/* Alloy Analyzer 4 -- Copyright (c) 2006-2009, Felix Chang
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files
* (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify,
* merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF
* OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
package edu.mit.csail.sdg.alloy4viz;
import java.util.Collection;
import java.util.List;
import edu.mit.csail.sdg.alloy4.ConstList;
import edu.mit.csail.sdg.alloy4.Util;
import edu.mit.csail.sdg.alloy4.ConstList.TempList;
/** Immutable; represents an Alloy relation of 2 or higher arity.
*
* <p><b>Thread Safety:</b> Can be called only by the AWT event thread.
*/
public final class AlloyRelation extends AlloyElement {
/** This caches an instance of the "extends" AlloyRelation, so we don't have to keep re-constructing it. */
public static final AlloyRelation EXTENDS = new AlloyRelation("extends", false, false, Util.asList(AlloyType.UNIV, AlloyType.UNIV));
/** This caches an instance of the "in" AlloyRelation, so we don't have to keep re-constructing it. */
public static final AlloyRelation IN = new AlloyRelation("in", false, false, Util.asList(AlloyType.SET, AlloyType.UNIV));
/** The unmodifiable list of types. */
private final ConstList<AlloyType> types;
/** Records whether this relation is known to be "private"; NOTE: this value is NOT USED during equals() comparison. */
public final boolean isPrivate;
/** Records whether this relation is known to be "meta"; NOTE: this value is NOT USED during equals() comparison. */
public final boolean isMeta;
/** Constructs a new AlloyRelation with that name and that list of types; types.size() must be 2 or above. */
public AlloyRelation(String name, boolean isPrivate, boolean isMeta, List<AlloyType> types) {
super(name);
if (types==null || types.size()<2)
throw new RuntimeException("An AlloyRelation object must have 2 or more types.");
this.types = ConstList.make(types);
this.isPrivate = isPrivate;
this.isMeta = isMeta;
}
/** Project this relation and return an unmodifiable list of remaining types (after removing zero or more columns)
* @param columns - the collection of columns to remove (0 is the first column, 1 is the second column...)
*/
public List<AlloyType> project(Collection<Integer> columns) {
TempList<AlloyType> list = new TempList<AlloyType>(types.size());
for(int i=0; i<types.size(); i++) if (!columns.contains(i)) list.add(types.get(i));
if (list.size()==types.size()) return types; else return list.makeConst();
}
/** Returns an unmodifiable list of AlloyTypes representing the relation's type. */
public List<AlloyType> getTypes() { return types; }
/** Returns the arity of the relation. */
public int getArity() { return types.size(); }
/** When comparing two AlloyRelation objects, we first compare the name, then the arity, then the types.
* <br> We guarantee x.equals(y) iff x.compareTo(y)==0
*/
public int compareTo(AlloyRelation other) {
if (other==null) return 1;
// First compare the names.
int n=Util.slashComparator.compare(getName(), other.getName()); if (n!=0) return n;
// Now compare the arity of the two relations
int arity = types.size();
if (arity!=other.types.size()) return (arity<other.types.size())?-1:1;
// Finally, compare each AlloyType
for(int i=0; i<arity; i++) {
n=types.get(i).compareTo(other.types.get(i));
if (n!=0) return n;
}
return 0;
}
/** When comparing two AlloyRelation objects, we first compare the name, then the arity, then the types.
* <br> We guarantee x.equals(y) iff x.compareTo(y)==0
*/
public int compareTo(AlloyElement other) {
if (!(other instanceof AlloyRelation)) return 1;
return compareTo((AlloyRelation)other);
}
/** This value is used to display this type in the Visualizer's customization screen. */
@Override public String toString() {
String answer = "";
boolean first = true;
for(AlloyType type: getTypes()) {
if (first) {first=false; answer=answer+getName()+" : ";} else answer=answer+" -> ";
answer=answer+type.getName();
}
return answer;
}
/** Two relations are equal if they have the same name, and the same list of types. */
@Override public boolean equals(Object other) {
if (!(other instanceof AlloyRelation)) return false;
if (other==this) return true;
AlloyRelation otherRelation = (AlloyRelation)other;
return getName().equals(otherRelation.getName()) && types.equals(otherRelation.types);
}
/** Computes a hash code based on the name and the list of types. */
@Override public int hashCode() { return 5*getName().hashCode() + 7*types.hashCode(); }
}