org.apache.iceberg.transforms.Transforms Maven / Gradle / Ivy
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* 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.iceberg.transforms;
import java.util.Locale;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.iceberg.PartitionSpec;
import org.apache.iceberg.Schema;
import org.apache.iceberg.relocated.com.google.common.base.Preconditions;
import org.apache.iceberg.types.Type;
/**
* Factory methods for transforms.
*
* Most users should create transforms using a
* {@link PartitionSpec#builderFor(Schema)} partition spec builder}.
*
* @see PartitionSpec#builderFor(Schema) The partition spec builder.
*/
public class Transforms {
private Transforms() {
}
private static final Pattern HAS_WIDTH = Pattern.compile("(\\w+)\\[(\\d+)\\]");
public static Transform fromString(Type type, String transform) {
Matcher widthMatcher = HAS_WIDTH.matcher(transform);
if (widthMatcher.matches()) {
String name = widthMatcher.group(1);
int parsedWidth = Integer.parseInt(widthMatcher.group(2));
if (name.equalsIgnoreCase("truncate")) {
return Truncate.get(type, parsedWidth);
} else if (name.equals("bucket")) {
return Bucket.get(type, parsedWidth);
}
}
if (transform.equalsIgnoreCase("identity")) {
return Identity.get(type);
}
try {
if (type.typeId() == Type.TypeID.TIMESTAMP) {
return Timestamps.valueOf(transform.toUpperCase(Locale.ENGLISH));
} else if (type.typeId() == Type.TypeID.DATE) {
return Dates.valueOf(transform.toUpperCase(Locale.ENGLISH));
}
} catch (IllegalArgumentException ignored) {
// fall through to return unknown transform
}
if (transform.equalsIgnoreCase("void")) {
return VoidTransform.get();
}
return new UnknownTransform<>(type, transform);
}
/**
* Returns an identity {@link Transform} that can be used for any type.
*
* @param type the {@link Type source type} for the transform
* @param Java type passed to this transform
* @return an identity transform
*/
public static Transform identity(Type type) {
return Identity.get(type);
}
/**
* Returns a year {@link Transform} for date or timestamp types.
*
* @param type the {@link Type source type} for the transform
* @param Java type passed to this transform
* @return a year transform
*/
@SuppressWarnings("unchecked")
public static Transform year(Type type) {
switch (type.typeId()) {
case DATE:
return (Transform) Dates.YEAR;
case TIMESTAMP:
return (Transform) Timestamps.YEAR;
default:
throw new IllegalArgumentException(
"Cannot partition type " + type + " by year");
}
}
/**
* Returns a month {@link Transform} for date or timestamp types.
*
* @param type the {@link Type source type} for the transform
* @param Java type passed to this transform
* @return a month transform
*/
@SuppressWarnings("unchecked")
public static Transform month(Type type) {
switch (type.typeId()) {
case DATE:
return (Transform) Dates.MONTH;
case TIMESTAMP:
return (Transform) Timestamps.MONTH;
default:
throw new IllegalArgumentException(
"Cannot partition type " + type + " by month");
}
}
/**
* Returns a day {@link Transform} for date or timestamp types.
*
* @param type the {@link Type source type} for the transform
* @param Java type passed to this transform
* @return a day transform
*/
@SuppressWarnings("unchecked")
public static Transform day(Type type) {
switch (type.typeId()) {
case DATE:
return (Transform) Dates.DAY;
case TIMESTAMP:
return (Transform) Timestamps.DAY;
default:
throw new IllegalArgumentException(
"Cannot partition type " + type + " by day");
}
}
/**
* Returns a hour {@link Transform} for timestamps.
*
* @param type the {@link Type source type} for the transform
* @param Java type passed to this transform
* @return a hour transform
*/
@SuppressWarnings("unchecked")
public static Transform hour(Type type) {
Preconditions.checkArgument(type.typeId() == Type.TypeID.TIMESTAMP,
"Cannot partition type %s by hour", type);
return (Transform) Timestamps.HOUR;
}
/**
* Returns a bucket {@link Transform} for the given type and number of buckets.
*
* @param type the {@link Type source type} for the transform
* @param numBuckets the number of buckets for the transform to produce
* @param Java type passed to this transform
* @return a transform that buckets values into numBuckets
*/
public static Transform bucket(Type type, int numBuckets) {
return Bucket.get(type, numBuckets);
}
/**
* Returns a truncate {@link Transform} for the given type and width.
*
* @param type the {@link Type source type} for the transform
* @param width the width to truncate data values
* @param Java type passed to this transform
* @return a transform that truncates the given type to width
*/
public static Transform truncate(Type type, int width) {
return Truncate.get(type, width);
}
/**
* Returns a {@link Transform} that always produces null.
*
* @param Java type accepted by the transform.
* @return a transform that always produces null (the void transform).
*/
public static Transform alwaysNull() {
return VoidTransform.get();
}
}