src/jdk.compiler/share/classes/com/sun/tools/sjavac/Util.java

rev 2819 : imported patch my-classpath-deps-00

*** 28,40 ****
--- 28,44 ----
  import java.io.File;
  import java.io.PrintWriter;
  import java.io.StringWriter;
  import java.nio.file.Path;
  import java.util.Arrays;
+ import java.util.Collection;
  import java.util.HashSet;
+ import java.util.Map;
  import java.util.Set;
  import java.util.StringTokenizer;
+ import java.util.function.Function;
+ import java.util.stream.Collectors;
  
  /**
   * Utilities.
   *
   *  <p><b>This is NOT part of any supported API.
*** 181,196 ****
--- 185,219 ----
          union.addAll(s1);
          union.addAll(s2);
          return union;
      }
  
+     public static <E> Set<E> subtract(Set<? extends E> orig,
+                                       Set<? extends E> toSubtract) {
+         Set<E> difference = new HashSet<>(orig);
+         difference.removeAll(toSubtract);
+         return difference;
+     }
+ 
      public static String getStackTrace(Throwable t) {
          StringWriter sw = new StringWriter();
          t.printStackTrace(new PrintWriter(sw));
          return sw.toString();
      }
  
      // TODO: Remove when refactoring from java.io.File to java.nio.file.Path.
      public static File pathToFile(Path path) {
          return path == null ? null : path.toFile();
      }
+ 
+     public static <E> Set<E> intersection(Collection<? extends E> c1,
+                                           Collection<? extends E> c2) {
+         Set<E> intersection = new HashSet<E>(c1);
+         intersection.retainAll(c2);
+         return intersection;
+     }
+ 
+     public static <I, T> Map<I, T> indexBy(Collection<? extends T> c,
+                                            Function<? super T, ? extends I> indexFunction) {
+         return c.stream().collect(Collectors.toMap(indexFunction, o -> o));
+     }
  }