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comparison graal/com.oracle.truffle.api/src/com/oracle/truffle/api/nodes/Node.java @ 7267:a4b84ba6dc2e

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Introduction of the Truffle API for efficient implementation of dynamic languages on top of the Graal VM. New projects com.oracle.truffle.api for the API definition and com.oracle.truffle.api.test for API tests and documentation.
author Thomas Wuerthinger <thomas.wuerthinger@oracle.com>
date Tue, 18 Dec 2012 15:33:55 +0100
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children 5e3d1a68664e
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7259:494d99e07614 7267:a4b84ba6dc2e
1 /*
2 * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23 package com.oracle.truffle.api.nodes;
24
25 import java.lang.annotation.*;
26 import java.util.*;
27
28 /**
29 * Abstract base class for all Truffle nodes.
30 */
31 public abstract class Node implements Cloneable {
32
33 /**
34 * Utility constant representing an empty node array.
35 */
36 public static final Node[] EMPTY_ARRAY = new Node[0];
37
38 private Node parent;
39
40 /**
41 * Marks array fields that are children of this node.
42 */
43 @Retention(RetentionPolicy.RUNTIME)
44 @Target({ElementType.FIELD})
45 public @interface Children {
46 }
47
48 /**
49 * Marks fields that represent child nodes of this node.
50 */
51 @Retention(RetentionPolicy.RUNTIME)
52 @Target({ElementType.FIELD})
53 public @interface Child {
54 }
55
56 /**
57 * Method that updates the link to the parent in the array of specified new child nodes to this node.
58 *
59 * @param newChildren the array of new children whose parent should be updated
60 * @return the array of new children
61 */
62 protected final <T extends Node> T[] adoptChildren(T[] newChildren) {
63 if (newChildren != null) {
64 for (T n : newChildren) {
65 adoptChild(n);
66 }
67 }
68 return newChildren;
69 }
70
71 /**
72 * Method that updates the link to the parent in the specified new child node to this node.
73 *
74 * @param newChild the new child whose parent should be updated
75 * @return the new child
76 */
77 protected final <T extends Node> T adoptChild(T newChild) {
78 if (newChild != null) {
79 ((Node) newChild).parent = this;
80 }
81 return newChild;
82 }
83
84 /**
85 * Returns properties of this node interesting for debugging and can be overwritten by subclasses to add their own
86 * custom properties.
87 *
88 * @return the properties as a key/value hash map
89 */
90 public Map<String, Object> getDebugProperties() {
91 Map<String, Object> properties = new HashMap<>();
92 return properties;
93 }
94
95 /**
96 * The current parent node of this node.
97 *
98 * @return the parent node
99 */
100 public final Node getParent() {
101 return parent;
102 }
103
104 /**
105 * Replaces one child of this node with another node.
106 *
107 * @param oldChild the old child
108 * @param newChild the new child that should replace the old child
109 * @return the new child
110 */
111 public final <T extends Node> T replaceChild(T oldChild, T newChild) {
112 NodeUtil.replaceChild(this, oldChild, newChild);
113 adoptChild(newChild);
114 return newChild;
115 }
116
117 /**
118 * Replaces this node with another node.
119 *
120 * @param newNode the new node that is the replacement
121 * @param reason a description of the reason for the replacement
122 * @return the new node
123 */
124 @SuppressWarnings({"unchecked"})
125 public <T extends Node> T replace(T newNode, String reason) {
126 assert this.getParent() != null;
127 return (T) this.getParent().replaceChild(this, newNode);
128 }
129
130 /**
131 * Replaces this node with another node.
132 *
133 * @param newNode the new node that is the replacement
134 * @return the new node
135 */
136 public <T extends Node> T replace(T newNode) {
137 return replace(newNode, "");
138 }
139
140 /**
141 * Invokes the {@link NodeVisitor#visit(Node)} method for this node and recursively also for all child nodes.
142 *
143 * @param nodeVisitor the visitor
144 */
145 public final void accept(NodeVisitor nodeVisitor) {
146 if (nodeVisitor.visit(this)) {
147 for (Node child : this.getChildren()) {
148 if (child != null) {
149 child.accept(nodeVisitor);
150 }
151 }
152 }
153 }
154
155 /**
156 * Iterator over the children of this node.
157 *
158 * @return the iterator
159 */
160 public final Iterable<Node> getChildren() {
161 final Node node = this;
162 return new Iterable<Node>() {
163
164 public Iterator<Node> iterator() {
165 return new NodeUtil.NodeIterator(node);
166 }
167 };
168 }
169
170 /**
171 * Creates a shallow copy of this node.
172 *
173 * @return the new copy
174 */
175 public Node copy() {
176 try {
177 return (Node) super.clone();
178 } catch (CloneNotSupportedException e) {
179 return null;
180 }
181 }
182
183 /**
184 * This method must never be called. It enforces that {@link Object#clone} is not directly called by subclasses.
185 * Use the {@link #copy()} method instead.
186 */
187 @Override
188 @Deprecated
189 protected final Object clone() throws CloneNotSupportedException {
190 throw new IllegalStateException("This method should never be called, use the copy method instead!");
191 }
192
193 /**
194 * Converts this node to a textual representation useful for debugging.
195 */
196 @Override
197 public String toString() {
198 StringBuilder sb = new StringBuilder(getClass().getSimpleName());
199 Map<String, Object> properties = getDebugProperties();
200 boolean hasProperties = false;
201 for (Map.Entry<String, Object> entry : properties.entrySet()) {
202 sb.append(hasProperties ? "," : "<");
203 hasProperties = true;
204 sb.append(entry.getKey()).append("=").append(entry.getValue());
205 }
206 if (hasProperties) {
207 sb.append(">");
208 }
209 sb.append("@").append(Integer.toHexString(hashCode()));
210 return sb.toString();
211 }
212 }