聊聊nifi的AbstractBinlogTableEventWriter

public abstract class AbstractBinlogTableEventWriter<T extends BinlogTableEventInfo> extends AbstractBinlogEventWriter<T> {
​
    protected void writeJson(T event) throws IOException {
        super.writeJson(event);
        if (event.getDatabaseName() != null) {
            jsonGenerator.writeStringField("database", event.getDatabaseName());
        } else {
            jsonGenerator.writeNullField("database");
        }
        if (event.getTableName() != null) {
            jsonGenerator.writeStringField("table_name", event.getTableName());
        } else {
            jsonGenerator.writeNullField("table_name");
        }
        if (event.getTableId() != null) {
            jsonGenerator.writeNumberField("table_id", event.getTableId());
        } else {
            jsonGenerator.writeNullField("table_id");
        }
    }
​
    // Default implementation for table-related binlog events
    @Override
    public long writeEvent(ProcessSession session, String transitUri, T eventInfo, long currentSequenceId, Relationship relationship) {
        FlowFile flowFile = session.create();
        flowFile = session.write(flowFile, (outputStream) -> {
            super.startJson(outputStream, eventInfo);
            writeJson(eventInfo);
            // Nothing in the body
            super.endJson();
        });
        flowFile = session.putAllAttributes(flowFile, getCommonAttributes(currentSequenceId, eventInfo));
        session.transfer(flowFile, relationship);
        session.getProvenanceReporter().receive(flowFile, transitUri);
        return currentSequenceId + 1;
    }
}

public class DDLEventWriter extends AbstractBinlogTableEventWriter<DDLEventInfo> {
​
    @Override
    public long writeEvent(ProcessSession session, String transitUri, DDLEventInfo eventInfo, long currentSequenceId, Relationship relationship) {
        FlowFile flowFile = session.create();
        flowFile = session.write(flowFile, (outputStream) -> {
            super.startJson(outputStream, eventInfo);
            super.writeJson(eventInfo);
            jsonGenerator.writeStringField("query", eventInfo.getQuery());
            super.endJson();
        });
        flowFile = session.putAllAttributes(flowFile, getCommonAttributes(currentSequenceId, eventInfo));
        session.transfer(flowFile, relationship);
        session.getProvenanceReporter().receive(flowFile, transitUri);
        return currentSequenceId + 1;
    }
}

public class InsertRowsWriter extends AbstractBinlogTableEventWriter<InsertRowsEventInfo> {
​
    /**
     * Creates and transfers a new flow file whose contents are the JSON-serialized value of the specified event, and the sequence ID attribute set
     *
     * @param session   A reference to a ProcessSession from which the flow file(s) will be created and transferred
     * @param eventInfo An event whose value will become the contents of the flow file
     * @return The next available CDC sequence ID for use by the CDC processor
     */
    @Override
    public long writeEvent(final ProcessSession session, String transitUri, final InsertRowsEventInfo eventInfo, final long currentSequenceId, Relationship relationship) {
        final AtomicLong seqId = new AtomicLong(currentSequenceId);
        for (Serializable[] row : eventInfo.getRows()) {
​
            FlowFile flowFile = session.create();
            flowFile = session.write(flowFile, outputStream -> {
​
                super.startJson(outputStream, eventInfo);
                super.writeJson(eventInfo);
​
                final BitSet bitSet = eventInfo.getIncludedColumns();
                writeRow(eventInfo, row, bitSet);
​
                super.endJson();
            });
​
            flowFile = session.putAllAttributes(flowFile, getCommonAttributes(seqId.get(), eventInfo));
            session.transfer(flowFile, relationship);
            session.getProvenanceReporter().receive(flowFile, transitUri);
            seqId.getAndIncrement();
        }
        return seqId.get();
    }
​
    protected void writeRow(InsertRowsEventInfo event, Serializable[] row, BitSet includedColumns) throws IOException {
        jsonGenerator.writeArrayFieldStart("columns");
        int i = includedColumns.nextSetBit(0);
        while (i != -1) {
            jsonGenerator.writeStartObject();
            jsonGenerator.writeNumberField("id", i + 1);
            ColumnDefinition columnDefinition = event.getColumnByIndex(i);
            Integer columnType = null;
            if (columnDefinition != null) {
                jsonGenerator.writeStringField("name", columnDefinition.getName());
                columnType = columnDefinition.getType();
                jsonGenerator.writeNumberField("column_type", columnType);
            }
            if (row[i] == null) {
                jsonGenerator.writeNullField("value");
            } else {
                jsonGenerator.writeObjectField("value", MySQLCDCUtils.getWritableObject(columnType, row[i]));
            }
            jsonGenerator.writeEndObject();
            i = includedColumns.nextSetBit(i + 1);
        }
        jsonGenerator.writeEndArray();
    }
}

public class UpdateRowsWriter extends AbstractBinlogTableEventWriter<UpdateRowsEventInfo> {
​
    /**
     * Creates and transfers a new flow file whose contents are the JSON-serialized value of the specified event, and the sequence ID attribute set
     *
     * @param session   A reference to a ProcessSession from which the flow file(s) will be created and transferred
     * @param eventInfo An event whose value will become the contents of the flow file
     * @return The next available CDC sequence ID for use by the CDC processor
     */
    @Override
    public long writeEvent(final ProcessSession session, String transitUri, final UpdateRowsEventInfo eventInfo, final long currentSequenceId, Relationship relationship) {
        final AtomicLong seqId = new AtomicLong(currentSequenceId);
        for (Map.Entry<Serializable[], Serializable[]> row : eventInfo.getRows()) {
​
            FlowFile flowFile = session.create();
            flowFile = session.write(flowFile, outputStream -> {
​
                super.startJson(outputStream, eventInfo);
                super.writeJson(eventInfo);
​
                final BitSet bitSet = eventInfo.getIncludedColumns();
                writeRow(eventInfo, row, bitSet);
​
                super.endJson();
            });
​
            flowFile = session.putAllAttributes(flowFile, getCommonAttributes(seqId.get(), eventInfo));
            session.transfer(flowFile, relationship);
            session.getProvenanceReporter().receive(flowFile, transitUri);
            seqId.getAndIncrement();
        }
        return seqId.get();
    }
​
    protected void writeRow(UpdateRowsEventInfo event, Map.Entry<Serializable[], Serializable[]> row, BitSet includedColumns) throws IOException {
​
        jsonGenerator.writeArrayFieldStart("columns");
        int i = includedColumns.nextSetBit(0);
        while (i != -1) {
            jsonGenerator.writeStartObject();
            jsonGenerator.writeNumberField("id", i + 1);
            ColumnDefinition columnDefinition = event.getColumnByIndex(i);
            Integer columnType = null;
            if (columnDefinition != null) {
                jsonGenerator.writeStringField("name", columnDefinition.getName());
                columnType = columnDefinition.getType();
                jsonGenerator.writeNumberField("column_type", columnType);
            }
            Serializable[] oldRow = row.getKey();
            Serializable[] newRow = row.getValue();
​
            if (oldRow[i] == null) {
                jsonGenerator.writeNullField("last_value");
            } else {
                jsonGenerator.writeObjectField("last_value", MySQLCDCUtils.getWritableObject(columnType, oldRow[i]));
            }
​
            if (newRow[i] == null) {
                jsonGenerator.writeNullField("value");
            } else {
                jsonGenerator.writeObjectField("value", MySQLCDCUtils.getWritableObject(columnType, newRow[i]));
            }
            jsonGenerator.writeEndObject();
            i = includedColumns.nextSetBit(i + 1);
        }
        jsonGenerator.writeEndArray();
    }
}

public class DeleteRowsWriter extends AbstractBinlogTableEventWriter<DeleteRowsEventInfo> {
​
    /**
     * Creates and transfers a new flow file whose contents are the JSON-serialized value of the specified event, and the sequence ID attribute set
     *
     * @param session   A reference to a ProcessSession from which the flow file(s) will be created and transferred
     * @param eventInfo An event whose value will become the contents of the flow file
     * @return The next available CDC sequence ID for use by the CDC processor
     */
    @Override
    public long writeEvent(final ProcessSession session, String transitUri, final DeleteRowsEventInfo eventInfo, final long currentSequenceId, Relationship relationship) {
        final AtomicLong seqId = new AtomicLong(currentSequenceId);
        for (Serializable[] row : eventInfo.getRows()) {
​
            FlowFile flowFile = session.create();
            flowFile = session.write(flowFile, outputStream -> {
​
                super.startJson(outputStream, eventInfo);
                super.writeJson(eventInfo);
​
                final BitSet bitSet = eventInfo.getIncludedColumns();
                writeRow(eventInfo, row, bitSet);
​
                super.endJson();
            });
​
            flowFile = session.putAllAttributes(flowFile, getCommonAttributes(seqId.get(), eventInfo));
            session.transfer(flowFile, relationship);
            session.getProvenanceReporter().receive(flowFile, transitUri);
            seqId.getAndIncrement();
        }
        return seqId.get();
    }
​
    protected void writeRow(DeleteRowsEventInfo event, Serializable[] row, BitSet includedColumns) throws IOException {
        jsonGenerator.writeArrayFieldStart("columns");
        int i = includedColumns.nextSetBit(0);
        while (i != -1) {
            jsonGenerator.writeStartObject();
            jsonGenerator.writeNumberField("id", i + 1);
            ColumnDefinition columnDefinition = event.getColumnByIndex(i);
            Integer columnType = null;
            if (columnDefinition != null) {
                jsonGenerator.writeStringField("name", columnDefinition.getName());
                columnType = columnDefinition.getType();
                jsonGenerator.writeNumberField("column_type", columnType);
            }
            if (row[i] == null) {
                jsonGenerator.writeNullField("value");
            } else {
                jsonGenerator.writeObjectField("value", MySQLCDCUtils.getWritableObject(columnType, row[i]));
            }
            jsonGenerator.writeEndObject();
            i = includedColumns.nextSetBit(i + 1);
        }
        jsonGenerator.writeEndArray();
    }
}