panda.lang.collection.CaseInsensitiveSet Maven / Gradle / Ivy

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package panda.lang.collection;

import java.util.AbstractSet;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

/**
 * Implementation of a Set that ignores the case of the
 * keys.
 * @param  the type of keys maintained by this set
 * 
 */
public class CaseInsensitiveSet implements Set {
	private transient Map map;

	public CaseInsensitiveSet() {
		map = new HashMap();
	}

	public CaseInsensitiveSet(Collection c) {
		map = new HashMap(Math.max((int) (c.size()/.75f) + 1, 16));
		addAll(c);
	}

	protected Object toCompareKey(Object key) {
		return key instanceof String ? ((String)key).toLowerCase() : key; 
	}

	@Override
	public void clear() {
		map.clear();
	}

	@Override
	public int size() {
		return map.size();
	}

	@Override
	public boolean isEmpty() {
		return map.isEmpty();
	}

	@Override
	public boolean contains(Object o) {
		return map.containsKey(toCompareKey(o));
	}

	@Override
	public Iterator iterator() {
		return map.values().iterator();
	}

	@Override
	public Object[] toArray() {
		return map.values().toArray();
	}

	@Override
	public  T[] toArray(T[] a) {
		return map.values().toArray(a);
	}

	@Override
	public boolean add(E e) {
		Object ck = toCompareKey(e);
		if (map.containsKey(ck)) {
			return false;
		}
		map.put(ck, e);
		return true;
	}

	@Override
	public boolean remove(Object o) {
		Object ck = toCompareKey(o);
		if (map.containsKey(ck)) {
			map.remove(ck);
			return true;
		}
		return false;
	}

	@Override
	public boolean containsAll(Collection c) {
		for (Object e : c) {
			if (!contains(e)) {
				return false;
			}
		}
		return true;
	}

	@Override
	public boolean addAll(Collection c) {
		boolean modified = false;
		for (E e : c) {
			if (add(e)) {
				modified = true;
			}
		}
		return modified;
	}

	@Override
	public boolean retainAll(Collection c) {
		boolean modified = false;

		Set