1 files changed, 132 insertions, 0 deletions
diff --git a/common-app-api/src/main/java/org/openecomp/sdc/common/util/StreamUtils.java b/common-app-api/src/main/java/org/openecomp/sdc/common/util/StreamUtils.java
new file mode 100644
index 0000000000..37769fbaef
--- /dev/null
+++ b/common-app-api/src/main/java/org/openecomp/sdc/common/util/StreamUtils.java
@@ -0,0 +1,132 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * SDC
+ * ================================================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
+ * ================================================================================
+ * Licensed 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.
+ * ============LICENSE_END=========================================================
+ */
+package org.openecomp.sdc.common.util;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Spliterator;
+import java.util.Spliterators.AbstractSpliterator;
+import java.util.function.Consumer;
+import java.util.function.Predicate;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
+
+/**
+ * Utility Class For Actions On Streams
+ *
+ * @author mshitrit
+ */
+public final class StreamUtils {
+
+    private StreamUtils() {
+        throw new UnsupportedOperationException();
+    }
+
+    /**
+     * Breaks the stream when the predicate is not met.<br> Does not evaluate elements after the stream breaks.<br> This method evaluates the
+     * stream.<br>
+     *
+     * @param stream
+     * @param predicate
+     * @return
+     */
+    public static <T> Stream<T> takeWhilePlusOneNoEval(Stream<T> stream, Predicate<T> predicate) {
+        List<T> results = new ArrayList<>();
+        Consumer<T> listAdder = results::add;
+        stream.map(e -> {
+            listAdder.accept(e);
+            return e;
+        }).filter(e -> !predicate.test(e)).findFirst();
+        return results.stream();
+    }
+
+    public static <T> Stream<T> takeWhile(Stream<T> stream, Predicate<T> predicate) {
+        return StreamSupport.stream(takeWhile(stream.spliterator(), predicate), false);
+    }
+
+    public static <T> Stream<T> takeWhilePlusOne(Stream<T> stream, Predicate<T> predicate) {
+        return StreamSupport.stream(takeWhile(stream.spliterator(), new StopAfterFailPredicate<>(predicate)), false);
+    }
+
+    private static <T> Spliterator<T> takeWhile(Spliterator<T> splitr, Predicate<T> predicate) {
+        return new MySplitIterator<>(splitr, predicate);
+    }
+
+    public static class MySplitIterator<T> extends AbstractSpliterator<T> implements Spliterator<T> {
+
+        boolean stillGoing = true;
+        private Spliterator<T> innerItr;
+        private Predicate<T> innerPred;
+
+        private MySplitIterator(Spliterator<T> splitItr, Predicate<T> pred) {
+            super(splitItr.estimateSize(), 0);
+            innerItr = splitItr;
+            innerPred = pred;
+        }
+
+        @Override
+        public boolean tryAdvance(Consumer<? super T> action) {
+            boolean canAdvance = true;
+            if (stillGoing) {
+                stillGoing = innerItr.tryAdvance(createConsumerWrapper(action));
+            } else {
+                canAdvance = false;
+            }
+            return canAdvance;
+        }
+
+        private Consumer<? super T> createConsumerWrapper(Consumer<? super T> action) {
+            return new Consumer<T>() {
+                @Override
+                public void accept(T t) {
+                    stillGoing = innerPred.test(t);
+                    if (stillGoing) {
+                        action.accept(t);
+                    }
+                }
+            };
+        }
+    }
+
+    public static class StopAfterFailPredicate<T> implements Predicate<T> {
+
+        boolean hasNotFailed;
+        Predicate<T> innerPredicate;
+
+        private StopAfterFailPredicate(Predicate<T> pred) {
+            hasNotFailed = true;
+            innerPredicate = pred;
+        }
+
+        ;
+
+        @Override
+        public boolean test(T t) {
+            boolean isPassed;
+            if (hasNotFailed) {
+                isPassed = true;
+                hasNotFailed = innerPredicate.test(t);
+            } else {
+                isPassed = false;
+            }
+            return isPassed;
+        }
+    }
+}