com.bah.culvert.adapter.DatabaseAdapter.java Source code

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Here is the source code for com.bah.culvert.adapter.DatabaseAdapter.java

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/**
 * Copyright 2011 Booz Allen Hamilton.
 * 
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership. Booz Allen Hamilton
 * 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 com.bah.culvert.adapter;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.util.List;

import org.apache.hadoop.conf.Configurable;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.Writable;

import com.bah.culvert.data.CColumn;
import com.bah.culvert.util.BaseConfigurable;

/**
 * A connection to a database. Subclasses of this object are used to connect to
 * a database.
 */
public abstract class DatabaseAdapter extends BaseConfigurable implements Configurable, Writable {

    public static final byte[][] NO_SPLIT_KEYS = new byte[0][];

    /**
     * Get a connection to the specified table
     * 
     * @param tableName to connect to
     * @return a {@link TableAdapter} connecting to the specified database
     */
    public abstract TableAdapter getTableAdapter(String tableName);

    public abstract void create(String tableName, byte[][] splitKeys, List<CColumn> columns);

    public void create(String tablename, List<CColumn> columns) {
        create(tablename, NO_SPLIT_KEYS, columns);
    }

    public abstract void delete(String tableName);

    /**
     * Verifies settings to connect to a databse and access a table.
     */
    public boolean verify() {
        // noop
        return true;
    }

    public abstract boolean tableExists(String tableName);

    @Override
    public void readFields(DataInput in) throws IOException {
        Configuration conf = new Configuration();
        conf.readFields(in);
        this.verify();

    }

    @Override
    public void write(DataOutput out) throws IOException {
        this.getConf().write(out);
    }
}