From: "Enrico Weigelt, metux IT consult" <[email protected]>
---
.../sf/freecol/common/util/CollectionUtils.java | 384 ++++++++++++++++-----
1 file changed, 297 insertions(+), 87 deletions(-)
diff --git a/src/net/sf/freecol/common/util/CollectionUtils.java
b/src/net/sf/freecol/common/util/CollectionUtils.java
index ec7662fee93..7f911e72ad8 100644
--- a/src/net/sf/freecol/common/util/CollectionUtils.java
+++ b/src/net/sf/freecol/common/util/CollectionUtils.java
@@ -34,7 +34,6 @@ import java.util.Map.Entry;
import java.util.Set;
import java.util.function.BinaryOperator;
import java.util.function.Consumer;
-import java.util.function.DoubleBinaryOperator;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.function.Supplier;
@@ -67,6 +66,12 @@ public class CollectionUtils {
public static final BinaryOperator<Double> doubleAccumulator
= (d1, d2) -> d1 + d2;
+ public static final BinaryOperator<Double> doubleMultiplicator
+ = new BinaryOperator<Double>() {
+ public Double apply(Double d1, Double d2) {
+ return d1 * d2;
+ }};
+
/** Useful comparators for mapEntriesBy* */
public static final Comparator<Integer> ascendingIntegerComparator
= Comparator.comparingInt(i -> i);
@@ -436,6 +441,12 @@ public class CollectionUtils {
return stream.allMatch(predicate);
}
+ public static final Predicate alwaysTruePred
+ = new Predicate() {
+ public boolean test(Object o) {
+ return true;
+ }};
+
/**
* Helper to create a predicate which is always true.
*
@@ -443,7 +454,7 @@ public class CollectionUtils {
* @return The always valid predicate for the stream type.
*/
public static <T> Predicate<T> alwaysTrue() {
- return (T t) -> true;
+ return alwaysTruePred;
}
/**
@@ -613,7 +624,7 @@ public class CollectionUtils {
*/
public static <T> int count(T[] array,
Predicate<? super T> predicate) {
- return count_internal(Arrays.stream(array), predicate);
+ return (array == null ? 0 :
(int)(Arrays.<T>stream(array).filter(predicate).count()));
}
/**
@@ -637,7 +648,7 @@ public class CollectionUtils {
*/
public static <T> int count(Collection<T> c,
Predicate<? super T> predicate) {
- return count_internal(c.stream(), predicate);
+ return (c == null ? 0 : (int)(c.stream().filter(predicate).count()));
}
/**
@@ -648,7 +659,7 @@ public class CollectionUtils {
* @return The number of items that matched.
*/
public static <T> int count(Stream<T> stream) {
- return (stream == null) ? 0 : count_internal(stream, alwaysTrue());
+ return (stream == null) ? 0 : (int)stream.count();
}
/**
@@ -661,20 +672,7 @@ public class CollectionUtils {
*/
public static <T> int count(Stream<T> stream,
Predicate<? super T> predicate) {
- return (stream == null) ? 0 : count_internal(stream, predicate);
- }
-
- /**
- * Implement count().
- *
- * @param <T> The stream member type.
- * @param stream The {@code Stream} to check.
- * @param predicate A {@code Predicate} to test with.
- * @return The number of items that matched.
- */
- private static <T> int count_internal(Stream<T> stream,
- Predicate<? super T> predicate) {
- return (int)stream.filter(predicate).count();
+ return (stream == null) ? 0 : (int)stream.filter(predicate).count();
}
/**
@@ -920,7 +918,7 @@ public class CollectionUtils {
*/
public static <T, R> Stream<R> flatten(T[] array,
Function<? super T, ? extends Stream<? extends R>> mapper) {
- return flatten_internal(Arrays.stream(array), alwaysTrue(), mapper);
+ return flatten_internal(Arrays.stream(array), mapper);
}
/**
@@ -950,7 +948,7 @@ public class CollectionUtils {
*/
public static <T, R> Stream<R> flatten(Collection<T> c,
Function<? super T, ? extends Stream<? extends R>> mapper) {
- return flatten_internal(c.stream(), alwaysTrue(), mapper);
+ return flatten_internal(c.stream(), mapper);
}
/**
@@ -981,7 +979,7 @@ public class CollectionUtils {
public static <T, R> Stream<R> flatten(Stream<T> stream,
Function<? super T, ? extends Stream<? extends R>> mapper) {
return (stream == null) ? Stream.<R>empty()
- : flatten_internal(stream, alwaysTrue(), mapper);
+ : flatten_internal(stream, mapper);
}
/**
@@ -1018,6 +1016,20 @@ public class CollectionUtils {
}
/**
+ * Flatten the members of a stream.
+ *
+ * @param <T> The stream member type.
+ * @param <R> The resulting stream member type.
+ * @param stream The {@code Stream} to flatten.
+ * @param mapper A mapping {@code Function} to apply.
+ * @return A stream of the mapped stream.
+ */
+ private static <T, R> Stream<R> flatten_internal(Stream<T> stream,
+ Function<? super T, ? extends Stream<? extends R>> mapper) {
+ return stream.filter(predicate).flatMap(mapper);
+ }
+
+ /**
* Apply a consumer to the entries of a map.
*
* @param <K> The map key type.
@@ -1333,7 +1345,7 @@ public class CollectionUtils {
* @return The maximum value found, or zero if the input is empty.
*/
public static <T> int max(T[] array, ToIntFunction<T> tif) {
- return max_internal(Arrays.stream(array), alwaysTrue(), tif);
+ return max_internal(Arrays.stream(array), tif);
}
/**
@@ -1359,7 +1371,7 @@ public class CollectionUtils {
* @return The maximum value found, or zero if the input is empty.
*/
public static <T> int max(Collection<T> c, ToIntFunction<T> tif) {
- return max_internal(c.stream(), alwaysTrue(), tif);
+ return max_internal(c.stream(), tif);
}
/**
@@ -1386,7 +1398,7 @@ public class CollectionUtils {
*/
public static <T> int max(Stream<T> stream, ToIntFunction<T> tif) {
return (stream == null) ? MAX_DEFAULT
- : max_internal(stream, alwaysTrue(), tif);
+ : max_internal(stream, tif);
}
/**
@@ -1421,6 +1433,20 @@ public class CollectionUtils {
}
/**
+ * Implement max.
+ *
+ * @param <T> The stream member type.
+ * @param stream The {@code Stream} to check.
+ * @param tif A {@code ToIntFunction} to map the stream to int with.
+ * @return The maximum value found, or zero if the input is empty.
+ */
+ private static <T> int max_internal(Stream<T> stream,
+ ToIntFunction<T> tif) {
+ return stream.mapToInt(tif).max()
+ .orElse(MAX_DEFAULT);
+ }
+
+ /**
* Find the selected member of an array that maximizes according
* to a given comparison.
*
@@ -1430,7 +1456,7 @@ public class CollectionUtils {
* @return The maximal value found, or null if none present.
*/
public static <T> T maximize(T[] array, Comparator<? super T> comparator) {
- return maximize_internal(Arrays.stream(array), alwaysTrue(),
+ return maximize_internal(Arrays.stream(array),
comparator);
}
@@ -1460,7 +1486,7 @@ public class CollectionUtils {
*/
public static <T> T maximize(Collection<T> c,
Comparator<? super T> comparator) {
- return maximize_internal(c.stream(), alwaysTrue(), comparator);
+ return maximize_internal(c.stream(), comparator);
}
/**
@@ -1491,7 +1517,7 @@ public class CollectionUtils {
public static <T> T maximize(Stream<T> stream,
Comparator<? super T> comparator) {
return (stream == null) ? null
- : maximize_internal(stream, alwaysTrue(), comparator);
+ : maximize_internal(stream, comparator);
}
/**
@@ -1516,6 +1542,20 @@ public class CollectionUtils {
*
* @param <T> The collection member type.
* @param stream The {@code Stream} to maximize from.
+ * @param comparator A {@code Comparator} to compare with.
+ * @return The maximal value found, or null if none present.
+ */
+ private static <T> T maximize_internal(Stream<T> stream,
+ Comparator<? super T> comparator) {
+ return stream.collect(Collectors.maxBy(comparator))
+ .orElse(null);
+ }
+
+ /**
+ * Implement maximize.
+ *
+ * @param <T> The collection member type.
+ * @param stream The {@code Stream} to maximize from.
* @param predicate A {@code Predicate} to match with.
* @param comparator A {@code Comparator} to compare with.
* @return The maximal value found, or null if none present.
@@ -1536,7 +1576,7 @@ public class CollectionUtils {
* @return The minimum value found, or zero if the input is empty.
*/
public static <T> int min(T[] array, ToIntFunction<T> tif) {
- return min_internal(Arrays.stream(array), alwaysTrue(), tif);
+ return min_internal(Arrays.stream(array), tif);
}
/**
@@ -1562,7 +1602,7 @@ public class CollectionUtils {
* @return The minimum value found, or zero if the input is empty.
*/
public static <T> int min(Collection<T> c, ToIntFunction<T> tif) {
- return min_internal(c.stream(), alwaysTrue(), tif);
+ return min_internal(c.stream(), tif);
}
/**
@@ -1589,7 +1629,7 @@ public class CollectionUtils {
*/
public static <T> int min(Stream<T> stream, ToIntFunction<T> tif) {
return (stream == null) ? MIN_DEFAULT
- : min_internal(stream, alwaysTrue(), tif);
+ : min_internal(stream, tif);
}
/**
@@ -1613,6 +1653,20 @@ public class CollectionUtils {
*
* @param <T> The stream member type.
* @param stream The {@code Stream} to check.
+ * @param tif A {@code ToIntFunction} to map the stream to int with.
+ * @return The minimum value found, or zero if the input is empty.
+ */
+ private static <T> int min_internal(Stream<T> stream,
+ ToIntFunction<T> tif) {
+ return stream.mapToInt(tif).min()
+ .orElse(MIN_DEFAULT);
+ }
+
+ /**
+ * Implement min.
+ *
+ * @param <T> The stream member type.
+ * @param stream The {@code Stream} to check.
* @param predicate A {@code Predicate} to match with.
* @param tif A {@code ToIntFunction} to map the stream to int with.
* @return The minimum value found, or zero if the input is empty.
@@ -1635,7 +1689,7 @@ public class CollectionUtils {
*/
public static <T> T minimize(T[] array,
Comparator<? super T> comparator) {
- return minimize_internal(Arrays.stream(array), alwaysTrue(),
+ return minimize_internal(Arrays.stream(array),
comparator);
}
@@ -1665,7 +1719,7 @@ public class CollectionUtils {
*/
public static <T> T minimize(Collection<T> c,
Comparator<? super T> comparator) {
- return minimize_internal(c.stream(), alwaysTrue(), comparator);
+ return minimize_internal(c.stream(), comparator);
}
/**
@@ -1696,7 +1750,7 @@ public class CollectionUtils {
public static <T> T minimize(Stream<T> stream,
Comparator<? super T> comparator) {
return (stream == null) ? null
- : minimize_internal(stream, alwaysTrue(), comparator);
+ : minimize_internal(stream, comparator);
}
/**
@@ -1726,6 +1780,21 @@ public class CollectionUtils {
* @return The minimal value found, or null if none present.
*/
private static <T> T minimize_internal(Stream<T> stream,
+ Comparator<? super T> comparator) {
+ return stream.collect(Collectors.minBy(comparator))
+ .orElse(null);
+ }
+
+ /**
+ * Implement minimize.
+ *
+ * @param <T> The stream member type.
+ * @param stream The {@code Stream} to minimize from.
+ * @param predicate A {@code Predicate} to match with.
+ * @param comparator A {@code Comparator} to compare with.
+ * @return The minimal value found, or null if none present.
+ */
+ private static <T> T minimize_internal(Stream<T> stream,
Predicate<? super T> predicate,
Comparator<? super T> comparator) {
return stream.filter(predicate).collect(Collectors.minBy(comparator))
@@ -1825,7 +1894,7 @@ public class CollectionUtils {
* @return The product of the values found.
*/
public static <T> double product(T[] array, ToDoubleFunction<T> tdf) {
- return product_internal(Arrays.stream(array), alwaysTrue(), tdf);
+ return product_internal(Arrays.stream(array), tdf);
}
/**
@@ -1852,7 +1921,7 @@ public class CollectionUtils {
*/
public static <T> double product(Collection<T> c,
ToDoubleFunction<T> tdf) {
- return product_internal(c.stream(), alwaysTrue(), tdf);
+ return product_internal(c.stream(), tdf);
}
/**
@@ -1881,7 +1950,7 @@ public class CollectionUtils {
public static <T> double product(Stream<T> stream,
ToDoubleFunction<T> tdf) {
return (stream == null) ? PRODUCT_DEFAULT
- : product_internal(stream, alwaysTrue(), tdf);
+ : product_internal(stream, tdf);
}
/**
@@ -1903,6 +1972,20 @@ public class CollectionUtils {
/**
* Take the product of the members of a stream.
*
+ * @param <T> The stream member type.
+ * @param stream The {@code Stream} to multiply.
+ * @param tdf A {@code ToDoubleFunction} to convert members to double.
+ * @return The product of the values found.
+ */
+ public static <T> double product_internal(Stream<T> stream,
+ ToDoubleFunction<T> tdf) {
+ return stream.mapToDouble(tdf)
+ .reduce(PRODUCT_DEFAULT, doubleMultiplicator);
+ }
+
+ /**
+ * Take the product of the members of a stream.
+ *
* @param predicate A {@code Predicate} to match with.
* @param <T> The stream member type.
* @param stream The {@code Stream} to multiply.
@@ -1912,9 +1995,8 @@ public class CollectionUtils {
public static <T> double product_internal(Stream<T> stream,
Predicate<? super T> predicate,
ToDoubleFunction<T> tdf) {
- final DoubleBinaryOperator mult = (d1, d2) -> d1 * d2;
return stream.filter(predicate).mapToDouble(tdf)
- .reduce(PRODUCT_DEFAULT, mult);
+ .reduce(PRODUCT_DEFAULT, doubleMultiplicator);
}
/**
@@ -2046,7 +2128,7 @@ public class CollectionUtils {
*/
private static <T> List<T> sort_internal(Stream<T> stream,
Comparator<? super T> comparator)
{
- return stream.sorted(comparator).collect(Collectors.toList());
+ return stream.sorted(comparator).collect(Collectors.<T>toList());
}
/**
@@ -2058,7 +2140,7 @@ public class CollectionUtils {
* @return The sum of the values found.
*/
public static <T> int sum(T[] array, ToIntFunction<T> tif) {
- return sum_internal(Arrays.stream(array), alwaysTrue(), tif);
+ return sum_internal(Arrays.stream(array), tif);
}
/**
@@ -2084,7 +2166,7 @@ public class CollectionUtils {
* @return The sum of the values found.
*/
public static <T> int sum(Collection<T> c, ToIntFunction<T> tif) {
- return sum_internal(c.stream(), alwaysTrue(), tif);
+ return sum_internal(c.stream(), tif);
}
/**
@@ -2111,7 +2193,7 @@ public class CollectionUtils {
*/
public static <T> int sum(Stream<T> stream, ToIntFunction<T> tif) {
return (stream == null) ? SUM_DEFAULT
- : sum_internal(stream, alwaysTrue(), tif);
+ : sum_internal(stream, tif);
}
/**
@@ -2134,6 +2216,19 @@ public class CollectionUtils {
*
* @param <T> The stream member type.
* @param stream The {@code Stream} to sum.
+ * @param tif A {@code ToIntFunction} to convert members to an int.
+ * @return The sum of the values found.
+ */
+ private static <T> int sum_internal(Stream<T> stream,
+ ToIntFunction<T> tif) {
+ return stream.mapToInt(tif).sum();
+ }
+
+ /**
+ * Take the sum of the members of a stream.
+ *
+ * @param <T> The stream member type.
+ * @param stream The {@code Stream} to sum.
* @param predicate A {@code Predicate} to match with.
* @param tif A {@code ToIntFunction} to convert members to an int.
* @return The sum of the values found.
@@ -2154,7 +2249,7 @@ public class CollectionUtils {
* @return The sum of the values found.
*/
public static <T> double sumDouble(T[] array, ToDoubleFunction<T> tdf) {
- return sumDouble_internal(Arrays.stream(array), alwaysTrue(), tdf);
+ return sumDouble_internal(Arrays.stream(array), tdf);
}
/**
@@ -2184,7 +2279,7 @@ public class CollectionUtils {
*/
public static <T> double sumDouble(Collection<T> c,
ToDoubleFunction<T> tdf) {
- return sumDouble_internal(c.stream(), alwaysTrue(), tdf);
+ return sumDouble_internal(c.stream(), tdf);
}
/**
@@ -2215,7 +2310,7 @@ public class CollectionUtils {
public static <T> double sumDouble(Stream<T> stream,
ToDoubleFunction<T> tdf) {
return (stream == null) ? SUM_DOUBLE_DEFAULT
- : sumDouble_internal(stream, alwaysTrue(), tdf);
+ : sumDouble_internal(stream, tdf);
}
/**
@@ -2250,6 +2345,19 @@ public class CollectionUtils {
}
/**
+ * Take the sum of the members of a stream.
+ *
+ * @param <T> The stream member type.
+ * @param stream The {@code Stream} to sum.
+ * @param tdf A {@code ToIntFunction} to convert members to a double.
+ * @return The sum of the values found.
+ */
+ private static <T> double sumDouble_internal(Stream<T> stream,
+ ToDoubleFunction<T> tdf) {
+ return stream.mapToDouble(tdf).sum();
+ }
+
+ /**
* Make a collector that takes lists and appends them.
*
* @param <T> The list member type.
@@ -2303,7 +2411,7 @@ public class CollectionUtils {
* @return A list of the stream contents.
*/
private static <T> List<T> toList_internal(Stream<T> stream) {
- return stream.collect(Collectors.toList());
+ return stream.collect(Collectors.<T>toList());
}
/**
@@ -2352,9 +2460,7 @@ public class CollectionUtils {
*/
public static <T> List<T> transform(T[] array,
Predicate<? super T> predicate) {
- return transform_internal(Arrays.stream(array), predicate,
- Function.<T>identity(), null,
- Collectors.toList());
+ return
Arrays.<T>stream(array).filter(predicate).collect(Collectors.<T>toList());
}
/**
@@ -2370,8 +2476,21 @@ public class CollectionUtils {
public static <T,R> List<R> transform(T[] array,
Predicate<? super T> predicate,
Function<? super T, ? extends R> mapper) {
- return transform_internal(Arrays.stream(array), predicate, mapper,
- null, Collectors.toList());
+ return
Arrays.<T>stream(array).filter(predicate).map(mapper).collect(Collectors.<R>toList());
+ }
+
+ /**
+ * Transform the contents of an array.
+ *
+ * @param <T> The array member type.
+ * @param <R> The resulting collection member type.
+ * @param array The array to transform.
+ * @param mapper A function to transform the selected items.
+ * @return The result of collecting the mapped predicate matches.
+ */
+ public static <T,R> List<R> transform(T[] array,
+ Function<? super T, ? extends R> mapper) {
+ return
Arrays.<T>stream(array).map(mapper).collect(Collectors.<R>toList());
}
/**
@@ -2390,8 +2509,24 @@ public class CollectionUtils {
Predicate<? super T> predicate,
Function<? super T, ? extends R> mapper,
Collector<R,?,C> collector) {
- return transform_internal(Arrays.stream(array), predicate, mapper,
- null, collector);
+ return
Arrays.<T>stream(array).filter(predicate).map(mapper).collect(collector);
+ }
+
+ /**
+ * Transform the contents of an array.
+ *
+ * @param <T> The array member type.
+ * @param <R> The resulting collection member type.
+ * @param <C> The resulting collection type.
+ * @param array The array to transform.
+ * @param mapper A function to transform the selected items.
+ * @param collector A {@code Collector} to collect the items.
+ * @return The result of collecting the mapped predicate matches.
+ */
+ public static <T,R,C> C transform(T[] array,
+ Function<? super T, ? extends R> mapper,
+ Collector<R,?,C> collector) {
+ return Arrays.<T>stream(array).map(mapper).collect(collector);
}
/**
@@ -2409,8 +2544,25 @@ public class CollectionUtils {
Predicate<? super T> predicate,
Function<? super T, ? extends R> mapper,
Comparator<? super R> comparator) {
- return transform_internal(Arrays.stream(array), predicate, mapper,
- comparator, Collectors.toList());
+ return Arrays.<T>stream(array).filter(predicate).map(mapper)
+ .sorted(comparator).collect(Collectors.<R>toList());
+ }
+
+ /**
+ * Transform the contents of an array and sort the result.
+ *
+ * @param <T> The array member type.
+ * @param <R> The resulting collection member type.
+ * @param array The array to transform.
+ * @param mapper A function to transform the selected items.
+ * @param comparator A {@code Comparator} to sort the items.
+ * @return A list of sorted mapped predicate matches.
+ */
+ public static <T,R> List<R> transform(T[] array,
+ Function<? super T, ? extends R> mapper,
+ Comparator<? super R> comparator) {
+ return Arrays.<T>stream(array).map(mapper)
+ .sorted(comparator).collect(Collectors.<R>toList());
}
/**
@@ -2423,8 +2575,7 @@ public class CollectionUtils {
*/
public static <T> List<T> transform(Collection<T> c,
Predicate<? super T> predicate) {
- return transform_internal(c.stream(), predicate,
Function.<T>identity(),
- null, Collectors.toList());
+ return c.stream().filter(predicate).collect(Collectors.<T>toList());
}
/**
@@ -2440,8 +2591,21 @@ public class CollectionUtils {
public static <T,R> List<R> transform(Collection<T> c,
Predicate<? super T> predicate,
Function<? super T, ? extends R> mapper) {
- return transform_internal(c.stream(), predicate, mapper, null,
- Collectors.toList());
+ return
c.stream().filter(predicate).map(mapper).collect(Collectors.<R>toList());
+ }
+
+ /**
+ * Transform the contents of a collection.
+ *
+ * @param <T> The collection member type.
+ * @param <R> The resulting collection member type.
+ * @param c The {@code Collection} to transform.
+ * @param mapper A function to transform the selected items.
+ * @return The result of collecting the mapped predicate matches.
+ */
+ public static <T,R> List<R> transform(Collection<T> c,
+ Function<? super T, ? extends R> mapper) {
+ return c.stream().map(mapper).collect(Collectors.<R>toList());
}
/**
@@ -2459,8 +2623,23 @@ public class CollectionUtils {
Predicate<? super T> predicate,
Function<? super T, ? extends R> mapper,
Comparator<? super R> comparator) {
- return transform_internal(c.stream(), predicate, mapper, comparator,
- Collectors.toList());
+ return
c.stream().filter(predicate).map(mapper).sorted(comparator).collect(Collectors.<R>toList());
+ }
+
+ /**
+ * Transform the contents of a collection and sort the result.
+ *
+ * @param <T> The collection member type.
+ * @param <R> The resulting collection member type.
+ * @param c The {@code Collection} to transform.
+ * @param mapper A function to transform the selected items.
+ * @param comparator A {@code Comparator} to sort the results.
+ * @return A list of sorted mapped predicate matches.
+ */
+ public static <T,R> List<R> transform(Collection<T> c,
+ Function<? super T, ? extends R> mapper,
+ Comparator<? super R> comparator) {
+ return
c.stream().map(mapper).sorted(comparator).collect(Collectors.<R>toList());
}
/**
@@ -2479,8 +2658,24 @@ public class CollectionUtils {
Predicate<? super T> predicate,
Function<? super T, ? extends R> mapper,
Collector<R,?,C> collector) {
- return transform_internal(c.stream(), predicate, mapper, null,
- collector);
+ return c.stream().filter(predicate).map(mapper).collect(collector);
+ }
+
+ /**
+ * Transform the contents of a collection.
+ *
+ * @param <T> The collection member type.
+ * @param <R> The resulting collection member type.
+ * @param <C> The resulting collection type.
+ * @param c The {@code Collection} to transform.
+ * @param mapper A function to transform the selected items.
+ * @param collector A {@code Collector} to aggregate the results.
+ * @return The result of collecting the mapped predicate matches.
+ */
+ public static <T,R,C> C transform(Collection<T> c,
+ Function<? super T, ? extends R> mapper,
+ Collector<R,?,C> collector) {
+ return c.stream().map(mapper).collect(collector);
}
/**
@@ -2493,9 +2688,7 @@ public class CollectionUtils {
*/
public static <T> List<T> transform(Stream<T> stream,
Predicate<? super T> predicate) {
- final Stream<T> s = (stream == null) ? Stream.<T>empty() : stream;
- return transform_internal(s, predicate, Function.<T>identity(),
- null, Collectors.toList());
+ return stream.filter(predicate).collect(Collectors.<T>toList());
}
/**
@@ -2511,9 +2704,21 @@ public class CollectionUtils {
public static <T,R> List<R> transform(Stream<T> stream,
Predicate<? super T> predicate,
Function<? super T, ? extends R> mapper) {
- final Stream<T> s = (stream == null) ? Stream.<T>empty() : stream;
- return transform_internal(s, predicate, mapper, null,
- Collectors.toList());
+ return
stream.filter(predicate).map(mapper).collect(Collectors.<R>toList());
+ }
+
+ /**
+ * Transform the contents of a stream.
+ *
+ * @param <T> The stream member type.
+ * @param <R> The resulting collection member type.
+ * @param stream The {@code Stream} to transform.
+ * @param mapper A function to transform the selected items.
+ * @return The result of collecting the mapped predicate matches.
+ */
+ public static <T,R> List<R> transform(Stream<T> stream,
+ Function<? super T, ? extends R> mapper) {
+ return stream.map(mapper).collect(Collectors.<R>toList());
}
/**
@@ -2530,10 +2735,24 @@ public class CollectionUtils {
public static <T,R> List<R> transform(Stream<T> stream,
Predicate<? super T> predicate,
Function<? super T, ? extends R> mapper,
+ Comparator<R> comparator) {
+ return
stream.filter(predicate).map(mapper).sorted(comparator).collect(Collectors.<R>toList());
+ }
+
+ /**
+ * Transform the contents of a stream.
+ *
+ * @param <T> The collection member type.
+ * @param <R> The resulting collection member type.
+ * @param stream The {@code Stream} to transform.
+ * @param mapper A function to transform the selected items.
+ * @param comparator A {@code Comparator} to sort the results.
+ * @return A list of sorted mapped predicate matches.
+ */
+ public static <T,R> List<R> transform(Stream<T> stream,
+ Function<? super T, ? extends R> mapper,
Comparator<? super R> comparator) {
- final Stream<T> s = (stream == null) ? Stream.<T>empty() : stream;
- return transform_internal(s, predicate, mapper, comparator,
- Collectors.toList());
+ return
stream.map(mapper).sorted(comparator).collect(Collectors.<R>toList());
}
/**
@@ -2552,32 +2771,23 @@ public class CollectionUtils {
Predicate<? super T> predicate,
Function<? super T, ? extends R> mapper,
Collector<R,?,C> collector) {
- final Stream<T> s = (stream == null) ? Stream.<T>empty() : stream;
- return transform_internal(s, predicate, mapper, null, collector);
+ return stream.filter(predicate).map(mapper).collect(collector);
}
/**
- * Underlying implementation for the transform functions.
+ * Transform the contents of a stream.
*
- * @param <T> The stream member type.
+ * @param <T> The collection member type.
* @param <R> The resulting collection member type.
* @param <C> The resulting collection type.
* @param stream The {@code Stream} to transform.
- * @param predicate A {@code Predicate} to select the items.
* @param mapper A function to transform the selected items.
- * @param comparator An optional {@code Comparator} to sort
- * the results.
* @param collector A {@code Collector} to aggregate the results.
* @return The result of collecting the mapped predicate matches.
*/
- private static <T,R,C> C transform_internal(Stream<T> stream,
- Predicate<? super T> predicate,
+ public static <T,R,C> C transform(Stream<T> stream,
Function<? super T, ? extends R> mapper,
- Comparator<? super R> comparator,
Collector<R,?,C> collector) {
- return (comparator == null)
- ? stream.filter(predicate).map(mapper).collect(collector)
- : stream.filter(predicate).map(mapper)
- .sorted(comparator).collect(collector);
+ return stream.map(mapper).collect(collector);
}
}
--
2.11.0.rc0.7.gbe5a750
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