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https://issues.apache.org/jira/browse/FLINK-2678?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15126975#comment-15126975
]
ASF GitHub Bot commented on FLINK-2678:
---------------------------------------
Github user sbcd90 commented on a diff in the pull request:
https://github.com/apache/flink/pull/1566#discussion_r51476173
--- Diff:
flink-core/src/main/java/org/apache/flink/api/common/typeutils/base/GenericArrayComparator.java
---
@@ -0,0 +1,205 @@
+/*
+ * 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.flink.api.common.typeutils.base;
+
+import org.apache.flink.api.common.typeutils.TypeComparator;
+import org.apache.flink.api.common.typeutils.TypeSerializer;
+import org.apache.flink.core.memory.DataInputView;
+import org.apache.flink.core.memory.DataOutputView;
+import org.apache.flink.core.memory.MemorySegment;
+
+import java.io.IOException;
+import java.lang.reflect.Array;
+import java.util.Arrays;
+
+public class GenericArrayComparator<T> extends TypeComparator<T[]>
implements java.io.Serializable {
+
+ private static final long serialVersionUID = 1L;
+
+ private transient T[] reference;
+
+ protected final boolean ascendingComparison;
+
+ private final TypeSerializer<T[]> serializer;
+
+ // For use by getComparators
+ @SuppressWarnings("rawtypes")
+ private final TypeComparator[] comparators = new TypeComparator[]
{this};
+
+ public GenericArrayComparator(boolean ascending, TypeSerializer<T[]>
serializer) {
+ this.ascendingComparison = ascending;
+ this.serializer = serializer;
+ }
+
+ @Override
+ public void setReference(T[] reference) {
+ this.reference = reference;
+ }
+
+ @Override
+ public boolean equalToReference(T[] candidate) {
+ return compare(this.reference, candidate) == 0;
+ }
+
+ @Override
+ public int compareToReference(TypeComparator<T[]> referencedComparator)
{
+ int comp = compare(((GenericArrayComparator<T>)
referencedComparator).reference, reference);
+ return ascendingComparison ? comp : -comp;
+ }
+
+ @Override
+ public int compareSerialized(DataInputView firstSource, DataInputView
secondSource) throws IOException {
+ T[] firstArray = serializer.deserialize(firstSource);
+ T[] secondArray = serializer.deserialize(secondSource);
+
+ int comp = compare(firstArray, secondArray);
+ return ascendingComparison ? comp : -comp;
+ }
+
+ @Override
+ public int extractKeys(Object record, Object[] target, int index) {
+ target[index] = record;
+ return 1;
+ }
+
+ @Override
+ public TypeComparator[] getFlatComparators() {
+ return comparators;
+ }
+
+ @Override
+ public boolean supportsNormalizedKey() {
+ return false;
+ }
+
+ @Override
+ public boolean supportsSerializationWithKeyNormalization() {
+ return false;
+ }
+
+ @Override
+ public int getNormalizeKeyLen() {
+ return 0;
+ }
+
+ @Override
+ public boolean isNormalizedKeyPrefixOnly(int keyBytes) {
+ throw new UnsupportedOperationException();
+ }
+
+ @Override
+ public void putNormalizedKey(T[] record, MemorySegment target, int
offset, int numBytes) {
+ throw new UnsupportedOperationException();
+ }
+
+ @Override
+ public void writeWithKeyNormalization(T[] record, DataOutputView
target) throws IOException {
+ throw new UnsupportedOperationException();
+ }
+
+ @Override
+ public T[] readWithKeyDenormalization(T[] reuse, DataInputView source)
throws IOException {
+ throw new UnsupportedOperationException();
+ }
+
+ @Override
+ public boolean invertNormalizedKey() {
+ return !ascendingComparison;
+ }
+
+ @Override
+ public int hash(T[] record) {
+ return Arrays.hashCode(record);
+ }
+
+ private int compareValues(Object first, Object second) {
+ if (first.getClass().equals(Boolean.class) &&
second.getClass().equals(Boolean.class)) {
+ return new BooleanComparator(true).compare((Boolean)
first, (Boolean) second);
+ }
+ else if (first.getClass().equals(Byte.class) &&
second.getClass().equals(Byte.class)) {
+ return new ByteComparator(true).compare((Byte) first,
(Byte) second);
+ }
+ else if (first.getClass().equals(Character.class) &&
second.getClass().equals(Character.class)) {
+ return new CharComparator(true).compare((Character)
first, (Character) second);
+ }
+ else if (first.getClass().equals(Double.class) &&
second.getClass().equals(Double.class)) {
+ return new DoubleComparator(true).compare((Double)
first, (Double) second);
+ }
+ else if (first.getClass().equals(Float.class) &&
second.getClass().equals(Float.class)) {
+ return new FloatComparator(true).compare((Float) first,
(Float) second);
+ }
+ else if (first.getClass().equals(Integer.class) &&
second.getClass().equals(Integer.class)) {
+ return new IntComparator(true).compare((Integer) first,
(Integer) second);
+ }
+ else if (first.getClass().equals(Long.class) &&
second.getClass().equals(Long.class)) {
+ return new LongComparator(true).compare((Long) first,
(Long) second);
+ }
+ else if (first.getClass().equals(Short.class) &&
second.getClass().equals(Short.class)) {
+ return new ShortComparator(true).compare((Short) first,
(Short) second);
+ }
+ else if (first.getClass().equals(String.class) &&
second.getClass().equals(String.class)) {
+ return new StringComparator(true).compare((String)
first, (String) second);
+ }
+ return -1;
+ }
+
+ @SuppressWarnings("unchecked")
+ private int parseGenericArray(Object firstArray, Object secondArray) {
+ int compareResult = 0;
+ if (firstArray.getClass().isArray() &&
secondArray.getClass().isArray()) {
+ int min = Array.getLength(firstArray);
+ int tempResult = 0;
+
+ if (min < Array.getLength(secondArray)) {
+ tempResult = -1;
+ }
+ if (min > Array.getLength(secondArray)) {
+ min = Array.getLength(secondArray);
+ tempResult = 1;
+ }
+
+ for(int i=0; i < min; i++) {
+ int val =
parseGenericArray(Array.get(firstArray, i), Array.get(secondArray, i));
+ if (val != 0 && compareResult == 0) {
+ compareResult = val;
+ }
+ }
+
+ if (compareResult == 0) {
+ compareResult = tempResult;
+ }
+ }
+ else {
+ compareResult = compareValues(firstArray, secondArray);
+ }
+ return compareResult;
+ }
+
+ @Override
+ public int compare(T[] first, T[] second) {
--- End diff --
`ObjectArrayTypeInfo.componentInfo` is of type `TypeInformation<T>` &
accessing a method like `createComparator` from one of the implementing classes
of `TypeInformation<T>` is difficult. One possible solution is to have a static
map like `TYPES` which maps classes to comparator classes. From
`ObjectArrayTypeInfo.componentInfo` I get the typeClass & access the
corresponding comparator from the map. Is there any other better solution?
> DataSet API does not support multi-dimensional arrays as keys
> -------------------------------------------------------------
>
> Key: FLINK-2678
> URL: https://issues.apache.org/jira/browse/FLINK-2678
> Project: Flink
> Issue Type: Wish
> Components: DataSet API
> Reporter: Till Rohrmann
> Assignee: Subhobrata Dey
> Priority: Minor
>
> The DataSet API does not support grouping/sorting on field which are
> multi-dimensional arrays. It could be helpful to also support these types.
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