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https://issues.apache.org/jira/browse/BEAM-4461?focusedWorklogId=143362&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-143362
]
ASF GitHub Bot logged work on BEAM-4461:
----------------------------------------
Author: ASF GitHub Bot
Created on: 12/Sep/18 04:22
Start Date: 12/Sep/18 04:22
Worklog Time Spent: 10m
Work Description: reuvenlax commented on a change in pull request #6317:
[BEAM-4461] Add mapping between FieldType and Java types.
URL: https://github.com/apache/beam/pull/6317#discussion_r216892966
##########
File path:
sdks/java/core/src/main/java/org/apache/beam/sdk/schemas/FieldTypeDescriptors.java
##########
@@ -0,0 +1,119 @@
+/*
+ * 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.beam.sdk.schemas;
+
+import static com.google.common.base.Preconditions.checkArgument;
+
+import com.google.common.collect.BiMap;
+import com.google.common.collect.ImmutableBiMap;
+import java.lang.reflect.ParameterizedType;
+import java.util.Collection;
+import java.util.Map;
+import org.apache.beam.sdk.schemas.Schema.FieldType;
+import org.apache.beam.sdk.schemas.Schema.TypeName;
+import org.apache.beam.sdk.values.Row;
+import org.apache.beam.sdk.values.TypeDescriptor;
+import org.apache.beam.sdk.values.TypeDescriptors;
+import org.joda.time.Instant;
+/**
+ * Utilities for converting between {@link Schema} field types and {@link
TypeDescriptor}s that
+ * define Java objects which can represent these field types.
+ */
+public class FieldTypeDescriptors {
+ private static final BiMap<TypeName, TypeDescriptor> PRIMITIVE_MAPPING =
+ ImmutableBiMap.<TypeName, TypeDescriptor>builder()
+ .put(TypeName.BYTE, TypeDescriptors.bytes())
+ .put(TypeName.INT16, TypeDescriptors.shorts())
+ .put(TypeName.INT32, TypeDescriptors.integers())
+ .put(TypeName.INT64, TypeDescriptors.longs())
+ .put(TypeName.DECIMAL, TypeDescriptors.bigdecimals())
+ .put(TypeName.FLOAT, TypeDescriptors.floats())
+ .put(TypeName.DOUBLE, TypeDescriptors.doubles())
+ .put(TypeName.STRING, TypeDescriptors.strings())
+ .put(TypeName.DATETIME, TypeDescriptor.of(Instant.class))
+ .put(TypeName.BOOLEAN, TypeDescriptors.booleans())
+ .put(TypeName.BYTES, TypeDescriptor.of(byte[].class))
+ .build();
+ /** Get a {@link TypeDescriptor} from a {@link FieldType}. */
+ public static TypeDescriptor javaTypeForFieldType(FieldType fieldType) {
+ switch (fieldType.getTypeName()) {
+ case ARRAY:
+ return
TypeDescriptors.lists(javaTypeForFieldType(fieldType.getCollectionElementType()));
+ case MAP:
+ return TypeDescriptors.maps(
+ javaTypeForFieldType(fieldType.getMapKeyType()),
+ javaTypeForFieldType(fieldType.getMapValueType()));
+ case ROW:
+ return TypeDescriptors.rows();
+ default:
+ return PRIMITIVE_MAPPING.get(fieldType.getTypeName());
+ }
+ }
+ /** Get a {@link FieldType} from a {@link TypeDescriptor}. */
+ public static FieldType fieldTypeForJavaType(TypeDescriptor typeDescriptor) {
+ if (typeDescriptor.isArray()
+ || typeDescriptor.isSubtypeOf(TypeDescriptor.of(Collection.class))) {
+ return getArrayFieldType(typeDescriptor);
+ } else if (typeDescriptor.isSubtypeOf(TypeDescriptor.of(Map.class))) {
+ return getMapFieldType(typeDescriptor);
+ } else if (typeDescriptor.isSubtypeOf(TypeDescriptor.of(Row.class))) {
+ throw new IllegalArgumentException(
+ "Cannot automatically determine a field type from a Row class"
+ + " as we cannot determine the schema. You should set a field
type explicitly.");
+ } else {
+ TypeName typeName = PRIMITIVE_MAPPING.inverse().get(typeDescriptor);
+ if (typeName == null) {
+ throw new RuntimeException("Couldn't find field type for " +
typeDescriptor);
+ }
+ FieldType fieldType = FieldType.of(typeName);
+ return fieldType;
+ }
+ }
+
+ private static FieldType getArrayFieldType(TypeDescriptor typeDescriptor) {
+ if (typeDescriptor.isArray()) {
+ if (typeDescriptor.getComponentType().getType().equals(byte.class)) {
+ return FieldType.BYTES;
+ } else {
+ return
FieldType.array(fieldTypeForJavaType(typeDescriptor.getComponentType()));
+ }
+ }
+ if (typeDescriptor.isSubtypeOf(TypeDescriptor.of(Collection.class))) {
+ TypeDescriptor<Collection<?>> collection =
typeDescriptor.getSupertype(Collection.class);
+ if (collection.getType() instanceof ParameterizedType) {
+ ParameterizedType ptype = (ParameterizedType) collection.getType();
+ java.lang.reflect.Type[] params = ptype.getActualTypeArguments();
+ checkArgument(params.length == 1);
Review comment:
Actually that would work. Here we are examining the Collection supertype
interface. In your example, KeySetView<K, V> implements Collection<K>, so there
is still only one parameter.
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Issue Time Tracking
-------------------
Worklog Id: (was: 143362)
Time Spent: 7h (was: 6h 50m)
> Create a library of useful transforms that use schemas
> ------------------------------------------------------
>
> Key: BEAM-4461
> URL: https://issues.apache.org/jira/browse/BEAM-4461
> Project: Beam
> Issue Type: Sub-task
> Components: sdk-java-core
> Reporter: Reuven Lax
> Assignee: Reuven Lax
> Priority: Major
> Time Spent: 7h
> Remaining Estimate: 0h
>
> e.g. JoinBy(fields). Project, Filter, etc.
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