logic.Extractor.java Source code

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Here is the source code for logic.Extractor.java

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/**
 * Copyright (c) 2015 Sven Meyer, Leotas Software Solutions, Germany
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */
package logic;

import generated.JavaLexer;
import generated.JavaParser;

import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Map;

import org.antlr.v4.runtime.ANTLRInputStream;
import org.antlr.v4.runtime.CommonTokenStream;
import org.antlr.v4.runtime.tree.ParseTree;
import org.antlr.v4.runtime.tree.ParseTreeWalker;

/**
 * Reads one file and extracts metrics using ANTLR.
 * 
 * @author Sven Meyer
 * @version 1.0.0
 * @since 1.0.0
 * 
 * @see https://theantlrguy.atlassian.net/wiki/display/ANTLR4/Parse+Tree+Listeners
 */
public class Extractor {

    /**
     * Returns a map, containing clazzName and count of methods, for the given
     * file.
     * 
     * Based upon the <a href=
     * "https://theantlrguy.atlassian.net/wiki/display/ANTLR4/Parse+Tree+Listeners">ANTLR-Tutorial</a>
     * 
     * @param importFile
     *            The file to import.
     * @return A map containing the clazzName and count of methods, extracted
     *         from {@code importFile}.
     * @throws Exception
     *             IO- and ANTLR-Exceptions, not catched for simplicity.
     */
    public Map<String, Integer> extract(File importFile) throws Exception {

        /** Prepare input for ANTLR. */
        InputStream is = new FileInputStream(importFile.getAbsolutePath());
        ANTLRInputStream input = new ANTLRInputStream(is);
        JavaLexer lexer = new JavaLexer(input);
        CommonTokenStream tokens = new CommonTokenStream(lexer);
        JavaParser parser = new JavaParser(tokens);

        /** Parse. */
        ParseTree tree = parser.compilationUnit();

        /** Create standard walker. */
        ParseTreeWalker walker = new ParseTreeWalker();

        /** Initiate walk of tree with listener. */
        Listener listener = new Listener(parser);
        walker.walk(listener, tree);

        /** Save the results. */
        Map<String, Integer> result = new HashMap<>();
        result.put(listener.getClazzName(), listener.getMethodCount());

        return result;
    }
}