DbTree.java

package com.sleepycat.je.dbi;
public class DbTree {
  /** 
 * To truncate, remove the database named by databaseName and create a new
 * database in its place.
 * @param returnCountif true, must return the count of records in the database,
 * which can be an expensive option.
 */
  long truncate(  Locker locker,  String databaseName,  boolean returnCount) throws DatabaseException {
    CursorImpl nameCursor=null;
    Locker autoTxn=null;
    try {
      NameLockResult result=lockNameLN(locker,databaseName,"truncate");
      nameCursor=result.nameCursor;
      if (nameCursor == null) {
        return 0;
      }
 else {
        DatabaseId newId=new DatabaseId(getNextDbId());
        DatabaseImpl newDb=(DatabaseImpl)result.dbImpl.clone();
        newDb.setId(newId);
        newDb.setTree(new Tree(newDb));
        CursorImpl idCursor=null;
        boolean operationOk=false;
        try {
          autoTxn=createLocker(envImpl);
          idCursor=new CursorImpl(idDatabase,autoTxn);
          idCursor.putLN(newId.getBytes(),new MapLN(newDb),false);
          operationOk=true;
        }
  finally {
          if (idCursor != null) {
            idCursor.close();
          }
          if (autoTxn != null) {
            autoTxn.operationEnd(operationOk);
          }
        }
        result.nameLN.setId(newDb.getId());
        long recordCount=0;
        if (returnCount) {
          recordCount=result.dbImpl.countRecords();
        }
        DatabaseEntry dataDbt=new DatabaseEntry(new byte[0]);
        nameCursor.putCurrent(dataDbt,null,null);
        this.hook296(locker,result,newDb);
        return recordCount;
      }
    }
 catch (    CloneNotSupportedException CNSE) {
      throw new DatabaseException(CNSE);
    }
 finally {
      if (nameCursor != null) {
        this.hook294(nameCursor);
        nameCursor.close();
      }
    }
  }
  /** 
 * Truncate a database named by databaseName. Return the new DatabaseImpl
 * object that represents the truncated database. The old one is marked as
 * deleted.
 * @deprecated This method used by Database.truncate()
 */
  TruncateResult truncate(  Locker locker,  DatabaseImpl oldDatabase,  boolean returnCount) throws DatabaseException {
    CursorImpl nameCursor=new CursorImpl(nameDatabase,locker);
    try {
      String databaseName=getDbName(oldDatabase.getId());
      DatabaseEntry keyDbt=new DatabaseEntry(databaseName.getBytes("UTF-8"));
      boolean found=(nameCursor.searchAndPosition(keyDbt,null,SearchMode.SET,LockType.WRITE) & CursorImpl.FOUND) != 0;
      if (!found) {
        throw new DatabaseException("Database " + databaseName + " not found in map tree");
      }
      NameLN nameLN=(NameLN)nameCursor.getCurrentLNAlreadyLatched(LockType.WRITE);
      assert nameLN != null;
      int handleCount=oldDatabase.getReferringHandleCount();
      if (handleCount > 1) {
        throw new DatabaseException("Can't truncate database " + databaseName + ","+ handleCount+ " open databases exist");
      }
      DatabaseImpl newDb;
      DatabaseId newId=new DatabaseId(getNextDbId());
      newDb=(DatabaseImpl)oldDatabase.clone();
      newDb.setId(newId);
      newDb.setTree(new Tree(newDb));
      CursorImpl idCursor=null;
      boolean operationOk=false;
      Locker autoTxn=null;
      try {
        autoTxn=createLocker(envImpl);
        idCursor=new CursorImpl(idDatabase,autoTxn);
        idCursor.putLN(newId.getBytes(),new MapLN(newDb),false);
        operationOk=true;
      }
  finally {
        if (idCursor != null) {
          idCursor.close();
        }
        if (autoTxn != null) {
          autoTxn.operationEnd(operationOk);
        }
      }
      nameLN.setId(newDb.getId());
      long count=0;
      if (returnCount) {
        count=oldDatabase.countRecords();
      }
      this.hook297(locker,oldDatabase);
      DatabaseEntry dataDbt=new DatabaseEntry(new byte[0]);
      nameCursor.putCurrent(dataDbt,null,null);
      return new TruncateResult(newDb,(int)count);
    }
 catch (    CloneNotSupportedException CNSE) {
      throw new DatabaseException(CNSE);
    }
catch (    UnsupportedEncodingException UEE) {
      throw new DatabaseException(UEE);
    }
 finally {
      this.hook295(nameCursor);
      nameCursor.close();
    }
  }
  protected void hook294(  CursorImpl nameCursor) throws DatabaseException {
  }
  protected void hook295(  CursorImpl nameCursor) throws DatabaseException {
  }
  protected void hook296(  Locker locker,  NameLockResult result,  DatabaseImpl newDb) throws DatabaseException, CloneNotSupportedException {
  }
  protected void hook297(  Locker locker,  DatabaseImpl oldDatabase) throws DatabaseException, CloneNotSupportedException, UnsupportedEncodingException {
  }
}