com.celements.sajson.Parser.java Source code

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Here is the source code for com.celements.sajson.Parser.java

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/*
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.
 *
 * 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 com.celements.sajson;

import java.io.IOException;
import java.io.StringReader;
import java.util.Stack;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.codehaus.jackson.JsonFactory;
import org.codehaus.jackson.JsonParseException;
import org.codehaus.jackson.JsonParser;
import org.codehaus.jackson.JsonToken;

public class Parser {

    private ILexicalParser<? extends IGenericLiteral> lexParser;
    private JsonParser parser;
    private static JsonFactory factory = new JsonFactory();
    private Stack<ECommand> workerStack = new Stack<ECommand>();
    private String lastKey = "";
    private String lastValue = "";

    private static Log LOGGER = LogFactory.getFactory().getInstance(Parser.class);

    public static <T extends IGenericLiteral> Parser createLexicalParser(T initLiteral,
            IEventHandler<T> eventHandler) {
        return new Parser(initLiteral, new LexicalParser<T>(initLiteral, eventHandler));
    }

    <T extends IGenericLiteral> Parser(T initLiteral, ILexicalParser<T> lexParser) {
        this.lexParser = lexParser;
    }

    public void parse(String jsonExpression) throws JsonParseException, IOException {
        StringReader jsonReader = new StringReader(jsonExpression);
        try {
            parser = factory.createJsonParser(jsonReader);
            workerStack.clear();
            JsonToken nextToken = parser.nextToken();
            lexParser.initEvent();
            while (parser.hasCurrentToken()) {
                switch (nextToken) {
                case VALUE_TRUE:
                case VALUE_FALSE:
                    boolean boolValue = parser.getBooleanValue();
                    lastValue = Boolean.toString(boolValue);
                    lexParser.booleanEvent(boolValue);
                    impliciteCloseProperty();
                    break;
                case VALUE_STRING:
                    lastValue = parser.getText();
                    lexParser.stringEvent(lastValue);
                    impliciteCloseProperty();
                    break;
                case START_ARRAY:
                    checkIllegalStackState(ECommand.DICTIONARY_COMMAND, nextToken);
                    workerStack.push(ECommand.ARRAY_COMMAND);
                    lexParser.openArrayEvent();
                    break;
                case END_ARRAY:
                    checkStackState(ECommand.ARRAY_COMMAND);
                    lexParser.closeArrayEvent();
                    workerStack.pop();
                    impliciteCloseProperty();
                    break;
                case START_OBJECT:
                    checkIllegalStackState(ECommand.DICTIONARY_COMMAND, nextToken);
                    workerStack.push(ECommand.DICTIONARY_COMMAND);
                    lexParser.openDictionaryEvent();
                    break;
                case END_OBJECT:
                    checkStackState(ECommand.DICTIONARY_COMMAND);
                    lexParser.closeDictionaryEvent();
                    workerStack.pop();
                    impliciteCloseProperty();
                    break;
                case FIELD_NAME:
                    checkStackState(ECommand.DICTIONARY_COMMAND);
                    workerStack.push(ECommand.PROPERTY_COMMAND);
                    lastKey = parser.getText();
                    lexParser.openPropertyEvent(lastKey);
                    break;
                default:
                    LOGGER.warn("unkown token [" + nextToken + "] lastKey [" + lastKey + "] lastValue [" + lastValue
                            + "].");
                    break;
                }
                nextToken = parser.nextToken();
            }
            lexParser.finishEvent();
        } finally {
            jsonReader.close();
        }
    }

    private void checkIllegalStackState(ECommand illegalCommand, JsonToken token) {
        if (!workerStack.isEmpty() && workerStack.peek() == illegalCommand) {
            throw new IllegalStateException("Found illegal " + token + " inside " + illegalCommand);
        }
    }

    private void checkStackState(ECommand expectedCommand) {
        if (workerStack.isEmpty() || workerStack.peek() != expectedCommand) {
            throw new IllegalStateException("Expecting " + expectedCommand + " but found " + workerStack.peek()
                    + " Last key [" + lastKey + "] last value [" + lastValue + "]");
        }
    }

    private void impliciteCloseProperty() {
        if (!workerStack.isEmpty() && workerStack.peek() == ECommand.PROPERTY_COMMAND) {
            lexParser.closePropertyEvent();
            workerStack.pop();
        }
    }

}