| 1 | /* |
|---|---|
| 2 | * Copyright (C) 2007-2010 Júlio Vilmar Gesser. |
| 3 | * Copyright (C) 2011, 2013-2020 The JavaParser Team. |
| 4 | * |
| 5 | * This file is part of JavaParser. |
| 6 | * |
| 7 | * JavaParser can be used either under the terms of |
| 8 | * a) the GNU Lesser General Public License as published by |
| 9 | * the Free Software Foundation, either version 3 of the License, or |
| 10 | * (at your option) any later version. |
| 11 | * b) the terms of the Apache License |
| 12 | * |
| 13 | * You should have received a copy of both licenses in LICENCE.LGPL and |
| 14 | * LICENCE.APACHE. Please refer to those files for details. |
| 15 | * |
| 16 | * JavaParser is distributed in the hope that it will be useful, |
| 17 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 19 | * GNU Lesser General Public License for more details. |
| 20 | */ |
| 21 | |
| 22 | package com.github.javaparser.ast.observer; |
| 23 | |
| 24 | import com.github.javaparser.ast.Node; |
| 25 | import com.github.javaparser.ast.NodeList; |
| 26 | |
| 27 | /** |
| 28 | * This AstObserver attach itself to all new nodes added to the nodes already observed. |
| 29 | */ |
| 30 | public abstract class PropagatingAstObserver implements AstObserver { |
| 31 | |
| 32 | /** |
| 33 | * Wrap a given observer to make it self-propagating. If the given observer is an instance of PropagatingAstObserver |
| 34 | * the observer is returned without changes. |
| 35 | */ |
| 36 | public static PropagatingAstObserver transformInPropagatingObserver(final AstObserver observer) { |
| 37 | if (observer instanceof PropagatingAstObserver) { |
| 38 | return (PropagatingAstObserver) observer; |
| 39 | } |
| 40 | return new PropagatingAstObserver() { |
| 41 | @Override |
| 42 | public void concretePropertyChange(Node observedNode, ObservableProperty property, Object oldValue, Object newValue) { |
| 43 | observer.propertyChange(observedNode, property, oldValue, newValue); |
| 44 | } |
| 45 | |
| 46 | @Override |
| 47 | public void concreteListChange(NodeList<?> observedNode, ListChangeType type, int index, Node nodeAddedOrRemoved) { |
| 48 | observer.listChange(observedNode, type, index, nodeAddedOrRemoved); |
| 49 | } |
| 50 | |
| 51 | @Override |
| 52 | public void parentChange(Node observedNode, Node previousParent, Node newParent) { |
| 53 | observer.parentChange(observedNode, previousParent, newParent); |
| 54 | } |
| 55 | }; |
| 56 | } |
| 57 | |
| 58 | @Override |
| 59 | public final void propertyChange(Node observedNode, ObservableProperty property, Object oldValue, Object newValue) { |
| 60 | considerRemoving(oldValue); |
| 61 | considerAdding(newValue); |
| 62 | concretePropertyChange(observedNode, property, oldValue, newValue); |
| 63 | } |
| 64 | |
| 65 | @Override |
| 66 | public final void listChange(NodeList<?> observedNode, ListChangeType type, int index, Node nodeAddedOrRemoved) { |
| 67 | if (type == ListChangeType.REMOVAL) { |
| 68 | considerRemoving(nodeAddedOrRemoved); |
| 69 | } else if (type == ListChangeType.ADDITION) { |
| 70 | considerAdding(nodeAddedOrRemoved); |
| 71 | } |
| 72 | concreteListChange(observedNode, type, index, nodeAddedOrRemoved); |
| 73 | } |
| 74 | |
| 75 | @Override |
| 76 | public void listReplacement(NodeList<?> observedNode, int index, Node oldNode, Node newNode) { |
| 77 | if (oldNode == newNode) { |
| 78 | return; |
| 79 | } |
| 80 | considerRemoving(oldNode); |
| 81 | considerAdding(newNode); |
| 82 | concreteListReplacement(observedNode, index, oldNode, newNode); |
| 83 | } |
| 84 | |
| 85 | public void concretePropertyChange(Node observedNode, ObservableProperty property, Object oldValue, Object newValue) { |
| 86 | // do nothing |
| 87 | } |
| 88 | |
| 89 | public void concreteListChange(NodeList<?> observedNode, ListChangeType type, int index, Node nodeAddedOrRemoved) { |
| 90 | // do nothing |
| 91 | } |
| 92 | |
| 93 | public void concreteListReplacement(NodeList<?> observedNode, int index, Node oldValue, Node newValue) { |
| 94 | // do nothing |
| 95 | } |
| 96 | |
| 97 | @Override |
| 98 | public void parentChange(Node observedNode, Node previousParent, Node newParent) { |
| 99 | // do nothing |
| 100 | } |
| 101 | |
| 102 | private void considerRemoving(Object element) { |
| 103 | if (element instanceof Observable) { |
| 104 | if (((Observable) element).isRegistered(this)) { |
| 105 | ((Observable) element).unregister(this); |
| 106 | } |
| 107 | } |
| 108 | } |
| 109 | |
| 110 | private void considerAdding(Object element) { |
| 111 | if (element instanceof Node) { |
| 112 | ((Node) element).registerForSubtree(this); |
| 113 | } else if (element instanceof Observable) { |
| 114 | ((Observable) element).register(this); |
| 115 | } |
| 116 | } |
| 117 | |
| 118 | } |
| 119 |
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