/*
* Copyright (C) 2014.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 or
* version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
package uk.me.parabola.mkgmap.reader.osm;
import java.util.ArrayList;
import java.util.HashMap;
import uk.me.parabola.imgfmt.MapFailedException;
/**
* A dictionary for tag names. Allows to translate a tag name to a unique Short value.
* @author GerdP
*
*/
public class TagDict{
private final static TagDict INSTANCE = new TagDict();
private final HashMap<String,Short> map = new HashMap<>();
private final ArrayList<String> list = new ArrayList<>();
public static final short INVALID_TAG_VALUE = 0;
/**
* create an empty dictionary
*/
private TagDict() {
map.put("invalid tag", INVALID_TAG_VALUE);
list.add("invalid tag");
}
/**
* give access to the singleton instance
* @return
*/
public static TagDict getInstance() {
return INSTANCE;
}
/**
* translate a tag name to a short value
* @param keyString the tag name
* @return a Short > 0 that can be used to retrieve
* the tag name with the get() method
*/
public synchronized short xlate (String keyString){
Short tagKey = map.get(keyString);
if (tagKey == null) {
short size = (short) list.size();
if (size == Short.MAX_VALUE){
// very unlikely, typically we have a few hundred tag names
throw new MapFailedException("Fatal: Too many different tags in style");
}
String s = keyString;
map.put(s, size);
//System.out.println(""+x + ":" + s);
list.add(s);
return size;
}
return tagKey.shortValue();
}
/**
* get the tagName for a tagKey. The caller has
* to make sure that the key is valid.
* @param key the tagKey (returned by xlate()
* @return the tagName
*/
public String get(short key){
if (key == INVALID_TAG_VALUE) return null;
return list.get(key);
}
/**
* The size of the dictionary. The highest known tagKey is
* size() - 1.
* @return
*/
public int size(){
return list.size();
}
}