examples/triggers/src/org/apache/cassandra/triggers/InvertedIndex.java

/**
 * 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.cassandra.triggers;

import java.io.InputStream;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Properties;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.apache.cassandra.db.Cell;
import org.apache.cassandra.db.ColumnFamily;
import org.apache.cassandra.db.Mutation;
import org.apache.cassandra.io.util.FileUtils;

public class InvertedIndex implements ITrigger
{
    private static final Logger logger = LoggerFactory.getLogger(InvertedIndex.class);
    private Properties properties = loadProperties();

    public Collection<Mutation> augment(ByteBuffer key, ColumnFamily update)
    {
        List<Mutation> mutations = new ArrayList<>(update.getColumnCount());

        String indexKeySpace = properties.getProperty("keyspace");
        String indexColumnFamily = properties.getProperty("table");
        for (Cell cell : update)
        {
            // Skip the row marker and other empty values, since they lead to an empty key.
            if (cell.value().remaining() > 0)
            {
                Mutation mutation = new Mutation(indexKeySpace, cell.value());
                mutation.add(indexColumnFamily, cell.name(), key, System.currentTimeMillis());
                mutations.add(mutation);
            }
        }

        return mutations;
    }

    private static Properties loadProperties()
    {
        Properties properties = new Properties();
        InputStream stream = InvertedIndex.class.getClassLoader().getResourceAsStream("InvertedIndex.properties");
        try
        {
            properties.load(stream);
        }
        catch (Exception e)
        {
            throw new RuntimeException(e);
        }
        finally
        {
            FileUtils.closeQuietly(stream);
        }
        logger.info("loaded property file, InvertedIndex.properties");
        return properties;
    }
}