Get Choice off Guava's Optional/Predicate/Function types.

Optional was easier than you'd think: it's very contained.

PiperOrigin-RevId: 736566288

Author: graememorgan

core/src/main/java/com/google/errorprone/refaster/BlockTemplate.java

@@ -19,7 +19,6 @@
 
 import com.google.auto.value.AutoValue;
 import com.google.common.base.CharMatcher;
-import com.google.common.base.Optional;
 import com.google.common.collect.ImmutableClassToInstanceMap;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
@@ -38,6 +37,7 @@
 import java.io.StringWriter;
 import java.lang.annotation.Annotation;
 import java.util.Map;
+import java.util.Optional;
 import java.util.logging.Logger;
 
 /**
@@ -99,7 +99,7 @@ public Iterable<BlockTemplateMatch> match(JCTree tree, Context context) {
       ImmutableList<JCStatement> targetStatements = ImmutableList.copyOf(block.getStatements());
       return matchesStartingAnywhere(block, 0, targetStatements, context)
           .findFirst()
-          .or(List.<BlockTemplateMatch>nil());
+          .orElse(List.nil());
     }
     return ImmutableList.of();
   }

core/src/main/java/com/google/errorprone/refaster/Choice.java

@@ -19,16 +19,16 @@
 import static com.google.common.base.Preconditions.checkNotNull;
 
 import com.google.common.annotations.VisibleForTesting;
-import com.google.common.base.Function;
-import com.google.common.base.Optional;
-import com.google.common.base.Predicate;
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Iterators;
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.errorprone.annotations.ForOverride;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Iterator;
+import java.util.Optional;
+import java.util.function.Function;
+import java.util.function.Predicate;
 
 /**
  * A representation of a choice with zero or more options, which may be evaluated lazily or
@@ -113,7 +113,7 @@ public Optional<T> findFirst() {
 
       @Override
       public Choice<T> filter(Predicate<? super T> predicate) {
-        return predicate.apply(t) ? this : Choice.<T>none();
+        return predicate.test(t) ? this : Choice.<T>none();
       }
 
       @Override
@@ -190,7 +190,7 @@ public String toString() {
   /** Returns the first valid option from this {@code Choice}. */
   public Optional<T> findFirst() {
     Iterator<T> itr = iterator();
-    return itr.hasNext() ? Optional.of(itr.next()) : Optional.<T>absent();
+    return itr.hasNext() ? Optional.of(itr.next()) : Optional.<T>empty();
   }
 
   /**
@@ -229,7 +229,11 @@ public <R> Choice<R> mapIfPresent(Function<? super T, Optional<R>> function) {
     return new Choice<R>() {
       @Override
       protected Iterator<R> iterator() {
-        return Optional.presentInstances(Iterables.transform(thisChoice.asIterable(), function))
+        return Iterables.transform(
+                Iterables.filter(
+                    Iterables.transform(thisChoice.asIterable(), function::apply),
+                    Optional::isPresent),
+                Optional::get)
             .iterator();
       }
     };
@@ -242,7 +246,7 @@ public <R> Choice<R> map(Function<? super T, R> function) {
     return new Choice<R>() {
       @Override
       protected Iterator<R> iterator() {
-        return Iterators.transform(thisChoice.iterator(), function);
+        return Iterators.transform(thisChoice.iterator(), function::apply);
       }
     };
   }
@@ -275,7 +279,7 @@ public Choice<T> filter(Predicate<? super T> predicate) {
     return new Choice<T>() {
       @Override
       protected Iterator<T> iterator() {
-        return Iterators.filter(thisChoice.iterator(), predicate);
+        return Iterators.filter(thisChoice.iterator(), predicate::test);
       }
 
       @Override

core/src/main/java/com/google/errorprone/refaster/ExpressionTemplate.java

@@ -22,7 +22,6 @@
 
 import com.google.auto.value.AutoValue;
 import com.google.common.base.Function;
-import com.google.common.base.Optional;
 import com.google.common.collect.ImmutableClassToInstanceMap;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
@@ -57,6 +56,7 @@
 import java.io.StringWriter;
 import java.lang.annotation.Annotation;
 import java.util.Map;
+import java.util.Optional;
 import java.util.logging.Logger;
 import org.jspecify.annotations.Nullable;
 
@@ -209,7 +209,7 @@ public Optional<Unifier> apply(Unifier unifier) {
                       unifier, inliner, new Warner(target), expectedTypes, actualTypes);
                 } catch (CouldNotResolveImportException e) {
                   logger.log(FINE, "Failure to resolve import", e);
-                  return Optional.absent();
+                  return Optional.empty();
                 }
               }
             });

core/src/main/java/com/google/errorprone/refaster/Inliner.java

@@ -16,7 +16,6 @@
 
 package com.google.errorprone.refaster;
 
-import com.google.common.base.Optional;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Maps;
 import com.google.common.collect.Sets;
@@ -45,6 +44,7 @@
 import com.sun.tools.javac.util.Name;
 import com.sun.tools.javac.util.Names;
 import java.util.Map;
+import java.util.Optional;
 import java.util.Set;
 
 /**
@@ -180,7 +180,7 @@ public <V> V getBinding(Bindings.Key<V> key) {
   }
 
   public <V> Optional<V> getOptionalBinding(Bindings.Key<V> key) {
-    return Optional.fromNullable(bindings.getBinding(key));
+    return Optional.ofNullable(bindings.getBinding(key));
   }
 
   public <R> com.sun.tools.javac.util.List<R> inlineList(

core/src/main/java/com/google/errorprone/refaster/PlaceholderMethod.java

@@ -15,7 +15,6 @@
 package com.google.errorprone.refaster;
 
 import com.google.auto.value.AutoValue;
-import com.google.common.base.Predicate;
 import com.google.common.base.Predicates;
 import com.google.common.collect.ClassToInstanceMap;
 import com.google.common.collect.ImmutableClassToInstanceMap;
@@ -32,13 +31,15 @@
 import com.google.errorprone.refaster.annotation.Placeholder;
 import com.sun.source.tree.ExpressionTree;
 import com.sun.source.tree.Tree;
+import com.sun.source.tree.Tree.Kind;
 import com.sun.tools.javac.tree.JCTree.JCExpression;
 import com.sun.tools.javac.tree.JCTree.JCStatement;
 import com.sun.tools.javac.util.List;
 import java.io.Serializable;
 import java.lang.annotation.Annotation;
 import java.util.Arrays;
 import java.util.Set;
+import java.util.function.Predicate;
 
 /**
  * Representation of a {@code Refaster} placeholder method, which can represent an arbitrary
@@ -62,7 +63,7 @@ static PlaceholderMethod create(
         annotations.containsKey(NotMatches.class)
             ? UTemplater.getValue(annotations.getInstance(NotMatches.class))
             : null;
-    Predicate<Tree.Kind> allowedKinds =
+    Predicate<Kind> allowedKinds =
         annotations.containsKey(OfKind.class)
             ? Predicates.<Tree.Kind>in(Arrays.asList(annotations.getInstance(OfKind.class).value()))
             : Predicates.<Tree.Kind>alwaysTrue();
@@ -74,7 +75,7 @@ public boolean matches(ExpressionTree t, VisitorState state) {
           return (allowsIdentity || !(t instanceof PlaceholderParamIdent))
               && (matchesClass == null || matchesClass.newInstance().matches(t, state))
               && (notMatchesClass == null || !notMatchesClass.newInstance().matches(t, state))
-              && allowedKinds.apply(t.getKind());
+              && allowedKinds.test(t.getKind());
         } catch (ReflectiveOperationException e) {
           throw new RuntimeException(e);
         }

core/src/main/java/com/google/errorprone/refaster/Template.java

@@ -18,7 +18,6 @@
 
 import static java.util.logging.Level.FINE;
 
-import com.google.common.base.Optional;
 import com.google.common.collect.ImmutableClassToInstanceMap;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
@@ -76,6 +75,7 @@
 import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Optional;
 import java.util.logging.Logger;
 import org.jspecify.annotations.Nullable;
 
@@ -223,15 +223,15 @@ protected Optional<Unifier> typecheck(
       }
 
       if (!checkBounds(unifier, inliner, warner)) {
-        return Optional.absent();
+        return Optional.empty();
       }
       return Optional.of(unifier);
     } catch (CouldNotResolveImportException e) {
       logger.log(FINE, "Failure to resolve an import", e);
-      return Optional.absent();
+      return Optional.empty();
     } catch (InferException e) {
       logger.log(FINE, "No valid instantiation found: " + e.getMessage());
-      return Optional.absent();
+      return Optional.empty();
     }
   }
 

core/src/main/java/com/google/errorprone/refaster/UBlank.java

@@ -111,7 +111,7 @@ public Choice<UnifierWithUnconsumedStatements> apply(UnifierWithUnconsumedStatem
   public com.sun.tools.javac.util.List<JCStatement> inlineStatements(Inliner inliner) {
     ListBuffer<JCStatement> buffer = new ListBuffer<>();
     for (StatementTree stmt :
-        inliner.getOptionalBinding(key()).or(ImmutableList.<StatementTree>of())) {
+        inliner.getOptionalBinding(key()).orElse(ImmutableList.<StatementTree>of())) {
       buffer.add((JCStatement) stmt);
     }
     return buffer.toList();

core/src/main/java/com/google/errorprone/refaster/UBlock.java

@@ -17,7 +17,6 @@
 package com.google.errorprone.refaster;
 
 import com.google.auto.value.AutoValue;
-import com.google.common.base.Optional;
 import com.google.common.collect.ImmutableList;
 import com.sun.source.tree.BlockTree;
 import com.sun.source.tree.StatementTree;
@@ -26,6 +25,7 @@
 import com.sun.tools.javac.tree.JCTree.JCStatement;
 import com.sun.tools.javac.util.ListBuffer;
 import java.util.List;
+import java.util.Optional;
 
 /**
  * {@link UTree} representation of a {@link BlockTree}.
@@ -58,7 +58,7 @@ static Choice<Unifier> unifyStatementList(
         (UnifierWithUnconsumedStatements state) ->
             state.unconsumedStatements().isEmpty()
                 ? Optional.of(state.unifier())
-                : Optional.<Unifier>absent());
+                : Optional.<Unifier>empty());
   }
 
   static com.sun.tools.javac.util.List<JCStatement> inlineStatementList(

core/src/main/java/com/google/errorprone/refaster/UIf.java

@@ -18,7 +18,6 @@
 
 import com.google.auto.value.AutoValue;
 import com.google.common.base.Function;
-import com.google.common.base.Optional;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Iterables;
 import com.google.errorprone.refaster.ControlFlowVisitor.Result;
@@ -27,6 +26,7 @@
 import com.sun.source.tree.TreeVisitor;
 import com.sun.tools.javac.tree.JCTree.JCStatement;
 import com.sun.tools.javac.util.List;
+import java.util.Optional;
 import org.jspecify.annotations.Nullable;
 
 /**
@@ -143,7 +143,7 @@ private static Function<Unifier, Choice<Unifier>> unifyUStatementWithSingleState
                           (UnifierWithUnconsumedStatements stateAfterThen) ->
                               stateAfterThen.unconsumedStatements().isEmpty()
                                   ? Optional.of(stateAfterThen.unifier())
-                                  : Optional.<Unifier>absent());
+                                  : Optional.<Unifier>empty());
                 })
             .flatMap(
                 unifierAfterThen -> {

core/src/main/java/com/google/errorprone/refaster/ULabeledStatement.java

@@ -47,7 +47,7 @@ static class Key extends Bindings.Key<CharSequence> {
   static @Nullable Name inlineLabel(@Nullable CharSequence label, Inliner inliner) {
     return (label == null)
         ? null
-        : inliner.asName(inliner.getOptionalBinding(new Key(label)).or(label));
+        : inliner.asName(inliner.getOptionalBinding(new Key(label)).orElse(label));
   }
 
   @Override

core/src/main/java/com/google/errorprone/refaster/ULambda.java

@@ -20,7 +20,6 @@
 import static com.google.errorprone.refaster.Unifier.unifyList;
 
 import com.google.auto.value.AutoValue;
-import com.google.common.base.Optional;
 import com.google.common.collect.ImmutableList;
 import com.sun.source.tree.LambdaExpressionTree;
 import com.sun.source.tree.TreeVisitor;
@@ -33,6 +32,7 @@
 import com.sun.tools.javac.tree.JCTree.JCVariableDecl;
 import com.sun.tools.javac.util.List;
 import com.sun.tools.javac.util.ListBuffer;
+import java.util.Optional;
 
 /**
  * {@code UTree} representation of a {@code LambdaExpressionTree}.

core/src/main/java/com/google/errorprone/refaster/ULocalVarIdent.java

@@ -17,11 +17,11 @@
 package com.google.errorprone.refaster;
 
 import com.google.auto.value.AutoValue;
-import com.google.common.base.Optional;
 import com.google.errorprone.util.ASTHelpers;
 import com.sun.source.tree.IdentifierTree;
 import com.sun.tools.javac.tree.JCTree.JCIdent;
 import java.util.Objects;
+import java.util.Optional;
 
 /**
  * Identifier corresponding to a template local variable.

core/src/main/java/com/google/errorprone/refaster/UPlaceholderExpression.java

@@ -19,7 +19,6 @@
 import com.google.auto.value.AutoValue;
 import com.google.common.base.Functions;
 import com.google.common.base.MoreObjects;
-import com.google.common.base.Optional;
 import com.google.common.collect.Collections2;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
@@ -36,6 +35,7 @@
 import com.sun.tools.javac.util.List;
 import com.sun.tools.javac.util.Names;
 import java.util.Map;
+import java.util.Optional;
 
 /**
  * {@code UTree} representation of an invocation of a placeholder method.
@@ -180,19 +180,19 @@ protected Choice<Unifier> defaultAction(Tree node, Unifier unifier) {
             if (prevBinding != null) {
               return prevBinding.toString().equals(state.result().toString())
                   ? Optional.of(resultUnifier)
-                  : Optional.<Unifier>absent();
+                  : Optional.<Unifier>empty();
             }
             JCExpression result = state.result();
             if (!placeholder()
                 .matcher()
                 .matches(result, UMatches.makeVisitorState(expr, resultUnifier))) {
-              return Optional.absent();
+              return Optional.empty();
             }
             result.type = expr.type;
             resultUnifier.putBinding(placeholder().exprKey(), result);
             return Optional.of(resultUnifier);
           } else {
-            return Optional.absent();
+            return Optional.empty();
           }
         });
   }