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https://issues.apache.org/jira/browse/BEAM-6054?focusedWorklogId=165435&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-165435
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ASF GitHub Bot logged work on BEAM-6054:
----------------------------------------
Author: ASF GitHub Bot
Created on: 13/Nov/18 13:52
Start Date: 13/Nov/18 13:52
Worklog Time Spent: 10m
Work Description: VaclavPlajt commented on a change in pull request
#7019: [BEAM-6054] Euphoria translation providers refactored.
URL: https://github.com/apache/beam/pull/7019#discussion_r233044884
##########
File path:
sdks/java/extensions/euphoria/src/main/java/org/apache/beam/sdk/extensions/euphoria/core/translate/provider/GenericTranslatorProvider.java
##########
@@ -0,0 +1,246 @@
+/*
+ * 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.extensions.euphoria.core.translate.provider;
+
+import static java.util.Objects.requireNonNull;
+
+import com.google.common.base.Preconditions;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+import java.util.function.Predicate;
+import
org.apache.beam.sdk.extensions.euphoria.core.client.operator.CompositeOperator;
+import org.apache.beam.sdk.extensions.euphoria.core.client.operator.FlatMap;
+import org.apache.beam.sdk.extensions.euphoria.core.client.operator.Join;
+import
org.apache.beam.sdk.extensions.euphoria.core.client.operator.ReduceByKey;
+import org.apache.beam.sdk.extensions.euphoria.core.client.operator.Union;
+import
org.apache.beam.sdk.extensions.euphoria.core.client.operator.base.Operator;
+import
org.apache.beam.sdk.extensions.euphoria.core.translate.CompositeOperatorTranslator;
+import
org.apache.beam.sdk.extensions.euphoria.core.translate.FlatMapTranslator;
+import org.apache.beam.sdk.extensions.euphoria.core.translate.JoinTranslator;
+import
org.apache.beam.sdk.extensions.euphoria.core.translate.OperatorTranslator;
+import
org.apache.beam.sdk.extensions.euphoria.core.translate.ReduceByKeyTranslator;
+import
org.apache.beam.sdk.extensions.euphoria.core.translate.TranslatorProvider;
+import org.apache.beam.sdk.extensions.euphoria.core.translate.UnionTranslator;
+
+/**
+ * Adjustable {@link TranslatorProvider} that selects first suitable
translation for the registered
+ * operator.
+ *
+ * <p>{@link OperatorTranslator Translators} can be added by calling variants
of {@link
+ * GenericTranslatorProvider.Builder#register(Class, OperatorTranslator)
register} method during
+ * build. Order of registration is important. Building is started by {@link
#newBuilder()}.
+ */
+public class GenericTranslatorProvider implements TranslatorProvider {
+
+ private final List<TranslationDescriptor> possibleTranslators;
+
+ private GenericTranslatorProvider(List<TranslationDescriptor>
possibleTranslators) {
+ this.possibleTranslators = possibleTranslators;
+ }
+
+ public static GenericTranslatorProvider createWithDefaultTranslators() {
+ return GenericTranslatorProvider.newBuilder()
+ .register(FlatMap.class, new FlatMapTranslator<>())
+ .register(Union.class, new UnionTranslator<>())
+ .register(ReduceByKey.class, new ReduceByKeyTranslator<>())
+ .register(Join.class, new JoinTranslator<>())
+ // register fallback operator translator to decompose composit
operators
+ .register(op -> op instanceof CompositeOperator, new
CompositeOperatorTranslator<>())
+ .build();
+ }
+
+ @Override
+ public <InputT, OutputT, OperatorT extends Operator<OutputT>>
+ Optional<OperatorTranslator<InputT, OutputT, OperatorT>>
findTranslator(OperatorT operator) {
+
+ for (TranslationDescriptor descriptor : possibleTranslators) {
+
+ @SuppressWarnings("unchecked")
+ Optional<OperatorTranslator<InputT, OutputT, OperatorT>> maybeTranslator
=
+ descriptor.getTranslatorWhenSuitable(operator);
+
+ if (maybeTranslator.isPresent()) {
+ return maybeTranslator;
+ }
+ }
+
+ return Optional.empty();
+ }
+
+ /**
+ * Create a new builder for provider.
+ *
+ * @return builder
+ */
+ public static Builder newBuilder() {
+ return new Builder();
+ }
+
+ /** {@link GenericTranslatorProvider} builder. */
+ public static class Builder {
+
+ private final List<TranslationDescriptor> possibleTranslators = new
ArrayList<>();
+
+ private Builder() {}
+
+ /**
+ * Registers given {@link OperatorTranslator} to be used for given
operator type.
+ *
+ * @param clazz class of an {@link Operator} to be translated
+ * @param operatorTranslator translator to register
+ * @param <OperatorT> type of an {@link Operator} to be translated
+ * @return this builder
+ */
+ public <OperatorT extends Operator<?>> Builder register(
+ Class<OperatorT> clazz, OperatorTranslator<?, ?, ? extends OperatorT>
operatorTranslator) {
+ possibleTranslators.add(TranslationDescriptor.of(clazz,
operatorTranslator));
+ return this;
+ }
+
+ /**
+ * Register given {@link OperatorTranslator} to be used for operator type
when given {@link
+ * Predicate} holds.
+ *
+ * @param clazz class of an {@link Operator} to be translated
+ * @param predicate user defined predicate which is tested to be true in
order to apply
+ * translator to an {@link Operator}
+ * @param operatorTranslator translator to register
+ * @param <OperatorT> type of an {@link Operator} to be translated
+ * @return this builder
+ */
+ public <OperatorT extends Operator<?>> Builder register(
+ Class<OperatorT> clazz,
+ Predicate<OperatorT> predicate,
+ OperatorTranslator<?, ?, ? extends OperatorT> operatorTranslator) {
+ possibleTranslators.add(TranslationDescriptor.of(clazz, predicate,
operatorTranslator));
+ return this;
+ }
+
+ /**
+ * Registers given {@link OperatorTranslator} to be used for any operator
when given {@link
+ * Predicate} holds.
+ *
+ * @param predicate user defined predicate which is tested to be true in
order to apply
+ * translator to an {@link Operator}. Note that predicate have to be
able to test any {@link
+ * Operator} instance including subtypes.
+ * @param operatorTranslator translator to register
+ * @return this builder
+ */
+ public Builder register(
+ Predicate<Operator> predicate, OperatorTranslator<?, ?, Operator>
operatorTranslator) {
+ possibleTranslators.add(TranslationDescriptor.of(predicate,
operatorTranslator));
+ return this;
+ }
+
+ public GenericTranslatorProvider build() {
+ return new GenericTranslatorProvider(possibleTranslators);
+ }
+ }
+
+ /**
+ * Container for optional {@link Predicate user defined predicate}, optional
{@link Class} of na
+ * operator to be translated and {@link OperatorTranslator} itself. The
predicate and operator
+ * class defines an optional checks. At least one of them have to be present.
+ *
+ * <p>The {@link OperatorTranslator} is allowed to translate an operator iff
it pass all the
+ * checks and {@link OperatorTranslator#canTranslate(Operator) can
translate} given operator. That
+ * allows users to write translators specific for any operator.
+ *
+ * @param <OperatorT> the type of the euphoria operator
+ */
+ private static class TranslationDescriptor<OperatorT extends Operator<?>> {
+
+ /** Class of an {@link Operator} given {@link #translator} can be applied
on. */
+ private final Optional<Class<OperatorT>> operatorClass;
+
+ /**
+ * User specified predicate, which determines whenever given {@link
#translator} can be used to
+ * translate an operator.
+ */
+ private final Optional<Predicate<OperatorT>> userDefinedPredicate;
+
+ private final OperatorTranslator<?, ?, OperatorT> translator;
+
+ private TranslationDescriptor(
+ Optional<Class<OperatorT>> operatorClass,
+ Optional<Predicate<OperatorT>> userDefinedPredicate,
+ OperatorTranslator<?, ?, ? extends OperatorT> translator) {
+ Preconditions.checkState(
+ operatorClass.isPresent() || userDefinedPredicate.isPresent(),
+ "At least user defined predicate or class of an operator have to be
given.");
+
+ @SuppressWarnings("unchecked")
+ OperatorTranslator<?, ?, OperatorT> castedTranslator =
+ (OperatorTranslator<?, ?, OperatorT>) translator;
+
+ this.operatorClass = operatorClass;
+ this.userDefinedPredicate = userDefinedPredicate;
+ this.translator = castedTranslator;
+ }
+
+ static <OperatorT extends Operator<?>> TranslationDescriptor<OperatorT> of(
+ Class<OperatorT> operatorClass,
+ Predicate<OperatorT> userDefinedPredicate,
+ OperatorTranslator<?, ?, ? extends OperatorT> translator) {
+ return new TranslationDescriptor<>(
+ Optional.of(requireNonNull(operatorClass)),
+ Optional.of(requireNonNull(userDefinedPredicate)),
+ requireNonNull(translator));
+ }
+
+ static <OperatorT extends Operator<?>> TranslationDescriptor<OperatorT> of(
+ Predicate<OperatorT> userDefinedPredicate,
+ OperatorTranslator<?, ?, ? extends OperatorT> translator) {
+ return new TranslationDescriptor<>(
+ Optional.empty(),
+ Optional.of(requireNonNull(userDefinedPredicate)),
Review comment:
fixed
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Issue Time Tracking
-------------------
Worklog Id: (was: 165435)
Time Spent: 1h 50m (was: 1h 40m)
> Refactor traslator providers
> -----------------------------
>
> Key: BEAM-6054
> URL: https://issues.apache.org/jira/browse/BEAM-6054
> Project: Beam
> Issue Type: Sub-task
> Components: dsl-euphoria
> Reporter: Vaclav Plajt
> Assignee: Vaclav Plajt
> Priority: Major
> Time Spent: 1h 50m
> Remaining Estimate: 0h
>
> We need following functionality:
> 1. Way of registering translator providers for operator type with optional
> user-defined predicate
> 1. Way of registering translator providers for any operator based on
> predicate. (e.g `CompositeOperatorTranslator`)
> 1. Way of chaining translator providers
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