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apache / groovy / 245fd29f8b9a92c6f602b8004786b54085f24653 / . / src / main / java / org / codehaus / groovy / vmplugin / v8 / PluginDefaultGroovyMethods.java
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/*
* 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.codehaus.groovy.vmplugin.v8;
import groovy.lang.Closure;
import groovy.lang.EmptyRange;
import groovy.lang.GString;
import groovy.lang.IntRange;
import groovy.transform.stc.ClosureParams;
import groovy.transform.stc.FirstParam;
import org.codehaus.groovy.runtime.DefaultGroovyMethodsSupport;
import org.codehaus.groovy.runtime.InvokerHelper;
import org.codehaus.groovy.runtime.NullObject;
import org.codehaus.groovy.runtime.RangeInfo;
import java.lang.reflect.Array;
import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.List;
import java.util.Objects;
import java.util.Optional;
import java.util.OptionalDouble;
import java.util.OptionalInt;
import java.util.OptionalLong;
import java.util.Set;
import java.util.Spliterator;
import java.util.Spliterators;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.function.Consumer;
import java.util.function.DoubleFunction;
import java.util.function.DoublePredicate;
import java.util.function.IntFunction;
import java.util.function.IntPredicate;
import java.util.function.LongFunction;
import java.util.function.LongPredicate;
import java.util.function.ToDoubleFunction;
import java.util.function.ToIntFunction;
import java.util.function.ToLongFunction;
import java.util.stream.BaseStream;
import java.util.stream.Collectors;
import java.util.stream.DoubleStream;
import java.util.stream.IntStream;
import java.util.stream.LongStream;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;
/**
* Defines new Groovy methods which appear on standard Java 8 classes within the
* Groovy environment.
*
* @since 2.5.0
*/
public class PluginDefaultGroovyMethods extends DefaultGroovyMethodsSupport {
// No instances, static methods only
private PluginDefaultGroovyMethods() {
}
/**
* Coerce an {@code Optional} instance to a {@code boolean} value.
* <pre class="groovyTestCase">
* assert !Optional.empty().asBoolean()
* assert Optional.of(1234).asBoolean()
* </pre>
*
* @param optional the Optional
* @return {@code true} if a value is present, otherwise {@code false}
*
* @since 2.5.0
*/
public static boolean asBoolean(final Optional<?> optional) {
return optional.isPresent();
}
/**
* If a value is present in the {@code OptionalInt}, returns the value,
* otherwise throws {@code NoSuchElementException}.
* <pre class="groovyTestCase">
* assert OptionalInt.of(1234).get() == 1234
* </pre>
*
* @since 3.0.0
*/
public static int get(final OptionalInt self) {
return self.getAsInt();
}
/**
* If a value is present in the {@code OptionalLong}, returns the value,
* otherwise throws {@code NoSuchElementException}.
* <pre class="groovyTestCase">
* assert OptionalLong.of(1234L).get() == 1234L
* </pre>
*
* @since 3.0.0
*/
public static long get(final OptionalLong self) {
return self.getAsLong();
}
/**
* If a value is present in the {@code OptionalDouble}, returns the value,
* otherwise throws {@code NoSuchElementException}.
* <pre class="groovyTestCase">
* assert OptionalDouble.of(Math.PI).get() == Math.PI
* </pre>
*
* @since 3.0.0
*/
public static double get(final OptionalDouble self) {
return self.getAsDouble();
}
/**
* Tests given value against specified type and changes generics of result.
* This is equivalent to: <code>self.filter(it -&gt; it instanceof Type).map(it -&gt; (Type) it)</code>
* <pre class="groovyTestCase">
* assert !Optional.empty().filter(Number).isPresent()
* assert !Optional.of('x').filter(Number).isPresent()
* assert Optional.of(1234).filter(Number).isPresent()
* assert Optional.of(1234).filter(Number).get().equals(1234)
* </pre>
*
* @since 3.0.0
*/
public static <T> Optional<T> filter(final Optional<?> self, final Class<T> type) {
return self.filter(type::isInstance).map(type::cast);
}
/**
* If a value is present in the {@code OptionalInt}, tests the value using
* the given predicate and returns the optional if the test returns true or
* else empty.
* <pre class="groovyTestCase">
* assert !OptionalInt.empty().filter(i -&gt; true).isPresent()
* assert OptionalInt.of(1234).filter(i -&gt; true).isPresent()
* assert !OptionalInt.of(1234).filter(i -&gt; false).isPresent()
* assert OptionalInt.of(1234).filter(i -&gt; true).getAsInt() == 1234
* </pre>
*
* @since 3.0.0
*/
public static OptionalInt filter(final OptionalInt self, final IntPredicate test) {
if (!self.isPresent() || !test.test(self.getAsInt())) {
return OptionalInt.empty();
}
return self;
}
/**
* If a value is present in the {@code OptionalLong}, tests the value using
* the given predicate and returns the optional if the test returns true or
* else empty.
* <pre class="groovyTestCase">
* assert !OptionalLong.empty().filter(n -&gt; true).isPresent()
* assert OptionalLong.of(123L).filter(n -&gt; true).isPresent()
* assert !OptionalLong.of(123L).filter(n -&gt; false).isPresent()
* assert OptionalLong.of(123L).filter(n -&gt; true).getAsLong() == 123L
* </pre>
*
* @since 3.0.0
*/
public static OptionalLong filter(final OptionalLong self, final LongPredicate test) {
if (!self.isPresent() || !test.test(self.getAsLong())) {
return OptionalLong.empty();
}
return self;
}
/**
* If a value is present in the {@code OptionalDouble}, tests the value using
* the given predicate and returns the optional if the test returns true or
* empty otherwise.
* <pre class="groovyTestCase">
* assert !OptionalDouble.empty().filter(n -&gt; true).isPresent()
* assert OptionalDouble.of(Math.PI).filter(n -&gt; true).isPresent()
* assert !OptionalDouble.of(Math.PI).filter(n -&gt; false).isPresent()
* assert OptionalDouble.of(Math.PI).filter(n -&gt; true).getAsDouble() == Math.PI
* </pre>
*
* @since 3.0.0
*/
public static OptionalDouble filter(final OptionalDouble self, final DoublePredicate test) {
if (!self.isPresent() || !test.test(self.getAsDouble())) {
return OptionalDouble.empty();
}
return self;
}
/**
* If a value is present in the {@code OptionalInt}, returns an {@code Optional}
* consisting of the result of applying the given function to the value or else empty.
* <pre class="groovyTestCase">
* assert !OptionalInt.empty().mapToObj(x -&gt; new Object()).isPresent()
* assert OptionalInt.of(1234).mapToObj(x -&gt; new Object()).isPresent()
* assert !OptionalInt.of(1234).mapToObj(x -&gt; null).isPresent()
* assert OptionalInt.of(1234).mapToObj(Integer::toString).get() == '1234'
* </pre>
*
* @since 3.0.0
*/
public static <T> Optional<T> mapToObj(final OptionalInt self, final IntFunction<? extends T> mapper) {
if (!self.isPresent()) {
return Optional.empty();
}
return Optional.ofNullable(mapper.apply(self.getAsInt()));
}
/**
* If a value is present in the {@code OptionalLong}, returns an {@code Optional}
* consisting of the result of applying the given function to the value or else empty.
* <pre class="groovyTestCase">
* assert !OptionalLong.empty().mapToObj(x -&gt; new Object()).isPresent()
* assert OptionalLong.of(123L).mapToObj(x -&gt; new Object()).isPresent()
* assert !OptionalLong.of(123L).mapToObj(x -&gt; null).isPresent()
* assert OptionalLong.of(1234L).mapToObj(Long::toString).get() == '1234'
* </pre>
*
* @since 3.0.0
*/
public static <T> Optional<T> mapToObj(final OptionalLong self, final LongFunction<? extends T> mapper) {
if (!self.isPresent()) {
return Optional.empty();
}
return Optional.ofNullable(mapper.apply(self.getAsLong()));
}
/**
* If a value is present in the {@code OptionalDouble}, returns an {@code Optional}
* consisting of the result of applying the given function to the value or else empty.
* <pre class="groovyTestCase">
* assert !OptionalDouble.empty().mapToObj(x -&gt; new Object()).isPresent()
* assert OptionalDouble.of(Math.PI).mapToObj(x -&gt; new Object()).isPresent()
* assert !OptionalDouble.of(Math.PI).mapToObj(x -&gt; null).isPresent()
* assert OptionalDouble.of(Math.PI).mapToObj(Double::toString).get().startsWith('3.14')
* </pre>
*
* @since 3.0.0
*/
public static <T> Optional<T> mapToObj(final OptionalDouble self, final DoubleFunction<? extends T> mapper) {
if (!self.isPresent()) {
return Optional.empty();
}
return Optional.ofNullable(mapper.apply(self.getAsDouble()));
}
/**
* If a value is present in the {@code OptionalInt}, returns an {@code OptionalInt}
* consisting of the result of applying the given function to the value or else empty.
* <pre class="groovyTestCase">
* assert !Optional.empty().mapToInt(x -&gt; 42).isPresent()
* assert Optional.of('x').mapToInt(x -&gt; 42).getAsInt() == 42
* </pre>
*
* @since 3.0.0
*/
public static <T> OptionalInt mapToInt(final Optional<T> self, final ToIntFunction<? super T> mapper) {
return self.map(t -> OptionalInt.of(mapper.applyAsInt(t))).orElseGet(OptionalInt::empty);
}
/**
* If a value is present in the {@code OptionalLong}, returns an {@code OptionalLong}
* consisting of the result of applying the given function to the value or else empty.
* <pre class="groovyTestCase">
* assert !Optional.empty().mapToLong(x -&gt; 42L).isPresent()
* assert Optional.of('x').mapToLong(x -&gt; 42L).getAsLong() == 42L
* </pre>
*
* @since 3.0.0
*/
public static <T> OptionalLong mapToLong(final Optional<T> self, final ToLongFunction<? super T> mapper) {
return self.map(t -> OptionalLong.of(mapper.applyAsLong(t))).orElseGet(OptionalLong::empty);
}
/**
* If a value is present in the {@code OptionalDouble}, returns an {@code OptionalDouble}
* consisting of the result of applying the given function to the value or else empty.
* <pre class="groovyTestCase">
* assert !Optional.empty().mapToDouble(x -&gt; Math.PI).isPresent()
* assert Optional.of('x').mapToDouble(x -&gt; Math.PI).getAsDouble() == Math.PI
* </pre>
*
* @since 3.0.0
*/
public static <T> OptionalDouble mapToDouble(final Optional<T> self, final ToDoubleFunction<? super T> mapper) {
return self.map(t -> OptionalDouble.of(mapper.applyAsDouble(t))).orElseGet(OptionalDouble::empty);
}
/**
* If the optional contains a value, returns an optional containing the transformed value obtained using the <code>transform</code> closure
* or otherwise an empty optional.
* <pre class="groovyTestCase">
* assert Optional.of("foobar").collect{ it.size() }.get() == 6
* assert !Optional.empty().collect{ it.size() }.isPresent()
* </pre>
*
* @param self an Optional
* @param transform the closure used to transform the optional value if present
* @return an Optional containing the transformed value or empty if the optional is empty or the transform returns null
*
* @since 3.0.0
*/
public static <S,T> Optional<T> collect(final Optional<S> self, @ClosureParams(FirstParam.FirstGenericType.class) final Closure<T> transform) {
Objects.requireNonNull(self);
Objects.requireNonNull(transform);
return self.map(transform::call);
}
/**
* Returns a Future asynchronously returning a transformed result.
* <pre class="_temp_disabled_groovyTestCase">
* import java.util.concurrent.*
* def executor = Executors.newSingleThreadExecutor()
* Future<String> foobar = executor.submit{ "foobar" }
* Future<Integer> foobarSize = foobar.collect{ it.size() }
* assert foobarSize.get() == 6
* executor.shutdown()
* </pre>
*
* @param self a Future
* @param transform the closure used to transform the Future value
* @return a Future allowing the transformed value to be obtained asynchronously
*
* @since 3.0.0
*/
public static <S,T> Future<T> collect(final Future<S> self, @ClosureParams(FirstParam.FirstGenericType.class) final Closure<T> transform) {
Objects.requireNonNull(self);
Objects.requireNonNull(transform);
return new TransformedFuture<T>(self, transform);
}
/**
* Overloads the {@code ++} operator for enums. It will invoke Groovy's
* default next behaviour for enums that do not have their own next method.
*
* @param self an Enum
* @return the next defined enum from the enum class
*
* @since 1.5.2
*/
public static Object next(final Enum self) {
for (Method method : self.getClass().getMethods()) {
if (method.getName().equals("next") && method.getParameterCount() == 0) {
return InvokerHelper.invokeMethod(self, "next", InvokerHelper.EMPTY_ARGS);
}
}
Object[] values = (Object[]) InvokerHelper.invokeStaticMethod(self.getClass(), "values", InvokerHelper.EMPTY_ARGS);
int index = Arrays.asList(values).indexOf(self);
return values[index < values.length - 1 ? index + 1 : 0];
}
/**
* Overloads the {@code --} operator for enums. It will invoke Groovy's
* default previous behaviour for enums that do not have their own previous method.
*
* @param self an Enum
* @return the previous defined enum from the enum class
*
* @since 1.5.2
*/
public static Object previous(final Enum self) {
for (Method method : self.getClass().getMethods()) {
if (method.getName().equals("previous") && method.getParameterCount() == 0) {
return InvokerHelper.invokeMethod(self, "previous", InvokerHelper.EMPTY_ARGS);
}
}
Object[] values = (Object[]) InvokerHelper.invokeStaticMethod(self.getClass(), "values", InvokerHelper.EMPTY_ARGS);
int index = Arrays.asList(values).indexOf(self);
return values[index > 0 ? index - 1 : values.length - 1];
}
/**
* Provides the standard Groovy <code>size()</code> method for <code>StringBuilder</code>.
*
* @param self a StringBuilder
* @return the length of the StringBuilder
*
* @since 1.5.2
*
* @see org.codehaus.groovy.runtime.StringGroovyMethods#size(CharSequence)
*/
@Deprecated
public static int size(final StringBuilder self) {
return self.length();
}
/**
* Overloads the left shift operator to provide an easy way to append multiple
* objects as string representations to a StringBuilder.
*
* @param self a StringBuilder
* @param value a value to append
* @return the StringBuilder on which this operation was invoked
*
* @since 1.5.2
*/
public static StringBuilder leftShift(final StringBuilder self, final Object value) {
if (value instanceof GString) {
// Force the conversion of the GString to string now, or appending
// is going to be extremely expensive, due to calls to GString#charAt,
// which is going to re-evaluate the GString for each character!
return self.append(value.toString());
}
if (value instanceof CharSequence) {
return self.append((CharSequence)value);
}
return self.append(value);
}
/**
* Supports the range subscript operator for StringBuilder.
* Index values are treated as characters within the builder.
*
* @param self a StringBuilder
* @param range a Range
* @param value the object that's toString() will be inserted
*
* @since 1.5.2
*/
public static void putAt(final StringBuilder self, final IntRange range, final Object value) {
RangeInfo info = DefaultGroovyMethodsSupport.subListBorders(self.length(), range);
self.replace(info.from, info.to, value.toString());
}
/**
* Supports the range subscript operator for StringBuilder.
*
* @param self a StringBuilder
* @param range a Range
* @param value the object that's toString() will be inserted
*
* @since 1.5.2
*/
public static void putAt(final StringBuilder self, final EmptyRange range, final Object value) {
RangeInfo info = DefaultGroovyMethodsSupport.subListBorders(self.length(), range);
self.replace(info.from, info.to, value.toString());
}
/**
* Appends a String to this StringBuilder.
*
* @param self a StringBuilder
* @param value a String
* @return a String
*
* @since 1.5.2
*/
public static String plus(final StringBuilder self, final String value) {
return self + value;
}
private static class TransformedFuture<E> implements Future<E> {
private final Future delegate;
private final Closure<E> transform;
private TransformedFuture(final Future delegate, final Closure<E> transform) {
this.delegate = delegate;
this.transform = transform;
}
@Override
public boolean cancel(final boolean mayInterruptIfRunning) {
return delegate.cancel(mayInterruptIfRunning);
}
@Override
public boolean isCancelled() {
return delegate.isCancelled();
}
@Override
public boolean isDone() {
return delegate.isDone();
}
@Override
public E get() throws InterruptedException, ExecutionException {
return transform.call(delegate.get());
}
@Override
public E get(final long timeout, final TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException {
return transform.call(delegate.get(timeout, unit));
}
}
/**
* Returns an array containing the elements of the stream.
* <pre class="groovyTestCase">
* import static groovy.test.GroovyAssert.shouldFail
*
* assert Arrays.equals([].stream().toArray(Object), new Object[0])
* assert Arrays.equals([].stream().toArray(String), new String[0])
* assert Arrays.equals([].stream().toArray(String[]), new String[0][])
* assert Arrays.equals(['x'].stream().toArray(Object), ['x'].toArray())
* assert Arrays.equals(['x'].stream().toArray(String), ['x'] as String[])
* assert Arrays.deepEquals([['x'] as String[]].stream().toArray(String[]), [['x'] as String[]] as String[][])
* assert Arrays.equals(['x'].stream().toArray(CharSequence), ['x'] as CharSequence[])
*
* shouldFail(ArrayStoreException) {
* ['x'].stream().toArray(Thread)
* }
*
* shouldFail(IllegalArgumentException) {
* ['x'].stream().toArray((Class) null)
* }
*
* // Stream#toArray(IntFunction) should still be used for closure literal:
* assert Arrays.equals(['x'].stream().toArray { n -&gt; new String[n] }, ['x'] as String[])
*
* // Stream#toArray(IntFunction) should still be used for method reference:
* assert Arrays.equals(['x'].stream().toArray(String[]::new), ['x'] as String[])
* </pre>
*
* @param self the stream
* @param type the array element type
*
* @since 3.0.4
*/
public static <T> T[] toArray(final Stream<? extends T> self, final Class<T> type) {
if (type == null) throw new IllegalArgumentException("type cannot be null");
return self.toArray(length -> (T[]) Array.newInstance(type, length));
}
/**
* Accumulates the elements of stream into a new List.
*
* @param self the stream
* @param <T> the type of element
* @return a new {@code java.util.List} instance
*
* @since 2.5.0
*/
public static <T> List<T> toList(final Stream<T> self) {
return self.collect(Collectors.toList());
}
/**
* Accumulates the elements of stream into a new Set.
*
* @param self the stream
* @param <T> the type of element
* @return a new {@code java.util.Set} instance
*
* @since 2.5.0
*/
public static <T> Set<T> toSet(final Stream<T> self) {
return self.collect(Collectors.toSet());
}
/**
* Accumulates the elements of stream into a new List.
*
* @param self the {@code java.util.stream.BaseStream}
* @param <T> the type of element
* @return a new {@code java.util.List} instance
*
* @since 2.5.0
*/
public static <T> List<T> toList(final BaseStream<T, ? extends BaseStream> self) {
return stream(self.iterator()).collect(Collectors.toList());
}
/**
* Accumulates the elements of stream into a new Set.
*
* @param self the {@code java.util.stream.BaseStream}
* @param <T> the type of element
* @return a new {@code java.util.Set} instance
*
* @since 2.5.0
*/
public static <T> Set<T> toSet(final BaseStream<T, ? extends BaseStream> self) {
return stream(self.iterator()).collect(Collectors.toSet());
}
/**
* Returns an empty sequential {@link Stream}.
*
* <pre class="groovyTestCase">
* def item = null
* assert item.stream().toList() == []
* assert !item.stream().findFirst().isPresent()
* </pre>
*
* @since 3.0.0
*/
public static <T> Stream<T> stream(final NullObject self) {
return Stream.empty();
}
/**
* Returns a sequential {@link Stream} containing a single element.
*
* <pre class="groovyTestCase">
* def item = 'string'
* assert item.stream().toList() == ['string']
* assert item.stream().findFirst().isPresent()
* </pre>
*
* @since 3.0.0
*/
public static <T> Stream<T> stream(final T self) {
return Stream.of(self);
}
/**
* Returns a sequential {@link Stream} with the specified array as its
* source.
*
* @param <T> The type of the array elements
* @param self The array, assumed to be unmodified during use
* @return a {@code Stream} for the array
*
* @since 2.5.0
*/
public static <T> Stream<T> stream(final T[] self) {
return Arrays.stream(self);
}
/**
* Returns a sequential {@link Stream} with the specified array as its
* source.
*
* @param self The array, assumed to be unmodified during use
* @return a {@code Stream} for the array
*
* @since 2.5.0
*/
public static Stream<Integer> stream(final int[] self) {
return Arrays.stream(self).boxed();
}
/**
* Returns a sequential {@link Stream} with the specified array as its
* source.
*
* @param self The array, assumed to be unmodified during use
* @return a {@code Stream} for the array
*
* @since 2.5.0
*/
public static Stream<Long> stream(final long[] self) {
return Arrays.stream(self).boxed();
}
/**
* Returns a sequential {@link Stream} with the specified array as its
* source.
*
* @param self The array, assumed to be unmodified during use
* @return a {@code Stream} for the array
*
* @since 2.5.0
*/
public static Stream<Double> stream(final double[] self) {
return Arrays.stream(self).boxed();
}
/**
* Returns a sequential {@link Stream} with the specified array as its
* source.
*
* @param self The array, assumed to be unmodified during use
* @return a {@code Stream} for the array
*
* @since 2.5.0
*/
public static Stream<Character> stream(final char[] self) {
return IntStream.range(0, self.length).mapToObj(i -> self[i]);
}
/**
* Returns a sequential {@link Stream} with the specified array as its
* source.
*
* @param self The array, assumed to be unmodified during use
* @return a {@code Stream} for the array
*
* @since 2.5.0
*/
public static Stream<Byte> stream(final byte[] self) {
return IntStream.range(0, self.length).mapToObj(i -> self[i]);
}
/**
* Returns a sequential {@link Stream} with the specified array as its
* source.
*
* @param self The array, assumed to be unmodified during use
* @return a {@code Stream} for the array
*
* @since 2.5.0
*/
public static Stream<Short> stream(final short[] self) {
return IntStream.range(0, self.length).mapToObj(i -> self[i]);
}
/**
* Returns a sequential {@link Stream} with the specified array as its
* source.
*
* @param self The array, assumed to be unmodified during use
* @return a {@code Stream} for the array
*
* @since 2.5.0
*/
public static Stream<Boolean> stream(final boolean[] self) {
return IntStream.range(0, self.length).mapToObj(i -> self[i]);
}
/**
* Returns a sequential {@link Stream} with the specified array as its
* source.
*
* @param self The array, assumed to be unmodified during use
* @return a {@code Stream} for the array
*
* @since 2.5.0
*/
public static Stream<Float> stream(final float[] self) {
return IntStream.range(0, self.length).mapToObj(i -> self[i]);
}
/**
* Returns a sequential {@link Stream} with the specified element(s) as its
* source.
* <pre class="groovyTestCase">
* def tokens = new StringTokenizer('one two')
* assert tokens.stream().toList() == ['one', 'two']
* </pre>
*
* @since 3.0.0
*/
public static <T> Stream<T> stream(final Enumeration<T> self) {
return stream(new Spliterators.AbstractSpliterator<T>(Long.MAX_VALUE, Spliterator.ORDERED) {
@Override
public void forEachRemaining(final Consumer<? super T> action) {
while (self.hasMoreElements()) {
action.accept(self.nextElement());
}
}
@Override
public boolean tryAdvance(final Consumer<? super T> action) {
if (self.hasMoreElements()) {
action.accept(self.nextElement());
return true;
}
return false;
}
});
}
/**
* Returns a sequential {@link Stream} with the specified element(s) as its
* source.
*
* <pre class="groovyTestCase">
* class Items implements Iterable<String> {
* Iterator<String> iterator() {
* ['one', 'two'].iterator()
* }
* }
* def items = new Items()
* assert items.stream().toList() == ['one', 'two']
* </pre>
*
* @since 3.0.0
*/
public static <T> Stream<T> stream(final Iterable<T> self) {
return StreamSupport.stream(self.spliterator(), false);
}
/**
* Returns a sequential {@link Stream} with the specified element(s) as its
* source.
*
* <pre class="groovyTestCase">
* [].iterator().stream().toList().isEmpty()
* ['one', 'two'].iterator().stream().toList() == ['one', 'two']
* </pre>
*
* @since 3.0.0
*/
public static <T> Stream<T> stream(final Iterator<T> self) {
return stream(Spliterators.spliteratorUnknownSize(self, Spliterator.ORDERED));
}
/**
* Returns a sequential {@link Stream} with the specified element(s) as its
* source.
*
* <pre class="groovyTestCase">
* [].spliterator().stream().toList().isEmpty()
* ['one', 'two'].spliterator().stream().toList() == ['one', 'two']
* </pre>
*
* @since 3.0.0
*/
public static <T> Stream<T> stream(final Spliterator<T> self) {
return StreamSupport.stream(self, false);
}
/**
* If a value is present in the {@link Optional}, returns a {@link Stream}
* with the value as its source or else an empty stream.
*
* @since 3.0.0
*/
public static <T> Stream<T> stream(final Optional<T> self) {
return self.map(Stream::of).orElseGet(Stream::empty);
}
/**
* If a value is present in the {@link OptionalInt}, returns an {@link IntStream}
* with the value as its source or else an empty stream.
*
* @since 3.0.0
*/
public static IntStream stream(final OptionalInt self) {
if (!self.isPresent()) {
return IntStream.empty();
}
return IntStream.of(self.getAsInt());
}
/**
* If a value is present in the {@link OptionalLong}, returns a {@link LongStream}
* with the value as its source or else an empty stream.
*
* @since 3.0.0
*/
public static LongStream stream(final OptionalLong self) {
if (!self.isPresent()) {
return LongStream.empty();
}
return LongStream.of(self.getAsLong());
}
/**
* If a value is present in the {@link OptionalDouble}, returns a {@link DoubleStream}
* with the value as its source or else an empty stream.
*
* @since 3.0.0
*/
public static DoubleStream stream(final OptionalDouble self) {
if (!self.isPresent()) {
return DoubleStream.empty();
}
return DoubleStream.of(self.getAsDouble());
}
}