AbstractJsonTokenizer.java

/*
 * MIT License
 *
 * Copyright (c) 2017 Konrad Kleczkowski
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

package com.github.repaj.libjson.io;

/**
 * Template class to implement JSON tokenizer.
 *
 * @author Konrad Kleczkowski
 */
@SuppressWarnings("WeakerAccess")
public abstract class AbstractJsonTokenizer implements JsonTokenizer {
    private JsonToken current;

    /**
     * If token type is the same as pending token, returns that token
     * and removes it from input.
     *
     * @param tokenType expected type of pending token
     * @return pending token it token type is the same as specified.
     * @throws JsonParseException   if expected and actual token types are mismatched
     * @throws JsonIOException      if I/O error occurs
     * @throws NullPointerException if <code>tokenType</code> is null
     */
    @Override
    public final String next(JsonTokenType tokenType) throws JsonParseException {
        if (!hasNext(tokenType)) {
            throw new JsonParseException("Expected " + tokenType + " token"
                    + (getLine() != -1 ? " at line " + getLine() : ""));
        }
        String match = current.getMatch();
        current = null;
        return match;
    }

    /**
     * Returns <code>true</code> if pending token is of specified type.
     *
     * @param tokenType expected type of pending token
     * @return <code>true</code> if pending token is of specified type, otherwise <code>false</code>
     * @throws JsonIOException      if I/O error occurs
     * @throws NullPointerException if <code>tokenType</code> is null
     */
    @Override
    public final boolean hasNext(JsonTokenType tokenType) {
        if (current == null) {
            current = next();
        }
        return tokenType == current.getTokenType();
    }

    /**
     * Removes token from a queue.
     *
     * @return token removed from a queue (must be non-null)
     * @throws JsonIOException    if I/O error occurs
     * @throws JsonParseException if end-of-file occurs
     */
    protected abstract JsonToken next();
}