Add Vocabulary.getMaxTokenType()

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

@@ -37,6 +37,14 @@ package org.antlr.v4.runtime;
  * @author Sam Harwell
  */
 public interface Vocabulary {
+
+	/**
+	 * Returns the highest token type value. It can be used to iterate from
+	 * zero to that number, thus querying all stored entries.
+	 * @return the highest token type value
+	 */
+	int getMaxTokenType();
+
 	/**
 	 * Gets the string literal associated with a token type. The string returned
 	 * by this method, when not {@code null}, can be used unaltered in a parser
@@ -85,7 +93,7 @@ public interface Vocabulary {
 	 *
 	 * <ul>
 	 *  <li>Tokens created by lexer rules.</li>
-	 *  <li>Tokens defined in a {@code tokens{}} block in a lexer or parser
+	 *  <li>Tokens defined in a <code>tokens{}</code> block in a lexer or parser
 	 *  grammar.</li>
 	 *  <li>The implicitly defined {@code EOF} token, which has the token type
 	 *  {@link Token#EOF}.</li>

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

@@ -57,6 +57,8 @@ public class VocabularyImpl implements Vocabulary {
 
 	private final String[] displayNames;
 
+	private final int maxTokenType;
+
 	/**
 	 * Constructs a new instance of {@link VocabularyImpl} from the specified
 	 * literal and symbolic token names.
@@ -94,6 +96,8 @@ public class VocabularyImpl implements Vocabulary {
 		this.literalNames = literalNames != null ? literalNames : EMPTY_NAMES;
 		this.symbolicNames = symbolicNames != null ? symbolicNames : EMPTY_NAMES;
 		this.displayNames = displayNames != null ? displayNames : EMPTY_NAMES;
+		this.maxTokenType = Math.max(this.displayNames.length,
+			Math.max(this.literalNames.length, this.symbolicNames.length));
 	}
 
 	/**
@@ -143,6 +147,11 @@ public class VocabularyImpl implements Vocabulary {
 		return new VocabularyImpl(literalNames, symbolicNames, tokenNames);
 	}
 
+	@Override
+	public int getMaxTokenType() {
+		return maxTokenType;
+	}
+
 	@Override
 	public String getLiteralName(int tokenType) {
 		if (tokenType >= 0 && tokenType < literalNames.length) {