package com.github.hakko.musiccabinet.parser.lastfm;
import static com.github.hakko.musiccabinet.parser.lastfm.ArtistSimilarityHandler.State.MATCH;
import static com.github.hakko.musiccabinet.parser.lastfm.ArtistSimilarityHandler.State.NAME;
import static org.apache.commons.lang.math.NumberUtils.toFloat;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
import com.github.hakko.musiccabinet.domain.model.music.Artist;
import com.github.hakko.musiccabinet.domain.model.music.ArtistRelation;
public class ArtistSimilarityHandler extends DefaultHandler {
private String artistName; // artist name this similarity is based on
private List<ArtistRelation> artistRelations = new ArrayList<>();
private ArtistRelation currentArtistRelation; // used internally while parsing
private State state; // stores state based on latest encountered start tag
private StringBuilder characterData; // used to assemble xml text passed by parser
// maps start tag to respective state, for tags where we read xml text() data
private static Map<String, State> xmlToStateMap = new HashMap<>();
private static final String TAG_SIMILAR_ARTISTS = "similarartists";
private static final String TAG_ARTIST = "artist";
private static final String TAG_NAME = "name";
private static final String TAG_MATCH = "match";
static {
xmlToStateMap.put(TAG_NAME, NAME);
xmlToStateMap.put(TAG_MATCH, MATCH);
}
enum State {
NAME, MATCH;
}
@Override
public void startElement(String uri, String localName, String qName, Attributes attributes)
throws SAXException {
if (TAG_SIMILAR_ARTISTS.equals(qName)) {
artistName = attributes.getValue(TAG_ARTIST);
} else if (TAG_ARTIST.equals(qName)) {
currentArtistRelation = new ArtistRelation();
} else {
state = xmlToStateMap.get(qName);
if (state != null) {
characterData = new StringBuilder();
}
}
}
@Override
public void endElement(String uri, String localName, String qName)
throws SAXException {
if (state != null) {
String chars = characterData.toString();
if (state == NAME) {
currentArtistRelation.setTarget(new Artist(chars));
} else if (state == MATCH) {
currentArtistRelation.setMatch(toFloat(chars));
}
state = null;
}
if (TAG_ARTIST.equals(qName)) {
artistRelations.add(currentArtistRelation);
}
}
@Override
public void characters(char[] ch, int start, int length) throws SAXException {
if (state != null) {
characterData.append(ch, start, length);
}
}
/* Variables to be exposured after parsing */
public String getArtistName() {
return artistName;
}
public List<ArtistRelation> getArtistRelations() {
return artistRelations;
}
}