public checkAndPut_args setValue(byte[] value) {
      this.value = value == null ? (java.nio.ByteBuffer)null     : java.nio.ByteBuffer.wrap(value.clone());
      return this;
    }
the expected value for the column parameter, if not
provided the check is for the non-existence of the
column in question
hbase-thrift/src/main/java/org/apache/hadoop/hbase/thrift/generated/Hbase.java