package org.paneris.bibliomania.fti;

 import java.io.File;

 import java.io.IOException;

 import org.melati.util.UnexpectedExceptionException;

 import com.sleepycat.db.Database;

 import com.sleepycat.db.DatabaseConfig;

 import com.sleepycat.db.DatabaseException;

 import com.sleepycat.db.DatabaseType;

 import com.sleepycat.db.MemoryException;

 import com.sleepycat.db.Cursor;

 import com.sleepycat.db.DatabaseEntry;

 import com.sleepycat.db.OperationStatus;

 import com.sleepycat.db.Transaction;

 public class DbUtils {

   public static void setUserMem(DatabaseEntry databaseEntry, int size) {

     databaseEntry.setData(new byte[size]);

     databaseEntry.setSize(size);

     databaseEntry.setUserBuffer(size, true);

   }

   public static void setUserMem(DatabaseEntry databaseEntry, byte[] data) {

     databaseEntry.setData(data);

     databaseEntry.setSize(data.length);

     databaseEntry.setUserBuffer(data.length, true);

   }

   public static DatabaseEntry userMemDatabaseEntry(int size) {

     DatabaseEntry databaseEntry = new DatabaseEntry();

     setUserMem(databaseEntry, size);

     return databaseEntry;

   }

   public static DatabaseEntry userMemDatabaseEntry(byte[] data) {

     DatabaseEntry DatabaseEntry = new DatabaseEntry();

     setUserMem(DatabaseEntry, data);

     return DatabaseEntry;

   }

   public static class UnexpectedDatabaseExceptionException

     extends UnexpectedExceptionException {

     private static final long serialVersionUID = -3258846592503363130L;

     public String path;

     public UnexpectedDatabaseExceptionException(Exception exception, String path) {

       super(exception);

       this.path = path == null ? "<unknown>" : path;

     }

     public String getMessage() {

       return "An unexpected exception arose using the Database `"

         + path

         + "':\n"

         + subException;

     }

   }

   public static OperationStatus get(Database Database, DatabaseEntry key, DatabaseEntry value, int estimate) {

     byte[] buf = value.getData();

     if (buf == null || buf.length == 0)

       buf = new byte[estimate];

     for (;;) {

       setUserMem(value, buf);

       try {

         return Database.get((Transaction)null, key, value, null); // was 0

       } catch (MemoryException e) {

         buf = new byte[buf.length * 2];

       } catch (DatabaseException e) {

         throw new UnexpectedDatabaseExceptionException(e, null);

       }

     }

   }

   public static OperationStatus get(Cursor cursor, DatabaseEntry key, DatabaseEntry value, int flags, int estimate) {

     byte[] buf = value.getData();

     if (buf == null || buf.length == 0)

       buf = new byte[estimate];

     for (;;) {

       setUserMem(value, buf);

       try {

         //return cursor.get(key, value, flags);

         return cursor.getFirst(key, value, null);

       } catch (MemoryException e) {

         buf = new byte[buf.length * 2];

       } catch (DatabaseException e) {

         throw new UnexpectedDatabaseExceptionException(e, null);

       }

     }

   }

   public static Database openOrCreateBTreeDb(File dir, String name, int cacheSize) 

       throws IOException, DatabaseException { 

     DatabaseConfig dc = new DatabaseConfig();

     if (cacheSize != 0)

       dc.setCacheSize(cacheSize);

     dc.setAllowCreate(true);

     dc.setType(DatabaseType.BTREE);

     if (new File(dir, name + ".db").exists())

       Database.upgrade(new File(dir, name + ".db").getPath(), dc);

     // db name should probably have been specified, but it was not

     Database it =  new Database(new File(dir, name + ".db").getPath(), 

         null, dc);

     return it;

   }

   public static void main(final String[] args) throws Exception {

     String dbHome = "/usr/local/share/bibliomania/workspace";

     openOrCreateBTreeDb(new File(dbHome), "idOfWord", 0);

     openOrCreateBTreeDb(new File(dbHome), "occurrencesOfWordInText",0);

     openOrCreateBTreeDb(new File(dbHome), "anchorOfIndex", 0);

     openOrCreateBTreeDb(new File(dbHome), "blockmarkOfIndex", 0);

     openOrCreateBTreeDb(new File(dbHome), "wordsInText", 0);

   }

 }