17f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael// Copyright 2016 The Bazel Authors. All rights reserved. 27f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael// 37f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael// Licensed under the Apache License, Version 2.0 (the "License"); 47f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael// you may not use this file except in compliance with the License. 57f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael// You may obtain a copy of the License at 67f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael// 77f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael// http://www.apache.org/licenses/LICENSE-2.0 87f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael// 97f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael// Unless required by applicable law or agreed to in writing, software 107f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael// distributed under the License is distributed on an "AS IS" BASIS, 117f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 127f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael// See the License for the specific language governing permissions and 137f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael// limitations under the License. 147f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichaelpackage com.google.devtools.build.android.desugar.testdata; 157f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael 167f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichaelimport com.google.devtools.build.android.desugar.testdata.separate.SeparateBaseClass; 177f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichaelimport java.io.IOException; 187f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichaelimport java.util.List; 197f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichaelimport java.util.concurrent.Callable; 207f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichaelimport java.util.function.Function; 217f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichaelimport java.util.function.Predicate; 227f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichaelimport java.util.stream.Collectors; 237f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael 247f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichaelpublic class MethodReference extends SeparateBaseClass<String> { 257f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael 267f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael private final List<String> names; 277f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael 287f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael public MethodReference(List<String> names) { 297f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael super(names); 307f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael this.names = names; 317f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael } 327f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael 337f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael // Class method reference 347f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael public void appendAll(StringBuilder dest) { 357f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael names.stream().forEach(dest::append); 367f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael } 377f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael 387f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael // Interface method reference (regression test for b/33304582) 397f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael public List<String> transform(Transformer<String> transformer) { 407f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael return names.stream().map(transformer::transform).collect(Collectors.toList()); 417f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael } 427f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael 437f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael // Private method reference (regression test for b/33378312) 447f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael public List<String> some() { 457f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael return names.stream().filter(MethodReference::startsWithS).collect(Collectors.toList()); 467f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael } 477f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael 487f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael // Protected method reference in a base class of another package (regression test for b/33378312) 497f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael public List<String> intersect(List<String> other) { 507f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael return other.stream().filter(this::contains).collect(Collectors.toList()); 517f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael } 527f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael 537f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael // Contains the same method reference as intersect 547f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael public List<String> onlyIn(List<String> other) { 557f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael Predicate<String> p = this::contains; 567f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael return other.stream().filter(p.negate()).collect(Collectors.toList()); 577f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael } 587f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael 597f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael // Private method reference to an instance method that throws (regression test for b/33378312) 607f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael public Callable<String> stringer() { 617f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael return this::throwing; 627f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael } 637f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael 647f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael /** Returns a method reference derived from an expression (object.toString()). */ 657f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael public static Function<Integer, Character> stringChars(Object object) { 667f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael return (object == null ? "" : object.toString())::charAt; 677f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael } 687f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael 697f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael /** Returns a method reference derived from a field */ 707f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael public Predicate<String> toPredicate() { 717f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael return names::contains; 727f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael } 737f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael 747f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael private static boolean startsWithS(String input) { 757f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael return input.startsWith("S"); 767f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael } 777f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael 787f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael private String throwing() throws Exception { 797f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael StringBuilder msg = new StringBuilder(); 807f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael appendAll(msg); 817f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael throw new IOException(msg.toString()); 827f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael } 837f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael 847f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael /** Interface to create a method reference for in {@link #transform}. */ 857f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael public interface Transformer<T> { 867f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael T transform(T input); 877f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael } 887f6f08b9b78fd02cdea4157980a42b576ae3c504ajmichael} 89