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Kafka: Integrating Engine tables with Kafka
/**
* Copyright (c) 2016-2022 Deephaven Data Labs and Patent Pending
*/
package io.deephaven.kafka.publish;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ObjectNode;
import io.deephaven.base.clock.Clock;
import io.deephaven.chunk.attributes.Values;
import io.deephaven.engine.table.ChunkSource;
import io.deephaven.engine.table.Table;
import io.deephaven.engine.util.string.StringUtils;
import io.deephaven.engine.table.ColumnSource;
import io.deephaven.chunk.*;
import io.deephaven.engine.rowset.RowSequence;
import io.deephaven.util.QueryConstants;
import io.deephaven.util.SafeCloseable;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.*;
public class JsonKeyOrValueSerializer implements KeyOrValueSerializer {
/**
* Our Json object to string converter
*/
private static final ObjectMapper OBJECT_MAPPER = new ObjectMapper();
/**
* An empty JSON object that we use as the template for each output row (contains all the nested nodes).
*/
private final ObjectNode emptyObjectNode;
/**
* The table we are reading from.
*/
private final Table source;
protected final String nestedObjectDelimiter;
protected final boolean outputNulls;
protected final List fieldProcessors = new ArrayList<>();
public JsonKeyOrValueSerializer(final Table source,
final String[] columnNames,
final String[] fieldNames,
final String timestampFieldName,
final String nestedObjectDelimiter,
final boolean outputNulls) {
this.source = source;
this.nestedObjectDelimiter = nestedObjectDelimiter;
this.outputNulls = outputNulls;
makeFieldProcessors(columnNames, fieldNames);
if (!StringUtils.isNullOrEmpty(timestampFieldName)) {
fieldProcessors.add(new TimestampFieldProcessor(timestampFieldName));
}
this.emptyObjectNode = OBJECT_MAPPER.createObjectNode();
// create any nested structure in our template
if (nestedObjectDelimiter != null) {
for (final JSONFieldProcessor fieldProcessor : this.fieldProcessors) {
final String[] processorFieldNames = fieldProcessor.fieldName.split(nestedObjectDelimiter);
ObjectNode node = emptyObjectNode;
for (int i = 1; i < processorFieldNames.length; i++) {
ObjectNode child = (ObjectNode) node.get(processorFieldNames[i - 1]);
if (child == null) {
child = OBJECT_MAPPER.createObjectNode();
node.set(processorFieldNames[i - 1], child);
}
node = child;
}
}
}
}
private interface FieldContext extends SafeCloseable {
}
abstract class JSONFieldProcessor {
final String fieldName;
protected final String[] fieldNames;
protected final String childNodeFieldName;
public JSONFieldProcessor(final String fieldName) {
this.fieldName = fieldName;
if (nestedObjectDelimiter != null) {
this.fieldNames = fieldName.split(nestedObjectDelimiter);
this.childNodeFieldName = fieldNames[fieldNames.length - 1];
} else {
this.fieldNames = new String[] {fieldName};
childNodeFieldName = fieldName;
}
}
protected ObjectNode getChildNode(final ObjectNode root) {
ObjectNode child = root;
for (int i = 0; i < fieldNames.length - 1; i++) {
child = (ObjectNode) child.get(fieldNames[i]);
}
return child;
}
abstract FieldContext makeContext(int size);
abstract void processField(FieldContext fieldContext,
WritableObjectChunk jsonChunk, RowSequence keys, boolean isRemoval);
}
abstract class JSONFieldProcessorImpl> extends JSONFieldProcessor {
private final ColumnSource chunkSource;
public JSONFieldProcessorImpl(final String fieldName, final ColumnSource chunkSource) {
super(fieldName);
this.chunkSource = chunkSource;
}
private class ContextImpl implements FieldContext {
ChunkSource.GetContext getContext;
ContextImpl(final int size) {
getContext = chunkSource.makeGetContext(size);
}
@Override
public void close() {
getContext.close();
}
}
@Override
FieldContext makeContext(int size) {
return new ContextImpl(size);
}
abstract void outputField(final int ii, final ObjectNode node, final ChunkType inputChunk);
@Override
void processField(
final FieldContext fieldContext,
final WritableObjectChunk jsonChunk,
final RowSequence keys,
final boolean previous) {
final ContextImpl contextImpl = (ContextImpl) fieldContext;
ChunkType inputChunk;
if (previous) {
inputChunk = (ChunkType) chunkSource.getPrevChunk(contextImpl.getContext, keys);
} else {
inputChunk = (ChunkType) chunkSource.getChunk(contextImpl.getContext, keys);
}
for (int ii = 0; ii < inputChunk.size(); ++ii) {
final ObjectNode node = getChildNode(jsonChunk.get(ii));
outputField(ii, node, inputChunk);
}
}
}
private JSONFieldProcessor makeByteFieldProcessor(final String fieldName, final ColumnSource chunkSource) {
return new JSONFieldProcessorImpl>(fieldName, chunkSource) {
@Override
void outputField(final int ii, final ObjectNode node, final ByteChunk inputChunk) {
final byte raw = inputChunk.get(ii);
if (raw == QueryConstants.NULL_BYTE) {
if (outputNulls) {
node.putNull(childNodeFieldName);
}
} else {
// No signature matches ObjectNode#put(String, byte).
// #set w/ ContainerNode#numberNode(byte) is the most appropriately typed call.
node.set(childNodeFieldName, node.numberNode(raw));
}
}
};
}
private JSONFieldProcessor makeCharFieldProcessor(final String fieldName, final ColumnSource chunkSource) {
return new JSONFieldProcessorImpl>(fieldName, chunkSource) {
@Override
void outputField(final int ii, final ObjectNode node, final CharChunk inputChunk) {
final char raw = inputChunk.get(ii);
if (raw == QueryConstants.NULL_CHAR) {
if (outputNulls) {
node.putNull(childNodeFieldName);
}
} else {
// No native support for char type; we'll treat as String.
node.put(childNodeFieldName, String.valueOf(raw));
}
}
};
}
private JSONFieldProcessor makeShortFieldProcessor(final String fieldName, final ColumnSource chunkSource) {
return new JSONFieldProcessorImpl>(fieldName, chunkSource) {
@Override
void outputField(final int ii, final ObjectNode node, final ShortChunk inputChunk) {
final short raw = inputChunk.get(ii);
if (raw == QueryConstants.NULL_SHORT) {
if (outputNulls) {
node.putNull(childNodeFieldName);
}
} else {
node.put(childNodeFieldName, raw);
}
}
};
}
private JSONFieldProcessor makeIntFieldProcessor(final String fieldName, final ColumnSource chunkSource) {
return new JSONFieldProcessorImpl>(fieldName, chunkSource) {
@Override
void outputField(final int ii, final ObjectNode node, final IntChunk inputChunk) {
final int raw = inputChunk.get(ii);
if (raw == QueryConstants.NULL_SHORT) {
if (outputNulls) {
node.putNull(childNodeFieldName);
}
} else {
node.put(childNodeFieldName, raw);
}
}
};
}
private JSONFieldProcessor makeLongFieldProcessor(final String fieldName, final ColumnSource chunkSource) {
return new JSONFieldProcessorImpl>(fieldName, chunkSource) {
@Override
void outputField(final int ii, final ObjectNode node, final LongChunk inputChunk) {
final long raw = inputChunk.get(ii);
if (raw == QueryConstants.NULL_LONG) {
if (outputNulls) {
node.putNull(childNodeFieldName);
}
} else {
node.put(childNodeFieldName, raw);
}
}
};
}
private JSONFieldProcessor makeFloatFieldProcessor(final String fieldName, final ColumnSource chunkSource) {
return new JSONFieldProcessorImpl>(fieldName, chunkSource) {
@Override
void outputField(final int ii, final ObjectNode node, final FloatChunk inputChunk) {
final float raw = inputChunk.get(ii);
if (raw == QueryConstants.NULL_FLOAT) {
if (outputNulls) {
node.putNull(childNodeFieldName);
}
} else {
node.put(childNodeFieldName, raw);
}
}
};
}
private JSONFieldProcessor makeDoubleFieldProcessor(final String fieldName, final ColumnSource chunkSource) {
return new JSONFieldProcessorImpl>(fieldName, chunkSource) {
@Override
void outputField(final int ii, final ObjectNode node, final DoubleChunk inputChunk) {
final double raw = inputChunk.get(ii);
if (raw == QueryConstants.NULL_DOUBLE) {
if (outputNulls) {
node.putNull(childNodeFieldName);
}
} else {
node.put(childNodeFieldName, raw);
}
}
};
}
@FunctionalInterface
interface PutFun {
void put(ObjectNode node, String childNodeFieldName, T raw);
}
private JSONFieldProcessor makeObjectFieldProcessor(
final String fieldName,
final ColumnSource chunkSource,
final PutFun putFun) {
return new JSONFieldProcessorImpl>(fieldName, chunkSource) {
@Override
void outputField(final int ii, final ObjectNode node, final ObjectChunk inputChunk) {
final T raw = inputChunk.get(ii);
if (raw == null) {
if (outputNulls) {
node.putNull(childNodeFieldName);
}
} else {
putFun.put(node, childNodeFieldName, raw);
}
}
};
}
private JSONFieldProcessor makeToStringFieldProcessor(final String fieldName, final ColumnSource chunkSource) {
return makeObjectFieldProcessor(
fieldName,
chunkSource,
(final ObjectNode node,
final String childNodeFieldName,
final Object raw) -> node.put(childNodeFieldName, Objects.toString(raw)));
}
private JSONFieldProcessor makeBooleanFieldProcessor(
final String fieldName,
final ColumnSource chunkSource) {
return makeObjectFieldProcessor(
fieldName,
chunkSource,
(PutFun) ObjectNode::put);
}
private JSONFieldProcessor makeBigIntegerFieldProcessor(
final String fieldName,
final ColumnSource chunkSource) {
return makeObjectFieldProcessor(
fieldName,
chunkSource,
(PutFun) ObjectNode::put);
}
private JSONFieldProcessor makeBigDecimalFieldProcessor(
final String fieldName,
final ColumnSource chunkSource) {
return makeObjectFieldProcessor(
fieldName,
chunkSource,
(PutFun) ObjectNode::put);
}
private class TimestampFieldProcessor extends JSONFieldProcessor {
public TimestampFieldProcessor(final String fieldName) {
super(fieldName);
}
@Override
FieldContext makeContext(final int size) {
return null;
}
@Override
public void processField(
final FieldContext fieldContext,
final WritableObjectChunk jsonChunk,
final RowSequence keys,
final boolean isRemoval) {
final String nanosString = String.valueOf(Clock.system().currentTimeNanos());
for (int ii = 0; ii < jsonChunk.size(); ++ii) {
getChildNode(jsonChunk.get(ii)).put(childNodeFieldName, nanosString);
}
}
}
void makeFieldProcessors(
final String[] columnNames,
final String[] fieldNames) {
if (fieldNames != null && fieldNames.length != columnNames.length) {
throw new IllegalArgumentException(
"fieldNames.length (" + fieldNames.length + ") != columnNames.length (" + columnNames.length + ")");
}
for (int i = 0; i < columnNames.length; ++i) {
final String columnName = columnNames[i];
try {
if (fieldNames == null) {
makeFieldProcessor(columnName, columnName);
} else {
makeFieldProcessor(columnName, fieldNames[i]);
}
} catch (RuntimeException e) {
throw new IllegalArgumentException("Unknown column name " + columnName + " for table", e);
}
}
}
/**
* Create a field processor that translates a given column from its Deephaven row number to output of the intended
* type.
*
*
* @param columnName The Deephaven column to be translated into publishable format
* @param fieldName The name of the field in the output (if needed).
*/
private void makeFieldProcessor(final String columnName, final String fieldName) {
// getColumn should throw a ColumnNotFoundException if it can't find the column, which will blow us up here.
final ColumnSource src = source.getColumnSource(columnName);
final Class type = src.getType();
if (type == byte.class) {
fieldProcessors.add(makeByteFieldProcessor(fieldName, src));
} else if (type == char.class) {
fieldProcessors.add(makeCharFieldProcessor(fieldName, src));
} else if (type == short.class) {
fieldProcessors.add(makeShortFieldProcessor(fieldName, src));
} else if (type == int.class) {
fieldProcessors.add(makeIntFieldProcessor(fieldName, src));
} else if (type == long.class) {
fieldProcessors.add(makeLongFieldProcessor(fieldName, src));
} else if (type == float.class) {
fieldProcessors.add(makeFloatFieldProcessor(fieldName, src));
} else if (type == double.class) {
fieldProcessors.add(makeDoubleFieldProcessor(fieldName, src));
} else if (type == Boolean.class) {
fieldProcessors.add(makeBooleanFieldProcessor(fieldName, src));
} else if (type == BigDecimal.class) {
fieldProcessors.add(makeBigDecimalFieldProcessor(fieldName, src));
} else if (type == BigInteger.class) {
fieldProcessors.add(makeBigIntegerFieldProcessor(fieldName, src));
} else {
fieldProcessors.add(makeToStringFieldProcessor(fieldName, src));
}
}
/**
* Process the given update RowSequence and returns a list of JSON strings, reach representing one row of data.
*
* @param toProcess An RowSequence indicating which rows were involved
* @param previous True if this should be performed using the 'previous' data instead of current, as for removals.
* @return A List of Strings containing all of the parsed update statements
*/
@Override
public ObjectChunk handleChunk(Context context, RowSequence toProcess,
boolean previous) {
final JsonContext jsonContext = (JsonContext) context;
jsonContext.outputChunk.setSize(0);
jsonContext.jsonChunk.setSize(toProcess.intSize());
for (int position = 0; position < toProcess.intSize(); ++position) {
jsonContext.jsonChunk.set(position, emptyObjectNode.deepCopy());
}
for (int ii = 0; ii < fieldProcessors.size(); ++ii) {
fieldProcessors.get(ii).processField(jsonContext.fieldContexts[ii], jsonContext.jsonChunk, toProcess,
previous);
}
for (int position = 0; position < toProcess.intSize(); ++position) {
try {
jsonContext.outputChunk.add(OBJECT_MAPPER.writeValueAsString(jsonContext.jsonChunk.get(position)));
} catch (JsonProcessingException e) {
throw new KafkaPublisherException("Failed to write JSON message", e);
}
}
return jsonContext.outputChunk;
}
@Override
public Context makeContext(int size) {
return new JsonContext(size);
}
private final class JsonContext implements Context {
private final WritableObjectChunk outputChunk;
private final WritableObjectChunk jsonChunk;
private final FieldContext[] fieldContexts;
public JsonContext(int size) {
this.outputChunk = WritableObjectChunk.makeWritableChunk(size);
this.jsonChunk = WritableObjectChunk.makeWritableChunk(size);
this.fieldContexts = new FieldContext[fieldProcessors.size()];
for (int ii = 0; ii < fieldProcessors.size(); ++ii) {
fieldContexts[ii] = fieldProcessors.get(ii).makeContext(size);
}
}
@Override
public void close() {
outputChunk.close();
jsonChunk.close();
SafeCloseable.closeAll(fieldContexts);
}
}
}
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