use java 8 features: List.sort, Comparator.comparing and others (#757)

* use java 8 features: List.sort, Comparator.comparing and others

* use java 8 features: remove unused import

* use java 8 features: remove unused imports

* fix NPE and remove useless null check

* fix indent and double copying

* remove unused import

* remove numberCoveredLines BiFunction
rename getTestsForClassName -> getLineCoverageForClassName

pitest-entry/src/main/java/org/pitest/bytecode/analysis/MethodTree.java

@@ -1,9 +1,7 @@
 package org.pitest.bytecode.analysis;
 
 import java.util.ArrayList;
-import java.util.LinkedList;
 import java.util.List;
-import java.util.ListIterator;
 
 import org.objectweb.asm.Opcodes;
 import org.objectweb.asm.tree.AbstractInsnNode;
@@ -73,12 +71,11 @@ public List<AnnotationNode> annotations() {
   }
 
   private List<AbstractInsnNode> createInstructionList() {
-    final List<AbstractInsnNode> list = new LinkedList<>();
-    final ListIterator<AbstractInsnNode> it = this.rawNode.instructions.iterator();
-    while (it.hasNext()) {
-        list.add(it.next());
+    final List<AbstractInsnNode> list = new ArrayList<>();
+    for (AbstractInsnNode abstractInsnNode : this.rawNode.instructions) {
+      list.add(abstractInsnNode);
     }
-    this.lazyInstructions = new ArrayList<>(list);
+    this.lazyInstructions = list;
     return this.lazyInstructions;
   }
 

pitest-entry/src/main/java/org/pitest/coverage/CoverageData.java

@@ -74,14 +74,13 @@ public CoverageData(final CodeSource code, final LineMap lm, Map<InstructionLoca
   }
 
   @Override
-  public Collection<TestInfo> getTestsForInstructionLocation(
-      InstructionLocation location) {
-    return this.instructionCoverage.get(location);
+  public Collection<TestInfo> getTestsForInstructionLocation(InstructionLocation location) {
+    return this.instructionCoverage.getOrDefault(location, Collections.emptySet());
   }
 
   @Override
   public Collection<TestInfo> getTestsForClassLine(final ClassLine classLine) {
-    final Collection<TestInfo> result = getTestsForClassName(
+    final Collection<TestInfo> result = getLineCoverageForClassName(
         classLine.getClassName()).get(classLine);
     if (result == null) {
       return Collections.emptyList();
@@ -109,7 +108,10 @@ public Collection<ClassInfo> getClassInfo(final Collection<ClassName> classes) {
 
   @Override
   public int getNumberOfCoveredLines(final Collection<ClassName> mutatedClass) {
-    return FCollection.fold(numberCoveredLines(), 0, mutatedClass);
+    return mutatedClass.stream()
+        .map(this::getLineCoverageForClassName)
+        .mapToInt(Map::size)
+        .sum();
   }
 
   @Override
@@ -147,7 +149,7 @@ private void addTestsToBlockMap(final TestInfo ti, InstructionLocation each) {
 
   @Override
   public BigInteger getCoverageIdForClass(final ClassName clazz) {
-    final Map<ClassLine, Set<TestInfo>> coverage = getTestsForClassName(clazz);
+    final Map<ClassLine, Set<TestInfo>> coverage = getLineCoverageForClassName(clazz);
     if (coverage.isEmpty()) {
       return BigInteger.ZERO;
     }
@@ -224,7 +226,7 @@ private int numberOfLines() {
   }
 
   private int coveredLines() {
-    return FCollection.fold(numberCoveredLines(), 0, allClasses());
+    return getNumberOfCoveredLines(allClasses());
   }
 
   private BiFunction<Integer, ClassInfo, Integer> numberLines() {
@@ -247,22 +249,7 @@ private TestInfo createTestInfo(final Description description,
         description.getQualifiedName(), executionTime, testee, linesCovered);
   }
 
-  private BiFunction<Integer, ClassName, Integer> numberCoveredLines() {
-    return (a, clazz) -> a + getNumberOfCoveredLines(clazz);
-  }
-
-  private int getNumberOfCoveredLines(final ClassName clazz) {
-    final Map<ClassLine, Set<TestInfo>> map = getTestsForClassName(clazz);
-    if (map != null) {
-      return map.size();
-    } else {
-      return 0;
-    }
-
-  }
-
-  private Map<ClassLine, Set<TestInfo>> getTestsForClassName(
-      final ClassName clazz) {
+  private Map<ClassLine, Set<TestInfo>> getLineCoverageForClassName(final ClassName clazz) {
     // Use any test that provided some coverage of the class
     // This fails to consider tests that only accessed a static variable
     // of the class in question as this does not register as coverage.

pitest-entry/src/main/java/org/pitest/mutationtest/MutationStatusMap.java

@@ -46,8 +46,7 @@ public void setStatusForMutation(final MutationDetails mutation,
 
   public void setStatusForMutations(
       final Collection<MutationDetails> mutations, final DetectionStatus status) {
-    FCollection.forEach(mutations,
-        putToMap(this.mutationMap, MutationStatusTestPair.notAnalysed(0, status)));
+    mutations.forEach(putToMap(this.mutationMap, MutationStatusTestPair.notAnalysed(0, status)));
   }
 
   public List<MutationResult> createMutationResults() {

pitest-entry/src/main/java/org/pitest/mutationtest/build/CompoundMutationInterceptor.java

@@ -1,9 +1,10 @@
 package org.pitest.mutationtest.build;
 
+import static java.util.Comparator.comparing;
+
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
-import java.util.Comparator;
 import java.util.List;
 
 import org.pitest.bytecode.analysis.ClassTree;
@@ -16,18 +17,16 @@ public class CompoundMutationInterceptor implements MutationInterceptor {
 
   public CompoundMutationInterceptor(List<? extends MutationInterceptor> interceptors) {
     this.children.addAll(interceptors);
-    Collections.sort(this.children, sortByType());
+    this.children.sort(comparing(MutationInterceptor::type));
   }
 
   public static MutationInterceptor nullInterceptor() {
-    return new CompoundMutationInterceptor(Collections.<MutationInterceptor>emptyList());
+    return new CompoundMutationInterceptor(Collections.emptyList());
   }
 
   @Override
   public void begin(ClassTree clazz) {
-    for (final MutationInterceptor each : this.children) {
-      each.begin(clazz);
-    }
+    this.children.forEach(each -> each.begin(clazz));
   }
 
   @Override
@@ -42,18 +41,12 @@ public Collection<MutationDetails> intercept(
 
   @Override
   public void end() {
-    for (final MutationInterceptor each : this.children) {
-      each.end();
-    }
+    this.children.forEach(MutationInterceptor::end);
   }
 
   @Override
   public InterceptorType type() {
     return InterceptorType.OTHER;
   }
 
-  private static Comparator<? super MutationInterceptor> sortByType() {
-    return (o1, o2) -> o1.type().compareTo(o2.type());
-  }
-
 }

pitest-entry/src/main/java/org/pitest/mutationtest/build/DefaultTestPrioritiser.java

@@ -1,7 +1,7 @@
 package org.pitest.mutationtest.build;
 
+import java.util.ArrayList;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
 import java.util.logging.Logger;
@@ -11,8 +11,6 @@
 import org.pitest.coverage.CoverageDatabase;
 import org.pitest.coverage.InstructionLocation;
 import org.pitest.coverage.TestInfo;
-import org.pitest.functional.FCollection;
-import org.pitest.functional.prelude.Prelude;
 import org.pitest.mutationtest.engine.MutationDetails;
 import org.pitest.util.Log;
 
@@ -69,10 +67,8 @@ private Collection<TestInfo> pickTests(MutationDetails mutation) {
 
   private List<TestInfo> prioritizeTests(ClassName clazz,
       Collection<TestInfo> testsForMutant) {
-    final List<TestInfo> sortedTis = FCollection.map(testsForMutant,
-        Prelude.id(TestInfo.class));
-    Collections.sort(sortedTis, new TestInfoPriorisationComparator(clazz,
-        TIME_WEIGHTING_FOR_DIRECT_UNIT_TESTS));
+    final List<TestInfo> sortedTis = new ArrayList<>(testsForMutant);
+    sortedTis.sort(new TestInfoPriorisationComparator(clazz, TIME_WEIGHTING_FOR_DIRECT_UNIT_TESTS));
     return sortedTis;
   }
 

pitest-entry/src/main/java/org/pitest/mutationtest/build/MutationTestBuilder.java

@@ -14,10 +14,10 @@
  */
 package org.pitest.mutationtest.build;
 
+import static java.util.Comparator.comparing;
+
 import java.util.ArrayList;
 import java.util.Collection;
-import java.util.Collections;
-import java.util.Comparator;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
@@ -58,7 +58,7 @@ public List<MutationAnalysisUnit> createMutationTestUnits(
     final List<MutationDetails> mutations = FCollection.flatMap(codeClasses,
         classToMutations());
 
-    Collections.sort(mutations, comparator());
+    mutations.sort(comparing(MutationDetails::getId));
 
     final Collection<MutationResult> analysedMutations = this.analyser
         .analyse(mutations);
@@ -82,14 +82,10 @@ public List<MutationAnalysisUnit> createMutationTestUnits(
       }
     }
 
-    Collections.sort(tus, new AnalysisPriorityComparator());
+    tus.sort(new AnalysisPriorityComparator());
     return tus;
   }
 
-  private Comparator<MutationDetails> comparator() {
-    return (arg0, arg1) -> arg0.getId().compareTo(arg1.getId());
-  }
-
   private Function<ClassName, Iterable<MutationDetails>> classToMutations() {
     return a -> MutationTestBuilder.this.mutationSource.createMutations(a);
   }

pitest-entry/src/main/java/org/pitest/mutationtest/build/intercept/javafeatures/InlinedFinallyBlockFilter.java

@@ -8,7 +8,6 @@
 
 import java.util.ArrayList;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.Comparator;
 import java.util.HashSet;
 import java.util.List;
@@ -67,7 +66,7 @@ public Collection<MutationDetails> intercept(
     }
 
     /* FIXME tests rely on order of returned mutants */
-    Collections.sort(combined, compareLineNumbers());
+    combined.sort(compareLineNumbers());
     return combined;
   }
 
@@ -77,7 +76,7 @@ public void end() {
   }
 
   private static Comparator<MutationDetails> compareLineNumbers() {
-    return (arg0, arg1) -> arg0.getLineNumber() - arg1.getLineNumber();
+    return Comparator.comparingInt(MutationDetails::getLineNumber);
   }
 
   private void checkForInlinedCode(final Collection<MutationDetails> combined,
@@ -97,7 +96,7 @@ private void checkForInlinedCode(final Collection<MutationDetails> combined,
     // to the base one (is this not implied by there being only 1 mutation in
     // the handler ????)
     final List<Integer> ids = map(each.getValue(), mutationToBlock());
-    if (ids.stream().filter(not(isEqual(firstBlock))).findFirst().isPresent()) {
+    if (ids.stream().anyMatch(not(isEqual(firstBlock)))) {
       combined.add(makeCombinedMutant(each.getValue()));
     } else {
       combined.addAll(each.getValue());

pitest-entry/src/main/java/org/pitest/mutationtest/config/SettingsFactory.java

@@ -167,6 +167,6 @@ private static Function<ProvidesFeature, Feature> toFeature() {
 
 
   private Comparator<Feature> byName() {
-    return (a,b) -> a.name().compareTo(b.name());
+    return Comparator.comparing(Feature::name);
   }
 }

pitest-entry/src/main/java/org/pitest/mutationtest/execute/MutationAnalysisExecutor.java

@@ -10,7 +10,6 @@
 import java.util.concurrent.TimeUnit;
 import java.util.logging.Logger;
 
-import org.pitest.functional.FCollection;
 import org.pitest.mutationtest.ClassMutationResults;
 import org.pitest.mutationtest.MutationMetaData;
 import org.pitest.mutationtest.MutationResultListener;
@@ -74,13 +73,11 @@ private void processResult(List<Future<MutationMetaData>> results)
   }
 
   private void signalRunStartToAllListeners() {
-    FCollection.forEach(this.listeners,
-        a -> a.runStart());
+    this.listeners.forEach(MutationResultListener::runStart);
   }
 
   private void signalRunEndToAllListeners() {
-    FCollection.forEach(this.listeners,
-        a -> a.runEnd());
+    this.listeners.forEach(MutationResultListener::runEnd);
   }
 
 }

pitest-entry/src/main/java/org/pitest/mutationtest/statistics/MutationStatisticsPrecursor.java

@@ -15,7 +15,7 @@ class MutationStatisticsPrecursor {
   private long                              numberOfTestsRun = 0;
 
   public void registerResults(final Collection<MutationResult> results) {
-    FCollection.forEach(results, register());
+    results.forEach(register());
   }
 
   private Consumer<MutationResult> register() {

pitest-entry/src/main/java/org/pitest/mutationtest/tooling/DirectorySourceLocator.java

@@ -37,15 +37,15 @@ private static class FileToReader implements Function<File, Optional<Reader>> {
     public Optional<Reader> apply(final File f) {
       if (f.exists()) {
         try {
-          return Optional.<Reader> ofNullable(new FileReader(f));
+          return Optional.of(new FileReader(f));
         } catch (final FileNotFoundException e) {
           return Optional.empty();
         }
       }
       return Optional.empty();
     }
 
-  };
+  }
 
   DirectorySourceLocator(final File root,
       final Function<File, Optional<Reader>> fileToReader) {

pitest-entry/src/main/java/org/pitest/mutationtest/verify/DefaultBuildVerifier.java

@@ -33,7 +33,7 @@ public void verify(final CodeSource code) {
 
     if (hasMutableCode(codeClasses)) {
       checkAtLeastOneClassHasLineNumbers(codeClasses);
-      FCollection.forEach(codeClasses, throwErrorIfHasNoSourceFile());
+      codeClasses.forEach(throwErrorIfHasNoSourceFile());
     }
   }
 

pitest-entry/src/test/java/org/pitest/mutationtest/build/AnalyisPriorityComparatorTest.java

@@ -3,7 +3,6 @@
 import static org.junit.Assert.assertEquals;
 
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 
 import org.junit.Test;
@@ -19,7 +18,7 @@ public void shouldPrioritiseLargestFirst() {
     final MutationAnalysisUnit b = unit(2);
     final MutationAnalysisUnit c = unit(3);
     final List<MutationAnalysisUnit> actual = Arrays.asList(a, b, c);
-    Collections.sort(actual, this.testee);
+    actual.sort(this.testee);
     assertEquals(Arrays.asList(c, b, a), actual);
   }
 
@@ -29,7 +28,7 @@ public void shouldPreserveCorrectOrder() {
     final MutationAnalysisUnit b = unit(2);
     final MutationAnalysisUnit c = unit(1);
     final List<MutationAnalysisUnit> actual = Arrays.asList(a, b, c);
-    Collections.sort(actual, this.testee);
+    actual.sort(this.testee);
     assertEquals(Arrays.asList(a, b, c), actual);
   }
 

pitest-entry/src/test/java/org/pitest/mutationtest/build/TestInfoPriorisationComparatorTest.java

@@ -18,7 +18,6 @@
 import static org.junit.Assert.assertThat;
 
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 
 import org.junit.Before;
@@ -82,7 +81,7 @@ public void shouldFavourTestsThatCoverFewerLinesInTheSameAmountOfTime() {
 
   private List<TestInfo> sortWithTestee(final TestInfo... testInfos) {
     final List<TestInfo> list = Arrays.asList(testInfos);
-    Collections.sort(list, this.testee);
+    list.sort(this.testee);
     return list;
   }
 

pitest-html-report/src/main/java/org/pitest/mutationtest/report/html/Line.java

@@ -14,7 +14,6 @@
  */
 package org.pitest.mutationtest.report.html;
 
-import java.util.Collections;
 import java.util.List;
 
 import java.util.Optional;
@@ -33,7 +32,7 @@ public Line(final long number, final String text,
     this.text = text;
     this.lineCovered = lineCovered;
     this.mutations = mutations;
-    Collections.sort(mutations, new ResultComparator());
+    mutations.sort(new ResultComparator());
   }
 
   public long getNumber() {