Added classpathFile parameter

Fixes #70

README.md

@@ -123,6 +123,11 @@ Optional system properties:
       Output directory into where the generated class files are written.
       Defaults to same as retrolambda.inputDir
 
+  retrolambda.classpathFile
+      File listing the classpath entries.
+      Alternative to retrolambda.classpath for avoiding the command line
+      length limit. The file must list one file per line with UTF-8 encoding.
+
   retrolambda.includedFiles
       List of files to process, instead of processing all files.
       This is useful for a build tool to support incremental compilation.
@@ -217,6 +222,9 @@ Version History
 
 ### Upcoming
 
+- Added the `-Dretrolambda.classpathFile` parameter to avoid 
+  the command line length limit
+  ([Issue #70](https://github.com/orfjackal/retrolambda/issues/70))
 - Added the `-Dretrolambda.includedFilesFile` parameter to avoid 
   the command line length limit
   ([Pull request #74](https://github.com/orfjackal/retrolambda/pull/74))

retrolambda/src/main/java/net/orfjackal/retrolambda/Config.java

@@ -19,8 +19,9 @@ public class Config {
     public static final String INPUT_DIR = PREFIX + "inputDir";
     public static final String OUTPUT_DIR = PREFIX + "outputDir";
     public static final String CLASSPATH = PREFIX + "classpath";
+    public static final String CLASSPATH_FILE = CLASSPATH + "File";
     public static final String INCLUDED_FILES = PREFIX + "includedFiles";
-    public static final String INCLUDED_FILES_FILE = PREFIX + "includedFilesFile";
+    public static final String INCLUDED_FILES_FILE = INCLUDED_FILES + "File";
 
     private static final List<String> requiredProperties = new ArrayList<>();
     private static final List<String> requiredPropertiesHelp = new ArrayList<>();
@@ -101,7 +102,11 @@ public boolean isDefaultMethodsEnabled() {
     }
 
     public Path getInputDir() {
-        return Paths.get(getRequiredProperty(INPUT_DIR));
+        String inputDir = p.getProperty(INPUT_DIR);
+        if (inputDir != null) {
+            return Paths.get(inputDir);
+        }
+        throw new IllegalArgumentException("Missing required property: " + INPUT_DIR);
     }
 
 
@@ -115,10 +120,10 @@ public Path getInputDir() {
 
     public Path getOutputDir() {
         String outputDir = p.getProperty(OUTPUT_DIR);
-        if (outputDir == null) {
-            return getInputDir();
+        if (outputDir != null) {
+            return Paths.get(outputDir);
         }
-        return Paths.get(outputDir);
+        return getInputDir();
     }
 
 
@@ -128,22 +133,32 @@ public Path getOutputDir() {
         requiredParameterHelp(CLASSPATH,
                 "Classpath containing the original class files and their dependencies.",
                 "Uses ; or : as the path separator, see java.io.File#pathSeparatorChar");
+        optionalParameterHelp(CLASSPATH_FILE,
+                "File listing the classpath entries.",
+                "Alternative to " + CLASSPATH + " for avoiding the command line",
+                "length limit. The file must list one file per line with UTF-8 encoding.");
     }
 
     public List<Path> getClasspath() {
-        String classpath = getRequiredProperty(CLASSPATH);
-        return Stream.of(classpath.split(File.pathSeparator))
-                .filter(path -> !path.isEmpty())
-                .map(Paths::get)
-                .collect(Collectors.toList());
-    }
-
-    private String getRequiredProperty(String key) {
-        String value = p.getProperty(key);
-        if (value == null) {
-            throw new IllegalArgumentException("Missing required property: " + key);
+        String classpath = p.getProperty(CLASSPATH);
+        if (classpath != null) {
+            return Stream.of(classpath.split(File.pathSeparator))
+                    .filter(path -> !path.isEmpty())
+                    .map(Paths::get)
+                    .collect(Collectors.toList());
+        }
+        String classpathFile = p.getProperty(CLASSPATH_FILE);
+        if (classpathFile != null) {
+            try {
+                return Files.readAllLines(Paths.get(classpathFile)).stream()
+                        .filter(line -> !line.isEmpty())
+                        .map(Paths::get)
+                        .collect(Collectors.toList());
+            } catch (IOException e) {
+                throw new RuntimeException("Failed to read " + CLASSPATH_FILE + " from " + classpathFile, e);
+            }
         }
-        return value;
+        throw new IllegalArgumentException("Missing required property: " + CLASSPATH);
     }
 
 

retrolambda/src/test/java/net/orfjackal/retrolambda/ConfigTest.java

@@ -74,9 +74,21 @@ public void classpath() {
         assertThat("multiple values", config().getClasspath(), is(Arrays.asList(Paths.get("one.jar"), Paths.get("two.jar"))));
     }
 
-    @Ignore // TODO
     @Test
-    public void classpath_file() {
+    public void classpath_file() throws IOException {
+        Path file = tempDir.newFile("classpath.txt").toPath();
+
+        Files.write(file, Arrays.asList("", "", "")); // empty lines are ignored
+        systemProperties.setProperty(Config.CLASSPATH_FILE, file.toString());
+        assertThat("zero values", config().getClasspath(), is(empty()));
+
+        Files.write(file, Arrays.asList("one.jar"));
+        systemProperties.setProperty(Config.CLASSPATH_FILE, file.toString());
+        assertThat("one value", config().getClasspath(), is(Arrays.asList(Paths.get("one.jar"))));
+
+        Files.write(file, Arrays.asList("one.jar", "two.jar"));
+        systemProperties.setProperty(Config.CLASSPATH_FILE, file.toString());
+        assertThat("multiple values", config().getClasspath(), is(Arrays.asList(Paths.get("one.jar"), Paths.get("two.jar"))));
     }
 
     @Test
@@ -102,19 +114,19 @@ public void included_files() {
 
     @Test
     public void included_files_file() throws IOException {
-        Path listFile = tempDir.newFile("list.txt").toPath();
+        Path file = tempDir.newFile("includedFiles.txt").toPath();
         assertThat("not set", config().getIncludedFiles(), is(nullValue()));
 
-        Files.write(listFile, Arrays.asList("", "", "")); // empty lines are ignored
-        systemProperties.setProperty(Config.INCLUDED_FILES_FILE, listFile.toString());
+        Files.write(file, Arrays.asList("", "", "")); // empty lines are ignored
+        systemProperties.setProperty(Config.INCLUDED_FILES_FILE, file.toString());
         assertThat("zero values", config().getIncludedFiles(), is(empty()));
 
-        Files.write(listFile, Arrays.asList("one.class"));
-        systemProperties.setProperty(Config.INCLUDED_FILES_FILE, listFile.toString());
+        Files.write(file, Arrays.asList("one.class"));
+        systemProperties.setProperty(Config.INCLUDED_FILES_FILE, file.toString());
         assertThat("one value", config().getIncludedFiles(), is(Arrays.asList(Paths.get("one.class"))));
 
-        Files.write(listFile, Arrays.asList("one.class", "two.class"));
-        systemProperties.setProperty(Config.INCLUDED_FILES_FILE, listFile.toString());
+        Files.write(file, Arrays.asList("one.class", "two.class"));
+        systemProperties.setProperty(Config.INCLUDED_FILES_FILE, file.toString());
         assertThat("multiple values", config().getIncludedFiles(), is(Arrays.asList(Paths.get("one.class"), Paths.get("two.class"))));
     }
 }