com.github.javaparser.utils.Log Maven / Gradle / Ivy

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/*
 * Copyright (C) 2007-2010 Júlio Vilmar Gesser.
 * Copyright (C) 2011, 2013-2021 The JavaParser Team.
 *
 * This file is part of JavaParser.
 *
 * JavaParser can be used either under the terms of
 * a) the GNU Lesser General Public License as published by
 *     the Free Software Foundation, either version 3 of the License, or
 *     (at your option) any later version.
 * b) the terms of the Apache License
 *
 * You should have received a copy of both licenses in LICENCE.LGPL and
 * LICENCE.APACHE. Please refer to those files for details.
 *
 * JavaParser is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 */

package com.github.javaparser.utils;

import java.io.IOException;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.util.function.Supplier;

import static com.github.javaparser.utils.CodeGenerationUtils.f;

/**
 * To avoid dependencies on logging frameworks, we have invented yet another logging framework :-)
 * 
 * See a blog about this
 */
public class Log {
    /**
     * This adapter logs to standard out and standard error.
     */
    public static class StandardOutStandardErrorAdapter implements Adapter {
        @Override
        public void info(Supplier messageSupplier) {
            System.out.println(messageSupplier.get());
        }

        @Override
        public void trace(Supplier messageSupplier) {
            System.out.println(messageSupplier.get());
        }

        @Override
        public void error(Supplier throwableSupplier, Supplier messageSupplier) {
            Throwable throwable = throwableSupplier.get();
            String message = messageSupplier.get();
            if (message == null) {
                System.err.println(throwable.getMessage());
                printStackTrace(throwable);
            } else if (throwable == null) {
                System.err.println(message);
            } else {
                System.err.println(message + ":" + throwable.getMessage());
                printStackTrace(throwable);
            }
        }

        private void printStackTrace(Throwable throwable) {
            try (StringWriter sw = new StringWriter(); PrintWriter pw = new PrintWriter(sw)) {
                throwable.printStackTrace(pw);
                trace(sw::toString);
            } catch (IOException e) {
                throw new AssertionError("Error in logging library");
            }
        }
    }

    /**
     * This adapter logs nothing.
     */
    public static class SilentAdapter implements Adapter {
        @Override
        public void info(Supplier messageSupplier) {
        }

        @Override
        public void trace(Supplier messageSupplier) {
        }

        @Override
        public void error(Supplier throwableSupplier, Supplier messageSupplier) {
        }
    }

    public interface Adapter {

        void info(Supplier message);

        void trace(Supplier message);

        /**
         * Both can supply a null.
         */
        void error(Supplier throwableSupplier, Supplier messageSupplier);
    }

    private static Adapter CURRENT_ADAPTER = new SilentAdapter();

    /**
     * Change how logging is handled. You can set your own implementation that forwards to your logging library.
     */
    public static void setAdapter(Adapter adapter) {
        CURRENT_ADAPTER = adapter;
    }

    /**
     * For logging information that may help solving a problem.
     */
    @SafeVarargs
    public static void trace(String format, Supplier