Improve Java examples

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MOS_MIGRATED_REVID=86787893

8 files changed, 138 insertions, 0 deletions

diff --git a/base_workspace/examples/java-skylark/README.md b/base_workspace/examples/java-skylark/README.md
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index 0000000000..970a859f54
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+++ b/base_workspace/examples/java-skylark/README.md
@@ -0,0 +1,7 @@
+Skylark Java Examples
+=====================
+
+Use the native Java rules (see the examples in
+_base_workspace/examples/java-native_) for building Java, not these. These
+files are examples of how Skylark rules can be used (see
+_tools/build_rules/java_rules_skylark.bzl_ for the rule definitions).
diff --git a/base_workspace/examples/java-skylark/src/main/java/com/example/myproject/BUILD b/base_workspace/examples/java-skylark/src/main/java/com/example/myproject/BUILD
new file mode 100644
index 0000000000..ed69d7f2b3
--- /dev/null
+++ b/base_workspace/examples/java-skylark/src/main/java/com/example/myproject/BUILD
@@ -0,0 +1,21 @@
+load("tools/build_rules/java_rules_skylark", "java_library", "java_binary", "java_test")
+
+package(default_visibility = ["//visibility:public"])
+
+java_binary(
+    name = "hello-world",
+    srcs = ["Greeter.java"],
+    main_class = "com.example.myproject.Greeter",
+)
+
+java_binary(
+    name = "hello-data",
+    main_class = "com.example.myproject.Greeter",
+    deps = [":hello-lib"],
+)
+
+java_library(
+    name = "hello-lib",
+    srcs = ["Greeter.java"],
+    data = ["//examples/java-skylark/src/main/resources:greeting"],
+)
diff --git a/base_workspace/examples/java-skylark/src/main/java/com/example/myproject/Greeter.java b/base_workspace/examples/java-skylark/src/main/java/com/example/myproject/Greeter.java
new file mode 100644
index 0000000000..b4d8516dc9
--- /dev/null
+++ b/base_workspace/examples/java-skylark/src/main/java/com/example/myproject/Greeter.java
@@ -0,0 +1,45 @@
+package com.example.myproject;
+
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.InputStream;
+import java.io.PrintStream;
+import java.util.Scanner;
+
+/**
+ * Prints a greeting which can be customized by building with data and/or passing in command-
+ * line arguments.
+ */
+public class Greeter {
+  static PrintStream out = System.out;
+
+  public static String getRunfiles() {
+    String path = System.getenv("JAVA_RUNFILES");
+    if (path == null) {
+      path = System.getenv("TEST_SRCDIR");
+    }
+    return path;
+  }
+
+  public static String convertStreamToString(InputStream is) throws Exception {
+    Scanner s = new Scanner(is).useDelimiter("\n");
+    return s.hasNext() ? s.next() : "";
+  }
+
+  public void hello(String obj) throws Exception {
+    String greeting = "Hello";
+    try {
+      String greetFile = getRunfiles() + "/examples/java-skylark/src/main/resources/greeting.txt";
+      greeting = convertStreamToString(new FileInputStream(greetFile));
+    } catch (FileNotFoundException e) {
+      // use default.
+    }
+    out.println(greeting + " " + obj);
+  }
+
+  public static void main(String... args) throws Exception {
+    Greeter g = new Greeter();
+    String obj = args.length > 0 ? args[0] : "world";
+    g.hello(obj);
+  }
+};
diff --git a/base_workspace/examples/java-skylark/src/main/resources/BUILD b/base_workspace/examples/java-skylark/src/main/resources/BUILD
new file mode 100644
index 0000000000..8347a3555a
--- /dev/null
+++ b/base_workspace/examples/java-skylark/src/main/resources/BUILD
@@ -0,0 +1,6 @@
+package(default_visibility = ["//visibility:public"])
+
+filegroup(
+    name = "greeting",
+    srcs = ["greeting.txt"],
+)
diff --git a/base_workspace/examples/java-skylark/src/main/resources/greeting.txt b/base_workspace/examples/java-skylark/src/main/resources/greeting.txt
new file mode 100644
index 0000000000..17654db5a1
--- /dev/null
+++ b/base_workspace/examples/java-skylark/src/main/resources/greeting.txt
@@ -0,0 +1 @@
+Heyo
diff --git a/base_workspace/examples/java-skylark/src/test/java/com/example/myproject/BUILD b/base_workspace/examples/java-skylark/src/test/java/com/example/myproject/BUILD
new file mode 100644
index 0000000000..90e71f97ac
--- /dev/null
+++ b/base_workspace/examples/java-skylark/src/test/java/com/example/myproject/BUILD
@@ -0,0 +1,16 @@
+load("tools/build_rules/java_rules_skylark", "java_test")
+
+java_test(
+    name = "pass",
+    srcs = ["TestHello.java"],
+    deps = [
+        "//examples/java-skylark/src/main/java/com/example/myproject:hello-lib",
+        "//third_party:junit4",
+    ],
+)
+
+java_test(
+    name = "fail",
+    srcs = ["Fail.java"],
+    main_class = "com.example.myproject.Fail",
+)
diff --git a/base_workspace/examples/java-skylark/src/test/java/com/example/myproject/Fail.java b/base_workspace/examples/java-skylark/src/test/java/com/example/myproject/Fail.java
new file mode 100644
index 0000000000..079e1e9f04
--- /dev/null
+++ b/base_workspace/examples/java-skylark/src/test/java/com/example/myproject/Fail.java
@@ -0,0 +1,7 @@
+package com.example.myproject;
+
+class Fail {
+  public static void main(String []args) {
+    System.exit(1);
+  }
+}
diff --git a/base_workspace/examples/java-skylark/src/test/java/com/example/myproject/TestHello.java b/base_workspace/examples/java-skylark/src/test/java/com/example/myproject/TestHello.java
new file mode 100644
index 0000000000..d50e6e503f
--- /dev/null
+++ b/base_workspace/examples/java-skylark/src/test/java/com/example/myproject/TestHello.java
@@ -0,0 +1,35 @@
+package com.example.myproject;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+import java.nio.charset.StandardCharsets;
+
+/**
+ * Tests different numbers of arguments to main().
+ *
+ * <p>With an empty args array, {@link Greeter} should print "Hello world". If there are one or more
+ * args, {@link Greeter} should print "Hello &lt;arg[0]&gt;".</p>
+ */
+public class TestHello {
+
+  @Test
+  public void testNoArgument() throws Exception {
+    ByteArrayOutputStream out = new ByteArrayOutputStream();
+    Greeter.out = new PrintStream(out);
+    Greeter.main();
+    assertEquals("Hello world\n", new String(out.toByteArray(), StandardCharsets.UTF_8));
+  }
+
+  @Test
+  public void testWithArgument() throws Exception {
+    ByteArrayOutputStream out = new ByteArrayOutputStream();
+    Greeter.out = new PrintStream(out);
+    Greeter.main("toto");
+    assertEquals("Hello toto\n", new String(out.toByteArray(), StandardCharsets.UTF_8));
+  }
+
+}