From 8fcefb4f98856998d857e90f73bb88af043ef3b8 Mon Sep 17 00:00:00 2001 From: Gary Gregory Date: Wed, 17 Jun 2020 17:37:14 -0400 Subject: [PATCH] Centralize stream code in our own 'stream' package as a parallel to the JRE's java.util.stream package. - Re-implement use of failable function interfaces based on our function package. - Deprecate old class. - Remove trainling whitespace. --- .../org/apache/commons/lang3/Functions.java | 2 +- .../org/apache/commons/lang3/Streams.java | 8 + .../commons/lang3/concurrent/Locks.java | 2 +- .../commons/lang3/function/Failable.java | 2 +- .../apache/commons/lang3/stream/Streams.java | 492 ++++++++++++++++++ .../org/apache/commons/lang3/StreamsTest.java | 16 +- .../commons/lang3/stream/StreamsTest.java | 187 +++++++ 7 files changed, 698 insertions(+), 11 deletions(-) create mode 100644 src/main/java/org/apache/commons/lang3/stream/Streams.java create mode 100644 src/test/java/org/apache/commons/lang3/stream/StreamsTest.java diff --git a/src/main/java/org/apache/commons/lang3/Functions.java b/src/main/java/org/apache/commons/lang3/Functions.java index 7c9ec3d45..4cf9d5589 100644 --- a/src/main/java/org/apache/commons/lang3/Functions.java +++ b/src/main/java/org/apache/commons/lang3/Functions.java @@ -31,6 +31,7 @@ import java.util.function.Predicate; import java.util.function.Supplier; import java.util.stream.Stream; +import org.apache.commons.lang3.Streams.FailableStream; import org.apache.commons.lang3.function.FailableBooleanSupplier; import org.apache.commons.lang3.function.FailableDoubleBinaryOperator; import org.apache.commons.lang3.function.FailableDoubleConsumer; @@ -39,7 +40,6 @@ import org.apache.commons.lang3.function.FailableIntConsumer; import org.apache.commons.lang3.function.FailableIntSupplier; import org.apache.commons.lang3.function.FailableLongConsumer; import org.apache.commons.lang3.function.FailableLongSupplier; -import org.apache.commons.lang3.stream.Streams.FailableStream; /** * This class provides utility functions, and classes for working with the {@code java.util.function} package, or more diff --git a/src/main/java/org/apache/commons/lang3/Streams.java b/src/main/java/org/apache/commons/lang3/Streams.java index 125aefec9..c6afd0a27 100644 --- a/src/main/java/org/apache/commons/lang3/Streams.java +++ b/src/main/java/org/apache/commons/lang3/Streams.java @@ -62,14 +62,18 @@ import org.apache.commons.lang3.Functions.FailablePredicate; * @see Stream * @see Functions * @since 3.10 + * @deprecated Use {@link org.apache.commons.lang3.stream.Streams}. */ +@Deprecated public class Streams { /** * A reduced, and simplified version of a {@link Stream} with * failable method signatures. * @param The streams element type. + * @deprecated Use {@link org.apache.commons.lang3.stream.Streams.FailableStream}. */ + @Deprecated public static class FailableStream { private Stream stream; @@ -435,6 +439,10 @@ public class Streams { return stream(stream.stream()); } + /** + * @deprecated Use {@link org.apache.commons.lang3.stream.Streams.ArrayCollector}. + */ + @Deprecated public static class ArrayCollector implements Collector, O[]> { private static final Set characteristics = Collections.emptySet(); private final Class elementType; diff --git a/src/main/java/org/apache/commons/lang3/concurrent/Locks.java b/src/main/java/org/apache/commons/lang3/concurrent/Locks.java index 99cea4dfb..e96f36bc1 100644 --- a/src/main/java/org/apache/commons/lang3/concurrent/Locks.java +++ b/src/main/java/org/apache/commons/lang3/concurrent/Locks.java @@ -24,7 +24,7 @@ import org.apache.commons.lang3.function.FailableConsumer; import org.apache.commons.lang3.function.FailableFunction; -/** +/** * Utility class for working with {@link java.util.concurrent.locks.Lock locked objects}. Locked objects are an * alternative to synchronization. * diff --git a/src/main/java/org/apache/commons/lang3/function/Failable.java b/src/main/java/org/apache/commons/lang3/function/Failable.java index bcc3e29d5..9ecc28388 100644 --- a/src/main/java/org/apache/commons/lang3/function/Failable.java +++ b/src/main/java/org/apache/commons/lang3/function/Failable.java @@ -32,7 +32,7 @@ import java.util.function.Predicate; import java.util.function.Supplier; import java.util.stream.Stream; -import org.apache.commons.lang3.Streams.FailableStream; +import org.apache.commons.lang3.stream.Streams.FailableStream; /** * This class provides utility functions, and classes for working with the {@code java.util.function} package, or more diff --git a/src/main/java/org/apache/commons/lang3/stream/Streams.java b/src/main/java/org/apache/commons/lang3/stream/Streams.java new file mode 100644 index 000000000..1954432c7 --- /dev/null +++ b/src/main/java/org/apache/commons/lang3/stream/Streams.java @@ -0,0 +1,492 @@ +/* + * 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.commons.lang3.stream; + +import java.lang.reflect.Array; +import java.util.ArrayList; +import java.util.Collection; +import java.util.Collections; +import java.util.List; +import java.util.Set; +import java.util.function.BiConsumer; +import java.util.function.BinaryOperator; +import java.util.function.Consumer; +import java.util.function.Function; +import java.util.function.Predicate; +import java.util.function.Supplier; +import java.util.stream.Collector; +import java.util.stream.Collectors; +import java.util.stream.Stream; + +import org.apache.commons.lang3.function.Failable; +import org.apache.commons.lang3.function.FailableConsumer; +import org.apache.commons.lang3.function.FailableFunction; +import org.apache.commons.lang3.function.FailablePredicate; + +/** + * Provides utility functions, and classes for working with the + * {@code java.util.stream} package, or more generally, with Java 8 lambdas. More + * specifically, it attempts to address the fact that lambdas are supposed + * not to throw Exceptions, at least not checked Exceptions, AKA instances + * of {@link Exception}. This enforces the use of constructs like + * 
+ *     Consumer<java.lang.reflect.Method> consumer = (m) -> {
+ *         try {
+ *             m.invoke(o, args);
+ *         } catch (Throwable t) {
+ *             throw Failable.rethrow(t);
+ *         }
+ *    };
+ *    stream.forEach(consumer);
+ *
+ * Using a {@link FailableStream}, this can be rewritten as follows: + * 
+ *     Streams.failable(stream).forEach((m) -> m.invoke(o, args));
+ *
+ * Obviously, the second version is much more concise and the spirit of + * Lambda expressions is met better than in the first version. + * + * @see Stream + * @see Failable + * @since 3.10 + */ +public class Streams { + + public static class ArrayCollector implements Collector, O[]> { + private static final Set characteristics = Collections.emptySet(); + private final Class elementType; + + public ArrayCollector(final Class elementType) { + this.elementType = elementType; + } + + @Override + public BiConsumer, O> accumulator() { + return List::add; + } + + @Override + public Set characteristics() { + return characteristics; + } + + @Override + public BinaryOperator> combiner() { + return (left, right) -> { + left.addAll(right); + return left; + }; + } + + @Override + public Function, O[]> finisher() { + return list -> { + @SuppressWarnings("unchecked") + final O[] array = (O[]) Array.newInstance(elementType, list.size()); + return list.toArray(array); + }; + } + + @Override + public Supplier> supplier() { + return ArrayList::new; + } +} + + /** + * A reduced, and simplified version of a {@link Stream} with + * failable method signatures. + * @param The streams element type. + */ + public static class FailableStream { + + private Stream stream; + private boolean terminated; + + /** + * Constructs a new instance with the given {@code stream}. + * @param stream The stream. + */ + public FailableStream(final Stream stream) { + this.stream = stream; + } + + /** + * Returns whether all elements of this stream match the provided predicate. + * May not evaluate the predicate on all elements if not necessary for + * determining the result. If the stream is empty then {@code true} is + * returned and the predicate is not evaluated. + * + *

This is a short-circuiting terminal operation. + * + * \@apiNote + * This method evaluates the universal quantification of the + * predicate over the elements of the stream (for all x P(x)). If the + * stream is empty, the quantification is said to be vacuously + * satisfied and is always {@code true} (regardless of P(x)). + * + * @param predicate A non-interfering, stateless predicate to apply to + * elements of this stream + * @return {@code true} If either all elements of the stream match the + * provided predicate or the stream is empty, otherwise {@code false}. + */ + public boolean allMatch(final FailablePredicate predicate) { + assertNotTerminated(); + return stream().allMatch(Failable.asPredicate(predicate)); + } + + /** + * Returns whether any elements of this stream match the provided + * predicate. May not evaluate the predicate on all elements if not + * necessary for determining the result. If the stream is empty then + * {@code false} is returned and the predicate is not evaluated. + * + *

This is a short-circuiting terminal operation. + * + * \@apiNote + * This method evaluates the existential quantification of the + * predicate over the elements of the stream (for some x P(x)). + * + * @param predicate A non-interfering, stateless predicate to apply to + * elements of this stream + * @return {@code true} if any elements of the stream match the provided + * predicate, otherwise {@code false} + */ + public boolean anyMatch(final FailablePredicate predicate) { + assertNotTerminated(); + return stream().anyMatch(Failable.asPredicate(predicate)); + } + + protected void assertNotTerminated() { + if (terminated) { + throw new IllegalStateException("This stream is already terminated."); + } + } + + /** + * Performs a mutable reduction operation on the elements of this stream using a + * {@code Collector}. A {@code Collector} + * encapsulates the functions used as arguments to + * {@link #collect(Supplier, BiConsumer, BiConsumer)}, allowing for reuse of + * collection strategies and composition of collect operations such as + * multiple-level grouping or partitioning. + * + *

If the underlying stream is parallel, and the {@code Collector} + * is concurrent, and either the stream is unordered or the collector is + * unordered, then a concurrent reduction will be performed + * (see {@link Collector} for details on concurrent reduction.) + * + *

This is a terminal operation. + * + *

When executed in parallel, multiple intermediate results may be + * instantiated, populated, and merged so as to maintain isolation of + * mutable data structures. Therefore, even when executed in parallel + * with non-thread-safe data structures (such as {@code ArrayList}), no + * additional synchronization is needed for a parallel reduction. + * + * \@apiNote + * The following will accumulate strings into an ArrayList: + * 

{@code
+             *     List asList = stringStream.collect(Collectors.toList());
+             * }
+ * + *

The following will classify {@code Person} objects by city: + * 

{@code
+             *     Map> peopleByCity
+             *         = personStream.collect(Collectors.groupingBy(Person::getCity));
+             * }
+ * + *

The following will classify {@code Person} objects by state and city, + * cascading two {@code Collector}s together: + * 

{@code
+             *     Map>> peopleByStateAndCity
+             *         = personStream.collect(Collectors.groupingBy(Person::getState,
+             *                                                      Collectors.groupingBy(Person::getCity)));
+             * }
+ * + * @param the type of the result + * @param the intermediate accumulation type of the {@code Collector} + * @param collector the {@code Collector} describing the reduction + * @return the result of the reduction + * @see #collect(Supplier, BiConsumer, BiConsumer) + * @see Collectors + */ + public R collect(final Collector collector) { + makeTerminated(); + return stream().collect(collector); + } + + /** + * Performs a mutable reduction operation on the elements of this FailableStream. + * A mutable reduction is one in which the reduced value is a mutable result + * container, such as an {@code ArrayList}, and elements are incorporated by updating + * the state of the result rather than by replacing the result. This produces a result equivalent to: + * 
{@code
+             *     R result = supplier.get();
+             *     for (T element : this stream)
+             *         accumulator.accept(result, element);
+             *     return result;
+             * }
+ * + *

Like {@link #reduce(Object, BinaryOperator)}, {@code collect} operations + * can be parallelized without requiring additional synchronization. + * + *

This is a terminal operation. + * + * \@apiNote There are many existing classes in the JDK whose signatures are + * well-suited for use with method references as arguments to {@code collect()}. + * For example, the following will accumulate strings into an {@code ArrayList}: + * 

{@code
+             *     List asList = stringStream.collect(ArrayList::new, ArrayList::add,
+             *                                                ArrayList::addAll);
+             * }
+ * + *

The following will take a stream of strings and concatenates them into a + * single string: + * 

{@code
+             *     String concat = stringStream.collect(StringBuilder::new, StringBuilder::append,
+             *                                          StringBuilder::append)
+             *                                 .toString();
+             * }
+ * + * @param type of the result + * @param Type of the accumulator. + * @param pupplier a function that creates a new result container. For a + * parallel execution, this function may be called + * multiple times and must return a fresh value each time. + * @param accumulator An associative, non-interfering, stateless function for + * incorporating an additional element into a result + * @param combiner An associative, non-interfering, stateless + * function for combining two values, which must be compatible with the + * accumulator function + * @return The result of the reduction + */ + public R collect(final Supplier pupplier, final BiConsumer accumulator, final BiConsumer combiner) { + makeTerminated(); + return stream().collect(pupplier, accumulator, combiner); + } + + /** + * Returns a FailableStream consisting of the elements of this stream that match + * the given FailablePredicate. + * + *

This is an intermediate operation. + * + * @param predicate a non-interfering, stateless predicate to apply to each + * element to determine if it should be included. + * @return the new stream + */ + public FailableStream filter(final FailablePredicate predicate){ + assertNotTerminated(); + stream = stream.filter(Failable.asPredicate(predicate)); + return this; + } + + /** + * Performs an action for each element of this stream. + * + *

This is a terminal operation. + * + *

The behavior of this operation is explicitly nondeterministic. + * For parallel stream pipelines, this operation does not + * guarantee to respect the encounter order of the stream, as doing so + * would sacrifice the benefit of parallelism. For any given element, the + * action may be performed at whatever time and in whatever thread the + * library chooses. If the action accesses shared state, it is + * responsible for providing the required synchronization. + * + * @param action a non-interfering action to perform on the elements + */ + public void forEach(final FailableConsumer action) { + makeTerminated(); + stream().forEach(Failable.asConsumer(action)); + } + + protected void makeTerminated() { + assertNotTerminated(); + terminated = true; + } + + /** + * Returns a stream consisting of the results of applying the given + * function to the elements of this stream. + * + *

This is an intermediate operation. + * + * @param The element type of the new stream + * @param mapper A non-interfering, stateless function to apply to each element + * @return the new stream + */ + public FailableStream map(final FailableFunction mapper) { + assertNotTerminated(); + return new FailableStream<>(stream.map(Failable.asFunction(mapper))); + } + + /** + * Performs a reduction on the elements of this stream, using the provided + * identity value and an associative accumulation function, and returns + * the reduced value. This is equivalent to: + * 

{@code
+             *     T result = identity;
+             *     for (T element : this stream)
+             *         result = accumulator.apply(result, element)
+             *     return result;
+             * }
+ * + * but is not constrained to execute sequentially. + * + *

The {@code identity} value must be an identity for the accumulator + * function. This means that for all {@code t}, + * {@code accumulator.apply(identity, t)} is equal to {@code t}. + * The {@code accumulator} function must be an associative function. + * + *

This is a terminal operation. + * + * \@apiNote Sum, min, max, average, and string concatenation are all special + * cases of reduction. Summing a stream of numbers can be expressed as: + * + * 

{@code
+             *     Integer sum = integers.reduce(0, (a, b) -> a+b);
+             * }
+ * + * or: + * + * 
{@code
+             *     Integer sum = integers.reduce(0, Integer::sum);
+             * }
+ * + *

While this may seem a more roundabout way to perform an aggregation + * compared to simply mutating a running total in a loop, reduction + * operations parallelize more gracefully, without needing additional + * synchronization and with greatly reduced risk of data races. + * + * @param identity the identity value for the accumulating function + * @param accumulator an associative, non-interfering, stateless + * function for combining two values + * @return the result of the reduction + */ + public O reduce(final O identity, final BinaryOperator accumulator) { + makeTerminated(); + return stream().reduce(identity, accumulator); + } + + /** + * Converts the FailableStream into an equivalent stream. + * @return A stream, which will return the same elements, which this FailableStream would return. + */ + public Stream stream() { + return stream; + } + } + + /** + * Converts the given {@link Collection} into a {@link FailableStream}. + * This is basically a simplified, reduced version of the {@link Stream} + * class, with the same underlying element stream, except that failable + * objects, like {@link FailablePredicate}, {@link FailableFunction}, or + * {@link FailableConsumer} may be applied, instead of + * {@link Predicate}, {@link Function}, or {@link Consumer}. The idea is + * to rewrite a code snippet like this: + * 

+     *     final List<O> list;
+     *     final Method m;
+     *     final Function<O,String> mapper = (o) -> {
+     *         try {
+     *             return (String) m.invoke(o);
+     *         } catch (Throwable t) {
+     *             throw Failable.rethrow(t);
+     *         }
+     *     };
+     *     final List<String> strList = list.stream()
+     *         .map(mapper).collect(Collectors.toList());
+     *
+ * as follows: + * 
+     *     final List<O> list;
+     *     final Method m;
+     *     final List<String> strList = Failable.stream(list.stream())
+     *         .map((o) -> (String) m.invoke(o)).collect(Collectors.toList());
+     *
+ * While the second version may not be quite as + * efficient (because it depends on the creation of additional, + * intermediate objects, of type FailableStream), it is much more + * concise, and readable, and meets the spirit of Lambdas better + * than the first version. + * @param The streams element type. + * @param stream The stream, which is being converted. + * @return The {@link FailableStream}, which has been created by + * converting the stream. + */ + public static FailableStream stream(final Collection stream) { + return stream(stream.stream()); + } + + /** + * Converts the given {@link Stream stream} into a {@link FailableStream}. + * This is basically a simplified, reduced version of the {@link Stream} + * class, with the same underlying element stream, except that failable + * objects, like {@link FailablePredicate}, {@link FailableFunction}, or + * {@link FailableConsumer} may be applied, instead of + * {@link Predicate}, {@link Function}, or {@link Consumer}. The idea is + * to rewrite a code snippet like this: + * 
+     *     final List<O> list;
+     *     final Method m;
+     *     final Function<O,String> mapper = (o) -> {
+     *         try {
+     *             return (String) m.invoke(o);
+     *         } catch (Throwable t) {
+     *             throw Failable.rethrow(t);
+     *         }
+     *     };
+     *     final List<String> strList = list.stream()
+     *         .map(mapper).collect(Collectors.toList());
+     *
+ * as follows: + * 
+     *     final List<O> list;
+     *     final Method m;
+     *     final List<String> strList = Failable.stream(list.stream())
+     *         .map((o) -> (String) m.invoke(o)).collect(Collectors.toList());
+     *
+ * While the second version may not be quite as + * efficient (because it depends on the creation of additional, + * intermediate objects, of type FailableStream), it is much more + * concise, and readable, and meets the spirit of Lambdas better + * than the first version. + * @param The streams element type. + * @param stream The stream, which is being converted. + * @return The {@link FailableStream}, which has been created by + * converting the stream. + */ + public static FailableStream stream(final Stream stream) { + return new FailableStream<>(stream); + } + + /** + * Returns a {@code Collector} that accumulates the input elements into a + * new array. + * + * @param pElementType Type of an element in the array. + * @param the type of the input elements + * @return a {@code Collector} which collects all the input elements into an + * array, in encounter order + */ + public static Collector toArray(final Class pElementType) { + return new ArrayCollector<>(pElementType); + } +} diff --git a/src/test/java/org/apache/commons/lang3/StreamsTest.java b/src/test/java/org/apache/commons/lang3/StreamsTest.java index a0b79f60c..df1316036 100644 --- a/src/test/java/org/apache/commons/lang3/StreamsTest.java +++ b/src/test/java/org/apache/commons/lang3/StreamsTest.java @@ -41,10 +41,10 @@ import org.junit.jupiter.api.TestFactory; import org.junit.jupiter.api.function.Executable; import org.xml.sax.SAXException; -class StreamsTest { +public class StreamsTest { @Test - void testSimpleStreamMap() { + public void testSimpleStreamMap() { final List input = Arrays.asList("1", "2", "3", "4", "5", "6"); final List output = Functions.stream(input).map(Integer::valueOf).collect(Collectors.toList()); assertEquals(6, output.size()); @@ -54,7 +54,7 @@ class StreamsTest { } @Test - void testSimpleStreamMapFailing() { + public void testSimpleStreamMapFailing() { final List input = Arrays.asList("1", "2", "3", "4 ", "5", "6"); final Executable testMethod = () -> Functions.stream(input).map(Integer::valueOf).collect(Collectors.toList()); final NumberFormatException thrown = assertThrows(NumberFormatException.class, testMethod); @@ -62,7 +62,7 @@ class StreamsTest { } @Test - void testSimpleStreamForEach() { + public void testSimpleStreamForEach() { final List input = Arrays.asList("1", "2", "3", "4", "5", "6"); final List output = new ArrayList<>(); Functions.stream(input).forEach(s -> output.add(Integer.valueOf(s))); @@ -73,7 +73,7 @@ class StreamsTest { } @Test - void testToArray() { + public void testToArray() { final String[] array = Arrays.asList("2", "3", "1").stream().collect(Streams.toArray(String.class)); assertNotNull(array); assertEquals(3, array.length); @@ -92,7 +92,7 @@ class StreamsTest { } @TestFactory - Stream simpleStreamForEachFailing() { + public Stream simpleStreamForEachFailing() { final List input = Arrays.asList("1", "2", "3", "4", "5", "6"); return Stream.of( @@ -127,7 +127,7 @@ class StreamsTest { } @Test - void testSimpleStreamFilter() { + public void testSimpleStreamFilter() { final List input = Arrays.asList("1", "2", "3", "4", "5", "6"); final List output = Functions.stream(input) .map(Integer::valueOf) @@ -155,7 +155,7 @@ class StreamsTest { } @TestFactory - Stream simpleStreamFilterFailing() { + public Stream simpleStreamFilterFailing() { final List input = Arrays.asList("1", "2", "3", "4", "5", "6"); final List output = Functions.stream(input) .map(Integer::valueOf) diff --git a/src/test/java/org/apache/commons/lang3/stream/StreamsTest.java b/src/test/java/org/apache/commons/lang3/stream/StreamsTest.java new file mode 100644 index 000000000..218fa334a --- /dev/null +++ b/src/test/java/org/apache/commons/lang3/stream/StreamsTest.java @@ -0,0 +1,187 @@ +/* + * 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.commons.lang3.stream; + +import static org.hamcrest.MatcherAssert.assertThat; +import static org.hamcrest.core.Is.is; +import static org.hamcrest.core.IsEqual.equalTo; +import static org.hamcrest.core.IsNull.nullValue; +import static org.junit.jupiter.api.Assertions.assertAll; +import static org.junit.jupiter.api.Assertions.assertEquals; +import static org.junit.jupiter.api.Assertions.assertNotNull; +import static org.junit.jupiter.api.Assertions.assertThrows; +import static org.junit.jupiter.api.DynamicTest.dynamicTest; + +import java.lang.reflect.UndeclaredThrowableException; +import java.util.ArrayList; +import java.util.Arrays; +import java.util.List; +import java.util.stream.Collectors; +import java.util.stream.Stream; + +import org.apache.commons.lang3.function.Failable; +import org.apache.commons.lang3.function.FailableConsumer; +import org.apache.commons.lang3.function.FailablePredicate; +import org.junit.jupiter.api.DynamicTest; +import org.junit.jupiter.api.Test; +import org.junit.jupiter.api.TestFactory; +import org.junit.jupiter.api.function.Executable; +import org.xml.sax.SAXException; + +public class StreamsTest { + + protected FailableConsumer asIntConsumer(final T pThrowable) { + return s -> { + final Integer i = Integer.valueOf(s); + if (i.intValue() == 4) { + throw pThrowable; + } + }; + } + + protected FailablePredicate asIntPredicate(final T pThrowable) { + return i -> { + if (i.intValue() == 5) { + if (pThrowable != null) { + throw pThrowable; + } + } + return i % 2 == 0; + }; + } + + private void assertEvenNumbers(final List output) { + assertEquals(3, output.size()); + for (int i = 0; i < 3; i++) { + assertEquals((i + 1) * 2, output.get(i).intValue()); + } + } + + @TestFactory + public Stream simpleStreamFilterFailing() { + final List input = Arrays.asList("1", "2", "3", "4", "5", "6"); + final List output = Failable.stream(input).map(Integer::valueOf).filter(asIntPredicate(null)) + .collect(Collectors.toList()); + assertEvenNumbers(output); + + return Stream.of( + + dynamicTest("IllegalArgumentException", () -> { + final IllegalArgumentException iae = new IllegalArgumentException("Invalid argument: " + 5); + final Executable testMethod = () -> Failable.stream(input).map(Integer::valueOf) + .filter(asIntPredicate(iae)).collect(Collectors.toList()); + final IllegalArgumentException thrown = assertThrows(IllegalArgumentException.class, testMethod); + assertThat(thrown.getMessage(), is(equalTo("Invalid argument: " + 5))); + }), + + dynamicTest("OutOfMemoryError", () -> { + final OutOfMemoryError oome = new OutOfMemoryError(); + final Executable testMethod = () -> Failable.stream(input).map(Integer::valueOf) + .filter(asIntPredicate(oome)).collect(Collectors.toList()); + final OutOfMemoryError thrown = assertThrows(OutOfMemoryError.class, testMethod); + assertThat(thrown.getMessage(), is(nullValue())); + }), + + dynamicTest("SAXException", () -> { + final SAXException se = new SAXException(); + final Executable testMethod = () -> Failable.stream(input).map(Integer::valueOf) + .filter(asIntPredicate(se)).collect(Collectors.toList()); + final UndeclaredThrowableException thrown = assertThrows(UndeclaredThrowableException.class, + testMethod); + assertAll(() -> assertThat(thrown.getMessage(), is(nullValue())), + () -> assertThat(thrown.getCause(), is(equalTo(se)))); + })); + } + + @TestFactory + public Stream simpleStreamForEachFailing() { + final List input = Arrays.asList("1", "2", "3", "4", "5", "6"); + + return Stream.of( + + dynamicTest("IllegalArgumentException", () -> { + final IllegalArgumentException ise = new IllegalArgumentException(); + final Executable testMethod = () -> Failable.stream(input).forEach(asIntConsumer(ise)); + final IllegalArgumentException thrown = assertThrows(IllegalArgumentException.class, testMethod); + assertThat(thrown.getMessage(), is(nullValue())); + }), + + dynamicTest("OutOfMemoryError", () -> { + final OutOfMemoryError oome = new OutOfMemoryError(); + final Executable oomeTestMethod = () -> Failable.stream(input).forEach(asIntConsumer(oome)); + final OutOfMemoryError oomeThrown = assertThrows(OutOfMemoryError.class, oomeTestMethod); + assertThat(oomeThrown.getMessage(), is(nullValue())); + }), + + dynamicTest("SAXException", () -> { + final SAXException se = new SAXException(); + final Executable seTestMethod = () -> Failable.stream(input).forEach(asIntConsumer(se)); + final UndeclaredThrowableException seThrown = assertThrows(UndeclaredThrowableException.class, + seTestMethod); + assertAll(() -> assertThat(seThrown.getMessage(), is(nullValue())), + () -> assertThat(seThrown.getCause(), is(equalTo(se)))); + })); + } + + @Test + public void testSimpleStreamFilter() { + final List input = Arrays.asList("1", "2", "3", "4", "5", "6"); + final List output = Failable.stream(input).map(Integer::valueOf).filter(i -> (i.intValue() % 2 == 0)) + .collect(Collectors.toList()); + assertEvenNumbers(output); + } + + @Test + public void testSimpleStreamForEach() { + final List input = Arrays.asList("1", "2", "3", "4", "5", "6"); + final List output = new ArrayList<>(); + Failable.stream(input).forEach(s -> output.add(Integer.valueOf(s))); + assertEquals(6, output.size()); + for (int i = 0; i < 6; i++) { + assertEquals(i + 1, output.get(i).intValue()); + } + } + + @Test + public void testSimpleStreamMap() { + final List input = Arrays.asList("1", "2", "3", "4", "5", "6"); + final List output = Failable.stream(input).map(Integer::valueOf).collect(Collectors.toList()); + assertEquals(6, output.size()); + for (int i = 0; i < 6; i++) { + assertEquals(i + 1, output.get(i).intValue()); + } + } + + @Test + public void testSimpleStreamMapFailing() { + final List input = Arrays.asList("1", "2", "3", "4 ", "5", "6"); + final Executable testMethod = () -> Failable.stream(input).map(Integer::valueOf).collect(Collectors.toList()); + final NumberFormatException thrown = assertThrows(NumberFormatException.class, testMethod); + assertEquals("For input string: \"4 \"", thrown.getMessage()); + } + + @Test + public void testToArray() { + final String[] array = Arrays.asList("2", "3", "1").stream().collect(Streams.toArray(String.class)); + assertNotNull(array); + assertEquals(3, array.length); + assertEquals("2", array[0]); + assertEquals("3", array[1]); + assertEquals("1", array[2]); + } + +}