core/src/main/java/org/apache/logging/log4j/core/impl/ThrowableFormatOptions.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.logging.log4j.core.impl;

import org.apache.logging.log4j.core.helpers.Constants;

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

/**
 * Contains options which control how a {@code throwable} pattern is formatted.
 */
public final class ThrowableFormatOptions {

    /**
     * Default instance of {@code ThrowableFormatOptions}.
     */
    protected static final ThrowableFormatOptions DEFAULT = new ThrowableFormatOptions();

    /**
     * Format the whole stack trace.
     */
    private static final String FULL = "full";

    /**
     * Do not format the exception.
     */
    private static final String NONE = "none";

    /**
     * Format only the first line of the throwable.
     */
    private static final String SHORT = "short";

    /**
     * The number of lines to write.
     */
    private final int lines;

    /**
     * The stack trace separator.
     */
    private final String separator;

    /**
     * The list of packages to filter.
     */
    private final List<String> packages;

    /**
     * Construct the options for printing stack trace.
     * @param lines The number of lines.
     * @param separator The stack trace separator.
     * @param packages The packages to filter.
     */
    protected ThrowableFormatOptions(final Integer lines, final String separator, final List<String> packages) {
        this.lines = lines == null ? Integer.MAX_VALUE : lines;
        this.separator = separator == null ? Constants.LINE_SEP : separator;
        this.packages = packages;
    }

    /**
     * Construct the options for printing stack trace.
     * @param packages The packages to filter.
     */
    protected ThrowableFormatOptions(final List<String> packages) {
        this(null, null, packages);
    }

    /**
     * Construct the options for printing stack trace.
     */
    protected ThrowableFormatOptions() {
        this(null, null, null);
    }

    /**
     * Returns the number of lines to write.
     * @return The number of lines to write.
     */
    public int getLines() {
        return this.lines;
    }

    /**
     * Returns the stack trace separator.
     * @return The stack trace separator.
     */
    public String getSeparator() {
        return this.separator;
    }

    /**
     * Returns the list of packages to filter.
     * @return The list of packages to filter.
     */
    public List<String> getPackages() {
        return this.packages;
    }

    /**
     * Determines if all lines should be printed.
     * @return true for all lines, false otherwise.
     */
    public boolean allLines() {
        return this.lines == Integer.MAX_VALUE;
    }

    /**
     * Determines if any lines should be printed.
     * @return true for any lines, false otherwise.
     */
    public boolean anyLines() {
        return this.lines > 0;
    }

    /**
     * Returns the minimum between the lines and the max lines.
     * @param maxLines The maximum number of lines.
     * @return The number of lines to print.
     */
    public int minLines(final int maxLines) {
        return this.lines > maxLines ? maxLines : this.lines;
    }

    /**
     * Determines if there are any packages to filter.
     * @return true if there are packages, false otherwise.
     */
    public boolean hasPackages() {
        return this.packages != null && !this.packages.isEmpty();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public String toString() {
        StringBuilder s = new StringBuilder();
        s.append("{").append(allLines() ? FULL : this.lines == 2 ? SHORT : anyLines() ? String.valueOf(this.lines) : NONE).append("}");
        s.append("{separator(").append(this.separator).append(")}");
        if (hasPackages()) {
            s.append("{filters(");
            for (String p : this.packages) {
                s.append(p).append(",");
            }
            s.deleteCharAt(s.length() - 1);
            s.append(")}");
        }
        return s.toString();
    }

    /**
     * Create a new instance based on the array of options.
     * @param options The array of options.
     */
    public static ThrowableFormatOptions newInstance(String[] options) {
        if (options == null || options.length == 0) {
            return DEFAULT;
        } else {
            // NOTE: The following code is present for backward compatibility
            // and was copied from Extended/RootThrowablePatternConverter.
            // This supports a single option with the format:
            //     %xEx{["none"|"short"|"full"|depth],[filters(packages)}
            // However, the convention for multiple options should be:
            //     %xEx{["none"|"short"|"full"|depth]}[{filters(packages)}]
            if (options.length == 1 && options[0] != null && options[0].length() > 0) {
                final String[] opts = options[0].split(",", 2);
                final String first = opts[0].trim();
                final Scanner scanner = new Scanner(first);
                if (opts.length > 1 && (first.equalsIgnoreCase(FULL) || first.equalsIgnoreCase(SHORT) || first.equalsIgnoreCase(NONE) || scanner.hasNextInt())) {
                    options = new String[]{first, opts[1].trim()};
                }
            }

            int lines = DEFAULT.lines;
            String separator = DEFAULT.separator;
            List<String> packages = DEFAULT.packages;
            for (int i = 0; i < options.length; i++) {
                if (options[i] != null) {
                    final String option = options[i].trim();
                    if (option.length() == 0) {
                        // continue;
                    } else if (option.startsWith("separator(") && option.endsWith(")")) {
                        separator = option.substring("separator(".length(), option.length() - 1);
                    } else if (option.startsWith("filters(") && option.endsWith(")")) {
                        final String filterStr = option.substring("filters(".length(), option.length() - 1);
                        if (filterStr.length() > 0) {
                            final String[] array = filterStr.split(",");
                            if (array.length > 0) {
                                packages = new ArrayList<String>(array.length);
                                for (String token : array) {
                                    token = token.trim();
                                    if (token.length() > 0) {
                                        packages.add(token);
                                    }
                                }
                            }
                        }
                    } else if (option.equalsIgnoreCase(NONE)) {
                        lines = 0;
                    } else if (option.equalsIgnoreCase(SHORT)) {
                        lines = 2;
                    } else if (!option.equalsIgnoreCase(FULL)) {
                        lines = Integer.parseInt(option);
                    }
                }
            }
            return new ThrowableFormatOptions(lines, separator, packages);
        }
    }
}