Env.java revision 2571:10fc81ac75b4 
1/*
2 * Copyright (c) 1999, 2013, 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.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package com.sun.tools.javac.comp;
27
28import com.sun.tools.javac.tree.*;
29import com.sun.tools.javac.tree.JCTree.JCLambda;
30import java.util.Iterator;
31import java.util.NoSuchElementException;
32
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 supported API.
41 *  If 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 */
45public class Env<A> implements Iterable<Env<A>> {
46
47    /** The next enclosing environment.
48     */
49    public Env<A> next;
50
51    /** The environment enclosing the current class.
52     */
53    public Env<A> outer;
54
55    /** The tree with which this environment is associated.
56     */
57    public JCTree tree;
58
59    /** The enclosing toplevel tree.
60     */
61    public JCTree.JCCompilationUnit toplevel;
62
63    /** The next enclosing class definition.
64     */
65    public JCTree.JCClassDecl enclClass;
66
67    /** The next enclosing method definition.
68     */
69    public JCTree.JCMethodDecl enclMethod;
70
71    /** A generic field for further information.
72     */
73    public A info;
74
75    /** Is this an environment for evaluating a base clause?
76     */
77    public boolean baseClause = false;
78
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    }
91
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<>(tree, info));
97    }
98
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    }
110
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    }
117
118    /** Return closest enclosing environment which points to a tree with given tag.
119     */
120    public Env<A> enclosing(JCTree.Tag tag) {
121        Env<A> env1 = this;
122        while (env1 != null && !env1.tree.hasTag(tag)) env1 = env1.next;
123        return env1;
124    }
125
126    @Override
127    public String toString() {
128        StringBuilder sb = new StringBuilder();
129        sb.append("Env[").append(info);
130//        if (enclMethod != null)
131//            sb.append(",enclMethod=").append(Pretty.toSimpleString(enclMethod));
132//        if (enclClass != null)
133//            sb.append(",enclClass=").append(Pretty.toSimpleString(enclClass));
134        if (outer != null)
135            sb.append(",outer=").append(outer);
136        sb.append("]");
137        return sb.toString();
138    }
139
140    public Iterator<Env<A>> iterator() {
141        return new Iterator<Env<A>>() {
142            Env<A> next = Env.this;
143            public boolean hasNext() {
144                return next.outer != null;
145            }
146            public Env<A> next() {
147                if (hasNext()) {
148                    Env<A> current = next;
149                    next = current.outer;
150                    return current;
151                }
152                throw new NoSuchElementException();
153
154            }
155            public void remove() {
156                throw new UnsupportedOperationException();
157            }
158        };
159    }
160
161    public JCLambda getLambda() {
162        Env<A> out = enclosing(JCTree.Tag.LAMBDA);
163
164        return out != null ? (JCLambda) out.tree : null;
165    }
166}
167