Java example source code file (ErrorManager.java)

This example Java source code file (ErrorManager.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

errormanager, parserexception, printwriter, source, string, stringbuilder

The ErrorManager.java Java example source code

/*
 * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package jdk.nashorn.internal.runtime;

import static jdk.nashorn.internal.runtime.ECMAErrors.rangeError;

import java.io.PrintWriter;
import jdk.nashorn.internal.parser.Token;

/**
 * Handles JavaScript error reporting.
 */
public class ErrorManager {
    // TODO - collect and sort/collapse error messages.
    // TODO - property based error messages.
    /** Reporting writer. */
    private final PrintWriter writer;

    /** Error count. */
    private int errors;

    /** Warning count */
    private int warnings;

    /** Limit of the number of messages. */
    private int limit;

    /** Treat warnings as errors. */
    private boolean warningsAsErrors;

    /**
     * Constructor
     */
    public ErrorManager() {
        this(new PrintWriter(System.err, true)); //bootstrapping, context may not be initialized
    }

    /**
     * Constructor.
     * @param writer I/O writer to report on.
     */
    public ErrorManager(final PrintWriter writer) {
        this.writer           = writer;
        this.limit            = 100;
        this.warningsAsErrors = false;
    }

    /**
     * Check to see if number of errors exceed limit.
     */
    private void checkLimit() {
        int count = errors;

        if (warningsAsErrors) {
            count += warnings;
        }

        if (limit != 0 && count > limit) {
            throw rangeError("too.many.errors", Integer.toString(limit));
        }
    }

    /**
     * Format an error message to include source and line information.
     * @param message Error message string.
     * @param source  Source file information.
     * @param line    Source line number.
     * @param column  Source column number.
     * @param token   Offending token descriptor.
     * @return formatted string
     */
    public static String format(final String message, final Source source, final int line, final int column, final long token) {
        final String        eoln     = System.lineSeparator();
        final int           position = Token.descPosition(token);
        final StringBuilder sb       = new StringBuilder();

        // Source description and message.
        sb.append(source.getName()).
            append(':').
            append(line).
            append(':').
            append(column).
            append(' ').
            append(message).
            append(eoln);

        // Source content.
        final String sourceLine = source.getSourceLine(position);
        sb.append(sourceLine).append(eoln);

        // Pointer to column.
        for (int i = 0; i < column; i++) {
            if (sourceLine.charAt(i) == '\t') {
                sb.append('\t');
            } else {
                sb.append(' ');
            }
        }

        sb.append('^');
        // Use will append eoln.
        // buffer.append(eoln);

        return sb.toString();
    }

    /**
     * Report an error using information provided by the ParserException
     *
     * @param e ParserException object
     */

    public void error(final ParserException e) {
        error(e.getMessage());
    }

    /**
     * Report an error message provided
     *
     * @param message Error message string.
     */
    public void error(final String message) {
        writer.println(message);
        writer.flush();
        errors++;
        checkLimit();
    }

    /**
     * Report a warning using information provided by the ParserException
     *
     * @param e ParserException object
     */
    public void warning(final ParserException e) {
        warning(e.getMessage());
    }

    /**
     * Report a warning message provided
     *
     * @param message Error message string.
     */
    public void warning(final String message) {
        writer.println(message);
        writer.flush();
        warnings++;
        checkLimit();
    }

    /**
     * Test to see if errors have occurred.
     * @return True if errors.
     */
    public boolean hasErrors() {
        return errors != 0;
    }

    /**
     * Get the message limit
     * @return max number of messages
     */
    public int getLimit() {
        return limit;
    }

    /**
     * Set the message limit
     * @param limit max number of messages
     */
    public void setLimit(final int limit) {
        this.limit = limit;
    }

    /**
     * Check whether warnings should be treated like errors
     * @return true if warnings should be treated like errors
     */
    public boolean isWarningsAsErrors() {
        return warningsAsErrors;
    }

    /**
     * Set warnings to be treated as errors
     * @param warningsAsErrors true if warnings should be treated as errors, false otherwise
     */
    public void setWarningsAsErrors(final boolean warningsAsErrors) {
        this.warningsAsErrors = warningsAsErrors;
    }

    /**
     * Get the number of errors
     * @return number of errors
     */
    public int getNumberOfErrors() {
        return errors;
    }

    /**
     * Get number of warnings
     * @return number of warnings
     */
    public int getNumberOfWarnings() {
        return warnings;
    }

    /**
     * Clear warnings and error count.
     */
    void reset() {
        warnings = 0;
        errors = 0;
    }
}