distributedlog-core/src/main/java/org/apache/distributedlog/EntryBuffer.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.distributedlog;

import io.netty.buffer.ByteBuf;
import java.io.IOException;
import org.apache.distributedlog.exceptions.InvalidEnvelopedEntryException;

/**
 * Write representation of a {@link Entry}.
 * It is a buffer of log record set, used for transmission.
 */
interface EntryBuffer extends TransmitListener {

    /**
     * Return if this record set contains user records.
     *
     * @return true if this record set contains user records, otherwise
     * return false.
     */
    boolean hasUserRecords();

    /**
     * Return number of records in current record set.
     *
     * @return number of records in current record set.
     */
    int getNumRecords();

    /**
     * Return number of bytes in current record set.
     *
     * @return number of bytes in current record set.
     */
    int getNumBytes();

    /**
     * Return max tx id in current record set.
     *
     * @return max tx id.
     */
    long getMaxTxId();

    /**
     * Get the buffer to transmit.
     *
     * <p>The caller is responsible for releasing the reference of the returned bytebuf object.
     *
     * @return the buffer to transmit.
     * @throws InvalidEnvelopedEntryException if the record set buffer is invalid
     * @throws IOException when encountered IOException during serialization
     */
    ByteBuf getBuffer() throws InvalidEnvelopedEntryException, IOException;

}