This is an automated email from the ASF dual-hosted git repository.
ggregory pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/commons-lang.git
The following commit(s) were added to refs/heads/master by this push:
new 8fcefb4 Centralize stream code in our own 'stream' package as a
parallel to the JRE's java.util.stream package.
8fcefb4 is described below
commit 8fcefb4f98856998d857e90f73bb88af043ef3b8
Author: Gary Gregory <garydgreg...@gmail.com>
AuthorDate: Wed Jun 17 17:37:14 2020 -0400
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.
---
.../java/org/apache/commons/lang3/Functions.java | 2 +-
.../java/org/apache/commons/lang3/Streams.java | 8 +
.../org/apache/commons/lang3/concurrent/Locks.java | 2 +-
.../apache/commons/lang3/function/Failable.java | 2 +-
.../org/apache/commons/lang3/stream/Streams.java | 492 +++++++++++++++++++++
.../java/org/apache/commons/lang3/StreamsTest.java | 16 +-
.../apache/commons/lang3/stream/StreamsTest.java | 187 ++++++++
7 files changed, 698 insertions(+), 11 deletions(-)
diff --git a/src/main/java/org/apache/commons/lang3/Functions.java
b/src/main/java/org/apache/commons/lang3/Functions.java
index 7c9ec3d..4cf9d55 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 125aefe..c6afd0a 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 <O> The streams element type.
+ * @deprecated Use {@link
org.apache.commons.lang3.stream.Streams.FailableStream}.
*/
+ @Deprecated
public static class FailableStream<O extends Object> {
private Stream<O> 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<O> implements Collector<O, List<O>,
O[]> {
private static final Set<Characteristics> characteristics =
Collections.emptySet();
private final Class<O> 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 99cea4d..e96f36b 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 bcc3e29..9ecc283 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 0000000..1954432
--- /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
+ * <pre>
+ * Consumer<java.lang.reflect.Method> consumer = (m) -> {
+ * try {
+ * m.invoke(o, args);
+ * } catch (Throwable t) {
+ * throw Failable.rethrow(t);
+ * }
+ * };
+ * stream.forEach(consumer);
+ * </pre>
+ * Using a {@link FailableStream}, this can be rewritten as follows:
+ * <pre>
+ * Streams.failable(stream).forEach((m) -> m.invoke(o, args));
+ * </pre>
+ * 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<O> implements Collector<O, List<O>, O[]>
{
+ private static final Set<Characteristics> characteristics =
Collections.emptySet();
+ private final Class<O> elementType;
+
+ public ArrayCollector(final Class<O> elementType) {
+ this.elementType = elementType;
+ }
+
+ @Override
+ public BiConsumer<List<O>, O> accumulator() {
+ return List::add;
+ }
+
+ @Override
+ public Set<Characteristics> characteristics() {
+ return characteristics;
+ }
+
+ @Override
+ public BinaryOperator<List<O>> combiner() {
+ return (left, right) -> {
+ left.addAll(right);
+ return left;
+ };
+ }
+
+ @Override
+ public Function<List<O>, O[]> finisher() {
+ return list -> {
+ @SuppressWarnings("unchecked")
+ final O[] array = (O[]) Array.newInstance(elementType,
list.size());
+ return list.toArray(array);
+ };
+ }
+
+ @Override
+ public Supplier<List<O>> supplier() {
+ return ArrayList::new;
+ }
+}
+
+ /**
+ * A reduced, and simplified version of a {@link Stream} with
+ * failable method signatures.
+ * @param <O> The streams element type.
+ */
+ public static class FailableStream<O extends Object> {
+
+ private Stream<O> stream;
+ private boolean terminated;
+
+ /**
+ * Constructs a new instance with the given {@code stream}.
+ * @param stream The stream.
+ */
+ public FailableStream(final Stream<O> 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.
+ *
+ * <p>This is a short-circuiting terminal operation.
+ *
+ * \@apiNote
+ * This method evaluates the <em>universal quantification</em> 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 <em>vacuously
+ * satisfied</em> 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<O, ?> 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.
+ *
+ * <p>This is a short-circuiting terminal operation.
+ *
+ * \@apiNote
+ * This method evaluates the <em>existential quantification</em>
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<O, ?> 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.
+ *
+ * <p>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.)
+ *
+ * <p>This is a terminal operation.
+ *
+ * <p>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:
+ * <pre>{@code
+ * List<String> asList =
stringStream.collect(Collectors.toList());
+ * }</pre>
+ *
+ * <p>The following will classify {@code Person} objects by city:
+ * <pre>{@code
+ * Map<String, List<Person>> peopleByCity
+ * =
personStream.collect(Collectors.groupingBy(Person::getCity));
+ * }</pre>
+ *
+ * <p>The following will classify {@code Person} objects by state
and city,
+ * cascading two {@code Collector}s together:
+ * <pre>{@code
+ * Map<String, Map<String, List<Person>>> peopleByStateAndCity
+ * =
personStream.collect(Collectors.groupingBy(Person::getState,
+ *
Collectors.groupingBy(Person::getCity)));
+ * }</pre>
+ *
+ * @param <R> the type of the result
+ * @param <A> 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 <A, R> R collect(final Collector<? super O, A, R>
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:
+ * <pre>{@code
+ * R result = supplier.get();
+ * for (T element : this stream)
+ * accumulator.accept(result, element);
+ * return result;
+ * }</pre>
+ *
+ * <p>Like {@link #reduce(Object, BinaryOperator)}, {@code
collect} operations
+ * can be parallelized without requiring additional
synchronization.
+ *
+ * <p>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}:
+ * <pre>{@code
+ * List<String> asList = stringStream.collect(ArrayList::new,
ArrayList::add,
+ *
ArrayList::addAll);
+ * }</pre>
+ *
+ * <p>The following will take a stream of strings and concatenates
them into a
+ * single string:
+ * <pre>{@code
+ * String concat = stringStream.collect(StringBuilder::new,
StringBuilder::append,
+ * StringBuilder::append)
+ * .toString();
+ * }</pre>
+ *
+ * @param <R> type of the result
+ * @param <A> 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 <A, R> R collect(final Supplier<R> pupplier, final
BiConsumer<R, ? super O> accumulator, final BiConsumer<R, R> combiner) {
+ makeTerminated();
+ return stream().collect(pupplier, accumulator, combiner);
+ }
+
+ /**
+ * Returns a FailableStream consisting of the elements of this
stream that match
+ * the given FailablePredicate.
+ *
+ * <p>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<O> filter(final FailablePredicate<O, ?>
predicate){
+ assertNotTerminated();
+ stream = stream.filter(Failable.asPredicate(predicate));
+ return this;
+ }
+
+ /**
+ * Performs an action for each element of this stream.
+ *
+ * <p>This is a terminal operation.
+ *
+ * <p>The behavior of this operation is explicitly
nondeterministic.
+ * For parallel stream pipelines, this operation does <em>not</em>
+ * 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<O, ?> 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.
+ *
+ * <p>This is an intermediate operation.
+ *
+ * @param <R> The element type of the new stream
+ * @param mapper A non-interfering, stateless function to apply to
each element
+ * @return the new stream
+ */
+ public <R> FailableStream<R> map(final FailableFunction<O, R, ?>
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:
+ * <pre>{@code
+ * T result = identity;
+ * for (T element : this stream)
+ * result = accumulator.apply(result, element)
+ * return result;
+ * }</pre>
+ *
+ * but is not constrained to execute sequentially.
+ *
+ * <p>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.
+ *
+ * <p>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:
+ *
+ * <pre>{@code
+ * Integer sum = integers.reduce(0, (a, b) -> a+b);
+ * }</pre>
+ *
+ * or:
+ *
+ * <pre>{@code
+ * Integer sum = integers.reduce(0, Integer::sum);
+ * }</pre>
+ *
+ * <p>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<O>
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<O> 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:
+ * <pre>
+ * 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());
+ * </pre>
+ * as follows:
+ * <pre>
+ * final List<O> list;
+ * final Method m;
+ * final List<String> strList = Failable.stream(list.stream())
+ * .map((o) -> (String)
m.invoke(o)).collect(Collectors.toList());
+ * </pre>
+ * While the second version may not be <em>quite</em> 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 <O> 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 <O> FailableStream<O> stream(final Collection<O> 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:
+ * <pre>
+ * 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());
+ * </pre>
+ * as follows:
+ * <pre>
+ * final List<O> list;
+ * final Method m;
+ * final List<String> strList = Failable.stream(list.stream())
+ * .map((o) -> (String)
m.invoke(o)).collect(Collectors.toList());
+ * </pre>
+ * While the second version may not be <em>quite</em> 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 <O> 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 <O> FailableStream<O> stream(final Stream<O> 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 <O> the type of the input elements
+ * @return a {@code Collector} which collects all the input elements into
an
+ * array, in encounter order
+ */
+ public static <O extends Object> Collector<O, ?, O[]> toArray(final
Class<O> 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 a0b79f6..df13160 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<String> input = Arrays.asList("1", "2", "3", "4", "5", "6");
final List<Integer> 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<String> 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<String> input = Arrays.asList("1", "2", "3", "4", "5", "6");
final List<Integer> 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<DynamicTest> simpleStreamForEachFailing() {
+ public Stream<DynamicTest> simpleStreamForEachFailing() {
final List<String> 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<String> input = Arrays.asList("1", "2", "3", "4", "5", "6");
final List<Integer> output = Functions.stream(input)
.map(Integer::valueOf)
@@ -155,7 +155,7 @@ class StreamsTest {
}
@TestFactory
- Stream<DynamicTest> simpleStreamFilterFailing() {
+ public Stream<DynamicTest> simpleStreamFilterFailing() {
final List<String> input = Arrays.asList("1", "2", "3", "4", "5", "6");
final List<Integer> 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 0000000..218fa33
--- /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 <T extends Throwable> FailableConsumer<String, T>
asIntConsumer(final T pThrowable) {
+ return s -> {
+ final Integer i = Integer.valueOf(s);
+ if (i.intValue() == 4) {
+ throw pThrowable;
+ }
+ };
+ }
+
+ protected <T extends Throwable> FailablePredicate<Integer, T>
asIntPredicate(final T pThrowable) {
+ return i -> {
+ if (i.intValue() == 5) {
+ if (pThrowable != null) {
+ throw pThrowable;
+ }
+ }
+ return i % 2 == 0;
+ };
+ }
+
+ private void assertEvenNumbers(final List<Integer> output) {
+ assertEquals(3, output.size());
+ for (int i = 0; i < 3; i++) {
+ assertEquals((i + 1) * 2, output.get(i).intValue());
+ }
+ }
+
+ @TestFactory
+ public Stream<DynamicTest> simpleStreamFilterFailing() {
+ final List<String> input = Arrays.asList("1", "2", "3", "4", "5", "6");
+ final List<Integer> 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<DynamicTest> simpleStreamForEachFailing() {
+ final List<String> 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<String> input = Arrays.asList("1", "2", "3", "4", "5", "6");
+ final List<Integer> output =
Failable.stream(input).map(Integer::valueOf).filter(i -> (i.intValue() % 2 ==
0))
+ .collect(Collectors.toList());
+ assertEvenNumbers(output);
+ }
+
+ @Test
+ public void testSimpleStreamForEach() {
+ final List<String> input = Arrays.asList("1", "2", "3", "4", "5", "6");
+ final List<Integer> 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<String> input = Arrays.asList("1", "2", "3", "4", "5", "6");
+ final List<Integer> 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<String> 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]);
+ }
+
+}
