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Posted to commits@groovy.apache.org by em...@apache.org on 2022/06/28 14:27:43 UTC
[groovy] branch master updated: GROOVY-10473: add `Stream` `getAt(int)` and `getAt(IntRange)` extensions
This is an automated email from the ASF dual-hosted git repository.
emilles pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/groovy.git
The following commit(s) were added to refs/heads/master by this push:
new 7129194e78 GROOVY-10473: add `Stream` `getAt(int)` and `getAt(IntRange)` extensions
7129194e78 is described below
commit 7129194e78335c6540a2d021cf6aff3c7dc897f2
Author: Eric Milles <er...@thomsonreuters.com>
AuthorDate: Sun Jun 26 16:59:27 2022 -0500
GROOVY-10473: add `Stream` `getAt(int)` and `getAt(IntRange)` extensions
---
.../groovy/runtime/StreamGroovyMethods.java | 80 ++++++++++++++++++++++
1 file changed, 80 insertions(+)
diff --git a/src/main/java/org/codehaus/groovy/runtime/StreamGroovyMethods.java b/src/main/java/org/codehaus/groovy/runtime/StreamGroovyMethods.java
index 2dd1df2ac8..0b004bffa1 100644
--- a/src/main/java/org/codehaus/groovy/runtime/StreamGroovyMethods.java
+++ b/src/main/java/org/codehaus/groovy/runtime/StreamGroovyMethods.java
@@ -18,6 +18,8 @@
*/
package org.codehaus.groovy.runtime;
+import groovy.lang.IntRange;
+
import java.lang.reflect.Array;
import java.util.Arrays;
import java.util.Collection;
@@ -45,6 +47,84 @@ public class StreamGroovyMethods {
private StreamGroovyMethods() {
}
+ /**
+ * Returns element at {@code index} or {@code null}.
+ * <p>
+ * This is a <a href="https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/util/stream/package-summary.html#StreamOps">short-circuiting terminal operation</a>.
+ *
+ * <pre class="groovyTestCase">
+ * import java.util.stream.Stream
+ * import static groovy.test.GroovyAssert.shouldFail
+ *
+ * Stream<String> stream = ['foo','bar','baz'].stream()
+ * shouldFail(IllegalArgumentException) { stream[-1] }
+ *
+ * stream = ['foo','bar','baz'].stream()
+ * assert stream[0] == 'foo'
+ *
+ * stream = ['foo','bar','baz'].stream()
+ * assert stream[1] == 'bar'
+ *
+ * stream = ['foo','bar','baz'].stream()
+ * assert stream[2] == 'baz'
+ *
+ * stream = ['foo','bar','baz'].stream()
+ * assert stream[3] === null
+ * </pre>
+ *
+ * @throws IllegalArgumentException if {@code index} is negative
+ *
+ * @since 5.0.0
+ */
+ public static <T> T getAt(final Stream<T> self, final int index) {
+ return self.skip(index).findFirst().orElse(null);
+ }
+
+ /**
+ * Returns element(s) in {@code range} or an empty list.
+ * <p>
+ * This is a <a href="https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/util/stream/package-summary.html#StreamOps">short-circuiting terminal operation</a>.
+ *
+ * <pre class="groovyTestCase">
+ * import java.util.stream.Stream
+ * import static groovy.test.GroovyAssert.shouldFail
+ *
+ * Stream<String> stream = ['foo','bar','baz'].stream()
+ * shouldFail(IllegalArgumentException) { stream[-1..0] }
+ *
+ * stream = ['foo','bar','baz'].stream()
+ * shouldFail(IllegalArgumentException) { stream[0..-1] }
+ *
+ * stream = ['foo','bar','baz'].stream()
+ * assert stream[0..<1] == ['foo']
+ *
+ * stream = ['foo','bar','baz'].stream()
+ * assert stream[1..<2] == ['bar']
+ *
+ * stream = ['foo','bar','baz'].stream()
+ * assert stream[2..<3] == ['baz']
+ *
+ * stream = ['foo','bar','baz'].stream()
+ * assert stream[3..<4] == []
+ *
+ * stream = ['foo','bar','baz'].stream()
+ * assert stream[0<..2] == ['bar','baz']
+ *
+ * stream = ['foo','bar','baz'].stream()
+ * assert stream[0..99] == ['foo','bar','baz']
+ * </pre>
+ *
+ * @throws IllegalArgumentException for negative index or reverse range
+ *
+ * @since 5.0.0
+ */
+ public static <T> List<T> getAt(final Stream<T> self, final IntRange range) {
+ if (range.isReverse()) throw new IllegalArgumentException("reverse range");
+ return self.skip(range.getFromInt()).limit(range.size()).collect(Collectors.toList());
+ }
+
+ //--------------------------------------------------------------------------
+
/**
* Returns a lazily concatenated stream whose elements are all the elements of this stream followed by all the elements of the {@link Collection} object.
*