Make more use of Java8 features in the non-rhino part of our codebase.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=188536568

src/com/google/javascript/jscomp/AbstractScope.java

@@ -248,9 +248,7 @@ public final Iterable<V> getAllAccessibleVariables() {
 
     while (s != null) {
       for (V v : s.getVarIterable()) {
-        if (!accessibleVars.containsKey(v.getName())){
-          accessibleVars.put(v.getName(), v);
-        }
+        accessibleVars.putIfAbsent(v.getName(), v);
       }
       s = s.getParent();
     }

src/com/google/javascript/jscomp/ControlFlowAnalysis.java

@@ -19,6 +19,7 @@
 import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.base.Preconditions.checkNotNull;
 import static com.google.common.base.Preconditions.checkState;
+import static java.util.Comparator.comparingInt;
 
 import com.google.common.base.Preconditions;
 import com.google.common.collect.HashMultimap;
@@ -70,13 +71,7 @@ public final class ControlFlowAnalysis implements Callback, CompilerPass {
   // CFG nodes that come first lexically should be visited first, because
   // they will often be executed first in the source program.
   private final Comparator<DiGraphNode<Node, Branch>> priorityComparator =
-      new Comparator<DiGraphNode<Node, Branch>>() {
-    @Override
-    public int compare(
-        DiGraphNode<Node, Branch> a, DiGraphNode<Node, Branch> b) {
-      return astPosition.get(a.getValue()) - astPosition.get(b.getValue());
-    }
-  };
+      comparingInt(digraphNode -> astPosition.get(digraphNode.getValue()));
 
   private int astPositionCounter;
   private int priorityCounter;
@@ -186,9 +181,7 @@ public void process(Node externs, Node root) {
     // Presumably, it doesn't really matter what priority they get, since
     // this shouldn't happen in real code.
     for (DiGraphNode<Node, Branch> candidate : cfg.getDirectedGraphNodes()) {
-      if (!nodePriorities.containsKey(candidate)) {
-        nodePriorities.put(candidate, ++priorityCounter);
-      }
+      nodePriorities.computeIfAbsent(candidate, k -> ++priorityCounter);
     }
 
     // Again, the implicit return node is always last.
@@ -1077,21 +1070,9 @@ private AstControlFlowGraph(Node entry,
     public Comparator<DiGraphNode<Node, Branch>> getOptionalNodeComparator(
         boolean isForward) {
       if (isForward) {
-        return new Comparator<DiGraphNode<Node, Branch>>() {
-          @Override
-          public int compare(
-              DiGraphNode<Node, Branch> n1, DiGraphNode<Node, Branch> n2) {
-            return getPosition(n1) - getPosition(n2);
-          }
-        };
+        return comparingInt(this::getPosition);
       } else {
-        return new Comparator<DiGraphNode<Node, Branch>>() {
-          @Override
-          public int compare(
-              DiGraphNode<Node, Branch> n1, DiGraphNode<Node, Branch> n2) {
-            return getPosition(n2) - getPosition(n1);
-          }
-        };
+        return comparingInt(this::getPosition).reversed();
       }
     }
 

src/com/google/javascript/jscomp/JSModuleGraph.java

@@ -390,11 +390,7 @@ List<JSModule> getTransitiveDepsDeepestFirst(JSModule m) {
 
   /** Returns the transitive dependencies of the module. */
   private Set<JSModule> getTransitiveDeps(JSModule m) {
-    Set<JSModule> deps = dependencyMap.get(m);
-    if (deps == null) {
-      deps = m.getAllDependencies();
-      dependencyMap.put(m, deps);
-    }
+    Set<JSModule> deps = dependencyMap.computeIfAbsent(m, JSModule::getAllDependencies);
     return deps;
   }
 
@@ -420,9 +416,7 @@ public ImmutableList<CompilerInput> manageDependencies(
         inputsByProvide.put(provide, input);
       }
       String moduleName = input.getPath().toModuleName();
-      if (!inputsByProvide.containsKey(moduleName)) {
-        inputsByProvide.put(moduleName, input);
-      }
+      inputsByProvide.putIfAbsent(moduleName, input);
     }
 
     // Dynamically imported files must be added to the module graph, but

src/com/google/javascript/jscomp/NodeUtil.java

@@ -1729,13 +1729,6 @@ public static boolean isNullOrUndefined(Node n) {
     return n.isNull() || isUndefined(n);
   }
 
-  static final Predicate<Node> IMMUTABLE_PREDICATE = new Predicate<Node>() {
-    @Override
-    public boolean apply(Node n) {
-      return isImmutableValue(n);
-    }
-  };
-
   static boolean isImmutableResult(Node n) {
     return allResultsMatch(n, NodeUtil::isImmutableValue);
   }
@@ -4015,9 +4008,7 @@ public void visit(Node n) {
         Node parent = n.getParent();
         if (parent != null && parent.isVar()) {
           String name = n.getString();
-          if (!vars.containsKey(name)) {
-            vars.put(name, n);
-          }
+          vars.putIfAbsent(name, n);
         }
       }
     }
@@ -4374,12 +4365,7 @@ public boolean apply(Node n) {
 
   static final Predicate<Node> MATCH_NOT_FUNCTION = n -> !n.isFunction();
 
-  static final Predicate<Node> MATCH_NOT_THIS_BINDING = new Predicate<Node>() {
-    @Override
-    public boolean apply(Node n) {
-      return !NodeUtil.isVanillaFunction(n);
-    }
-  };
+  static final Predicate<Node> MATCH_NOT_THIS_BINDING = n -> !NodeUtil.isVanillaFunction(n);
 
   /**
    * A predicate for matching statements without exiting the current scope.

src/com/google/javascript/jscomp/PersistentInputStore.java

@@ -55,9 +55,7 @@ CompilerInput getCachedZipEntry(SourceFile zipEntry) {
       if (zipEntries.isEmpty()) {
         zipEntries = new HashMap<>();
       }
-      if (!zipEntries.containsKey(originalPath)) {
-        zipEntries.put(originalPath, CompilerInput.makePersistentInput(zipEntry));
-      }
+      zipEntries.computeIfAbsent(originalPath, k -> CompilerInput.makePersistentInput(zipEntry));
       return zipEntries.get(originalPath);
     }
 

src/com/google/javascript/jscomp/ReferenceCollectingCallback.java

@@ -351,11 +351,8 @@ private static boolean isBlockBoundary(Node n, Node parent) {
 
   private void addReference(Var v, Reference reference) {
     // Create collection if none already
-    ReferenceCollection referenceInfo = referenceMap.get(v);
-    if (referenceInfo == null) {
-      referenceInfo = new ReferenceCollection();
-      referenceMap.put(v, referenceInfo);
-    }
+    ReferenceCollection referenceInfo =
+        referenceMap.computeIfAbsent(v, k -> new ReferenceCollection());
 
     // Add this particular reference
     referenceInfo.add(reference);

src/com/google/javascript/jscomp/TypedScope.java

@@ -18,7 +18,6 @@
 
 import static com.google.common.base.Preconditions.checkState;
 
-import com.google.common.base.Predicate;
 import com.google.common.collect.Iterables;
 import com.google.javascript.rhino.JSDocInfo;
 import com.google.javascript.rhino.Node;
@@ -57,17 +56,6 @@ public class TypedScope extends AbstractScope<TypedScope, TypedVar>
   // Scope.java contains an arguments field.
   // We haven't added it here because it's unused by the passes that need typed scopes.
 
-  private static final Predicate<TypedVar> DECLARATIVELY_UNBOUND_VARS_WITHOUT_TYPES =
-    new Predicate<TypedVar>() {
-      @Override
-      public boolean apply(TypedVar var) {
-        return var.getParentNode() != null
-          && var.getType() == null
-          && var.getParentNode().isVar()
-          && !var.isExtern();
-      }
-    };
-
   TypedScope(TypedScope parent, Node rootNode) {
     super(rootNode);
     checkChildScope(parent);
@@ -155,7 +143,14 @@ TypedVar makeArgumentsVar() {
   }
 
   public Iterable<TypedVar> getDeclarativelyUnboundVarsWithoutTypes() {
-    return Iterables.filter(getVarIterable(), DECLARATIVELY_UNBOUND_VARS_WITHOUT_TYPES);
+    return Iterables.filter(
+        getVarIterable(),
+        var ->
+            // declaratively unbound vars without types
+            var.getParentNode() != null
+                && var.getType() == null
+                && var.getParentNode().isVar()
+                && !var.isExtern());
   }
 
   static interface TypeResolver {

src/com/google/javascript/jscomp/VariableMap.java

@@ -17,6 +17,7 @@
 package com.google.javascript.jscomp;
 
 import static java.nio.charset.StandardCharsets.UTF_8;
+import static java.util.Map.Entry.comparingByKey;
 
 import com.google.common.annotations.GwtIncompatible;
 import com.google.common.annotations.VisibleForTesting;
@@ -32,9 +33,7 @@
 import java.io.OutputStreamWriter;
 import java.io.Writer;
 import java.text.ParseException;
-import java.util.Comparator;
 import java.util.Map;
-import java.util.Map.Entry;
 
 /**
  * Stores the mapping from original variable name to new variable names.
@@ -44,14 +43,6 @@ public final class VariableMap {
 
   private static final char SEPARATOR = ':';
 
-  private static final Comparator<Map.Entry<String, String>> ENTRY_COMPARATOR =
-      new Comparator<Map.Entry<String, String>>() {
-    @Override
-    public int compare(Entry<String, String> e1, Entry<String, String> e2) {
-      return e1.getKey().compareTo(e2.getKey());
-    }
-  };
-
   /** Maps between original source name to new name */
   private final ImmutableBiMap<String, String> map;
 
@@ -116,7 +107,7 @@ public byte[] toBytes() {
     try {
       // The output order should be stable.
       for (Map.Entry<String, String> entry :
-          ImmutableSortedSet.copyOf(ENTRY_COMPARATOR, map.entrySet())) {
+          ImmutableSortedSet.copyOf(comparingByKey(), map.entrySet())) {
         writer.write(escape(entry.getKey()));
         writer.write(SEPARATOR);
         writer.write(escape(entry.getValue()));

src/com/google/javascript/jscomp/bundle/CachedTransformer.java

@@ -31,7 +31,7 @@ public class CachedTransformer implements Source.Transformer {
 
   public CachedTransformer(
       Source.Transformer delegate, CacheBuilder<? super Source, ? super Source> builder) {
-    this.cache = builder.build(CacheLoader.from(source -> delegate.transform(source)));
+    this.cache = builder.build(CacheLoader.from(delegate::transform));
   }
 
   public CachedTransformer(Source.Transformer delegate, String spec) {

src/com/google/javascript/jscomp/bundle/Source.java

@@ -155,7 +155,7 @@ public interface Transformer {
     Source transform(Source input);
 
     static Transformer of(Function<Source, Source> function) {
-      return x -> function.apply(x);
+      return function::apply;
     }
 
     /** Returns an identity transformer. */
@@ -165,7 +165,7 @@ static Transformer identity() {
 
     /** Converts this Transformer to a Function. */
     default Function<Source, Source> asFunction() {
-      return x -> transform(x);
+      return this::transform;
     }
 
     /** Concatenates two Transformers. */

src/com/google/javascript/jscomp/debugger/common/CompilationParam.java

@@ -16,6 +16,8 @@
 
 package com.google.javascript.jscomp.debugger.common;
 
+import static java.util.Comparator.comparing;
+
 import com.google.javascript.jscomp.AnonymousFunctionNamingPolicy;
 import com.google.javascript.jscomp.CheckLevel;
 import com.google.javascript.jscomp.CompilerOptions;
@@ -1040,14 +1042,7 @@ private static String diagGroupWarningInfo(String diagGroupsMember) {
   static CompilationParam[] getSortedValues() {
     ArrayList<CompilationParam> values = new ArrayList<>(Arrays.asList(CompilationParam.values()));
 
-    Collections.sort(
-        values,
-        new java.util.Comparator<CompilationParam>() {
-          @Override
-          public int compare(CompilationParam o1, CompilationParam o2) {
-            return o1.toString().compareTo(o2.toString());
-          }
-        });
+    Collections.sort(values, comparing(CompilationParam::toString));
 
     return values.toArray(new CompilationParam[0]);
   }

src/com/google/javascript/jscomp/deps/DependencyInfo.java

@@ -16,12 +16,14 @@
 
 package com.google.javascript.jscomp.deps;
 
+import static com.google.common.collect.ImmutableList.toImmutableList;
+
 import com.google.auto.value.AutoValue;
-import com.google.common.base.Function;
 import com.google.common.base.Joiner;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Iterables;
+import com.google.common.collect.Streams;
 import com.google.errorprone.annotations.Immutable;
 import java.io.IOException;
 import java.io.Serializable;
@@ -62,15 +64,7 @@ public enum Type {
     }
 
     public static ImmutableList<String> asSymbolList(Iterable<Require> requires) {
-      return ImmutableList.copyOf(
-          Iterables.transform(
-              requires,
-              new Function<Require, String>() {
-                @Override
-                public String apply(Require input) {
-                  return input.getSymbol();
-                }
-              }));
+      return Streams.stream(requires).map(Require::getSymbol).collect(toImmutableList());
     }
 
     public static Require googRequireSymbol(String symbol) {
@@ -217,13 +211,7 @@ private static void writeJsObject(Appendable out, Map<String, String> map) throw
     /** Prints a list of strings formatted as a JavaScript array of string literals. */
     private static void writeJsArray(Appendable out, Collection<String> values) throws IOException {
       Iterable<String> quoted =
-          Iterables.transform(
-              values,
-              new Function<String, String>() {
-                @Override public String apply(String arg) {
-                  return "'" + arg.replace("'", "\\'") + "'";
-                }
-              });
+          Iterables.transform(values, arg -> "'" + arg.replace("'", "\\'") + "'");
       out.append("[");
       out.append(Joiner.on(", ").join(quoted));
       out.append("]");

src/com/google/javascript/jscomp/deps/DepsFileParser.java

@@ -16,13 +16,13 @@
 
 package com.google.javascript.jscomp.deps;
 
+import static com.google.common.collect.ImmutableList.toImmutableList;
+
 import com.google.common.annotations.GwtIncompatible;
 import com.google.common.base.CharMatcher;
 import com.google.common.base.Function;
 import com.google.common.base.Functions;
-import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
-import com.google.common.collect.Iterables;
 import com.google.common.io.Files;
 import com.google.javascript.jscomp.ErrorManager;
 import com.google.javascript.jscomp.deps.DependencyInfo.Require;
@@ -38,7 +38,6 @@
 import java.util.logging.Logger;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
-import javax.annotation.Nullable;
 
 /**
  * A parser that can extract dependency information from existing deps.js files.
@@ -173,15 +172,10 @@ protected boolean parseLine(String line) throws ParseException {
             SimpleDependencyInfo.builder(path, filePath)
                 .setProvides(parseJsStringArray(depArgsMatch.group(2)))
                 .setRequires(
-                    ImmutableList.copyOf(
-                        Iterables.transform(
-                            parseJsStringArray(depArgsMatch.group(3)),
-                            new Function<String, Require>() {
-                              @Override
-                              public Require apply(@Nullable String input) {
-                                return Require.parsedFromDeps(input);
-                              }
-                            })))
+                    parseJsStringArray(depArgsMatch.group(3))
+                        .stream()
+                        .map(Require::parsedFromDeps)
+                        .collect(toImmutableList()))
                 .setLoadFlags(parseLoadFlags(depArgsMatch.group(4)))
                 .build();