test/com/facebook/buck/rules/DefaultJavaLibraryRuleTest.java

/*
 * Copyright 2012-present Facebook, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may
 * not use this file except in compliance with the License. You may obtain
 * a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */

package com.facebook.buck.rules;

import static com.facebook.buck.util.BuckConstant.BIN_DIR;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNotEquals;
import static org.junit.Assert.assertNotNull;

import com.facebook.buck.model.BuildTarget;
import com.facebook.buck.model.BuildTargetFactory;
import com.facebook.buck.model.BuildTargetPattern;
import com.facebook.buck.shell.Command;
import com.facebook.buck.shell.ExecutionContext;
import com.facebook.buck.shell.JavacInMemoryCommand;
import com.facebook.buck.shell.JavacOptionsUtil;
import com.facebook.buck.command.io.MkdirAndSymlinkFileCommand;
import com.facebook.buck.shell.Verbosity;
import com.facebook.buck.testutil.MoreAsserts;
import com.facebook.buck.testutil.RuleMap;
import com.facebook.buck.util.BuckConstant;
import com.facebook.buck.util.DefaultDirectoryTraverser;
import com.facebook.buck.util.Functions;
import com.google.common.base.Predicate;
import com.google.common.base.Suppliers;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.ImmutableSetMultimap;
import com.google.common.collect.ImmutableSortedSet;
import com.google.common.collect.Iterables;
import com.google.common.collect.Maps;

import org.easymock.EasyMock;
import org.junit.Test;

import java.io.File;
import java.io.IOException;
import java.util.List;
import java.util.Map;

public class DefaultJavaLibraryRuleTest {
  private static final String ANNOTATION_SCENARIO_TARGET =
      "//android/java/src/com/facebook:fb";
  private static final String ANNOTATION_SCENARIO_GEN_PATH =
      BuckConstant.ANNOTATION_DIR + "/android/java/src/com/facebook/__fb_gen__";

  @Test
  public void testAddResourceCommandsWithBuildFileParentOfSrcDirectory() {
    // Files:
    // android/java/BUILD
    // android/java/src/com/facebook/base/data.json
    // android/java/src/com/facebook/common/util/data.json
    BuildTarget buildTarget = BuildTargetFactory.newInstance(
        "//android/java", "resources", new File("android/java/BUILD"));
    ImmutableSortedSet<BuildRule> deps = ImmutableSortedSet.of();
    ImmutableSet<BuildTargetPattern> visibilityPatterns = ImmutableSet.of();
    DefaultJavaLibraryRule javaRule = new DefaultJavaLibraryRule(
        new BuildRuleParams(buildTarget, deps, visibilityPatterns),
        ImmutableSet.<String>of() /* srcs */,
        ImmutableSet.of(
            "android/java/src/com/facebook/base/data.json",
            "android/java/src/com/facebook/common/util/data.json"),
        null,
        AnnotationProcessingParams.EMPTY);

    ImmutableList.Builder<Command> commands = ImmutableList.builder();
    JavaPackageFinder javaPackageFinder = createJavaPackageFinder();
    javaRule.addResourceCommands(
        commands, BIN_DIR + "/android/java/lib__resources__classes", javaPackageFinder);
    List<? extends Command> expected = ImmutableList.of(
        new MkdirAndSymlinkFileCommand(
            "android/java/src/com/facebook/base/data.json",
            BIN_DIR + "/android/java/lib__resources__classes/com/facebook/base/data.json"),
        new MkdirAndSymlinkFileCommand(
            "android/java/src/com/facebook/common/util/data.json",
            BIN_DIR + "/android/java/lib__resources__classes/com/facebook/common/util/data.json"));
    MoreAsserts.assertListEquals(expected, commands.build());
    EasyMock.verify(javaPackageFinder);
  }

  @Test
  public void testAddResourceCommandsWithBuildFileParentOfJavaPackage() {
    // Files:
    // android/java/src/BUILD
    // android/java/src/com/facebook/base/data.json
    // android/java/src/com/facebook/common/util/data.json
    BuildTarget buildTarget = BuildTargetFactory.newInstance(
        "//android/java/src", "resources", new File("android/java/src/BUILD"));
    ImmutableSortedSet<BuildRule> deps = ImmutableSortedSet.of();
    ImmutableSet<BuildTargetPattern> visibilityPatterns = ImmutableSet.of();
    DefaultJavaLibraryRule javaRule = new DefaultJavaLibraryRule(
        new BuildRuleParams(buildTarget, deps, visibilityPatterns),
        ImmutableSet.<String>of() /* srcs */,
        ImmutableSet.of(
            "android/java/src/com/facebook/base/data.json",
            "android/java/src/com/facebook/common/util/data.json"),
        /* proguargConfig */ null,
        AnnotationProcessingParams.EMPTY);

    ImmutableList.Builder<Command> commands = ImmutableList.builder();
    JavaPackageFinder javaPackageFinder = createJavaPackageFinder();
    javaRule.addResourceCommands(
        commands, BIN_DIR + "/android/java/src/lib__resources__classes", javaPackageFinder);
    List<? extends Command> expected = ImmutableList.of(
        new MkdirAndSymlinkFileCommand(
            "android/java/src/com/facebook/base/data.json",
            BIN_DIR + "/android/java/src/lib__resources__classes/com/facebook/base/data.json"),
        new MkdirAndSymlinkFileCommand(
            "android/java/src/com/facebook/common/util/data.json",
            BIN_DIR + "/android/java/src/lib__resources__classes/com/facebook/common/util/data.json"));
    MoreAsserts.assertListEquals(expected, commands.build());
    EasyMock.verify(javaPackageFinder);
  }

  @Test
  public void testAddResourceCommandsWithBuildFileInJavaPackage() {
    // Files:
    // android/java/src/com/facebook/BUILD
    // android/java/src/com/facebook/base/data.json
    // android/java/src/com/facebook/common/util/data.json
    BuildTarget buildTarget = BuildTargetFactory.newInstance(
        "//android/java/src/com/facebook",
        "resources",
        new File("android/java/src/com/facebook/BUILD"));
    ImmutableSortedSet<BuildRule> deps = ImmutableSortedSet.of();
    ImmutableSet<BuildTargetPattern> visibilityPatterns = ImmutableSet.of();
    DefaultJavaLibraryRule javaRule = new DefaultJavaLibraryRule(
        new BuildRuleParams(buildTarget, deps, visibilityPatterns),
        ImmutableSet.<String>of() /* srcs */,
        ImmutableSet.of(
            "android/java/src/com/facebook/base/data.json",
            "android/java/src/com/facebook/common/util/data.json"),
        /* proguargConfig */ null,
        AnnotationProcessingParams.EMPTY);

    ImmutableList.Builder<Command> commands = ImmutableList.builder();
    JavaPackageFinder javaPackageFinder = createJavaPackageFinder();
    javaRule.addResourceCommands(
        commands,
        BIN_DIR + "/android/java/src/com/facebook/lib__resources__classes",
        javaPackageFinder);
    List<? extends Command> expected = ImmutableList.of(
        new MkdirAndSymlinkFileCommand(
            "android/java/src/com/facebook/base/data.json",
            BIN_DIR + "/android/java/src/com/facebook/lib__resources__classes/com/facebook/base/data.json"),
        new MkdirAndSymlinkFileCommand(
            "android/java/src/com/facebook/common/util/data.json",
            BIN_DIR + "/android/java/src/com/facebook/lib__resources__classes/com/facebook/common/util/data.json"));
    MoreAsserts.assertListEquals(expected, commands.build());
    EasyMock.verify(javaPackageFinder);
  }

  /** Make sure that when isAndroidLibrary is true, that the Android bootclasspath is used. */
  @Test
  public void testBuildInternalWithAndroidBootclasspath() throws IOException {
    BuildTarget buildTarget = BuildTargetFactory.newInstance("//android/java/src/com/facebook:fb");
    ImmutableSet<String> srcs = ImmutableSet.<String>of("android/java/src/com/facebook/Main.java");
    DefaultJavaLibraryRule javaLibrary = new AndroidLibraryRule(
        new BuildRuleParams(
            buildTarget,
            /* deps */ ImmutableSortedSet.<BuildRule>of(),
            /* visibilityTargets */ ImmutableSet.<BuildTargetPattern>of()
        ),
        srcs,
        /* resources */ ImmutableSet.<String>of(),
        /* proguard_config*/ null,
        /* annotationProcessors */ AnnotationProcessingParams.EMPTY,
        /* manifestFile */ null,
        JavacOptionsUtil.DEFAULT_SOURCE_LEVEL,
        JavacOptionsUtil.DEFAULT_TARGET_LEVEL);

    String bootclasspath = "effects.jar:maps.jar:usb.jar:";
    BuildContext context = createBuildContext(javaLibrary, bootclasspath);

    List<Command> commands = javaLibrary.buildInternal(context);
    // Find the JavacInMemoryCommand and verify its bootclasspath.
    Command command = Iterables.find(commands, new Predicate<Command>() {
      @Override
      public boolean apply(Command command) {
        return command instanceof JavacInMemoryCommand;
      }
    });
    assertNotNull("Expected a JavacInMemoryCommand in the command list.", command);
    JavacInMemoryCommand javac = (JavacInMemoryCommand)command;
    assertEquals("Should compile Main.java rather than generated R.java.", srcs, javac.getSrcs());

    EasyMock.verify(context);
  }

  /**
   * Verify that no annotation options are there if we do not add an
   * annotation processor.
   */
  @Test
  public void testNoAnnotationProcessor() throws IOException {
    AnnotationProcessingScenario scenario = new AnnotationProcessingScenario();

    ImmutableList<String> parameters = scenario.buildAndGetCompileParameters();

    for (String parameter : parameters) {
      assertNotEquals("Expected no -processorpath parameters", parameter, "-processorpath");
      assertNotEquals("Expected no -processor parameters", parameter, "-processor");
      assertNotEquals("Expected no -s parameters", parameter, "-s");
      assertFalse("Expected no annotation options", parameter.startsWith("-A"));
    }
  }

  /**
   * Verify adding an annotation processor java binary.
   */
  @Test
  public void testAddAnnotationProcessorJavaBinary() throws IOException {
    AnnotationProcessingScenario scenario = new AnnotationProcessingScenario();
    scenario.addAnnotationProcessorTarget(AnnotationProcessorTarget.VALID_JAVA_BINARY);

    scenario.getAnnotationProcessingParamsBuilder()
        .addAllProcessors(ImmutableList.of("MyProcessor"));

    ImmutableList<String> parameters = scenario.buildAndGetCompileParameters();

    MoreAsserts.assertContainsOne(parameters, "-processorpath");
    MoreAsserts.assertContainsOne(parameters, "-processor");
    MoreAsserts.assertContainsOne(parameters, "MyProcessor");
    MoreAsserts.assertContainsOne(parameters, "-s");
    MoreAsserts.assertContainsOne(parameters, ANNOTATION_SCENARIO_GEN_PATH);

    assertEquals(
        "Expected '-processor MyProcessor' parameters",
        parameters.indexOf("-processor") + 1,
        parameters.indexOf("MyProcessor"));
    assertEquals(
        "Expected '-s " + ANNOTATION_SCENARIO_GEN_PATH + "' parameters",
        parameters.indexOf("-s") + 1,
        parameters.indexOf(ANNOTATION_SCENARIO_GEN_PATH));

    for (String parameter : parameters) {
      assertFalse("Expected no annotation options", parameter.startsWith("-A"));
    }
  }

  /**
   * Verify adding an annotation processor prebuilt jar.
   */
  @Test
  public void testAddAnnotationProcessorPrebuiltJar() throws IOException {
    AnnotationProcessingScenario scenario = new AnnotationProcessingScenario();
    scenario.addAnnotationProcessorTarget(AnnotationProcessorTarget.VALID_PREBUILT_JAR);

    scenario.getAnnotationProcessingParamsBuilder()
        .addAllProcessors(ImmutableList.of("MyProcessor"));

    ImmutableList<String> parameters = scenario.buildAndGetCompileParameters();

    MoreAsserts.assertContainsOne(parameters, "-processorpath");
    MoreAsserts.assertContainsOne(parameters, "-processor");
    MoreAsserts.assertContainsOne(parameters, "MyProcessor");
    MoreAsserts.assertContainsOne(parameters, "-s");
    MoreAsserts.assertContainsOne(parameters, ANNOTATION_SCENARIO_GEN_PATH);
  }

  /**
   * Verify adding an annotation processor java library.
   */
  @Test
  public void testAddAnnotationProcessorJavaLibrary() throws IOException {
    AnnotationProcessingScenario scenario = new AnnotationProcessingScenario();
    scenario.addAnnotationProcessorTarget(AnnotationProcessorTarget.VALID_PREBUILT_JAR);

    scenario.getAnnotationProcessingParamsBuilder()
        .addAllProcessors(ImmutableList.of("MyProcessor"));

    ImmutableList<String> parameters = scenario.buildAndGetCompileParameters();

    MoreAsserts.assertContainsOne(parameters, "-processorpath");
    MoreAsserts.assertContainsOne(parameters, "-processor");
    MoreAsserts.assertContainsOne(parameters, "MyProcessor");
    MoreAsserts.assertContainsOne(parameters, "-s");
    MoreAsserts.assertContainsOne(parameters, ANNOTATION_SCENARIO_GEN_PATH);
  }

  /**
   * Verify adding multiple annotation processors.
   */
  @Test
  public void testAddAnnotationProcessorJar() throws IOException {
    AnnotationProcessingScenario scenario = new AnnotationProcessingScenario();
    scenario.addAnnotationProcessorTarget(AnnotationProcessorTarget.VALID_PREBUILT_JAR);
    scenario.addAnnotationProcessorTarget(AnnotationProcessorTarget.VALID_JAVA_BINARY);
    scenario.addAnnotationProcessorTarget(AnnotationProcessorTarget.VALID_JAVA_LIBRARY);

    scenario.getAnnotationProcessingParamsBuilder()
        .addAllProcessors(ImmutableList.of("MyProcessor"));

    ImmutableList<String> parameters = scenario.buildAndGetCompileParameters();

    MoreAsserts.assertContainsOne(parameters, "-processorpath");
    MoreAsserts.assertContainsOne(parameters, "-processor");
    MoreAsserts.assertContainsOne(parameters, "MyProcessor");
    MoreAsserts.assertContainsOne(parameters, "-s");
    MoreAsserts.assertContainsOne(parameters, ANNOTATION_SCENARIO_GEN_PATH);
  }

  @Test
  public void testGetClasspathEntriesMap() {
    Map<String, BuildRule> buildRuleIndex = Maps.newHashMap();

    BuildTarget libraryOneTarget = BuildTargetFactory.newInstance("//:libone");
    JavaLibraryRule libraryOne = DefaultJavaLibraryRule.newJavaLibraryRuleBuilder()
        .setBuildTarget(libraryOneTarget)
        .addSrc("java/src/com/libone/bar.java")
        .build(buildRuleIndex);
    buildRuleIndex.put(libraryOne.getFullyQualifiedName(), libraryOne);

    BuildTarget libraryTwoTarget = BuildTargetFactory.newInstance("//:libtwo");
    JavaLibraryRule libraryTwo = DefaultJavaLibraryRule.newJavaLibraryRuleBuilder()
        .setBuildTarget(libraryTwoTarget)
        .addSrc("java/src/com/libtwo/foo.java")
        .addDep("//:libone")
        .build(buildRuleIndex);
    buildRuleIndex.put(libraryTwo.getFullyQualifiedName(), libraryTwo);

    BuildTarget parentTarget = BuildTargetFactory.newInstance("//:parent");
    JavaLibraryRule parent = DefaultJavaLibraryRule.newJavaLibraryRuleBuilder()
        .setBuildTarget(parentTarget)
        .addSrc("java/src/com/parent/meh.java")
        .addDep("//:libtwo")
        .build(buildRuleIndex);
    buildRuleIndex.put(parent.getFullyQualifiedName(), parent);

    assertEquals(ImmutableSetMultimap.of(
          libraryOne, "buck-out/gen/lib__libone__output/libone.jar",
          libraryTwo, "buck-out/gen/lib__libtwo__output/libtwo.jar",
          parent, "buck-out/gen/lib__parent__output/parent.jar"),
        parent.getClasspathEntriesMap());
  }

  /**
   * Verify adding an annotation processor java binary with options.
   */
  @Test
  public void testAddAnnotationProcessorWithOptions() throws IOException {
    AnnotationProcessingScenario scenario = new AnnotationProcessingScenario();
    scenario.addAnnotationProcessorTarget(AnnotationProcessorTarget.VALID_JAVA_BINARY);

    scenario.getAnnotationProcessingParamsBuilder().addAllProcessors(ImmutableList.of("MyProcessor"));
    scenario.getAnnotationProcessingParamsBuilder().addParameter("MyParameter");
    scenario.getAnnotationProcessingParamsBuilder().addParameter("MyKey=MyValue");
    scenario.getAnnotationProcessingParamsBuilder().setProcessOnly(true);

    ImmutableList<String> parameters = scenario.buildAndGetCompileParameters();

    MoreAsserts.assertContainsOne(parameters, "-processorpath");
    MoreAsserts.assertContainsOne(parameters, "-processor");
    MoreAsserts.assertContainsOne(parameters, "MyProcessor");
    MoreAsserts.assertContainsOne(parameters, "-s");
    MoreAsserts.assertContainsOne(parameters, ANNOTATION_SCENARIO_GEN_PATH);
    MoreAsserts.assertContainsOne(parameters, "-proc:only");

    assertEquals(
        "Expected '-processor MyProcessor' parameters",
        parameters.indexOf("-processor") + 1,
        parameters.indexOf("MyProcessor"));
    assertEquals(
        "Expected '-s " + ANNOTATION_SCENARIO_GEN_PATH + "' parameters",
        parameters.indexOf("-s") + 1,
        parameters.indexOf(ANNOTATION_SCENARIO_GEN_PATH));

    MoreAsserts.assertContainsOne(parameters, "-AMyParameter");
    MoreAsserts.assertContainsOne(parameters, "-AMyKey=MyValue");
  }

  // Utilities

  private JavaPackageFinder createJavaPackageFinder() {
    JavaPackageFinder javaPackageFinder = EasyMock.createMock(JavaPackageFinder.class);
    EasyMock.expect(javaPackageFinder.findJavaPackageFolderForPath(
        "android/java/src/com/facebook/base/data.json"))
        .andReturn("com/facebook/base/");
    EasyMock.expect(javaPackageFinder.findJavaPackageFolderForPath(
        "android/java/src/com/facebook/common/util/data.json"))
        .andReturn("com/facebook/common/util/");

    EasyMock.replay(javaPackageFinder);
    return javaPackageFinder;
  }

  private BuildContext createBuildContext(DefaultJavaLibraryRule javaLibrary, String bootclasspath) {
    DependencyGraph graph = RuleMap.createGraphFromBuildRules(
        ImmutableMap.<String, BuildRule>of(
            javaLibrary.getFullyQualifiedName(),
            javaLibrary));

    BuildContext context = EasyMock.createMock(BuildContext.class);
    EasyMock.expect(context.getDependencyGraph()).andReturn(graph);
    EasyMock.expect(context.getAndroidBootclasspathSupplier()).andReturn(Suppliers.ofInstance(
        bootclasspath));
    EasyMock.expect(context.getJavaPackageFinder()).andReturn(
        EasyMock.createMock(JavaPackageFinder.class));
    EasyMock.replay(context);

    return context;
  }

  private enum AnnotationProcessorTarget {
    INVALID("//tools/java/src/com/facebook/somejava:generator") {
      @Override
      public BuildRule createRule(BuildTarget target) {
        return new Genrule(
            createBuildRuleParams(target),
            ImmutableList.of("MyInput"),
            "echo hi",
            "MyOutput",
            Functions.RELATIVE_TO_ABSOLUTE_PATH);
      }
    },
    VALID_PREBUILT_JAR("//tools/java/src/com/someone/library:prebuilt-processors") {
      @Override
      public BuildRule createRule(BuildTarget target) {
        return new PrebuiltJarRule(
            createBuildRuleParams(target),
            "MyJar",
            null,
            null);
      }
    },
    VALID_JAVA_BINARY("//tools/java/src/com/facebook/annotations:custom-processors") {
      @Override
      public BuildRule createRule(BuildTarget target) {
        return new JavaBinaryRule(
            createBuildRuleParams(target),
            "com.facebook.Main",
            null,
            null,
            new DefaultDirectoryTraverser());
      }
    },
    VALID_JAVA_LIBRARY("//tools/java/src/com/facebook/somejava:library") {
      @Override
      public BuildRule createRule(BuildTarget target) {
        return new DefaultJavaLibraryRule(
            createBuildRuleParams(target),
            ImmutableSet.<String>of("MyClass.java"),
            ImmutableSet.<String>of(),
            "MyProguardConfig",
            AnnotationProcessingParams.EMPTY);
      }
    };

    private final String targetName;

    private AnnotationProcessorTarget(String targetName) {
      this.targetName = targetName;
    }

    protected BuildRuleParams createBuildRuleParams(BuildTarget target) {
      return new BuildRuleParams(
          target,
          ImmutableSortedSet.<BuildRule>of(),
          ImmutableSet.of(BuildTargetPattern.MATCH_ALL));
    }

    public BuildTarget createTarget() {
      return BuildTargetFactory.newInstance(targetName);
    }

    public abstract BuildRule createRule(BuildTarget target);
  }

  // Captures all the common code between the different annotation processing test scenarios.
  private class AnnotationProcessingScenario {
    private final Map<String,BuildRule> buildRuleIndex;
    private final AnnotationProcessingParams.Builder annotationProcessingParamsBuilder;
    private ExecutionContext executionContext;
    private BuildContext buildContext;

    public AnnotationProcessingScenario() {
      annotationProcessingParamsBuilder = new AnnotationProcessingParams.Builder();
      buildRuleIndex = Maps.newHashMap();
    }

    public AnnotationProcessingParams.Builder getAnnotationProcessingParamsBuilder() {
      return annotationProcessingParamsBuilder;
    }

    public void addAnnotationProcessorTarget(AnnotationProcessorTarget processor) {
      BuildTarget target = processor.createTarget();
      BuildRule rule = processor.createRule(target);

      annotationProcessingParamsBuilder.addProcessorBuildTarget(target);
      buildRuleIndex.put(target.getFullyQualifiedName(), rule);
    }

    public ImmutableList<String> buildAndGetCompileParameters() throws IOException {
      DefaultJavaLibraryRule javaLibrary = createJavaLibraryRule();
      buildContext = createBuildContext(javaLibrary, "");
      List<Command> commands = javaLibrary.buildInternal(buildContext);
      JavacInMemoryCommand javacCommand = lastJavacCommand(commands);

      executionContext = EasyMock.createMock(ExecutionContext.class);
      EasyMock.expect(executionContext.getVerbosity()).andReturn(Verbosity.SILENT);
      EasyMock.replay(executionContext);

      ImmutableList<String> options = javacCommand.getOptions(executionContext);

      EasyMock.verify(buildContext, executionContext);
      return options;
    }

    private DefaultJavaLibraryRule createJavaLibraryRule() {
      BuildTarget buildTarget = BuildTargetFactory.newInstance(ANNOTATION_SCENARIO_TARGET);
      annotationProcessingParamsBuilder.setOwnerTarget(buildTarget);

      ImmutableSet<String> srcs = ImmutableSet.of("android/java/src/com/facebook/Main.java");
      return new AndroidLibraryRule(
          new BuildRuleParams(
              buildTarget,
            /* deps */ ImmutableSortedSet.<BuildRule>of(),
            /* visibilityPatterns */ ImmutableSet.<BuildTargetPattern>of()
          ),
          srcs,
        /* resources */ ImmutableSet.<String>of(),
        /* proguardConfig */ null,
        /* annotationProcessors */ annotationProcessingParamsBuilder.build(buildRuleIndex),
        /* manifestFile */ null,
          JavacOptionsUtil.DEFAULT_SOURCE_LEVEL,
          JavacOptionsUtil.DEFAULT_TARGET_LEVEL);
    }

    private JavacInMemoryCommand lastJavacCommand(Iterable<Command> commands) {
      Command javac = null;
      for (Command command : commands) {
        if (command instanceof JavacInMemoryCommand) {
          javac = command;
          // Intentionally no break here, since we want the last one.
        }
      }
      assertNotNull("Expected a JavacInMemoryCommand in command list", javac);
      return (JavacInMemoryCommand)javac;
    }
  }
}