Sat, 01 Dec 2007 00:00:00 +0000
Initial load
1 /*
2 * Copyright 1999-2006 Sun Microsystems, Inc. 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. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Sun in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any questions.
24 */
26 package com.sun.tools.javac.comp;
28 import com.sun.tools.javac.util.*;
29 import com.sun.tools.javac.tree.*;
30 import java.util.Iterator;
31 import java.util.NoSuchElementException;
33 /** A class for environments, instances of which are passed as
34 * arguments to tree visitors. Environments refer to important ancestors
35 * of the subtree that's currently visited, such as the enclosing method,
36 * the enclosing class, or the enclosing toplevel node. They also contain
37 * a generic component, represented as a type parameter, to carry further
38 * information specific to individual passes.
39 *
40 * <p><b>This is NOT part of any API supported by Sun Microsystems. If
41 * you write code that depends on this, you do so at your own risk.
42 * This code and its internal interfaces are subject to change or
43 * deletion without notice.</b>
44 */
45 public class Env<A> implements Iterable<Env<A>> {
47 /** The next enclosing environment.
48 */
49 public Env<A> next;
51 /** The environment enclosing the current class.
52 */
53 public Env<A> outer;
55 /** The tree with which this environment is associated.
56 */
57 public JCTree tree;
59 /** The enclosing toplevel tree.
60 */
61 public JCTree.JCCompilationUnit toplevel;
63 /** The next enclosing class definition.
64 */
65 public JCTree.JCClassDecl enclClass;
67 /** The next enclosing method definition.
68 */
69 public JCTree.JCMethodDecl enclMethod;
71 /** A generic field for further information.
72 */
73 public A info;
75 /** Is this an environment for evaluating a base clause?
76 */
77 public boolean baseClause = false;
79 /** Create an outermost environment for a given (toplevel)tree,
80 * with a given info field.
81 */
82 public Env(JCTree tree, A info) {
83 this.next = null;
84 this.outer = null;
85 this.tree = tree;
86 this.toplevel = null;
87 this.enclClass = null;
88 this.enclMethod = null;
89 this.info = info;
90 }
92 /** Duplicate this environment, updating with given tree and info,
93 * and copying all other fields.
94 */
95 public Env<A> dup(JCTree tree, A info) {
96 return dupto(new Env<A>(tree, info));
97 }
99 /** Duplicate this environment into a given Environment,
100 * using its tree and info, and copying all other fields.
101 */
102 public Env<A> dupto(Env<A> that) {
103 that.next = this;
104 that.outer = this.outer;
105 that.toplevel = this.toplevel;
106 that.enclClass = this.enclClass;
107 that.enclMethod = this.enclMethod;
108 return that;
109 }
111 /** Duplicate this environment, updating with given tree,
112 * and copying all other fields.
113 */
114 public Env<A> dup(JCTree tree) {
115 return dup(tree, this.info);
116 }
118 /** Return closest enclosing environment which points to a tree with given tag.
119 */
120 public Env<A> enclosing(int tag) {
121 Env<A> env1 = this;
122 while (env1 != null && env1.tree.getTag() != tag) env1 = env1.next;
123 return env1;
124 }
126 public String toString() {
127 return "Env[" + info + (outer == null ? "" : ",outer=" + outer) + "]";
128 }
130 public Iterator<Env<A>> iterator() {
131 return new Iterator<Env<A>>() {
132 Env<A> next = Env.this;
133 public boolean hasNext() {
134 return next.outer != null;
135 }
136 public Env<A> next() {
137 if (hasNext()) {
138 Env<A> current = next;
139 next = current.outer;
140 return current;
141 }
142 throw new NoSuchElementException();
144 }
145 public void remove() {
146 throw new UnsupportedOperationException();
147 }
148 };
149 }
150 }