| /******************************************************************************* |
| * Copyright (c) 2014, 2018 Willink Transformations and others. |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License v2.0 |
| * which accompanies this distribution, and is available at |
| * http://www.eclipse.org/legal/epl-v20.html |
| * |
| * Contributors: |
| * E.D. Willink - Initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.ocl.pivot.values; |
| |
| import org.eclipse.jdt.annotation.NonNull; |
| import org.eclipse.jdt.annotation.Nullable; |
| import org.eclipse.ocl.pivot.TemplateParameter; |
| import org.eclipse.ocl.pivot.Type; |
| |
| /** |
| * TemplateParameterSubstitutions defines the interaction with the matching of formal TemplateParameters and actual types. |
| * Formal template parameters are identified by theit integer intexes in a flattened list starting at the outer-most TemplateableElement. |
| * The template parameter indexes in Collection(T1)::product(T2)(...)... are therefore 0 for T1, and 1 for T2. |
| * <p> |
| * A derived TemplateParameterSubstitutionVisitor determines the bindings by recursive analysis of a pair of formal and actual expression/type trees. |
| * <p> |
| * The EMPTY instance handles the degenerate case of no template parameters. |
| */ |
| public interface TemplateParameterSubstitutions |
| { |
| /** |
| * Return the highest common actual type of the formal templateParameter, returning null if unknown. |
| */ |
| @Nullable Type get(@Nullable TemplateParameter templateParameter); |
| |
| /** |
| * Return true if there are no formal TemplateParameters with actual values. |
| */ |
| boolean isEmpty(); |
| |
| /** |
| * Install actualType as the resolutions of formalTemplateParameter, returning the highest common type of actualType |
| * and any pre-existing resolution. |
| */ |
| @NonNull Type put(@NonNull TemplateParameter formalTemplateParameter, @NonNull Type actualType); |
| |
| public static final @NonNull TemplateParameterSubstitutions EMPTY = new Empty(); |
| |
| public static class Empty implements TemplateParameterSubstitutions |
| { |
| @Override |
| public @Nullable Type get(@Nullable TemplateParameter templateParameter) { |
| return null; |
| } |
| |
| @Override |
| public boolean isEmpty() { |
| return true; |
| } |
| |
| @Override |
| public @NonNull Type put(@NonNull TemplateParameter formalTemplateParameter, @NonNull Type actualType) { |
| return actualType; |
| } |
| |
| @Override |
| public String toString() { |
| return "{}"; |
| } |
| } |
| } |