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The Apache Cassandra Project develops a highly scalable second-generation distributed database, bringing together Dynamo's fully distributed design and Bigtable's ColumnFamily-based data model.
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.cassandra.cql3;
import java.io.IOException;
import java.util.*;
import com.fasterxml.jackson.core.util.BufferRecyclers;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.apache.cassandra.schema.ColumnMetadata;
import org.apache.cassandra.schema.TableMetadata;
import org.apache.cassandra.cql3.functions.Function;
import org.apache.cassandra.db.marshal.AbstractType;
import org.apache.cassandra.db.marshal.UTF8Type;
import org.apache.cassandra.exceptions.InvalidRequestException;
import org.apache.cassandra.serializers.MarshalException;
/** Term-related classes for INSERT JSON support. */
public class Json
{
public static final ObjectMapper JSON_OBJECT_MAPPER = new ObjectMapper();
public static final ColumnIdentifier JSON_COLUMN_ID = new ColumnIdentifier("[json]", true);
/**
* Quotes string contents using standard JSON quoting.
*/
public static String quoteAsJsonString(String s)
{
// In future should update to directly use `JsonStringEncoder.getInstance()` but for now:
return new String(BufferRecyclers.getJsonStringEncoder().quoteAsString(s));
}
public static Object decodeJson(String json)
{
try
{
return JSON_OBJECT_MAPPER.readValue(json, Object.class);
}
catch (IOException exc)
{
throw new MarshalException("Error decoding JSON string: " + exc.getMessage());
}
}
public interface Raw
{
public Prepared prepareAndCollectMarkers(TableMetadata metadata, Collection receivers, VariableSpecifications boundNames);
}
/**
* Represents a literal JSON string in an INSERT JSON statement.
* For example: INSERT INTO mytable (key, col) JSON '{"key": 0, "col": 0}';
*/
public static class Literal implements Raw
{
private final String text;
public Literal(String text)
{
this.text = text;
}
public Prepared prepareAndCollectMarkers(TableMetadata metadata, Collection receivers, VariableSpecifications boundNames)
{
return new PreparedLiteral(parseJson(text, receivers));
}
}
/**
* Represents a marker for a JSON string in an INSERT JSON statement.
* For example: INSERT INTO mytable (key, col) JSON ?;
*/
public static class Marker implements Raw
{
protected final int bindIndex;
public Marker(int bindIndex)
{
this.bindIndex = bindIndex;
}
public Prepared prepareAndCollectMarkers(TableMetadata metadata, Collection receivers, VariableSpecifications boundNames)
{
boundNames.add(bindIndex, makeReceiver(metadata));
return new PreparedMarker(bindIndex, receivers);
}
private ColumnSpecification makeReceiver(TableMetadata metadata)
{
return new ColumnSpecification(metadata.keyspace, metadata.name, JSON_COLUMN_ID, UTF8Type.instance);
}
}
/**
* A prepared, full set of JSON values.
*/
public static abstract class Prepared
{
public abstract Term.Raw getRawTermForColumn(ColumnMetadata def, boolean defaultUnset);
}
/**
* A prepared literal set of JSON values
*/
private static class PreparedLiteral extends Prepared
{
private final Map columnMap;
public PreparedLiteral(Map columnMap)
{
this.columnMap = columnMap;
}
public Term.Raw getRawTermForColumn(ColumnMetadata def, boolean defaultUnset)
{
Term value = columnMap.get(def.name);
return value == null
? (defaultUnset ? Constants.UNSET_LITERAL : Constants.NULL_LITERAL)
: new ColumnValue(value);
}
}
/**
* A prepared bind marker for a set of JSON values
*/
private static class PreparedMarker extends Prepared
{
private final int bindIndex;
private final Collection columns;
public PreparedMarker(int bindIndex, Collection columns)
{
this.bindIndex = bindIndex;
this.columns = columns;
}
public RawDelayedColumnValue getRawTermForColumn(ColumnMetadata def, boolean defaultUnset)
{
return new RawDelayedColumnValue(this, def, defaultUnset);
}
}
/**
* A Terminal for a single column.
*
* Note that this is intrinsically an already prepared term, but this still implements Term.Raw so that we can
* easily use it to create raw operations.
*/
private static class ColumnValue extends Term.Raw
{
private final Term term;
public ColumnValue(Term term)
{
this.term = term;
}
@Override
public Term prepare(String keyspace, ColumnSpecification receiver) throws InvalidRequestException
{
return term;
}
@Override
public TestResult testAssignment(String keyspace, ColumnSpecification receiver)
{
return TestResult.NOT_ASSIGNABLE;
}
public AbstractType getExactTypeIfKnown(String keyspace)
{
return null;
}
public String getText()
{
return term.toString();
}
}
/**
* A Raw term for a single column. Like ColumnValue, this is intrinsically already prepared.
*/
private static class RawDelayedColumnValue extends Term.Raw
{
private final PreparedMarker marker;
private final ColumnMetadata column;
private final boolean defaultUnset;
public RawDelayedColumnValue(PreparedMarker prepared, ColumnMetadata column, boolean defaultUnset)
{
this.marker = prepared;
this.column = column;
this.defaultUnset = defaultUnset;
}
@Override
public Term prepare(String keyspace, ColumnSpecification receiver) throws InvalidRequestException
{
return new DelayedColumnValue(marker, column, defaultUnset);
}
@Override
public TestResult testAssignment(String keyspace, ColumnSpecification receiver)
{
return TestResult.WEAKLY_ASSIGNABLE;
}
public AbstractType getExactTypeIfKnown(String keyspace)
{
return null;
}
public String getText()
{
return marker.toString();
}
}
/**
* A NonTerminal for a single column. As with {@code ColumnValue}, this is intrinsically a prepared.
*/
private static class DelayedColumnValue extends Term.NonTerminal
{
private final PreparedMarker marker;
private final ColumnMetadata column;
private final boolean defaultUnset;
public DelayedColumnValue(PreparedMarker prepared, ColumnMetadata column, boolean defaultUnset)
{
this.marker = prepared;
this.column = column;
this.defaultUnset = defaultUnset;
}
@Override
public void collectMarkerSpecification(VariableSpecifications boundNames)
{
// We've already collected what we should (and in practice this method is never called).
}
@Override
public boolean containsBindMarker()
{
return true;
}
@Override
public Terminal bind(QueryOptions options) throws InvalidRequestException
{
Term term = options.getJsonColumnValue(marker.bindIndex, column.name, marker.columns);
return term == null
? (defaultUnset ? Constants.UNSET_VALUE : null)
: term.bind(options);
}
@Override
public void addFunctionsTo(List functions)
{
}
}
/**
* Given a JSON string, return a map of columns to their values for the insert.
*/
public static Map parseJson(String jsonString, Collection expectedReceivers)
{
try
{
Map valueMap = JSON_OBJECT_MAPPER.readValue(jsonString, Map.class);
if (valueMap == null)
throw new InvalidRequestException("Got null for INSERT JSON values");
handleCaseSensitivity(valueMap);
Map columnMap = new HashMap<>(expectedReceivers.size());
for (ColumnSpecification spec : expectedReceivers)
{
// We explicitely test containsKey() because the value itself can be null, and we want to distinguish an
// explicit null value from no value
if (!valueMap.containsKey(spec.name.toString()))
continue;
Object parsedJsonObject = valueMap.remove(spec.name.toString());
if (parsedJsonObject == null)
{
// This is an explicit user null
columnMap.put(spec.name, Constants.NULL_VALUE);
}
else
{
try
{
columnMap.put(spec.name, spec.type.fromJSONObject(parsedJsonObject));
}
catch(MarshalException exc)
{
throw new InvalidRequestException(String.format("Error decoding JSON value for %s: %s", spec.name, exc.getMessage()));
}
}
}
if (!valueMap.isEmpty())
{
throw new InvalidRequestException(String.format(
"JSON values map contains unrecognized column: %s", valueMap.keySet().iterator().next()));
}
return columnMap;
}
catch (IOException exc)
{
throw new InvalidRequestException(String.format("Could not decode JSON string as a map: %s. (String was: %s)", exc.toString(), jsonString));
}
catch (MarshalException exc)
{
throw new InvalidRequestException(exc.getMessage());
}
}
/**
* Handles unquoting and case-insensitivity in map keys.
*/
public static void handleCaseSensitivity(Map valueMap)
{
for (String mapKey : new ArrayList<>(valueMap.keySet()))
{
// if it's surrounded by quotes, remove them and preserve the case
if (mapKey.startsWith("\"") && mapKey.endsWith("\""))
{
valueMap.put(mapKey.substring(1, mapKey.length() - 1), valueMap.remove(mapKey));
continue;
}
// otherwise, lowercase it if needed
String lowered = mapKey.toLowerCase(Locale.US);
if (!mapKey.equals(lowered))
valueMap.put(lowered, valueMap.remove(mapKey));
}
}
}
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