org.swisspush.gateleen.player.log.ReaderRequestLog Maven / Gradle / Ivy

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package org.swisspush.gateleen.player.log;

import org.swisspush.gateleen.player.exchange.Exchange;
import org.json.JSONException;
import org.json.JSONObject;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.Reader;
import java.util.Iterator;
import java.util.NoSuchElementException;

/**
 * Request log providing exchanges from a serialized JSON stream, as the one generated by the logging filter.
 *
 * @author https://github.com/lbovet [Laurent Bovet]
 */
public abstract class ReaderRequestLog extends RequestLog {

    private String urlPrefix;

    class ExchangeIterator implements Iterator {
        private BufferedReader bufferedReader;
        private Exchange readAhead;

        ExchangeIterator() {
            bufferedReader = new BufferedReader(getReader());
        }

        @Override
        public boolean hasNext() {
            if(readAhead != null) {
                return true;
            }
            try {
                readAhead = next();
                return true;
            } catch (NoSuchElementException e) {
                return false;
            }
        }

        @Override
        public Exchange next() {
            if (readAhead != null) {
                Exchange result = readAhead;
                readAhead = null;
                return result;
            } else {
                try {
                    String line = "";
                    while(line != null && ( line.trim().equals("") || line.trim().startsWith("#"))) {
                        line = bufferedReader.readLine();
                    }
                    if (line == null) {
                        throw new NoSuchElementException();
                    }
                    try {
                        return new Exchange(urlPrefix, new JSONObject(line));
                    } catch (JSONException e) {
                        throw new RuntimeException(e);
                    }
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
        }

        @Override
        public void remove() {
            throw new UnsupportedOperationException();
        }
    }

    protected abstract Reader getReader();

    public ReaderRequestLog(String urlPrefix) {
        this.urlPrefix = urlPrefix;
    }

    @Override
    public Iterator iterator() {
        return new ExchangeIterator();
    }
}