com.wepay.waltz.common.metadata.ReplicaId Maven / Gradle / Ivy

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Waltz is a distributed/replicated write ahead log for transactions.

There is a newer version: 0.13.2

package com.wepay.waltz.common.metadata;

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

/**
 * This class is used to identify a replica using the partition Id and the
 * Storage noce connect string.
 */
public class ReplicaId implements Comparable {

    private static final byte VERSION = 1;

    public final int partitionId;
    public final String storageNodeConnectString;

    /**
     * Class constructor.
     * @param partitionId The partition Id.
     * @param storageNodeConnectString Storage connect string in host:port format.
     */
    public ReplicaId(int partitionId, String storageNodeConnectString) {
        this.partitionId = partitionId;
        this.storageNodeConnectString = storageNodeConnectString;
    }

    /**
     * Writes replica Id metadata via the {@link DataOutput} provided.
     * @param out The interface that converts the data to a series of bytes.
     * @throws IOException thrown if the write fails.
     */
    public void writeTo(DataOutput out) throws IOException {
        out.writeByte(VERSION);
        out.writeInt(partitionId);
        out.writeUTF(storageNodeConnectString);
    }

    /**
     * Reads replica Id metadata via the {@link DataInput} provided.
     * @param in The interface that reads bytes from a binary stream and converts it
     *        to the data of required type.
     * @return Returns the {@code ReplicaId}.
     * @throws IOException thrown if the read fails.
     */
    public static ReplicaId readFrom(DataInput in) throws IOException {
        byte version = in.readByte();

        if (version != VERSION) {
            throw new IOException("unsupported version");
        }

        int partitionId = in.readInt();
        String storageNodeConnectString = in.readUTF();

        return new ReplicaId(partitionId, storageNodeConnectString);
    }


    @Override
    public int hashCode() {
        return partitionId * storageNodeConnectString.hashCode();
    }

    @Override
    public boolean equals(Object obj) {
        return obj instanceof ReplicaId
            && this.partitionId == ((ReplicaId) obj).partitionId
            && this.storageNodeConnectString.equals(((ReplicaId) obj).storageNodeConnectString);
    }

    @Override
    public int compareTo(ReplicaId other) {
        int cmp = Integer.compare(partitionId, other.partitionId);
        if (cmp != 0) {
            return cmp;
        }
        return storageNodeConnectString.compareTo(other.storageNodeConnectString);
    }

    @Override
    public String toString() {
        return "ReplicaId(" + partitionId + "," + storageNodeConnectString + ")";
    }

}