ANTLR is a powerful parser generator for multiple programming languages including Java.

ANTLR contains 2 major modules:

• Runtime - For building and executing parsers/lexers generated in Java.
• Tool (The Parser Generator) - For generating parsers/lexers Java class.

ANTLR Runtime Source Code files are provided in the distribution packge (antlr4-4.10.1.zip). You can download them at ANTLR Website.

You can also browse the source code below:

⏎ org/antlr/v4/runtime/misc/MultiMap.java

/*
 * Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
 * Use of this file is governed by the BSD 3-clause license that
 * can be found in the LICENSE.txt file in the project root.
 */

package org.antlr.v4.runtime.misc;

import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;

public class MultiMap<K, V> extends LinkedHashMap<K, List<V>> {
	public void map(K key, V value) {
		List<V> elementsForKey = get(key);
		if ( elementsForKey==null ) {
			elementsForKey = new ArrayList<V>();
			super.put(key, elementsForKey);
		}
		elementsForKey.add(value);
	}

	public List<Pair<K,V>> getPairs() {
		List<Pair<K,V>> pairs = new ArrayList<Pair<K,V>>();
		for (K key : keySet()) {
			for (V value : get(key)) {
				pairs.add(new Pair<K,V>(key, value));
			}
		}
		return pairs;
	}
}

⏎ org/antlr/v4/runtime/misc/MultiMap.java

Or download all of them as a single archive file:

File name: antlr-runtime-4.10.1-sources.jar
File size: 308953 bytes
Release date: 2022-04-15
Download 

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⇐ What Is ANTLR Parser Generator

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