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package com.amazonaws.athena.connector.lambda.data;
/*-
* #%L
* Amazon Athena Query Federation SDK
* %%
* Copyright (C) 2019 Amazon Web Services
* %%
* Licensed 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.
* #L%
*/
import com.google.common.collect.ImmutableMap;
import org.apache.arrow.vector.types.Types;
import org.apache.arrow.vector.types.pojo.ArrowType;
import org.apache.arrow.vector.types.pojo.Field;
import org.apache.arrow.vector.types.pojo.FieldType;
import org.apache.arrow.vector.types.pojo.Schema;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
/**
* Convenience builder that can be used to create new Apache Arrow Schema for common
* types more easily than alternative methods of construction, especially for complex types.
*/
public class SchemaBuilder
{
//Using LinkedHashMap to maintain the order of elements in fields and present consistent schema view.
private final Map fields = new LinkedHashMap<>();
private final ImmutableMap.Builder metadata = ImmutableMap.builder();
//Using LinkedHashMap because Apache Arrow makes field order important so honoring that contract here
private final Map nestedFieldBuilderMap = new LinkedHashMap<>();
public SchemaBuilder addField(Field field)
{
fields.put(field.getName(), field);
return this;
}
/**
* Adds a new Field with the provided details to the Schema as a top-level Field with no children.
*
* @param fieldName The name of the field to add.
* @param type The type of the field to add.
* @return This SchemaBuilder itself.
*/
public SchemaBuilder addField(String fieldName, ArrowType type)
{
fields.put(fieldName, new Field(fieldName, FieldType.nullable(type), null));
return this;
}
/**
* Adds a new Field with the provided details to the Schema as a top-level Field.
*
* @param fieldName The name of the field to add.
* @param type The type of the field to add.
* @param children The list of child fields to add to the new Field.
* @return This SchemaBuilder itself.
*/
public SchemaBuilder addField(String fieldName, ArrowType type, List children)
{
fields.put(fieldName, new Field(fieldName, FieldType.nullable(type), children));
return this;
}
/**
* Adds a new STRUCT Field to the Schema as a top-level Field.
*
* @param fieldName The name of the field to add.
* @return This SchemaBuilder itself.
*/
public SchemaBuilder addStructField(String fieldName)
{
nestedFieldBuilderMap.put(fieldName, FieldBuilder.newBuilder(fieldName, Types.MinorType.STRUCT.getType()));
return this;
}
/**
* Adds a new LIST Field to the Schema as a top-level Field.
*
* @param fieldName The name of the field to add.
* @param type The concrete type of the values that are held within the list.
* @return This SchemaBuilder itself.
*/
public SchemaBuilder addListField(String fieldName, ArrowType type)
{
fields.put(fieldName, new Field(fieldName, FieldType.nullable(Types.MinorType.LIST.getType()),
Collections.singletonList(new Field("", FieldType.nullable(type), null))));
return this;
}
/**
* Adds a new Field as a child of the requested top-level parent field.
*
* @param parent The name of the pre-existing top-level parent field to add a child field to.
* @param child The name of the new child field.
* @param type The type of the new child field to add.
* @return This SchemaBuilder itself.
* @note For more complex nesting, please use FieldBuilder.
*/
public SchemaBuilder addChildField(String parent, String child, ArrowType type)
{
nestedFieldBuilderMap.get(parent).addField(child, type, null);
return this;
}
/**
* Adds a new Field as a child of the requested top-level parent field.
*
* @param parent The name of the pre-existing top-level parent field to add a child field to.
* @param child The child field to add to the parent.
* @return This SchemaBuilder itself.
* @note For more complex nesting, please use FieldBuilder.
*/
public SchemaBuilder addChildField(String parent, Field child)
{
nestedFieldBuilderMap.get(parent).addField(child);
return this;
}
/**
* Adds a new VARCHAR Field to the Schema as a top-level Field with no children.
*
* @param fieldName The name of the field to add.
* @return This SchemaBuilder itself.
*/
public SchemaBuilder addStringField(String fieldName)
{
fields.put(fieldName, new Field(fieldName, FieldType.nullable(Types.MinorType.VARCHAR.getType()), null));
return this;
}
/**
* Adds a new INT Field to the Schema as a top-level Field with no children.
*
* @param fieldName The name of the field to add.
* @return This SchemaBuilder itself.
*/
public SchemaBuilder addIntField(String fieldName)
{
fields.put(fieldName, new Field(fieldName, FieldType.nullable(Types.MinorType.INT.getType()), null));
return this;
}
/**
* Adds a new TINYINT Field to the Schema as a top-level Field with no children.
*
* @param fieldName The name of the field to add.
* @return This SchemaBuilder itself.
*/
public SchemaBuilder addTinyIntField(String fieldName)
{
fields.put(fieldName, new Field(fieldName, FieldType.nullable(Types.MinorType.TINYINT.getType()), null));
return this;
}
/**
* Adds a new SMALLINT Field to the Schema as a top-level Field with no children.
*
* @param fieldName The name of the field to add.
* @return This SchemaBuilder itself.
*/
public SchemaBuilder addSmallIntField(String fieldName)
{
fields.put(fieldName, new Field(fieldName, FieldType.nullable(Types.MinorType.SMALLINT.getType()), null));
return this;
}
/**
* Adds a new FLOAT8 Field to the Schema as a top-level Field with no children.
*
* @param fieldName The name of the field to add.
* @return This SchemaBuilder itself.
*/
public SchemaBuilder addFloat8Field(String fieldName)
{
fields.put(fieldName, new Field(fieldName, FieldType.nullable(Types.MinorType.FLOAT8.getType()), null));
return this;
}
/**
* Adds a new FLOAT4 Field to the Schema as a top-level Field with no children.
*
* @param fieldName The name of the field to add.
* @return This SchemaBuilder itself.
*/
public SchemaBuilder addFloat4Field(String fieldName)
{
fields.put(fieldName, new Field(fieldName, FieldType.nullable(Types.MinorType.FLOAT4.getType()), null));
return this;
}
/**
* Adds a new BIGINT Field to the Schema as a top-level Field with no children.
*
* @param fieldName The name of the field to add.
* @return This SchemaBuilder itself.
*/
public SchemaBuilder addBigIntField(String fieldName)
{
fields.put(fieldName, new Field(fieldName, FieldType.nullable(Types.MinorType.BIGINT.getType()), null));
return this;
}
/**
* Adds a new BIT Field to the Schema as a top-level Field with no children.
*
* @param fieldName The name of the field to add.
* @return This SchemaBuilder itself.
*/
public SchemaBuilder addBitField(String fieldName)
{
fields.put(fieldName, new Field(fieldName, FieldType.nullable(Types.MinorType.BIT.getType()), null));
return this;
}
/**
* Adds a new DECIMAL Field to the Schema as a top-level Field with no children.
*
* @param fieldName The name of the field to add.
* @param precision The precision to use for the new decimal field.
* @param scale The scale to use for the new decimal field.
* @return This SchemaBuilder itself.
*/
public SchemaBuilder addDecimalField(String fieldName, int precision, int scale)
{
fields.put(fieldName, new Field(fieldName, FieldType.nullable(new ArrowType.Decimal(precision, scale)), null));
return this;
}
/**
* Adds a new DateDay Field to the Schema as a top-level Field with no children.
*
* @param fieldName The name of the field to add.
* @return This SchemaBuilder itself.
*/
public SchemaBuilder addDateDayField(String fieldName)
{
fields.put(fieldName, new Field(fieldName, FieldType.nullable(Types.MinorType.DATEDAY.getType()), null));
return this;
}
/**
* Adds a new DateMilli Field to the Schema as a top-level Field with no children.
*
* @param fieldName The name of the field to add.
* @return This SchemaBuilder itself.
*/
public SchemaBuilder addDateMilliField(String fieldName)
{
fields.put(fieldName, new Field(fieldName, FieldType.nullable(Types.MinorType.DATEMILLI.getType()), null));
return this;
}
/**
* Adds the provided metadata to the Schema.
*
* @param key The key of the metadata to add.
* @param value The value of the metadata to add.
* @return This SchemaBuilder itself.
*/
public SchemaBuilder addMetadata(String key, String value)
{
metadata.put(key, value);
return this;
}
public Field getField(String name)
{
return fields.get(name);
}
public FieldBuilder getNestedField(String name)
{
return nestedFieldBuilderMap.get(name);
}
/**
* Creates a new SchemaBuilder.
*
* @return A new SchemaBuilder.
*/
public static SchemaBuilder newBuilder()
{
return new SchemaBuilder();
}
/**
* Builds an Apache Arrow Schema from the collected metadata and fields.
*
* @return A new Apache Arrow Schema.
* @note Attempting to reuse this builder will have unexpected side affects.
*/
public Schema build()
{
for (Map.Entry next : nestedFieldBuilderMap.entrySet()) {
fields.put(next.getKey(), next.getValue().build());
}
return new Schema(fields.values(), metadata.build());
}
}
