1 /*
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   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
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  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).
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  22  * or visit www.oracle.com if you need additional information or have any
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  25 
  26 /**
  27  * <h1>Library for generating Java source code</h1>.
  28  *
  29  * <p>
  30  * CodeModel is a library that allows you to generate Java source
  31  * code in a type-safe fashion.
  32  *
  33  * <p>
  34  * With CodeModel, you build the java source code by first building AST,
  35  * then writing it out as text files that is Java source files.
  36  * The AST looks like this:
  37  *
  38  * {@DotDiagram
  39     digraph G {
  40         cls1 [label="JDefinedClass"];
  41         cls2 [label="JDefinedClass"];
  42         JCodeModel -> cls1 [label="generated class"];
  43         JCodeModel -> cls2 [label="generated class"];
  44 
  45         m1 [label="JMethod"];
  46         m2 [label="JMethod"];
  47 
  48         cls1 -> m1;
  49         cls1 -> m2;
  50         cls1 -> JField;
  51 
  52         m1 -> JVar [label="method parameter"];
  53         m1 -> JBlock [label="code"];
  54     }
  55  * }
  56  *
  57  * <p>
  58  * You bulid this tree mostly from top-down. So, you first create
  59  * a new {@link JDefinedClass} from {@link JCodeModel}, then you
  60  * create a {@link JMethod} from {@link JDefinedClass}, and so on.
  61  *
  62  * <p>
  63  * This design brings the following beneefits:
  64  *
  65  * <ul>
  66  *  <li>source code can be written in random order
  67  *  <li>generated source code nicely imports other classes
  68  *  <li>generated source code is lexically always correct
  69  *      (no unbalanced parenthesis, etc.)
  70  *  <li>code generation becomes relatively type-safe
  71  * </ul>
  72  *
  73  * The price you pay for that is
  74  * increased memory footprint and the generation speed.
  75  * See <a href="#performance">performance section</a> for
  76  * more discussions about the performance and possible improvements.
  77  *
  78  *
  79  * <h2>Using CodeModel</h2>
  80  * <p>
  81  * {@link com.sun.codemodel.internal.JCodeModel} is the entry point to
  82  * the library. See its javadoc for more details about how to use
  83  * CodeModel.
  84  *
  85  *
  86  *
  87  * <h2>Performance</h2>
  88  * <p>
  89  * Generally speaking, CodeModel is expected to be used in
  90  * an environment where the resource constraint is not severe.
  91  * Therefore, we haven't spent much effort in trying to make
  92  * this library lean and mean.
  93  *
  94  * <p>
  95  * That said, we did some benchmark and performance analysis.
  96  * In case anyone is interested in making this library
  97  * better performance wise, here's the findings.
  98  *
  99  * <p>
 100  * {@link List}s {@link Map}s, and other collections take up
 101  * a lot of space. Allocating those things lazily is generally
 102  * a good idea.
 103  *
 104  * <p>
 105  * Compared to template-based code generator, the writing operation
 106  * is slow, as it needs to traverse each AST node. Consider
 107  * pre-encoding tokens (like 'public') to the target encoding,
 108  * and consider exploting the subtree equivalence.
 109  *
 110  * @ArchitectureDocument
 111  */
 112 package com.sun.codemodel.internal;
 113 
 114 import java.util.List;
 115 import java.util.Map;