SimpleFormatter.java

/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2011, Red Hat, Inc., and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

package org.gatein.common.xml.stax.writer.formatting;

import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamWriter;


/**
 * @author <a href="mailto:nscavell@redhat.com">Nick Scavelli</a>
 * @version $Revision$
 */
public class SimpleFormatter implements XmlStreamingFormatter {

    public static final int DEFAULT_INDENT_SIZE = 3;
    public static final char DEFAULT_INDENT_CHAR = ' ';
    public static final String DEFAULT_NEWLINE;

    static {
        String newline = null;
        try {
            newline = System.getProperty("line.separator");
        } catch (Throwable ignored) {
        }
        if (newline == null)
            newline = "\n";

        DEFAULT_NEWLINE = newline;
    }

    private String indentSequence;
    private String newline;
    private int depth = 0;

    private int previousEvent;

    public SimpleFormatter() {
        this(DEFAULT_INDENT_CHAR, DEFAULT_INDENT_SIZE, DEFAULT_NEWLINE);
    }

    public SimpleFormatter(char indentCharacter, int indentSize, String newline) {
        if (newline == null)
            throw new IllegalArgumentException("newline cannot be null");
        this.newline = newline;

        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < indentSize; i++) {
            sb.append(indentCharacter);
        }
        indentSequence = sb.toString();
    }

    public void before(XMLStreamWriter writer, int event) throws XMLStreamException {
        switch (event) {
            case START_ELEMENT:
                depth++;
                nl(writer);
                indent(writer);
                break;
            case END_ELEMENT:
                if (previousEvent == END_ELEMENT) {
                    nl(writer);
                    indent(writer);
                }
                depth--;
        }
    }

    public void after(XMLStreamWriter writer, int event) throws XMLStreamException {
        previousEvent = event;
    }

    private void nl(XMLStreamWriter writer) throws XMLStreamException {
        writer.writeCharacters(newline);
    }

    private void indent(XMLStreamWriter writer) throws XMLStreamException {
        for (int i = 0; i < depth - 1; i++) {
            writer.writeCharacters(indentSequence);
        }
    }
}