tikhomirov@648: /*
tikhomirov@648:  * Copyright (c) 2013 TMate Software Ltd
tikhomirov@648:  *  
tikhomirov@648:  * This program is free software; you can redistribute it and/or modify
tikhomirov@648:  * it under the terms of the GNU General Public License as published by
tikhomirov@648:  * the Free Software Foundation; version 2 of the License.
tikhomirov@648:  *
tikhomirov@648:  * This program is distributed in the hope that it will be useful,
tikhomirov@648:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
tikhomirov@648:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
tikhomirov@648:  * GNU General Public License for more details.
tikhomirov@648:  *
tikhomirov@648:  * For information on how to redistribute this software under
tikhomirov@648:  * the terms of a license other than GNU General Public License
tikhomirov@648:  * contact TMate Software at support@hg4j.com
tikhomirov@648:  */
tikhomirov@648: package org.tmatesoft.hg.internal;
tikhomirov@648: 
tikhomirov@648: import java.util.Collection;
tikhomirov@648: import java.util.Collections;
tikhomirov@648: import java.util.HashSet;
tikhomirov@648: import java.util.Set;
tikhomirov@648: 
tikhomirov@648: import org.tmatesoft.hg.core.Nodeid;
tikhomirov@648: 
tikhomirov@648: /**
tikhomirov@648:  * Unmodifiable collection of revisions with handy set operations
tikhomirov@648:  * 
tikhomirov@648:  * @author Artem Tikhomirov
tikhomirov@648:  * @author TMate Software Ltd.
tikhomirov@648:  */
tikhomirov@648: public final class RevisionSet {
tikhomirov@648: 	
tikhomirov@648: 	private final Set<Nodeid> elements;
tikhomirov@648: 	
tikhomirov@648: 	public RevisionSet(Collection<Nodeid> revisions) {
tikhomirov@648: 		this(revisions == null ? new HashSet<Nodeid>() : new HashSet<Nodeid>(revisions));
tikhomirov@648: 	}
tikhomirov@648: 	
tikhomirov@648: 	private RevisionSet(HashSet<Nodeid> revisions) {
tikhomirov@648: 		if (revisions.isEmpty()) {
tikhomirov@648: 			elements = Collections.<Nodeid>emptySet();
tikhomirov@648: 		} else {
tikhomirov@648: 			elements = revisions;
tikhomirov@648: 		}
tikhomirov@648: 	}
tikhomirov@648: 
tikhomirov@648: 	public RevisionSet roots() {
tikhomirov@648: 		throw Internals.notImplemented();
tikhomirov@648: 	}
tikhomirov@648: 	
tikhomirov@648: 	public RevisionSet heads() {
tikhomirov@648: 		throw Internals.notImplemented();
tikhomirov@648: 	}
tikhomirov@648: 
tikhomirov@648: 	public RevisionSet intersect(RevisionSet other) {
tikhomirov@648: 		if (isEmpty()) {
tikhomirov@648: 			return this;
tikhomirov@648: 		}
tikhomirov@648: 		if (other.isEmpty()) {
tikhomirov@648: 			return other;
tikhomirov@648: 		}
tikhomirov@648: 		HashSet<Nodeid> copy = new HashSet<Nodeid>(elements);
tikhomirov@648: 		copy.retainAll(other.elements);
tikhomirov@648: 		return copy.size() == elements.size() ? this : new RevisionSet(copy);
tikhomirov@648: 	}
tikhomirov@648: 	
tikhomirov@648: 	public RevisionSet subtract(RevisionSet other) {
tikhomirov@648: 		if (isEmpty() || other.isEmpty()) {
tikhomirov@648: 			return this;
tikhomirov@648: 		}
tikhomirov@648: 		HashSet<Nodeid> copy = new HashSet<Nodeid>(elements);
tikhomirov@648: 		copy.removeAll(other.elements);
tikhomirov@648: 		return copy.size() == elements.size() ? this : new RevisionSet(copy);
tikhomirov@648: 	}
tikhomirov@648: 
tikhomirov@648: 	public RevisionSet union(RevisionSet other) {
tikhomirov@648: 		if (isEmpty()) {
tikhomirov@648: 			return other;
tikhomirov@648: 		}
tikhomirov@648: 		if (other.isEmpty()) {
tikhomirov@648: 			return this;
tikhomirov@648: 		}
tikhomirov@648: 		HashSet<Nodeid> copy = new HashSet<Nodeid>(elements);
tikhomirov@648: 		copy.addAll(other.elements);
tikhomirov@648: 		return new RevisionSet(copy);
tikhomirov@648: 	}
tikhomirov@648: 
tikhomirov@648: 	/**
tikhomirov@648: 	 * A ^ B := (A\B).union(B\A)
tikhomirov@648: 	 * A ^ B := A.union(B) \ A.intersect(B)
tikhomirov@648: 	 */
tikhomirov@648: 	public RevisionSet symmetricDifference(RevisionSet other) {
tikhomirov@648: 		if (isEmpty()) {
tikhomirov@648: 			return this;
tikhomirov@648: 		}
tikhomirov@648: 		if (other.isEmpty()) {
tikhomirov@648: 			return other;
tikhomirov@648: 		}
tikhomirov@648: 		HashSet<Nodeid> copyA = new HashSet<Nodeid>(elements);
tikhomirov@648: 		HashSet<Nodeid> copyB = new HashSet<Nodeid>(other.elements);
tikhomirov@648: 		copyA.removeAll(other.elements);
tikhomirov@648: 		copyB.removeAll(elements);
tikhomirov@648: 		copyA.addAll(copyB);
tikhomirov@648: 		return new RevisionSet(copyA);
tikhomirov@648: 	}
tikhomirov@648: 
tikhomirov@648: 	public boolean isEmpty() {
tikhomirov@648: 		return elements.isEmpty();
tikhomirov@648: 	}
tikhomirov@648: 
tikhomirov@648: 	@Override
tikhomirov@648: 	public String toString() {
tikhomirov@648: 		StringBuilder sb = new StringBuilder();
tikhomirov@648: 		sb.append('<');
tikhomirov@648: 		if (!isEmpty()) {
tikhomirov@648: 			sb.append(elements.size());
tikhomirov@648: 			sb.append(':');
tikhomirov@648: 		}
tikhomirov@648: 		for (Nodeid n : elements) {
tikhomirov@648: 			sb.append(n.shortNotation());
tikhomirov@648: 			sb.append(',');
tikhomirov@648: 		}
tikhomirov@648: 		if (sb.length() > 1) {
tikhomirov@648: 			sb.setCharAt(sb.length() - 1, '>');
tikhomirov@648: 		} else {
tikhomirov@648: 			sb.append('>');
tikhomirov@648: 		}
tikhomirov@648: 		return sb.toString();
tikhomirov@648: 	}
tikhomirov@648: 	
tikhomirov@648: 	@Override
tikhomirov@648: 	public boolean equals(Object obj) {
tikhomirov@648: 		if (false == obj instanceof RevisionSet) {
tikhomirov@648: 			return false;
tikhomirov@648: 		}
tikhomirov@648: 		return elements.equals(((RevisionSet) obj).elements);
tikhomirov@648: 	}
tikhomirov@648: 	
tikhomirov@648: 	@Override
tikhomirov@648: 	public int hashCode() {
tikhomirov@648: 		return elements.hashCode();
tikhomirov@648: 	}
tikhomirov@648: }