Implement criterion which don't need a file.

sdg-core/src/main/java/es/upv/mist/slicing/slicing/ClassFileLineCriterion.java

+package es.upv.mist.slicing.slicing;
+
+import com.github.javaparser.ast.CompilationUnit;
+import com.github.javaparser.ast.NodeList;
+import com.github.javaparser.ast.body.TypeDeclaration;
+
+import java.util.Objects;
+import java.util.Optional;
+
+public class ClassFileLineCriterion extends LineNumberCriterion {
+  private final String fullyQualifiedClassName;
+
+  public ClassFileLineCriterion(final String fullyQualifiedClassName, int lineNumber, String variable) {
+    super(lineNumber, variable);
+    this.fullyQualifiedClassName = fullyQualifiedClassName;
+  }
+
+  /** Locates the compilation unit that corresponds to this criterion's file. */
+  protected Optional<CompilationUnit> findCompilationUnit(NodeList<CompilationUnit> cus) {
+    for (CompilationUnit cu : cus) {
+      if (cu.getTypes().stream()
+              .map(TypeDeclaration::getFullyQualifiedName)
+              .map(o -> o.orElse(null))
+              .anyMatch(type -> Objects.equals(type, fullyQualifiedClassName)))
+        return Optional.of(cu);
+    }
+    return Optional.empty();
+  }
+
+  @Override
+  public String toString() {
+    return fullyQualifiedClassName + "#" + lineNumber + ":" + variable;
+  }
+}