new Comparator that orders BaseContentEntry's based on
   * their updated times (later updated times come first).
   */
  public static Comparator<BaseContentEntry<?>> getReverseUpdatedComparator() {
    return new UpdatedComparator(false);
  }
  
  /**
   * Returns a new Comparator that orders BaseContentEntry's alphabetically
   * by their titles.
   */
  public static Comparator<BaseContentEntry<?>> getTitleComparator() {
    return new TitleComparator();
  }
  
  /**
   * Compares BaseContentEntry's based on their titles.
   */
  private static class TitleComparator implements Comparator<BaseContentEntry<?>> {
    
    /**
     * Returns a positive integer if {@code e1}'s title comes after {@code e2}'s
     * title alphabetically.
     */
    @Override
    public int compare(BaseContentEntry<?> e1, BaseContentEntry<?> e2) {
      return e1.getTitle().getPlainText().compareTo(e2.getTitle().getPlainText());
    }
  }
  
  /** 
   * Compares BaseContentEntry's based on when they were last updated.
   */
  private static class UpdatedComparator implements Comparator<BaseContentEntry<?>> {
    
    private boolean forward;
    
    public UpdatedComparator(boolean forward) {
      this.forward = forward;
    }
    
    /**
     * Orders two entries such that the more recently updated entry comes first.
     */
    @Override
    public int compare(BaseContentEntry<?> e1, BaseContentEntry<?> e2) {
      int compare = e1.getUpdated().compareTo(e2.getUpdated());
      return forward ? compare : -compare;
    }
  }
}