Filters.java

package com.mysema.rdfbean.query;

import java.util.ArrayList;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;

import com.mysema.query.types.Predicate;
import com.mysema.rdfbean.model.Block;
import com.mysema.rdfbean.model.Blocks;
import com.mysema.rdfbean.model.GroupBlock;

/**
 * @author tiwe
 * 
 */
public class Filters {

    private final Set<Predicate> filters = new LinkedHashSet<Predicate>();

    private Set<Block> optBlocks = new LinkedHashSet<Block>();

    private Set<Predicate> optFilters = new LinkedHashSet<Predicate>();

    private boolean inOptional = false;

    public Set<Predicate> getFilters() {
        return filters;
    }

    public int size() {
        return filters.size();
    }

    public void add(Predicate predicate) {
        if (inOptional) {
            if (predicate instanceof Block) {
                optBlocks.add((Block) predicate);
            } else {
                optFilters.add(predicate);
            }
        } else {
            filters.add(predicate);
        }

    }

    public boolean inOptional() {
        return inOptional;
    }

    public void beginOptional() {
        inOptional = true;
    }

    public void endOptional() {
        if (optBlocks.isEmpty()) {
            filters.addAll(optFilters);
        } else {
            filters.add(Blocks.optional(
                    new ArrayList<Block>(optBlocks),
                    optFilters.toArray(new Predicate[optFilters.size()])));
        }
        optBlocks = new LinkedHashSet<Block>();
        optFilters = new LinkedHashSet<Predicate>();
        inOptional = false;
    }

    public Predicate[] toArray() {
        return filters.toArray(new Predicate[filters.size()]);
    }

    public Block asBlock() {
        List<Block> b = new ArrayList<Block>();
        List<Predicate> f = new ArrayList<Predicate>();
        for (Predicate filter : filters) {
            if (filter instanceof Block) {
                b.add((Block) filter);
            } else {
                f.add(filter);
            }
        }
        return new GroupBlock(b, f.toArray(new Predicate[f.size()]));
    }

}