/**
*
*/
package soottocfg.cfg.expression.literal;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import soottocfg.cfg.SourceLocation;
import soottocfg.cfg.expression.Expression;
import soottocfg.cfg.expression.IdentifierExpression;
import soottocfg.cfg.type.ReferenceType;
import soottocfg.cfg.type.Type;
import soottocfg.cfg.variable.Variable;
/**
* @author schaef
*
*/
public class NullLiteral extends Expression implements Literal{
private static final long serialVersionUID = -5790805200149816187L;
public NullLiteral(SourceLocation loc) {
super(loc);
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
sb.append("$null$");
return sb.toString();
}
@Override
public Set<IdentifierExpression> getUseIdentifierExpressions() {
return new HashSet<IdentifierExpression>();
}
@Override
public Set<Variable> getDefVariables() {
// because this can't happen on the left.
Set<Variable> used = new HashSet<Variable>();
return used;
}
@Override
public Type getType() {
return ReferenceType.instance();
}
@Override
public boolean equals(Object other) {
if (other instanceof NullLiteral) {
return true;
}
return false;
}
@Override
public int hashCode() {
return 17;
}
@Override
public Expression deepCopy() {
return new NullLiteral(getSourceLocation());
}
@Override
public Expression substitute(Map<Variable, Variable> subs) {
return this.deepCopy();
}
@Override
public Expression substituteVarWithExpression(Map<Variable, Expression> subs) {
return this.deepCopy();
}
}