FragmentList.java

package marubinotto.piggydb.model;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;

import marubinotto.util.Assert;
import marubinotto.util.CollectionUtils;

public class FragmentList<F extends Fragment> implements Iterable<F> {
	
	private List<F> fragments;
	
	private Map<Long, F> id2fragment;
	private List<F>	duplicates;
	
	public FragmentList() {
		setFragments(new ArrayList<F>());
	}

	public FragmentList(List<F> fragments) {
		setFragments(fragments);
	}
	
	public FragmentList(F fragment) {
		Assert.Arg.notNull(fragment, "fragment");
		
		List<F> fragments = new ArrayList<F>();
		fragments.add(fragment);
		setFragments(fragments);
	}
	
	@SuppressWarnings("unchecked")
	public static <SF extends Fragment> FragmentList<SF> createByDownCast(List<Fragment> fragments) {
		Assert.Arg.notNull(fragments, "fragments");
		
		List<SF> downCasted = new ArrayList<SF>();
		for (Fragment fragment : fragments) {
			downCasted.add((SF)fragment);
		}
		return new FragmentList<SF>(downCasted);
	}
	
	private void setFragments(List<F> fragments) {
		Assert.Arg.notNull(fragments, "fragments");
		
		this.fragments = fragments;
		
		this.id2fragment = new HashMap<Long, F>();
		this.duplicates = new ArrayList<F>();
		
		for (F fragment : this.fragments) {
			if (this.id2fragment.containsKey(fragment.getId())) 
				this.duplicates.add(fragment);
			else 
				this.id2fragment.put(fragment.getId(), fragment);
		}
	}
	
	public List<F> getFragments() {
		return this.fragments;
	}
	
	public List<Fragment> covariantCast() {
	  return CollectionUtils.<Fragment>covariantCast(this.fragments);
	}

	public Iterator<F> iterator() {
		return this.fragments.iterator();
	}
	
	public boolean isEmpty() {
		return this.fragments.isEmpty();
	}
	
	public F get(Long id) {
		Assert.Arg.notNull(id, "id");
		return this.id2fragment.get(id);
	}
	
	public Set<Long> ids() {
		return this.id2fragment.keySet();
	}
	
	public List<F> getDuplicates() {
		return this.duplicates;
	}

	@SuppressWarnings("unchecked")
	public FragmentList<F> getChildren() {
		List<F> children = new ArrayList<F>();
		for (F fragment : this) {
			for (Fragment child : fragment.getChildren()) {
				children.add((F)child);
			}
		}
		return new FragmentList<F>(children);
	}
}