Modernize: Use slf4j and joptsimple.

9 files changed, 149 insertions, 258 deletions

diff --git a/build.gradle b/build.gradle
index ce1a8cd..3460d83 100644
--- a/build.gradle
+++ b/build.gradle
@@ -29,11 +29,16 @@ apply plugin: 'application'
 apply plugin: 'velocity'
 
 dependencies {
+	def slf4jVersion = '1.7.7'
+
     compile 'com.google.code.findbugs:jsr305:2.0.2'
-	compile 'gnu.getopt:java-getopt:1.0.13'
-	// compile 'net.sf.jopt-simple:jopt-simple:4.7'
+	// compile 'gnu.getopt:java-getopt:1.0.13'
+	compile "org.slf4j:slf4j-api:$slf4jVersion"
+	compile 'net.sf.jopt-simple:jopt-simple:4.7'
 	compile 'org.apache.ant:ant:1.7.0'
 
+	runtime "org.slf4j:slf4j-jcl:$slf4jVersion"
+
 	testCompile 'junit:junit:4.11'
 	// testCompile 'com.google.guava:guava:18.0'
 	testCompile 'commons-logging:commons-logging:1.2'
@@ -47,6 +52,8 @@ velocity {
 	context m
 }
 
+mainClassName = "org.anarres.cpp.Main"
+
 test {
 	systemProperty 'org.apache.commons.logging.Log', 'org.apache.commons.logging.impl.SimpleLog'
 	systemProperty 'org.apache.commons.logging.simplelog.defaultlog', 'debug'
diff --git a/install b/install
new file mode 120000
index 0000000..a40f9f7
--- /dev/null
+++ b/install
@@ -0,0 +1 @@
+build/install/jcpp/
\ No newline at end of file
diff --git a/src/main/java/org/anarres/cpp/CppReader.java b/src/main/java/org/anarres/cpp/CppReader.java
index 9157a93..5517f47 100644
--- a/src/main/java/org/anarres/cpp/CppReader.java
+++ b/src/main/java/org/anarres/cpp/CppReader.java
@@ -19,6 +19,7 @@ package org.anarres.cpp;
 import java.io.Closeable;
 import java.io.IOException;
 import java.io.Reader;
+import javax.annotation.Nonnull;
 import static org.anarres.cpp.Token.CCOMMENT;
 import static org.anarres.cpp.Token.CPPCOMMENT;
 import static org.anarres.cpp.Token.EOF;
@@ -34,11 +35,11 @@ import static org.anarres.cpp.Token.EOF;
  */
 public class CppReader extends Reader implements Closeable {
 
-    private Preprocessor cpp;
+    private final Preprocessor cpp;
     private String token;
     private int idx;
 
-    public CppReader(final Reader r) {
+    public CppReader(@Nonnull final Reader r) {
         cpp = new Preprocessor(new LexerSource(r, true) {
             @Override
             public String getName() {
@@ -50,7 +51,7 @@ public class CppReader extends Reader implements Closeable {
         idx = 0;
     }
 
-    public CppReader(Preprocessor p) {
+    public CppReader(@Nonnull Preprocessor p) {
         cpp = p;
         token = "";
         idx = 0;
@@ -59,6 +60,7 @@ public class CppReader extends Reader implements Closeable {
     /**
      * Returns the Preprocessor used by this CppReader.
      */
+    @Nonnull
     public Preprocessor getPreprocessor() {
         return cpp;
     }
@@ -68,7 +70,7 @@ public class CppReader extends Reader implements Closeable {
      *
      * This is a convnience method.
      */
-    public void addMacro(String name)
+    public void addMacro(@Nonnull String name)
             throws LexerException {
         cpp.addMacro(name);
     }
@@ -78,7 +80,7 @@ public class CppReader extends Reader implements Closeable {
      *
      * This is a convnience method.
      */
-    public void addMacro(String name, String value)
+    public void addMacro(@Nonnull String name, @Nonnull String value)
             throws LexerException {
         cpp.addMacro(name, value);
     }
@@ -138,10 +140,7 @@ public class CppReader extends Reader implements Closeable {
     @Override
     public void close()
             throws IOException {
-        if (cpp != null) {
-            cpp.close();
-            cpp = null;
-        }
+        cpp.close();
         token = null;
     }
 
diff --git a/src/main/java/org/anarres/cpp/DefaultPreprocessorListener.java b/src/main/java/org/anarres/cpp/DefaultPreprocessorListener.java
index 6d3929d..68f6e89 100644
--- a/src/main/java/org/anarres/cpp/DefaultPreprocessorListener.java
+++ b/src/main/java/org/anarres/cpp/DefaultPreprocessorListener.java
@@ -17,6 +17,9 @@ package org.anarres.cpp;
  * permissions and limitations under the License.
  */
 import javax.annotation.Nonnegative;
+import javax.annotation.Nonnull;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * A handler for preprocessor events, primarily errors and warnings.
@@ -27,6 +30,8 @@ import javax.annotation.Nonnegative;
  */
 public class DefaultPreprocessorListener implements PreprocessorListener {
 
+    private static final Logger LOG = LoggerFactory.getLogger(DefaultPreprocessorListener.class);
+
     private int errors;
     private int warnings;
 
@@ -49,8 +54,8 @@ public class DefaultPreprocessorListener implements PreprocessorListener {
         return warnings;
     }
 
-    protected void print(String msg) {
-        System.err.println(msg);
+    protected void print(@Nonnull String msg) {
+        LOG.info(msg);
     }
 
     /**
@@ -60,6 +65,7 @@ public class DefaultPreprocessorListener implements PreprocessorListener {
      * implementation. It may simply record the error message, or
      * it may throw an exception.
      */
+    @Override
     public void handleWarning(Source source, int line, int column,
             String msg)
             throws LexerException {
@@ -75,6 +81,7 @@ public class DefaultPreprocessorListener implements PreprocessorListener {
      * implementation. It may simply record the error message, or
      * it may throw an exception.
      */
+    @Override
     public void handleError(Source source, int line, int column,
             String msg)
             throws LexerException {
@@ -83,6 +90,7 @@ public class DefaultPreprocessorListener implements PreprocessorListener {
                 + ": error: " + msg);
     }
 
+    @Override
     public void handleSourceChange(Source source, String event) {
     }
 
diff --git a/src/main/java/org/anarres/cpp/Feature.java b/src/main/java/org/anarres/cpp/Feature.java
index cc7f818..369d79c 100644
--- a/src/main/java/org/anarres/cpp/Feature.java
+++ b/src/main/java/org/anarres/cpp/Feature.java
@@ -33,7 +33,6 @@ public enum Feature {
     KEEPCOMMENTS,
     /** Preserves comments in the lexed output, even when inactive. */
     KEEPALLCOMMENTS,
-    VERBOSE,
     DEBUG,
     /** Supports lexing of objective-C. */
     OBJCSYNTAX,
diff --git a/src/main/java/org/anarres/cpp/Main.java b/src/main/java/org/anarres/cpp/Main.java
index 3bc02eb..5a3e113 100644
--- a/src/main/java/org/anarres/cpp/Main.java
+++ b/src/main/java/org/anarres/cpp/Main.java
@@ -16,54 +16,27 @@
  */
 package org.anarres.cpp;
 
-import gnu.getopt.Getopt;
-import gnu.getopt.LongOpt;
 import java.io.File;
 import java.io.PrintStream;
+import java.util.Arrays;
 import java.util.EnumSet;
+import java.util.List;
+import javax.annotation.Nonnull;
+import joptsimple.OptionParser;
+import joptsimple.OptionSet;
+import joptsimple.OptionSpec;
+import joptsimple.ValueConverter;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * (Currently a simple test class).
  */
 public class Main {
 
-    private static class Option extends LongOpt {
-
-        private final String eg;
-        private final String help;
-
-        public Option(String word, int arg, int ch,
-                String eg, String help) {
-            super(word, arg, null, ch);
-            this.eg = eg;
-            this.help = help;
-        }
-    }
-
-    private static final Option[] OPTS = new Option[]{
-        new Option("help", LongOpt.NO_ARGUMENT, 'h', null,
-        "Displays help and usage information."),
-        new Option("define", LongOpt.REQUIRED_ARGUMENT, 'D', "name=definition",
-        "Defines the given macro."),
-        new Option("undefine", LongOpt.REQUIRED_ARGUMENT, 'U', "name",
-        "Undefines the given macro, previously either builtin or defined using -D."),
-        new Option("include", LongOpt.REQUIRED_ARGUMENT, 1, "file",
-        "Process file as if \"#" + "include \"file\"\" appeared as the first line of the primary source file."),
-        new Option("incdir", LongOpt.REQUIRED_ARGUMENT, 'I', "dir",
-        "Adds the directory dir to the list of directories to be searched for header files."),
-        new Option("iquote", LongOpt.REQUIRED_ARGUMENT, 0, "dir",
-        "Adds the directory dir to the list of directories to be searched for header files included using \"\"."),
-        new Option("warning", LongOpt.REQUIRED_ARGUMENT, 'W', "type",
-        "Enables the named warning class (" + getWarnings() + ")."),
-        new Option("no-warnings", LongOpt.NO_ARGUMENT, 'w', null,
-        "Disables ALL warnings."),
-        new Option("verbose", LongOpt.NO_ARGUMENT, 'v', null,
-        "Operates incredibly verbosely."),
-        new Option("debug", LongOpt.NO_ARGUMENT, 3, null,
-        "Operates incredibly verbosely."),
-        new Option("version", LongOpt.NO_ARGUMENT, 2, null,
-        "Prints jcpp's version number (" + Version.getVersion() + ")"),};
+    private static final Logger LOG = LoggerFactory.getLogger(Main.class);
 
+    @Nonnull
     private static CharSequence getWarnings() {
         StringBuilder buf = new StringBuilder();
         for (Warning w : Warning.values()) {
@@ -80,12 +53,52 @@ public class Main {
     }
 
     public void run(String[] args) throws Exception {
-        Option[] opts = OPTS;
-        String sopts = getShortOpts(opts);
-        Getopt g = new Getopt("jcpp", args, sopts, opts);
-        int c;
-        String arg;
-        int idx;
+
+        OptionParser parser = new OptionParser();
+        OptionSpec<?> helpOption = parser.accepts("help",
+                "Displays command-line help.")
+                .forHelp();
+        OptionSpec<?> versionOption = parser.acceptsAll(Arrays.asList("version"),
+                "Displays the product version (" + Version.getVersion() + ") and exits.")
+                .forHelp();
+
+        OptionSpec<?> debugOption = parser.acceptsAll(Arrays.asList("debug"),
+                "Enables debug output.");
+
+        OptionSpec<String> defineOption = parser.acceptsAll(Arrays.asList("define", "D"),
+                "Defines the given macro.")
+                .withRequiredArg().ofType(String.class).describedAs("name[=definition]");
+        OptionSpec<String> undefineOption = parser.acceptsAll(Arrays.asList("undefine", "U"),
+                "Undefines the given macro, previously either builtin or defined using -D.")
+                .withRequiredArg().describedAs("name");
+        OptionSpec<File> includeOption = parser.accepts("include",
+                "Process file as if \"#" + "include \"file\"\" appeared as the first line of the primary source file.")
+                .withRequiredArg().ofType(File.class).describedAs("file");
+        OptionSpec<File> incdirOption = parser.acceptsAll(Arrays.asList("incdir", "I"),
+                "Adds the directory dir to the list of directories to be searched for header files.")
+                .withRequiredArg().ofType(File.class).describedAs("dir");
+        OptionSpec<File> iquoteOption = parser.acceptsAll(Arrays.asList("iquote"),
+                "Adds the directory dir to the list of directories to be searched for header files included using \"\".")
+                .withRequiredArg().ofType(File.class).describedAs("dir");
+        OptionSpec<String> warningOption = parser.acceptsAll(Arrays.asList("warning", "W"),
+                "Enables the named warning class (" + getWarnings() + ").")
+                .withRequiredArg().ofType(String.class).describedAs("warning");
+        OptionSpec<Void> noWarningOption = parser.acceptsAll(Arrays.asList("no-warnings", "w"),
+                "Disables ALL warnings.");
+        OptionSpec<File> inputsOption = parser.nonOptions()
+                .ofType(File.class).describedAs("Files to process.");
+
+        OptionSet options = parser.parse(args);
+
+        if (options.has(helpOption)) {
+            parser.printHelpOn(System.out);
+            return;
+        }
+
+        if (options.has(versionOption)) {
+            version(System.out);
+            return;
+        }
 
         Preprocessor pp = new Preprocessor();
         pp.addFeature(Feature.DIGRAPHS);
@@ -100,78 +113,56 @@ public class Main {
         pp.getFrameworksPath().add("/Library/Frameworks");
         pp.getFrameworksPath().add("/Local/Library/Frameworks");
 
-        GETOPT:
-        while ((c = g.getopt()) != -1) {
-            switch (c) {
-                case 'D':
-                    arg = g.getOptarg();
-                    idx = arg.indexOf('=');
-                    if (idx == -1)
-                        pp.addMacro(arg);
-                    else
-                        pp.addMacro(arg.substring(0, idx),
-                                arg.substring(idx + 1));
-                    break;
-                case 'U':
-                    pp.getMacros().remove(g.getOptarg());
-                    break;
-                case 'I':
-                    pp.getSystemIncludePath().add(g.getOptarg());
-                    break;
-                case 0:	// --iquote=
-                    pp.getQuoteIncludePath().add(g.getOptarg());
-                    break;
-                case 'W':
-                    arg = g.getOptarg().toUpperCase();
-                    arg = arg.replace('-', '_');
-                    if (arg.equals("ALL"))
-                        pp.addWarnings(EnumSet.allOf(Warning.class));
-                    else
-                        pp.addWarning(Enum.valueOf(Warning.class, arg));
-                    break;
-                case 'w':
-                    pp.getWarnings().clear();
-                    break;
-                case 1:	// --include=
-                    // pp.addInput(new File(g.getOptarg()));
-                    // Comply exactly with spec.
-                    pp.addInput(new StringLexerSource(
-                            "#" + "include \"" + g.getOptarg() + "\"\n"
-                    ));
-                    break;
-                case 2:	// --version
-                    version(System.out);
-                    return;
-                case 'v':
-                    pp.addFeature(Feature.VERBOSE);
-                    break;
-                case 3:
-                    pp.addFeature(Feature.DEBUG);
-                    break;
-                case 'h':
-                    usage(getClass().getName(), opts);
-                    return;
-                default:
-                    throw new Exception("Illegal option " + (char) c);
-                case '?':
-                    continue;	/* Make failure-proof. */
+        if (options.has(debugOption))
+            pp.addFeature(Feature.DEBUG);
 
-            }
+        if (options.has(noWarningOption))
+            pp.getWarnings().clear();
+
+        for (String warning : options.valuesOf(warningOption)) {
+            warning = warning.toUpperCase();
+            warning = warning.replace('-', '_');
+            if (warning.equals("ALL"))
+                pp.addWarnings(EnumSet.allOf(Warning.class));
+            else
+                pp.addWarning(Enum.valueOf(Warning.class, warning));
+        }
+
+        for (String arg : options.valuesOf(defineOption)) {
+            int idx = arg.indexOf('=');
+            if (idx == -1)
+                pp.addMacro(arg);
+            else
+                pp.addMacro(arg.substring(0, idx), arg.substring(idx + 1));
         }
+        for (String arg : options.valuesOf(undefineOption)) {
+            pp.getMacros().remove(arg);
+        }
+
+        for (File dir : options.valuesOf(incdirOption))
+            pp.getSystemIncludePath().add(dir.getAbsolutePath());
+        for (File dir : options.valuesOf(iquoteOption))
+            pp.getQuoteIncludePath().add(dir.getAbsolutePath());
+        for (File file : options.valuesOf(includeOption))
+            // Comply exactly with spec.
+            pp.addInput(new StringLexerSource("#" + "include \"" + file + "\"\n"));
 
-        for (int i = g.getOptind(); i < args.length; i++)
-            pp.addInput(new FileLexerSource(new File(args[i])));
-        if (g.getOptind() == args.length)
+        List<File> inputs = options.valuesOf(inputsOption);
+        if (inputs.isEmpty()) {
             pp.addInput(new InputLexerSource(System.in));
+        } else {
+            for (File input : inputs)
+                pp.addInput(new FileLexerSource(input));
+        }
 
-        if (pp.getFeature(Feature.VERBOSE)) {
-            System.err.println("#" + "include \"...\" search starts here:");
+        if (pp.getFeature(Feature.DEBUG)) {
+            LOG.info("#" + "include \"...\" search starts here:");
             for (String dir : pp.getQuoteIncludePath())
-                System.err.println("  " + dir);
-            System.err.println("#" + "include <...> search starts here:");
+                LOG.info("  " + dir);
+            LOG.info("#" + "include <...> search starts here:");
             for (String dir : pp.getSystemIncludePath())
-                System.err.println("  " + dir);
-            System.err.println("End of search list.");
+                LOG.info("  " + dir);
+            LOG.info("End of search list.");
         }
 
         try {
@@ -184,137 +175,21 @@ public class Main {
                 System.out.print(tok.getText());
             }
         } catch (Exception e) {
-            e.printStackTrace(System.err);
+            StringBuilder buf = new StringBuilder("Preprocessor failed:\n");
             Source s = pp.getSource();
             while (s != null) {
-                System.err.println(" -> " + s);
+                buf.append(" -> ").append(s).append("\n");
                 s = s.getParent();
             }
+            LOG.error(buf.toString(), e);
         }
 
     }
 
-    private void version(PrintStream out) {
+    private static void version(@Nonnull PrintStream out) {
         out.println("Anarres Java C Preprocessor version " + Version.getVersion());
         out.println("Copyright (C) 2008-2014 Shevek (http://www.anarres.org/).");
         out.println("This is free software; see the source for copying conditions.  There is NO");
         out.println("warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.");
     }
-
-    private static String getShortOpts(Option[] opts)
-            throws Exception {
-        StringBuilder buf = new StringBuilder();
-        for (Option opt : opts) {
-            char c = (char) opt.getVal();
-            if (!Character.isLetterOrDigit(c))
-                continue;
-            for (int j = 0; j < buf.length(); j++)
-                if (buf.charAt(j) == c)
-                    throw new Exception(
-                            "Duplicate short option " + c
-                    );
-            buf.append(c);
-            switch (opt.getHasArg()) {
-                case LongOpt.NO_ARGUMENT:
-                    break;
-                case LongOpt.OPTIONAL_ARGUMENT:
-                    buf.append("::");
-                    break;
-                case LongOpt.REQUIRED_ARGUMENT:
-                    buf.append(":");
-                    break;
-            }
-        }
-        return buf.toString();
-    }
-
-    /* This is incomplete but nearly there. */
-    /**
-     * Wraps a string.
-     *
-     * The output form is:
-     * <pre>
-     * prefix     in[0]
-     * &lt;--indent-&gt; in[1]
-     * &lt;--indent-&gt; in[2]
-     * &lt;-----width----&gt;
-     * </pre>
-     */
-    /* XXX There's some of this in commons. */
-    private static String wrap(String in, String prefix,
-            int indent, int width) {
-        StringBuilder buf = new StringBuilder(prefix);
-
-        while (buf.length() < indent)
-            buf.append(' ');
-
-        int start = 0;
-
-        while (start < in.length()) {
-            while (start < in.length()
-                    && Character.isWhitespace(in.charAt(start)))
-                start++;
-
-            int end = start + width - indent;
-
-            if (end > in.length()) {
-                buf.append(in.substring(start));
-                break;
-            }
-
-            int idx = end;
-            while (!Character.isWhitespace(in.charAt(idx)))
-                idx--;
-
-            if (idx == start) {
-                idx = end - 1;
-                buf.append(in.substring(start, idx));
-                buf.append('-');
-            } else {
-                buf.append(in.substring(start, idx));
-                start = idx;
-            }
-
-            start = idx;
-        }
-
-        return buf.toString();
-    }
-
-    private static void usage(String command, Option[] options) {
-        StringBuilder text = new StringBuilder("Usage: ");
-        text.append(command).append('\n');
-        for (Option option : options) {
-            StringBuilder line = new StringBuilder();
-            Option opt = option;
-            line.append("    --").append(opt.getName());
-            switch (opt.getHasArg()) {
-                case LongOpt.NO_ARGUMENT:
-                    break;
-                case LongOpt.OPTIONAL_ARGUMENT:
-                    line.append("[=").append(opt.eg).append(']');
-                    break;
-                case LongOpt.REQUIRED_ARGUMENT:
-                    line.append('=').append(opt.eg);
-                    break;
-            }
-            if (Character.isLetterOrDigit(opt.getVal()))
-                line.append(" (-").append((char) opt.getVal()).append(")");
-            if (line.length() < 30) {
-                while (line.length() < 30)
-                    line.append(' ');
-            } else {
-                line.append('\n');
-                for (int j = 0; j < 30; j++)
-                    line.append(' ');
-            }
-            /* This should use wrap. */
-            line.append(opt.help);
-            line.append('\n');
-            text.append(line);
-        }
-
-        System.out.println(text);
-    }
-
 }
diff --git a/src/main/java/org/anarres/cpp/Preprocessor.java b/src/main/java/org/anarres/cpp/Preprocessor.java
index 43fba89..6bcf3fb 100644
--- a/src/main/java/org/anarres/cpp/Preprocessor.java
+++ b/src/main/java/org/anarres/cpp/Preprocessor.java
@@ -33,6 +33,8 @@ import java.util.Stack;
 import java.util.TreeMap;
 import javax.annotation.CheckForNull;
 import javax.annotation.Nonnull;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import static org.anarres.cpp.PreprocessorCommand.*;
 import static org.anarres.cpp.Token.*;
 
@@ -73,6 +75,8 @@ import static org.anarres.cpp.Token.*;
  */
 public class Preprocessor implements Closeable {
 
+    private static final Logger LOG = LoggerFactory.getLogger(Preprocessor.class);
+
     private static final Source INTERNAL = new Source() {
         @Override
         public Token token()
@@ -600,7 +604,7 @@ public class Preprocessor implements Closeable {
             Token tok = source_token;
             source_token = null;
             if (getFeature(Feature.DEBUG))
-                System.err.println("Returning unget token " + tok);
+                LOG.debug("Returning unget token " + tok);
             return tok;
         }
 
@@ -622,7 +626,7 @@ public class Preprocessor implements Closeable {
                 continue;
             }
             if (getFeature(Feature.DEBUG))
-                System.err.println("Returning fresh token " + tok);
+                LOG.debug("Returning fresh token " + tok);
             return tok;
         }
     }
@@ -1064,7 +1068,7 @@ public class Preprocessor implements Closeable {
         }
 
         if (getFeature(Feature.DEBUG))
-            System.err.println("Defined macro " + m);
+            LOG.debug("Defined macro " + m);
         addMacro(m);
 
         return tok;	/* NL or EOF. */
@@ -1104,7 +1108,7 @@ public class Preprocessor implements Closeable {
         if (!file.isFile())
             return false;
         if (getFeature(Feature.DEBUG))
-            System.err.println("pp: including " + file);
+            LOG.debug("pp: including " + file);
         includes.add(file);
         push_source(file.getSource(), true);
         return true;
@@ -1497,9 +1501,7 @@ public class Preprocessor implements Closeable {
             throws IOException,
             LexerException {
         /*
-         * System.out.flush();
          * (new Exception("expr(" + priority + ") called")).printStackTrace();
-         * System.err.flush();
          */
 
         Token tok = expr_token();
@@ -1638,9 +1640,7 @@ public class Preprocessor implements Closeable {
         }
 
         /*
-         * System.out.flush();
          * (new Exception("expr returning " + lhs)).printStackTrace();
-         * System.err.flush();
          */
         // System.out.println("expr returning " + lhs);
         return lhs;
@@ -2059,7 +2059,7 @@ public class Preprocessor implements Closeable {
             LexerException {
         Token tok = _token();
         if (getFeature(Feature.DEBUG))
-            System.err.println("pp: Returning " + tok);
+            LOG.debug("pp: Returning " + tok);
         return tok;
     }
 
diff --git a/src/main/java/org/anarres/cpp/PreprocessorListener.java b/src/main/java/org/anarres/cpp/PreprocessorListener.java
index 6a4cb22..3443714 100644
--- a/src/main/java/org/anarres/cpp/PreprocessorListener.java
+++ b/src/main/java/org/anarres/cpp/PreprocessorListener.java
@@ -16,6 +16,8 @@
  */
 package org.anarres.cpp;
 
+import javax.annotation.Nonnull;
+
 /**
  * A handler for preprocessor events, primarily errors and warnings.
  *
@@ -32,8 +34,8 @@ public interface PreprocessorListener {
      * implementation. It may simply record the error message, or
      * it may throw an exception.
      */
-    public void handleWarning(Source source, int line, int column,
-            String msg)
+    public void handleWarning(@Nonnull Source source, int line, int column,
+            @Nonnull String msg)
             throws LexerException;
 
     /**
@@ -43,10 +45,10 @@ public interface PreprocessorListener {
      * implementation. It may simply record the error message, or
      * it may throw an exception.
      */
-    public void handleError(Source source, int line, int column,
-            String msg)
+    public void handleError(@Nonnull Source source, int line, int column,
+            @Nonnull String msg)
             throws LexerException;
 
-    public void handleSourceChange(Source source, String event);
+    public void handleSourceChange(@Nonnull Source source, @Nonnull String event);
 
 }
diff --git a/src/main/java/org/anarres/cpp/Warning.java b/src/main/java/org/anarres/cpp/Warning.java
index da2b2c6..80d184a 100644
--- a/src/main/java/org/anarres/cpp/Warning.java
+++ b/src/main/java/org/anarres/cpp/Warning.java
@@ -28,5 +28,5 @@ public enum Warning {
     UNUSED_MACROS,
     ENDIF_LABELS,
     ERROR,
-	// SYSTEM_HEADERS
+    // SYSTEM_HEADERS
 }