Transaction.java

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package org.apache.doris.transaction;

import org.apache.doris.common.UserException;

public interface Transaction {

    void commit() throws UserException;

    void rollback();

    /**
     * Receives one serialized commit fragment produced by BE after writing a
     * data fragment. Implementations deserialize their connector-specific Thrift
     * payload and accumulate it for {@link #commit()}.
     *
     * <p>Default is a no-op for transactions that do not collect BE commit data.</p>
     *
     * @param commitFragment the serialized connector-specific commit payload
     */
    default void addCommitData(byte[] commitFragment) {
        // no-op: write transactions override this
    }

    /**
     * Whether this transaction allocates write block ranges through a write-time
     * BE&rarr;FE callback (e.g. maxcompute). Default {@code false}.
     */
    default boolean supportsWriteBlockAllocation() {
        return false;
    }

    /**
     * Allocates a contiguous range of write block ids for the given write
     * session, returning the first allocated id. Only invoked when
     * {@link #supportsWriteBlockAllocation()} returns {@code true}; the default
     * throws.
     *
     * @param writeSessionId opaque connector-defined write session identifier
     * @param count          number of block ids to allocate
     * @return the first allocated block id
     * @throws UserException on validation failure or allocation overflow
     */
    default long allocateWriteBlockRange(String writeSessionId, long count) throws UserException {
        throw new UnsupportedOperationException("write block allocation not supported");
    }

    /** Returns the number of rows affected by the write(s) in this transaction. */
    default long getUpdateCnt() {
        return 0;
    }
}