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1   /*
2    * Copyright (c) 2010, 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  
26  package jdk.nashorn.internal.ir;
27  
28  import jdk.nashorn.internal.ir.annotations.Immutable;
29  import jdk.nashorn.internal.ir.visitor.NodeVisitor;
30  
31  /**
32   * IR representation for executing bare expressions. Basically, an expression
33   * node means "this code will be executed" and evaluating it results in
34   * statements being added to the IR
35   */
36  @Immutable
37  public final class ExpressionStatement extends Statement {
38      /** Expression to execute. */
39      private final Expression expression;
40  
41      /**
42       * Constructor
43       *
44       * @param lineNumber line number
45       * @param token      token
46       * @param finish     finish
47       * @param expression the expression to execute
48       */
49      public ExpressionStatement(final int lineNumber, final long token, final int finish, final Expression expression) {
50          super(lineNumber, token, finish);
51          this.expression = expression;
52      }
53  
54      private ExpressionStatement(final ExpressionStatement expressionStatement, final Expression expression) {
55          super(expressionStatement);
56          this.expression = expression;
57      }
58  
59      @Override
60      public boolean isTerminal() {
61          return expression.isTerminal();
62      }
63  
64      @Override
65      public Node accept(final NodeVisitor<? extends LexicalContext> visitor) {
66          if (visitor.enterExpressionStatement(this)) {
67              return visitor.leaveExpressionStatement(setExpression((Expression)expression.accept(visitor)));
68          }
69  
70          return this;
71      }
72  
73      @Override
74      public void toString(final StringBuilder sb) {
75          expression.toString(sb);
76      }
77  
78      /**
79       * Return the expression to be executed
80       * @return the expression
81       */
82      public Expression getExpression() {
83          return expression;
84      }
85  
86      /**
87       * Reset the expression to be executed
88       * @param expression the expression
89       * @return new or same execute node
90       */
91      public ExpressionStatement setExpression(final Expression expression) {
92          if (this.expression == expression) {
93              return this;
94          }
95          return new ExpressionStatement(this, expression);
96      }
97  }