import java.util.ArrayList;

import java.util.List;

class ChannelCollectionImpl implements ChannelCollection {

private List<Channel> channelList = new ArrayList<>();

@Override

public void addChannel(Channel channel) {

channelList.add(channel);

}

@Override

public void removeChannel(Channel channel) {

channelList.remove(channel);

}

@Override

public ChannelIterator iterator(ChannelType channelType) {

return new ChannelIteratorImpl(channelType, channelList);

}

private class ChannelIteratorImpl implements ChannelIterator {

private ChannelType type;

private List<Channel> channelList;

private int position;

public ChannelIteratorImpl(ChannelType type, List<Channel> channelsList) {

this.type = type;

this.channelList = channelsList;

}

@Override

public boolean hasNext() {

while (position < channelList.size()) {

Channel c = channelList.get(position);

if (c.getTYPE().equals(type) || type.equals(ChannelType.ALL)) {

return true;

} else

position++;

}

return false;

}

@Override

public Channel next() {

Channel ch = channelList.get(position);

position++;

return ch;

}

}

}