OAK-11451 : reverted code changes for Iterables.concat with Iterable<Iterable<E>>

Author: Rishabh Kumar

oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/index/property/PropertyIndexLookup.java

@@ -28,14 +28,12 @@
 import java.util.Collections;
 import java.util.List;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 import org.apache.commons.collections4.IterableUtils;
 import org.apache.jackrabbit.oak.api.PropertyState;
 import org.apache.jackrabbit.oak.api.PropertyValue;
 import org.apache.jackrabbit.oak.api.Type;
 import org.apache.jackrabbit.oak.commons.PathUtils;
-import org.apache.jackrabbit.oak.commons.collections.StreamUtils;
 import org.apache.jackrabbit.oak.plugins.index.IndexConstants;
 import org.apache.jackrabbit.oak.plugins.index.property.strategy.IndexStoreStrategy;
 import org.apache.jackrabbit.oak.spi.mount.MountInfoProvider;
@@ -128,7 +126,7 @@ public Iterable<String> query(Filter filter, String propertyName,
             iterables.add(s.query(filter, propertyName, indexMeta,
                     encode(value, pattern)));
         }
-        return StreamUtils.toStream(iterables).flatMap(StreamUtils::toStream).collect(Collectors.toList());
+        return Iterables.concat(iterables);
     }
 
     Set<IndexStoreStrategy> getStrategies(NodeState definition) {

oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/index/property/PropertyIndexPlan.java

@@ -24,9 +24,7 @@
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Set;
-import java.util.stream.Collectors;
 
-import org.apache.commons.collections4.IterableUtils;
 import org.apache.jackrabbit.oak.commons.PathUtils;
 import org.apache.jackrabbit.oak.commons.collections.SetUtils;
 import org.apache.jackrabbit.oak.commons.collections.StreamUtils;
@@ -218,7 +216,7 @@ Cursor execute() {
         for (IndexStoreStrategy s : strategies) {
             iterables.add(s.query(filter, name, definition, values));
         }
-        Cursor cursor = Cursors.newPathCursor(StreamUtils.toStream(iterables).flatMap(StreamUtils::toStream).collect(Collectors.toList()),
+        Cursor cursor = Cursors.newPathCursor(Iterables.concat(iterables),
                 settings);
         if (depth > 1) {
             cursor = Cursors.newAncestorCursor(cursor, depth - 1, settings);

oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/index/reference/ReferenceIndex.java

@@ -33,10 +33,7 @@
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Set;
-import java.util.stream.Collectors;
 
-import org.apache.commons.collections4.IterableUtils;
-import org.apache.jackrabbit.oak.commons.collections.StreamUtils;
 import org.apache.jackrabbit.oak.plugins.index.property.Multiplexers;
 import org.apache.jackrabbit.oak.plugins.index.property.strategy.IndexStoreStrategy;
 import org.apache.jackrabbit.oak.query.SQL2Parser;
@@ -136,7 +133,7 @@ private Cursor lookup(NodeState root, String uuid,
             iterables.add(s.query(filter, index + "("
                     + uuid + ")", indexRoot, Set.of(uuid)));
         }
-        Iterable<String> paths = StreamUtils.toStream(iterables).flatMap(StreamUtils::toStream).collect(Collectors.toList());
+        Iterable<String> paths = Iterables.concat(iterables);
 
         if (!"*".equals(name)) {
             paths = filter(paths, path -> name.equals(getName(path)));

oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/nodetype/EffectiveNodeTypeImpl.java

@@ -24,7 +24,6 @@
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.stream.Collectors;
 
 import javax.jcr.PropertyType;
 import javax.jcr.RepositoryException;
@@ -36,11 +35,8 @@
 import javax.jcr.nodetype.NodeType;
 import javax.jcr.nodetype.PropertyDefinition;
 
-import org.apache.commons.collections4.IterableUtils;
 import org.apache.jackrabbit.oak.api.PropertyState;
 import org.apache.jackrabbit.oak.api.Tree;
-import org.apache.jackrabbit.oak.commons.collections.IteratorUtils;
-import org.apache.jackrabbit.oak.commons.collections.StreamUtils;
 import org.apache.jackrabbit.oak.plugins.value.jcr.PartialValueFactory;
 import org.apache.jackrabbit.oak.spi.nodetype.EffectiveNodeType;
 import org.jetbrains.annotations.NotNull;
@@ -208,9 +204,8 @@ public Iterable<PropertyDefinition> getMandatoryPropertyDefinitions() {
     @NotNull
     @Override
     public Iterable<NodeDefinition> getNamedNodeDefinitions(@NotNull final String oakName) {
-        return StreamUtils.toStream(Iterables.transform(nodeTypes.values(), input -> input.getDeclaredNamedNodeDefinitions(oakName)))
-                .flatMap(StreamUtils::toStream)
-                .collect(Collectors.toList());
+        return Iterables.concat(Iterables.transform(nodeTypes.values(),
+                input -> input.getDeclaredNamedNodeDefinitions(oakName)));
     }
 
     /**

oak-core/src/main/java/org/apache/jackrabbit/oak/security/internal/SecurityProviderRegistration.java

@@ -16,12 +16,10 @@
  */
 package org.apache.jackrabbit.oak.security.internal;
 
-import org.apache.commons.collections4.IterableUtils;
 import org.apache.jackrabbit.guava.common.collect.Iterables;
 import org.apache.jackrabbit.guava.common.io.Closer;
 import org.apache.jackrabbit.api.security.JackrabbitAccessControlManager;
 import org.apache.jackrabbit.oak.commons.PropertiesUtil;
-import org.apache.jackrabbit.oak.commons.collections.StreamUtils;
 import org.apache.jackrabbit.oak.osgi.OsgiWhiteboard;
 import org.apache.jackrabbit.oak.plugins.tree.RootProvider;
 import org.apache.jackrabbit.oak.plugins.tree.TreeProvider;
@@ -88,7 +86,6 @@
 import java.util.Set;
 import java.util.SortedMap;
 import java.util.TreeMap;
-import java.util.stream.Collectors;
 
 import static org.apache.jackrabbit.oak.commons.IOUtils.closeQuietly;
 import static org.apache.jackrabbit.oak.spi.security.ConfigurationParameters.EMPTY;
@@ -531,7 +528,7 @@ private void maybeRegister() {
 
         closer = Closer.create();
         Iterable<Iterable<Monitor<?>>> monitors = Iterables.transform(securityProvider.getConfigurations(), sc -> sc.getMonitors(statisticsProvider));
-        for (Monitor monitor : StreamUtils.toStream(monitors).flatMap(StreamUtils::toStream).collect(Collectors.toList())) {
+        for (Monitor monitor : Iterables.concat(monitors)) {
             Registration reg = whiteboard.register(monitor.getMonitorClass(), monitor, monitor.getMonitorProperties());
             closer.register(reg::unregister);
 

oak-security-spi/src/main/java/org/apache/jackrabbit/oak/spi/security/CompositeConfiguration.java

@@ -22,9 +22,7 @@
 import org.apache.jackrabbit.guava.common.collect.Iterables;
 import org.apache.jackrabbit.oak.api.PropertyState;
 import org.apache.jackrabbit.oak.api.Tree;
-import org.apache.jackrabbit.oak.commons.collections.IteratorUtils;
 import org.apache.jackrabbit.oak.commons.collections.SetUtils;
-import org.apache.jackrabbit.oak.commons.collections.StreamUtils;
 import org.apache.jackrabbit.oak.plugins.tree.RootProvider;
 import org.apache.jackrabbit.oak.plugins.tree.TreeLocation;
 import org.apache.jackrabbit.oak.plugins.tree.TreeProvider;
@@ -264,8 +262,8 @@ public Context getContext() {
     @NotNull
     @Override
     public Iterable<Monitor<?>> getMonitors(@NotNull StatisticsProvider statisticsProvider) {
-        return StreamUtils.toStream(Iterables.transform(getConfigurations(), securityConfiguration -> securityConfiguration.getMonitors(statisticsProvider)))
-                .flatMap(StreamUtils::toStream).collect(Collectors.toList());
+        return Iterables.concat(
+                Iterables.transform(getConfigurations(), securityConfiguration -> securityConfiguration.getMonitors(statisticsProvider)));
     }
 
     private static final class Ranking {

oak-store-document/src/main/java/org/apache/jackrabbit/oak/plugins/document/Branch.java

@@ -32,13 +32,9 @@
 import java.util.TreeMap;
 import java.util.concurrent.ConcurrentSkipListMap;
 import java.util.function.Predicate;
-import java.util.stream.Collectors;
 
-import org.apache.commons.collections4.IterableUtils;
 import org.apache.jackrabbit.guava.common.collect.Iterables;
 
-import org.apache.jackrabbit.oak.commons.collections.IteratorUtils;
-import org.apache.jackrabbit.oak.commons.collections.StreamUtils;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -283,7 +279,7 @@ public boolean test(Map.Entry<Revision, BranchCommit> input) {
                         && input.getKey().compareRevisionTime(r) <= 0;
             }
         }::test), input -> input.getValue().getModifiedPaths());
-        return IteratorUtils.toIterable(StreamUtils.toStream(paths).flatMap(StreamUtils::toStream).iterator());
+        return Iterables.concat(paths);
     }
 
     @Override
@@ -409,8 +405,9 @@ protected boolean isRebase() {
 
         @Override
         Iterable<Path> getModifiedPaths() {
-            Iterable<Iterable<Path>> paths = transform(previous.values(), BranchCommit::getModifiedPaths);
-            return StreamUtils.toStream(paths).flatMap(StreamUtils::toStream).collect(Collectors.toSet());
+            Iterable<Iterable<Path>> paths = transform(previous.values(),
+                    branchCommit -> branchCommit.getModifiedPaths());
+            return Iterables.concat(paths);
         }
 
         /**

oak-store-document/src/main/java/org/apache/jackrabbit/oak/plugins/document/NodeDocument.java

@@ -59,8 +59,6 @@
 import org.apache.jackrabbit.oak.api.PropertyState;
 import org.apache.jackrabbit.oak.commons.PathUtils;
 import org.apache.jackrabbit.oak.commons.collections.DequeUtils;
-import org.apache.jackrabbit.oak.commons.collections.IteratorUtils;
-import org.apache.jackrabbit.oak.commons.collections.StreamUtils;
 import org.apache.jackrabbit.oak.commons.json.JsopBuilder;
 import org.apache.jackrabbit.oak.commons.json.JsopReader;
 import org.apache.jackrabbit.oak.commons.json.JsopTokenizer;
@@ -1818,8 +1816,7 @@ public Iterator<Entry<Revision, String>> iterator() {
                 }
             };
         } else {
-            changes = IteratorUtils.toIterable(StreamUtils.toStream(transform(List.copyOf(ranges), rangeToChanges::apply))
-                    .flatMap(StreamUtils::toStream).iterator());
+            changes = Iterables.concat(transform(List.copyOf(ranges), rangeToChanges::apply));
         }
         return filter(changes, input -> !readRev.isRevisionNewer(input.getKey()));
     }

oak-store-document/src/test/java/org/apache/jackrabbit/oak/plugins/document/NodeDocumentTest.java

@@ -967,7 +967,6 @@ public void tooManyReadsOnGetVisibleChanges() throws Exception {
             public <T extends Document> T find(Collection<T> collection,
                                                String key) {
                 if (Utils.getPathFromId(key).startsWith("p")) {
-                    System.out.println("find " + key);
                     prevDocCalls.add(key);
                 }
                 return super.find(collection, key);
@@ -984,7 +983,6 @@ public <T extends Document> T find(Collection<T> collection,
         for (int i = 0; i < 20; i++) {
             prevDocCalls.clear();
             String value = doc.getVisibleChanges("p", headRevisions.get(i), null).iterator().next().getValue();
-            System.out.println(value);
             assertEquals(String.valueOf(numChanges - (i + 1)), value);
             assertTrue("too many calls for previous documents: " + prevDocCalls + " : " + prevDocCalls.size(),
                     prevDocCalls.size() <= 3);