Fix .interp file parsing test for the Java runtime.

runtime-testsuite/test/org/antlr/v4/test/runtime/BaseRuntimeTestSupport.java

@@ -225,6 +225,7 @@ protected ATN createATN(Grammar g, boolean useSerializer) {
 
 		return atn;
 	}
+
 	protected void semanticProcess(Grammar g) {
 		if ( g.ast!=null && !g.ast.hasErrors ) {
 //			System.out.println(g.ast.toStringTree());

runtime-testsuite/test/org/antlr/v4/test/runtime/java/TestInterpreterDataReader.java

@@ -1,27 +1,54 @@
 package org.antlr.v4.test.runtime.java;
 
+import org.antlr.v4.Tool;
 import org.antlr.v4.runtime.Vocabulary;
+import org.antlr.v4.runtime.VocabularyImpl;
 import org.antlr.v4.runtime.atn.ATN;
+import org.antlr.v4.runtime.atn.ATNDeserializer;
 import org.antlr.v4.runtime.atn.ATNSerializer;
 import org.antlr.v4.runtime.misc.InterpreterDataReader;
+import org.antlr.v4.runtime.misc.Utils;
+import org.antlr.v4.tool.Grammar;
 import org.junit.Assert;
 import org.junit.Test;
 
+import java.io.IOException;
 import java.lang.reflect.Field;
 import java.net.URL;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
 
-public class TestInterpreterDataReader {
-
+/** This file represents a simple sanity checks on the parsing of the .interp file
+ *  available to the Java runtime for interpreting rather than compiling and executing parsers.
+ */
+public class TestInterpreterDataReader extends BaseJavaTest {
     @Test
-    public void testParseFile() throws NoSuchFieldException, IllegalAccessException {
-        final ClassLoader loader = Thread.currentThread().getContextClassLoader();
-        // pay attention to the path where the InterpDataReaderTest.interp is stored.
-        final URL stuff = loader.getResource("org/antlr/v4/test/runtime/InterpDataReaderTest.interp");
-        Assert.assertNotNull(stuff);
+    public void testParseFile() throws IOException, NoSuchFieldException, IllegalAccessException, org.antlr.runtime.RecognitionException {
+		Grammar g = new Grammar(
+				"grammar Calc;\n" +
+				"s :  expr EOF\n" +
+				"  ;\n" +
+				"expr\n" +
+				"  :  INT            # number\n" +
+				"  |  expr (MUL | DIV) expr  # multiply\n" +
+				"  |  expr (ADD | SUB) expr  # add\n" +
+				"  ;\n" +
+				"\n" +
+				"INT : [0-9]+;\n" +
+				"MUL : '*';\n" +
+				"DIV : '/';\n" +
+				"ADD : '+';\n" +
+				"SUB : '-';\n" +
+				"WS : [ \\t]+ -> channel(HIDDEN);");
+		String interpString = Tool.generateInterpreterData(g);
+		Path interpFile = Files.createTempFile(null, null);
+		Files.write(interpFile, interpString.getBytes(StandardCharsets.UTF_8));
 
-        InterpreterDataReader.InterpreterData interpreterData = InterpreterDataReader.parseFile(stuff.getPath());
+        InterpreterDataReader.InterpreterData interpreterData = InterpreterDataReader.parseFile(interpFile.toString());
         Field atnField = interpreterData.getClass().getDeclaredField("atn");
         Field vocabularyField = interpreterData.getClass().getDeclaredField("vocabulary");
         Field ruleNamesField = interpreterData.getClass().getDeclaredField("ruleNames");
@@ -36,30 +63,21 @@ public void testParseFile() throws NoSuchFieldException, IllegalAccessException
 
         ATN atn = (ATN) atnField.get(interpreterData);
         Vocabulary vocabulary = (Vocabulary) vocabularyField.get(interpreterData);
-        List<String> ruleNames = castList(ruleNamesField.get(interpreterData), String.class);
+		String[] literalNames = ((VocabularyImpl) vocabulary).getLiteralNames();
+		String[] symbolicNames = ((VocabularyImpl) vocabulary).getSymbolicNames();
+		List<String> ruleNames = castList(ruleNamesField.get(interpreterData), String.class);
         List<String> channels = castList(channelsField.get(interpreterData), String.class);
         List<String> modes = castList(modesField.get(interpreterData), String.class);
 
-        char[] atnChars = ATNSerializer.getSerializedAsChars(atn);
-        Assert.assertTrue(atnChars.length > 0);
-        Assert.assertNotNull(vocabulary);
-        Assert.assertEquals(11, ruleNames.size());
-        Assert.assertEquals(2, channels.size());
-        Assert.assertEquals(1, modes.size());
-    }
+		Assert.assertEquals(6, vocabulary.getMaxTokenType());
+		Assert.assertArrayEquals(new String[]{"s","expr"}, ruleNames.toArray());
+		Assert.assertArrayEquals(new String[]{"", "", "'*'", "'/'", "'+'", "'-'", ""}, literalNames);
+		Assert.assertArrayEquals(new String[]{"", "INT", "MUL", "DIV", "ADD", "SUB", "WS"}, symbolicNames);
+		Assert.assertNull(channels);
+		Assert.assertNull(modes);
 
-    @Test
-    public void testParseFileError() {
-        final ClassLoader loader = Thread.currentThread().getContextClassLoader();
-        final URL stuff = loader.getResource("org/antlr/v4/test/runtime/InterpDataReaderTest2.interp");
-        Assert.assertNotNull(stuff);
-
-        try {
-            InterpreterDataReader.InterpreterData interpreterData = InterpreterDataReader.parseFile(stuff.getPath());
-        } catch (Exception e) {
-            Assert.assertEquals(e.getClass(), RuntimeException.class);
-            Assert.assertEquals(e.getMessage(), "Unexpected data entry");
-        }
+        char[] atnChars = ATNSerializer.getSerializedAsChars(atn);
+		Assert.assertEquals(ATNDeserializer.SERIALIZED_VERSION, atnChars[0]);
     }
 
     private <T> List<T> castList(Object obj, Class<T> clazz) {

runtime/Java/src/org/antlr/v4/runtime/VocabularyImpl.java

@@ -173,4 +173,18 @@ public String getDisplayName(int tokenType) {
 
 		return Integer.toString(tokenType);
 	}
+
+	// Because this is an actual implementation object, we can provide access methods for vocabulary symbols
+
+	public String[] getLiteralNames() {
+		return literalNames;
+	}
+
+	public String[] getSymbolicNames() {
+		return symbolicNames;
+	}
+
+	public String[] getDisplayNames() {
+		return displayNames;
+	}
 }

tool/src/org/antlr/v4/Tool.java

@@ -390,7 +390,15 @@ public void processNonCombinedGrammar(Grammar g, boolean gencode) {
 
 		if ( generate_ATN_dot ) generateATNs(g);
 
-		if (gencode && g.tool.getNumErrors()==0 ) generateInterpreterData(g);
+		if (gencode && g.tool.getNumErrors()==0 ) {
+			String interpFile = generateInterpreterData(g);
+			try (Writer fw = getOutputFileWriter(g, g.name + ".interp")) {
+				fw.write(interpFile);
+			}
+			catch (IOException ioe) {
+				errMgr.toolError(ErrorType.CANNOT_WRITE_FILE, ioe);
+			}
+		}
 
 		// PERFORM GRAMMAR ANALYSIS ON ATN: BUILD DECISION DFAs
 		AnalysisPipeline anal = new AnalysisPipeline(g);
@@ -690,7 +698,7 @@ public void generateATNs(Grammar g) {
 		}
 	}
 
-	private void generateInterpreterData(Grammar g) {
+	public static String generateInterpreterData(Grammar g) {
 		StringBuilder content = new StringBuilder();
 
 		content.append("token literal names:\n");
@@ -738,18 +746,7 @@ private void generateInterpreterData(Grammar g) {
 		content.append("atn:\n");
 		content.append(serializedATN.toString());
 
-		try {
-			Writer fw = getOutputFileWriter(g, g.name + ".interp");
-			try {
-				fw.write(content.toString());
-			}
-			finally {
-				fw.close();
-			}
-		}
-		catch (IOException ioe) {
-			errMgr.toolError(ErrorType.CANNOT_WRITE_FILE, ioe);
-		}
+		return content.toString();
 	}
 
 	/** This method is used by all code generators to create new output