/*

 * Copyright (c) 2016, 2018, 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

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 */

package jdk.jfr.internal.jfc;

import java.util.LinkedHashMap;

import java.util.Map;

import jdk.internal.org.xml.sax.Attributes;

import jdk.internal.org.xml.sax.SAXException;

import jdk.internal.org.xml.sax.helpers.DefaultHandler;

final class JFCParserHandler extends DefaultHandler {

    private static final String ELEMENT_CONFIGURATION = "configuration";

    private static final String ELEMENT_EVENT_TYPE = "event";

    private static final String ELEMENT_SETTING = "setting";

    private static final String ATTRIBUTE_NAME = "name";

    private static final String ATTRIBUTE_LABEL = "label";

    private static final String ATTRIBUTE_DESCRIPTION = "description";

    private static final String ATTRIBUTE_PROVIDER = "provider";

    private static final String ATTRIBUTE_VERSION = "version";

    final Map<String, String> settings = new LinkedHashMap<String, String>();

    private String currentEventPath;

    private String currentSettingsName;

    private StringBuilder currentCharacters;

    String label;

    String provider;

    String description;

    @Override

    public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {

        switch (qName.toLowerCase()) {

        case ELEMENT_CONFIGURATION:

            String version = attributes.getValue(ATTRIBUTE_VERSION);

            if (version == null || !version.startsWith("2.")) {

               throw new SAXException("This version of Flight Recorder can only read JFC file format version 2.x");

            }

            label = attributes.getValue(ATTRIBUTE_LABEL);

            description = getOptional(attributes, ATTRIBUTE_DESCRIPTION, "");

            provider = getOptional(attributes, ATTRIBUTE_PROVIDER, "");

            break;

        case ELEMENT_EVENT_TYPE:

            currentEventPath = attributes.getValue(ATTRIBUTE_NAME);

            break;

        case ELEMENT_SETTING:

            currentSettingsName = attributes.getValue(ATTRIBUTE_NAME);

            break;

        }

        currentCharacters = null;

    }

    private String getOptional(Attributes attributes, String name, String defaultValue) {

        String value = attributes.getValue(name);

        return value == null ? defaultValue : value;

    }

    @Override

    public void characters(char[] ch, int start, int length) throws SAXException {

        if (currentCharacters == null) {

            currentCharacters = new StringBuilder(length);

        }

        currentCharacters.append(ch, start, length);

    }

    @Override

    public void endElement(String uri, String localName, String qName) {

        switch (qName.toLowerCase()) {

        case ELEMENT_CONFIGURATION:

            break;

        case ELEMENT_EVENT_TYPE:

            currentEventPath = null;

            break;

        case ELEMENT_SETTING:

            String settingsValue = currentCharacters == null ? "" : currentCharacters.toString();

            settings.put(currentEventPath + "#" + currentSettingsName, "" + settingsValue);

            currentSettingsName = null;

            break;

        }

    }

    public Map<String, String> getSettings() {

        return settings;

    }

}