Data commit

Task/Rosetta-Code-Rank-languages-by-popularity/Java/rosetta-code-rank-languages-by-popularity.java

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+import  java.net.URL;
+import  java.net.URLConnection;
+import  java.io.*;
+import  java.util.*;
+
+public class GetRCLanguages
+{
+    // Custom sort Comparator for sorting the language list
+    // assumes the first character is the page count and the rest is the language name
+    private static class LanguageComparator implements Comparator<String>
+    {
+        public int compare( String a, String b )
+        {
+            // as we "know" we will be comparaing languages, we will assume the Strings have the appropriate format
+            int result = ( b.charAt( 0 ) - a.charAt( 0 ) );
+            if( result == 0 )
+            {
+                // the counts are the same - compare the names
+                result = a.compareTo( b );
+            } // if result == 0
+        return result;
+        } // compare
+    } // LanguageComparator
+
+    // get the string following marker in text
+    private static String after( String text, int marker )
+    {
+        String result = "";
+        int    pos    = text.indexOf( marker );
+        if( pos >= 0 )
+        {
+            // the marker is in the string
+            result = text.substring( pos + 1 );
+        } // if pos >= 0
+    return result;
+    } // after
+
+    // read and parse the content of path
+    // results returned in gcmcontinue and languageList
+    public static void parseContent( String path
+                                   , String[] gcmcontinue
+                                   , ArrayList<String> languageList
+                                   )
+    {
+        try
+        {
+
+            URL            url = new URL( path );
+            URLConnection  rc  = url.openConnection();
+            // Rosetta Code objects to the default Java user agant so use a blank one
+            rc.setRequestProperty( "User-Agent", "" );
+            BufferedReader bfr = new BufferedReader( new InputStreamReader( rc.getInputStream() ) );
+
+            gcmcontinue[0]      = "";
+            String languageName = "?";
+            String line         = bfr.readLine();
+            while( line != null )
+            {
+                line = line.trim();
+                if     ( line.startsWith( "[title]" ) )
+                {
+                    // have a programming language - should look like "[title] => Category:languageName"
+                    languageName = after( line, ':' ).trim();
+                }
+                else if( line.startsWith( "[pages]" ) )
+                {
+                    // number of pages the language has (probably)
+                    String pageCount = after( line, '>' ).trim();
+                    if( pageCount.compareTo( "Array" ) != 0 )
+                    {
+                        // haven't got "[pages] => Array" - must be a number of pages
+                        languageList.add( ( (char) Integer.parseInt( pageCount ) ) + languageName );
+                        languageName = "?";
+                    } // if [pageCount.compareTo( "Array" ) != 0
+                }
+                else if( line.startsWith( "[gcmcontinue]" ) )
+                {
+                    // have an indication of wether there is more data or not
+                    gcmcontinue[0] = after( line, '>' ).trim();
+                } // if various line starts
+                line = bfr.readLine();
+            } // while line != null
+            bfr.close();
+        }
+        catch( Exception e )
+        {
+            e.printStackTrace();
+        } // try-catch
+    } // parseContent
+
+    public static void main( String[] args )
+    {
+        // get the languages
+        ArrayList<String> languageList = new ArrayList<String>( 1000 );
+        String[]          gcmcontinue  = new String[1];
+        gcmcontinue[0]                 = "";
+        do
+        {
+            String path = ( "http://www.rosettacode.org/mw/api.php?action=query"
+                          + "&generator=categorymembers"
+                          + "&gcmtitle=Category:Programming%20Languages"
+                          + "&gcmlimit=500"
+                          + ( gcmcontinue[0].compareTo( "" ) == 0 ? "" : ( "&gcmcontinue=" + gcmcontinue[0] ) )
+                          + "&prop=categoryinfo"
+                          + "&format=txt"
+                          );
+            parseContent( path, gcmcontinue, languageList );
+        }
+        while( gcmcontinue[0].compareTo( "" ) != 0 );
+        // sort the languages
+        String[] languages = languageList.toArray(new String[]{});
+        Arrays.sort( languages, new LanguageComparator() );
+        // print the languages
+        int    lastTie    = -1;
+        int    lastCount  = -1;
+        for( int lPos = 0; lPos < languages.length; lPos ++ )
+        {
+            int    count = (int) ( languages[ lPos ].charAt( 0 ) );
+            System.out.format( "%4d: %4d: %s\n"
+                             , 1 + ( count == lastCount ? lastTie : lPos )
+                             , count
+                             , languages[ lPos ].substring( 1 )
+                             );
+            if( count != lastCount )
+            {
+                lastTie   = lPos;
+                lastCount = count;
+            } // if count != lastCount
+        } // for lPos
+    } // main
+} // GetRCLanguages