1  /*
     2   * Licensed to the Apache Software Foundation (ASF) under one or more
     3   *  contributor license agreements.  The ASF licenses this file to You
     4   * under the Apache License, Version 2.0 (the "License"); you may not
     5   * use this file except in compliance with the License.
     6   * You may obtain a copy of the License at
     7   *
     8   *     http://www.apache.org/licenses/LICENSE-2.0
     9   *
    10   * Unless required by applicable law or agreed to in writing, software
    11   * distributed under the License is distributed on an "AS IS" BASIS,
    12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13   * See the License for the specific language governing permissions and
    14   * limitations under the License.  For additional information regarding
    15   * copyright in this work, please see the NOTICE file in the top level
    16   * directory of this distribution.
    17   */
    18  
    19  package org.apache.roller.weblogger.business.plugins.entry;
    20  
    21  import java.io.BufferedReader;
    22  import java.io.StringReader;
    23  import java.util.Map;
    24  import org.apache.commons.logging.Log;
    25  import org.apache.commons.logging.LogFactory;
    26  import org.apache.roller.weblogger.WebloggerException;
    27  import org.apache.roller.weblogger.pojos.WeblogEntry;
    28  import org.apache.roller.weblogger.pojos.Weblog;
    29  import org.apache.roller.weblogger.business.plugins.entry.WeblogEntryPlugin;
    30  
    31  
    32  /**
    33   * Simple page plugin that converts paragraphs of plain text into html paragraphs.
    34   * We wrap each full paragraph in html <p> opening and closing tags, and
    35   * also add <br> tags to the end of lines with breaks inside a paragraph.
    36   *
    37   * Example:
    38   * This is one
    39   * paragraph
    40   *
    41   * Becomes:
    42   * <p>This is one<br/>
    43   * paragraph</p>
    44   *
    45   */
    46  public class ConvertLineBreaksPlugin implements WeblogEntryPlugin {
    47      
             /* 
    P/P       *  Method: org.apache.roller.weblogger.business.plugins.entry.ConvertLineBreaksPlugin__static_init
              * 
              *  Postconditions:
              *    init'ed(mLogger)
              */
    48      private static Log mLogger = LogFactory.getLog(ConvertLineBreaksPlugin.class);
    49      
    50      private static final String name = "Convert Line Breaks";
    51      private static final String description = "Convert plain text paragraphs to html by adding p and br tags";
    52      private static final String version = "0.1";
    53      
    54      
             /* 
    P/P       *  Method: void org.apache.roller.weblogger.business.plugins.entry.ConvertLineBreaksPlugin()
              * 
              *  Preconditions:
              *    mLogger != null
              */
    55      public ConvertLineBreaksPlugin() {
    56          mLogger.debug("Instantiating ConvertLineBreaksPlugin v"+this.version);
    57      }
    58      
    59      
    60      public String getName() {
                 /* 
    P/P           *  Method: String getName()
                  * 
                  *  Postconditions:
                  *    return_value == &"Convert Line Breaks"
                  */
    61          return name;
    62      }
    63      
    64      
    65      public String getDescription() {
                 /* 
    P/P           *  Method: String getDescription()
                  * 
                  *  Postconditions:
                  *    return_value == &"Convert plain text paragraphs to html by adding p and br tags"
                  */
    66          return description;
    67      }
    68      
    69      
    70      public void init(Weblog website) throws WebloggerException {
    71          // we don't need to do any init.
                 /* 
    P/P           *  Method: void init(Weblog)
                  * 
                  *  Preconditions:
                  *    mLogger != null
                  */
    72          mLogger.debug("initing");
    73      }
    74      
    75      
    76      /**
    77       * Transform the given plain text into html text by inserting p and br
    78       * tags around paragraphs and after line breaks.
    79       */
    80      public String render(WeblogEntry entry, String str) {
    81          
                 /* 
    P/P           *  Method: String render(WeblogEntry, String)
                  * 
                  *  Preconditions:
                  *    (soft) mLogger != null
                  * 
                  *  Postconditions:
                  *    java.lang.StringBuffer:toString(...)._tainted == 0
                  *    return_value == One-of{&"", str, &java.lang.StringBuffer:toString(...)}
                  *    return_value != null
                  * 
                  *  Test Vectors:
                  *    str: Addr_Set{null}, Inverse{null}
                  *    java.io.BufferedReader:readLine(...)@98: Addr_Set{null}, Inverse{null}
                  *    java.lang.String:equals(...)@82: {0}, {1}
                  *    java.lang.String:length(...)@100: {0}, {1..232-1}
                  *    java.lang.String:length(...)@105: {0}, {1..232-1}
                  *    java.lang.String:length(...)@109: {1..232-1}, {0}
                  */
    82          if(str == null || str.trim().equals(""))
    83              return "";
    84          
    85          mLogger.debug("Rendering string of length "+str.length());
    86          
    87          /* setup a buffered reader and iterate through each line
    88           * inserting html as needed
    89           *
    90           * NOTE: we consider a paragraph to be 2 endlines with no text between them
    91           */
    92          StringBuffer buf = new StringBuffer();
    93          try {
    94              BufferedReader br = new BufferedReader(new StringReader(str));
    95              
    96              String line = null;
    97              boolean insidePara = false;
    98              while((line = br.readLine()) != null) {
    99                  
   100                  if(!insidePara && line.trim().length() > 0) {
   101                      // start of a new paragraph
   102                      buf.append("\n<p>");
   103                      buf.append(line);
   104                      insidePara = true;
   105                  } else if(insidePara && line.trim().length() > 0) {
   106                      // another line in an existing paragraph
   107                      buf.append("<br/>\n");
   108                      buf.append(line);
   109                  } else if(insidePara && line.trim().length() < 1) {
   110                      // end of a paragraph
   111                      buf.append("</p>\n\n");
   112                      insidePara = false;
   113                  }
   114              }
   115              
   116              // if the text ends without an empty line then we need to
   117              // terminate the last paragraph now
   118              if(insidePara)
   119                  buf.append("</p>\n\n");
   120              
   121          } catch(Exception e) {
   122              mLogger.warn("trouble rendering text.", e);
   123              return str;
   124          }
   125          
   126          return buf.toString();
   127      }
   128      
   129  }