/*
 * FindBugs - Find Bugs in Java programs
 * Copyright (C) 2006, University of Maryland
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library 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
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package edu.umd.cs.findbugs.ba.npe;

import java.util.Collection;
import java.util.Iterator;
import java.util.LinkedList;

import edu.umd.cs.findbugs.annotations.CheckForNull;
import edu.umd.cs.findbugs.ba.Location;
import edu.umd.cs.findbugs.ba.vna.ValueNumber;
import edu.umd.cs.findbugs.util.MultiMap;

/**
 * @author pugh
 */
public class UsagesRequiringNonNullValues {

    public static class Pair {
        public final ValueNumber vn;
        public final PointerUsageRequiringNonNullValue pu;

        Pair(ValueNumber vn, PointerUsageRequiringNonNullValue pu) {
            this.vn = vn;
            this.pu = pu;
        }

        @Override
        public String toString() {
            return vn.toString();
        }
    }

    MultiMap<Location, Pair> map = new MultiMap<Location, Pair>(LinkedList.class);
    
    public String toString() {
        StringBuffer buf = new StringBuffer();
        for(Location loc : map.keySet()) {
            buf.append(loc.getHandle().getPosition() + ":" + loc.getHandle().getInstruction() +"\n");
            for(Pair p : getPairs(loc)) {
                buf.append("  ").append(p.vn).append("\n");
            }
        }
        return buf.toString();
    }

    public void add(Location loc, ValueNumber vn, PointerUsageRequiringNonNullValue usage) {
        Pair p = new Pair(vn, usage);
        if (DerefFinder.DEBUG)
            System.out.println("At " + loc + " adding dereference " + p);

        map.add(loc, p);
    }

    public @CheckForNull
    PointerUsageRequiringNonNullValue get(Location loc, ValueNumber vn) {
        PointerUsageRequiringNonNullValue secondBest = null;
        for (Pair p : map.get(loc)) {
            if (p.vn.equals(vn))
                return p.pu;
            else secondBest = p.pu;
        }
        return secondBest;
    }

    public Collection<? extends Pair> getPairs(Location loc) {
        return map.get(loc);
    }

    public Iterable<ValueNumber> getValueNumbers(final Location loc) {
        return new Iterable<ValueNumber>() {
            final Collection<Pair> values = map.get(loc);

            public Iterator<ValueNumber> iterator() {
                return new Iterator<ValueNumber>() {
                    Iterator<Pair> i = values.iterator();

                    public boolean hasNext() {
                        return i.hasNext();
                    }

                    public ValueNumber next() {
                        return i.next().vn;
                    }

                    public void remove() {
                        throw new UnsupportedOperationException();

                    }
                };
            }
        };
    }

}

@@ -2759,757 +2759,8 @@
 %0A   
- public Iterable%3CValueNumber%3E getValueNumbers(final Location loc) %7B%0A        return new Iterable%3CValueNumber%3E() %7B%0A            final Collection%3CPair%3E values = map.get(loc);%0A%0A            public Iterator%3CValueNumber%3E iterator() %7B%0A                return new Iterator%3CValueNumber%3E() %7B%0A                    Iterator%3CPair%3E i = values.iterator();%0A%0A                    public boolean hasNext() %7B%0A                        return i.hasNext();%0A                    %7D%0A%0A                    public ValueNumber next() %7B%0A                        return i.next().vn;%0A                    %7D%0A%0A                    public void remove() %7B%0A                        throw new UnsupportedOperationException();%0A%0A                    %7D%0A                %7D;%0A            %7D%0A        %7D;%0A    %7D
 %0A%0A%7D%0A

fix 1.5 dependency on Iterable