external/storm-kafka/src/jvm/storm/kafka/StringScheme.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 storm.kafka;

import backtype.storm.spout.Scheme;
import backtype.storm.tuple.Fields;
import backtype.storm.tuple.Values;
import backtype.storm.utils.Utils;

import java.nio.ByteBuffer;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.List;

public class StringScheme implements Scheme {
    private static final Charset UTF8_CHARSET = StandardCharsets.UTF_8;
    public static final String STRING_SCHEME_KEY = "str";

    public List<Object> deserialize(ByteBuffer bytes) {
        return new Values(deserializeString(bytes));
    }

    public static String deserializeString(ByteBuffer string) {
        if (string.hasArray()) {
            int base = string.arrayOffset();
            return new String(string.array(), base + string.position(), string.remaining());
        } else {
            return new String(Utils.toByteArray(string), UTF8_CHARSET);
        }
    }

    public Fields getOutputFields() {
        return new Fields(STRING_SCHEME_KEY);
    }
}