net.ageto.gyrex.logback.extensions.csv.CsvPatternLayout.java Source code

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Here is the source code for net.ageto.gyrex.logback.extensions.csv.CsvPatternLayout.java

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/**
 * Copyright (c) 2012 Gunnar Wagenknecht and others.
 * All rights reserved. 
 * 
 * This program and the accompanying materials are made available under the terms of the 
 * Eclipse Public License v1.0 which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *     Gunnar Wagenknecht - initial API and implementation
 */
package net.ageto.gyrex.logback.extensions.csv;

import java.lang.reflect.Field;

import org.apache.commons.csv.CSVFormat;
import org.apache.commons.csv.CSVFormat.CSVFormatBuilder;
import org.apache.commons.csv.Quote;

import ch.qos.logback.classic.PatternLayout;
import ch.qos.logback.classic.spi.ILoggingEvent;
import ch.qos.logback.core.pattern.Converter;

/**
 * Specialization of {@link PatternLayout} what ensures values are properly
 * escaped for CSV output.
 * <p>
 * The pattern is split into fields using {@link #getSeparator() a separator}.
 * Each field value
 * </p>
 */
public class CsvPatternLayout extends PatternLayout {

    String separator;
    String encapsulator;
    String newline;
    String escape;

    Converter<ILoggingEvent> head;

    public String getEncapsulator() {
        return encapsulator;
    }

    public String getSeparator() {
        return separator;
    }

    public void setEncapsulator(final String encapsulator) {
        this.encapsulator = encapsulator;
    }

    public void setSeparator(final String separator) {
        this.separator = separator;
    }

    @SuppressWarnings("unchecked")
    @Override
    public void start() {
        final CSVFormatBuilder formatBuilder = CSVFormat.newBuilder();

        if (separator != null) {
            if (separator.length() != 1) {
                addError("Invalid separator:'" + separator + "'");
                return;
            }
            formatBuilder.withDelimiter(separator.charAt(0));
        }

        if (newline != null) {
            if (newline.length() == 0) {
                addError("Invalid newline:'" + newline + "'");
                return;
            }
            formatBuilder.withRecordSeparator(newline);
        }

        if (encapsulator != null) {
            if (encapsulator.length() != 1) {
                addError("Invalid encapsulator:'" + encapsulator + "'");
                return;
            }
            formatBuilder.withQuoteChar(encapsulator.charAt(0));
            formatBuilder.withQuotePolicy(Quote.MINIMAL);
        }

        if (escape != null) {
            if (escape.length() != 1) {
                addError("Invalid escape:'" + escape + "'");
                return;
            }
            formatBuilder.withEscape(escape.charAt(0));
            if (encapsulator == null) {
                formatBuilder.withQuotePolicy(Quote.NONE);
            }
        }

        super.start();

        try {
            final Field field = getClass().getDeclaredField("head");
            if (!field.isAccessible()) {
                field.setAccessible(true);
            }
            head = (Converter<ILoggingEvent>) field.get(this);
        } catch (final Exception e) {
            addError("Unable to initialize internal variable", e);
            stop();
            return;
        }

    }

    @Override
    protected String writeLoopOnConverters(final ILoggingEvent event) {
        final StringBuilder buf = new StringBuilder(128);
        Converter<ILoggingEvent> c = head;
        while (c != null) {
            c.write(buf, event);
            c = c.getNext();
        }
        return buf.toString();
    }
}