/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.jena.tdb.transaction;

import org.apache.jena.query.ReadWrite ;
import org.apache.jena.sparql.core.DatasetGraphWrapper;
import org.apache.jena.tdb.store.DatasetGraphTDB;

/**
 * A DatasetGraph that is a single transaction.
 * It does not support transactions.
 * It is the DatasetGraph aspect of a Transaction (single use).
 */
public class DatasetGraphTxn extends DatasetGraphWrapper {
    
    private Transaction transaction;

    /*package*/ DatasetGraphTxn(DatasetGraphTDB dsg, Transaction txn) {
        super(dsg);
        this.transaction = txn;
    }

    public Transaction getTransaction() {
        return transaction;
    }

    /** Return the view (storage) for this transaction */
    public DatasetGraphTDB getView() {
        return (DatasetGraphTDB)getWrapped();
    }

    @Override public void begin(ReadWrite mode) { 
        throw new IllegalStateException() ;
    }
    
    @Override
    public void commit() {
        transaction.commit();
    }

    @Override
    public void abort() {
        transaction.abort();
    }

    @Override
    public String toString() {
        return "Txn:" + super.toString();
    }

    @Override
    public void end() {
        if ( transaction != null )
            transaction.close();
        transaction = null;
    }
}