BencodeEncoder v1.0.0

package me.rabrg.torrent.bencode;

import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

/**
 *
 * @author Ryan Greene
 *
 */
public final class BencodeEncoder {

    @SuppressWarnings("unchecked")
    public String encode(final Object object) {
        if (object instanceof String) {
            return encodeString((String) object);
        } else if (object instanceof Integer) {
            return encodeInteger((int) object);
        } else if (object instanceof List) {
            return encodeList((List<Object>) object);
        } else if (object instanceof Map) {
            return encodeMap((Map<String, Object>) object);
        }
        throw new IllegalStateException("the object " + object + " is not a type that can be encoded in bencode");
    }

    public String encodeString(final String string) {
        return new StringBuffer().append(string.length()).append(':').append(string).toString();
    }

    public String encodeInteger(final int integer) {
        return new StringBuffer().append('i').append(integer).append('e').toString();
    }

    public String encodeList(final List<Object> list) {
        final StringBuffer stringBuffer = new StringBuffer().append('l');
        for (final Object object : list) {
            stringBuffer.append(encode(object));
        }
        return stringBuffer.append('e').toString();
    }

    public String encodeMap(final Map<String, Object> map) {
        final StringBuffer stringBuffer = new StringBuffer().append('d');
        final Iterator<Entry<String, Object>> iterator = map.entrySet().iterator();
        while (iterator.hasNext()) {
            final Entry<String, Object> entry = iterator.next();
            stringBuffer.append(encodeString(entry.getKey())).append(encode(entry.getVa​lue()));
            iterator.remove();
        }
        return stringBuffer.append('e').toString();
    }
}