/*
* Kodkod -- Copyright (c) 2005-present, Emina Torlak
*
* 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 kodkod.ast.visitor;
import java.util.Collections;
import java.util.IdentityHashMap;
import java.util.Map;
import java.util.Set;
import kodkod.ast.BinaryExpression;
import kodkod.ast.BinaryFormula;
import kodkod.ast.BinaryIntExpression;
import kodkod.ast.ComparisonFormula;
import kodkod.ast.Comprehension;
import kodkod.ast.ConstantExpression;
import kodkod.ast.ConstantFormula;
import kodkod.ast.Decl;
import kodkod.ast.Decls;
import kodkod.ast.ExprToIntCast;
import kodkod.ast.Expression;
import kodkod.ast.Formula;
import kodkod.ast.IfExpression;
import kodkod.ast.IfIntExpression;
import kodkod.ast.IntComparisonFormula;
import kodkod.ast.IntConstant;
import kodkod.ast.IntExpression;
import kodkod.ast.IntToExprCast;
import kodkod.ast.MultiplicityFormula;
import kodkod.ast.NaryExpression;
import kodkod.ast.NaryFormula;
import kodkod.ast.NaryIntExpression;
import kodkod.ast.Node;
import kodkod.ast.NotFormula;
import kodkod.ast.ProjectExpression;
import kodkod.ast.QuantifiedFormula;
import kodkod.ast.Relation;
import kodkod.ast.RelationPredicate;
import kodkod.ast.SumExpression;
import kodkod.ast.UnaryExpression;
import kodkod.ast.UnaryIntExpression;
import kodkod.ast.Variable;
/**
* <p>A depth first collector. Subclasses should override the
* methods in which detection is performed to return the appropriate set.
* For example, a Variable collector could be implemented
* simply by subclassing this implementation and overriding
* the {@link #visit(Variable) } method to return a singleton set containing
* the input argument.</p>
*
* @specfield cached: set Node // result of visiting these nodes will be cached
* @specfield cache: Node -> lone Set<T>
* @specfield cached in cache.Node
* @author Emina Torlak
*/
public abstract class AbstractCollector<T> implements
ReturnVisitor<Set<T>, Set<T>, Set<T>, Set<T>> {
protected final Map<Node, Set<T>> cache;
protected final Set<Node> cached;
/**
* Constructs a depth first collector which will cache the results
* of visiting the given nodes and re-use them on subsequent visits.
* @ensures this.cached' = cached && no this.cache
*/
protected AbstractCollector(Set<Node> cached) {
this.cached = cached;
this.cache = new IdentityHashMap<Node,Set<T>>(cached.size());
}
/**
* Constructs a depth-first collectior which will cache
* the results of visiting the given nodes in the given map,
* and re-use them on subsequent visits.
* @ensures this.cached' = cached && this.cache' = cache
*/
protected AbstractCollector(Set<Node> cached, Map<Node, Set<T>> cache) {
this.cached = cached;
this.cache = cache;
}
/**
* If n has been visited and a value for it cached,
* the cached value is returned. Otherwise null is returned.
* @return this.cache[n]
*/
protected Set<T> lookup(Node n) {
return cache.get(n);
}
/**
* Caches the given value for the specified node, if
* this is a caching visitor, and returns it.
* @ensures n in this.cached => this.cache' = this.cache ++ n->reduce(val), this.cache' = this.cache
* @return val
*/
protected Set<T> cache(Node n, Set<T> val) {
if (cached.contains(n)) {
cache.put(n, reduce(val));
}
return val;
}
/**
* Returns the set that has the same contents as val, but that may
* be more efficiently implemented than val.
* @return val.size()=0 => Collections.EMPTY_SET,
* val.size()=1 => Collections.singleton(val.iterator().next()),
* val
*/
protected Set<T> reduce(Set<T> val) {
switch(val.size()) {
case 0 : return Collections.emptySet();
case 1 : return Collections.singleton(val.iterator().next());
default : return val;
}
}
/**
* Returns a new, empty, modifiable set.
* @return a new, empty, modifiable set.
*/
protected abstract Set<T> newSet() ;
/**
* Calls lookup(decls) and returns the cached value, if any.
* If no cached value exists, visits each child, caches the
* union of the sets returned by the children and returns it.
* @return let x = lookup(decls) |
* x != null => x,
* cache(decls, decls.declarations[0].accept(this) +...+ decls.declarations[decls.size-1].accept(this))
*/
public Set<T> visit(Decls decls) {
Set<T> ret = lookup(decls);
if (ret!=null) return ret;
ret = newSet();
for(Decl d: decls) {
ret.addAll(d.accept(this));
}
return cache(decls, ret);
}
/**
* Calls lookup(decl) and returns the cached value, if any.
* If no cached value exists, visits each child, caches the
* union of the sets returned by the children and returns it.
* @return let x = lookup(decl) |
* x != null => x,
* cache(decls, decl.variable.accept(this) + decl.expression.accept(this))
*/
public Set<T> visit(Decl decl) {
Set<T> ret = lookup(decl);
if (ret!=null) return ret;
ret = newSet();
ret.addAll(decl.variable().accept(this));
ret.addAll(decl.expression().accept(this));
return cache(decl,ret);
}
/**
* Returns Collections.EMPTY_SET
* @return Collections.EMPTY_SET
*/
@SuppressWarnings("unchecked")
public Set<T> visit(Relation relation) {
return Collections.EMPTY_SET;
}
/**
* Returns Collections.EMPTY_SET
* @return Collections.EMPTY_SET
*/
@SuppressWarnings("unchecked")
public Set<T> visit(Variable variable) {
return Collections.EMPTY_SET;
}
/**
* Returns Collections.EMPTY_SET
* @return Collections.EMPTY_SET
*/
@SuppressWarnings("unchecked")
public Set<T> visit(ConstantExpression constExpr) {
return Collections.EMPTY_SET;
}
/**
* Calls lookup(expr) and returns the cached value, if any.
* If no cached value exists, visits each child, caches the
* union of the children's return values and returns it.
* @return let x = lookup(expr) |
* x != null => x,
* cache(expr, expr.child(0).accept(this) + .. + expr.child(expr.size()-1).accept(this))
*/
public Set<T> visit(NaryExpression expr) {
Set<T> ret = lookup(expr);
if (ret!=null) return ret;
ret = newSet();
for(Expression child : expr) {
ret.addAll(child.accept(this));
}
return cache(expr, ret);
}
/**
* Calls lookup(binExpr) and returns the cached value, if any.
* If no cached value exists, visits each child, caches the
* union of the children's return values and returns it.
* @return let x = lookup(binExpr) |
* x != null => x,
* cache(binExpr, binExpr.left.accept(this) + binExpr.right.accept(this))
*/
public Set<T> visit(BinaryExpression binExpr) {
Set<T> ret = lookup(binExpr);
if (ret!=null) return ret;
ret = newSet();
ret.addAll(binExpr.left().accept(this));
ret.addAll(binExpr.right().accept(this));
return cache(binExpr, ret);
}
/**
* Calls lookup(unaryExpr) and returns the cached value, if any.
* If no cached value exists, visits the child, caches its return value and returns it.
* @return let x = lookup(unaryExpr) |
* x != null => x,
* cache(unaryExpr, unaryExpr.expression.accept(this))
*/
public Set<T> visit(UnaryExpression unaryExpr) {
Set<T> ret = lookup(unaryExpr);
if (ret!=null) return ret;
ret = newSet();
ret.addAll(unaryExpr.expression().accept(this));
return cache(unaryExpr,ret);
}
/**
* Calls lookup(comprehension) and returns the cached value, if any.
* If no cached value exists, visits each child, caches the
* union of the children's return values and returns it.
* @return let x = lookup(comprehension) |
* x != null => x,
* cache(comprehension, comprehension.declarations.accept(this) + comprehension.formula.accept(this))
*/
public Set<T> visit(Comprehension comprehension) {
Set<T> ret = lookup(comprehension);
if (ret!=null) return ret;
ret = newSet();
ret.addAll(comprehension.decls().accept(this));
ret.addAll(comprehension.formula().accept(this));
return cache(comprehension, ret);
}
/**
* Calls lookup(ifExpr) and returns the cached value, if any.
* If no cached value exists, visits each child, caches the
* union of the children's return values and returns it.
* @return let x = lookup(ifExpr) |
* x != null => x,
* cache(ifExpr, ifExpr.condition.accept(this) + ifExpr.thenExpr.accept(this) + ifExpr.elseExpr.accept(this))
*/
public Set<T> visit(IfExpression ifExpr) {
Set<T> ret = lookup(ifExpr);
if (ret!=null) return ret;
ret = newSet();
ret.addAll(ifExpr.condition().accept(this));
ret.addAll(ifExpr.thenExpr().accept(this));
ret.addAll(ifExpr.elseExpr().accept(this));
return cache(ifExpr, ret);
}
/**
* Calls lookup(project) and returns the cached value, if any. If no cached
* value exists, visits each child, caches the union of the children's return
* values and returns it.
* @return let x = lookup(project) |
* x != null => x,
* cache(project, project.expression.accept(this) + project.columns[int].accept(this))
*/
public Set<T> visit(ProjectExpression project) {
Set<T> ret = lookup(project);
if (ret!=null) return ret;
ret = newSet();
ret.addAll(project.expression().accept(this));
for(int i = 0, arity = project.arity(); i < arity; i++) {
ret.addAll(project.column(i).accept(this));
}
return cache(project,ret);
}
/**
* Calls lookup(castExpr) and returns the cached value, if any.
* If no cached value exists, visits the child, caches its return value and returns it.
* @return let x = lookup(castExpr) |
* x != null => x,
* cache(intExpr, castExpr.intExpr.accept(this))
*/
public Set<T> visit(IntToExprCast castExpr) {
Set<T> ret = lookup(castExpr);
if (ret!=null) return ret;
ret = newSet();
ret.addAll(castExpr.intExpr().accept(this));
return cache(castExpr,ret);
}
/**
* Returns Collections.EMPTY_SET
* @return Collections.EMPTY_SET
*/
@SuppressWarnings("unchecked")
public Set<T> visit(IntConstant intConst) {
return Collections.EMPTY_SET;
}
/**
* Calls lookup(intExpr) and returns the cached value, if any.
* If no cached value exists, visits each child, caches the
* union of the children's return values and returns it.
* @return let x = lookup(intExpr) |
* x != null => x,
* cache(intExpr, intExpr.condition.accept(this) + intExpr.thenExpr.accept(this) + intExpr.elseExpr.accept(this))
*/
public Set<T> visit(IfIntExpression intExpr) {
Set<T> ret = lookup(intExpr);
if (ret!=null) return ret;
ret = newSet();
ret.addAll(intExpr.condition().accept(this));
ret.addAll(intExpr.thenExpr().accept(this));
ret.addAll(intExpr.elseExpr().accept(this));
return cache(intExpr, ret);
}
/**
* Calls lookup(intExpr) and returns the cached value, if any.
* If no cached value exists, visits the child, caches its return value and returns it.
* @return let x = lookup(intExpr) |
* x != null => x,
* cache(intExpr, intExpr.expression.accept(this))
*/
public Set<T> visit(ExprToIntCast intExpr) {
Set<T> ret = lookup(intExpr);
if (ret!=null) return ret;
ret = newSet();
ret.addAll(intExpr.expression().accept(this));
return cache(intExpr,ret);
}
/**
* Calls lookup(intExpr) and returns the cached value, if any.
* If no cached value exists, visits each child, caches the
* union of the children's return values and returns it.
* @return let x = lookup(intExpr) |
* x != null => x,
* cache(intExpr, intExpr.child(0).accept(this) + .. + intExpr.child(intExpr.size()-1).accept(this))
*/
public Set<T> visit(NaryIntExpression intExpr) {
Set<T> ret = lookup(intExpr);
if (ret!=null) return ret;
ret = newSet();
for(IntExpression child : intExpr) {
ret.addAll(child.accept(this));
}
return cache(intExpr, ret);
}
/**
* Calls lookup(intExpr) and returns the cached value, if any.
* If no cached value exists, visits each child, caches the
* union of the children's return values and returns it.
* @return let x = lookup(intExpr) |
* x != null => x,
* cache(intExpr, intExpr.left.accept(this) + intExpr.right.accept(this))
*/
public Set<T> visit(BinaryIntExpression intExpr) {
Set<T> ret = lookup(intExpr);
if (ret!=null) return ret;
ret = newSet();
ret.addAll(intExpr.left().accept(this));
ret.addAll(intExpr.right().accept(this));
return cache(intExpr, ret);
}
/**
* Calls lookup(intExpr) and returns the cached value, if any.
* If no cached value exists, visits the child, caches its return value and returns it.
* @return let x = lookup(intExpr) |
* x != null => x,
* cache(intExpr, intExpr.expression.accept(this))
*/
public Set<T> visit(UnaryIntExpression intExpr) {
Set<T> ret = lookup(intExpr);
if (ret!=null) return ret;
ret = newSet();
ret.addAll(intExpr.intExpr().accept(this));
return cache(intExpr,ret);
}
/**
* Calls lookup(intExpr) and returns the cached value, if any.
* If no cached value exists, visits each child, caches the
* union of the children's return values and returns it.
* @return let x = lookup(intExpr) |
* x != null => x,
* cache(intExpr, intExpr.decls.accept(this) + intExpr.intExpr.accept(this))
*/
public Set<T> visit(SumExpression intExpr) {
Set<T> ret = lookup(intExpr);
if (ret!=null) return ret;
ret = newSet();
ret.addAll(intExpr.decls().accept(this));
ret.addAll(intExpr.intExpr().accept(this));
return cache(intExpr, ret);
}
/**
* Calls lookup(intComp) and returns the cached value, if any.
* If no cached value exists, visits each child, caches the
* union of the children's return values and returns it.
* @return let x = lookup(intComp) |
* x != null => x,
* cache(intComp, intComp.left.accept(this) + intComp.right.accept(this))
*/
public Set<T> visit(IntComparisonFormula intComp) {
Set<T> ret = lookup(intComp);
if (ret!=null) return ret;
ret = newSet();
ret.addAll(intComp.left().accept(this));
ret.addAll(intComp.right().accept(this));
return cache(intComp, ret);
}
/**
* Calls lookup(quantFormula) and returns the cached value, if any.
* If no cached value exists, visits each child, caches the
* union of the children's return values and returns it.
* @return let x = lookup(quantFormula) |
* x != null => x,
* cache(quantFormula, quantFormula.declarations.accept(this) + quantFormula.formula.accept(this))
*/
public Set<T> visit(QuantifiedFormula quantFormula) {
Set<T> ret = lookup(quantFormula);
if (ret!=null) return ret;
ret = newSet();
ret.addAll(quantFormula.decls().accept(this));
ret.addAll(quantFormula.formula().accept(this));
return cache(quantFormula, ret);
}
/**
* Calls lookup(formula) and returns the cached value, if any.
* If no cached value exists, visits each child, caches the
* union of the children's return values and returns it.
* @return let x = lookup(formula) |
* x != null => x,
* cache(formula, formula.child(0).accept(this) + .. + formula.child(formula.size()-1).accept(this))
*/
public Set<T> visit(NaryFormula formula) {
Set<T> ret = lookup(formula);
if (ret!=null) return ret;
ret = newSet();
for(Formula child : formula) {
ret.addAll(child.accept(this));
}
return cache(formula, ret);
}
/**
* Calls lookup(binFormula) and returns the cached value, if any.
* If no cached value exists, visits each child, caches the
* union of the children's return values and returns it.
* @return let x = lookup(binFormula) |
* x != null => x,
* cache(binFormula, binFormula.left.accept(this) + binFormula.right.accept(this))
*/
public Set<T> visit(BinaryFormula binFormula) {
Set<T> ret = lookup(binFormula);
if (ret!=null) return ret;
ret = newSet();
ret.addAll(binFormula.left().accept(this));
ret.addAll(binFormula.right().accept(this));
return cache(binFormula, ret);
}
/**
* Calls lookup(not) and returns the cached value, if any.
* If no cached value exists, visits the child, caches its return value and returns it.
* @return let x = lookup(not) |
* x != null => x,
* cache(not, not.formula.accept(this))
*/
public Set<T> visit(NotFormula not) {
Set<T> ret = lookup(not);
if (ret!=null) return ret;
ret = newSet();
ret.addAll(not.formula().accept(this));
return cache(not, ret);
}
/**
* Returns Collections.EMPTY_SET
* @return Collections.EMPTY_SET
*/
@SuppressWarnings("unchecked")
public Set<T> visit(ConstantFormula constant) {
return Collections.EMPTY_SET;
}
/**
* Calls lookup(compFormula) and returns the cached value, if any.
* If no cached value exists, visits each child, caches the
* union of the children's return values and returns it.
* @return let x = lookup(compFormula) |
* x != null => x,
* cache(compFormula,compFormula.left.accept(this) + compFormula.right.accept(this))
*/
public Set<T> visit(ComparisonFormula compFormula) {
Set<T> ret = lookup(compFormula);
if (ret!=null) return ret;
ret = newSet();
ret.addAll(compFormula.left().accept(this));
ret.addAll(compFormula.right().accept(this));
return cache(compFormula, ret);
}
/**
* Calls lookup(multFormula) and returns the cached value, if any.
* If no cached value exists, visits the child, caches its return value and returns it.
* @return let x = lookup(multFormula) |
* x != null => x,
* cache(multFormula, multFormula.expression.accept(this))
*/
public Set<T> visit(MultiplicityFormula multFormula) {
Set<T> ret = lookup(multFormula);
if (ret!=null) return ret;
ret = newSet();
ret.addAll(multFormula.expression().accept(this));
return cache(multFormula, ret);
}
/**
* Calls lookup(predicate) and returns the cached value, if any.
* If no cached value exists, visits each child, caches the
* disjunction of the children's return values and returns it.
* @return let x = lookup(predicate) |
* x != null => x,
* cache(predicate, some n: predicate.children | n.accept(this))
*/
public Set<T> visit(RelationPredicate pred) {
Set<T> ret = lookup(pred);
if (ret!=null) return ret;
ret = newSet();
ret.addAll(pred.relation().accept(this));
switch(pred.name()) {
case ACYCLIC :
break;
case FUNCTION :
final RelationPredicate.Function fp = (RelationPredicate.Function) pred;
ret.addAll(fp.domain().accept(this));
ret.addAll(fp.range().accept(this));
break;
case TOTAL_ORDERING :
final RelationPredicate.TotalOrdering tp = (RelationPredicate.TotalOrdering) pred;
ret.addAll(tp.ordered().accept(this));
ret.addAll(tp.first().accept(this));
ret.addAll(tp.last().accept(this));
break;
default :
throw new IllegalArgumentException("unknown relation predicate: " + pred.name());
}
return cache(pred,ret);
}
}