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1   /**
2    * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
3    */
4   package net.sourceforge.pmd.dcd;
5   
6   import java.io.File;
7   import java.io.FilenameFilter;
8   import java.util.ArrayList;
9   import java.util.Arrays;
10  import java.util.List;
11  
12  import net.sourceforge.pmd.dcd.graph.UsageGraph;
13  import net.sourceforge.pmd.dcd.graph.UsageGraphBuilder;
14  import net.sourceforge.pmd.util.FileFinder;
15  import net.sourceforge.pmd.util.filter.Filter;
16  import net.sourceforge.pmd.util.filter.Filters;
17  
18  /**
19   * The Dead Code Detector is used to find dead code.  What is dead code?
20   * Dead code is code which is not used by other code?  It exists, but it not
21   * used.  Unused code is clutter, which can generally be a candidate for
22   * removal.
23   * <p>
24   * When performing dead code detection, there are various sets of files/classes
25   * which must be identified.  An analogy of the dead code analysis as
26   * a <em>foot race</em> is used to help clarify each of these sets:
27   * <ol>
28   * <li>The <em>direct users</em> is the set of Classes which will always be
29   * parsed to determine what code they use.  This set is the starting point of
30   * the race.</li>
31   * <li>The <em>indirect users</em> is the set of Classes which will only be
32   * parsed if they are accessed by code in the <em>direct users</em> set, or
33   * in the <em>indirect users</em> set.  This set is the course of the race.</li>
34   * <li>The <em>dead code candidates</em> are the set of Classes which are the
35   * focus of the dead code detection.  This set is the finish line of the
36   * race.</li>
37   * </ol>
38   * <p>
39   * Typically there is intersection between the set of <em>direct users</em>,
40   * <em>indirect users</em> and <em>dead code candidates</em>, although it is
41   * not required.  If the sets are defined too tightly, there the potential for
42   * a lot of code to be considered as dead code.  You may need to expand the
43   * <em>direct users</em> or <em>indirect users</em> sets, or explore using
44   * different options.
45   *
46   * @author Ryan Gustafson <ryan.gustafson@gmail.com>,
47   */
48  public class DCD {
49  	//
50  	// TODO Implement the direct users, indirect users, and dead code
51  	// candidate sets.  Use the pmd.util.filter.Filter APIs.  Need to come up
52  	// with something like Ant's capabilities for <fileset>, it's a decent way
53  	// to describe a collection of files in a directory structure.  That or we
54  	// just adopt Ant, and screw command line/external configuration?
55  	//
56  	// TODO Better yet, is there a way to enumerate all available classes using
57  	// ClassLoaders instead of having to specify Java file names as surrogates
58  	// for the Classes we truly desire?
59  	//
60  	// TODO Methods defined on classes/interfaces not within the scope of
61  	// analysis which are implemented/overridden, are not usage violations.
62  	//
63  	// TODO Static final String and primitive types are often inlined by the
64  	// compiler, so there may actually be no explicit usages.
65  	//
66  	// TODO Ignore "public static void main(String[])"
67  	//
68  	// TODO Check for method which is always overridden, and never called
69  	// directly.
70  	//
71  	// TODO For methods, record which classes/interfaces methods they are
72  	// overriding/implementing.
73  	//
74  	// TODO Allow recognition of indirect method patterns, like those used by
75  	// EJB Home and Remote interfaces with corresponding implementation classes.
76  	//
77  	// TODO
78  	// 1) For each class/member, a set of other class/members which reference.
79  	// 2) For every class/member which is part of an interface or super-class,
80  	// allocate those references to the interface/super-class.
81  	//
82  
83  	public static void dump(UsageGraph usageGraph, boolean verbose) {
84  		usageGraph.accept(new DumpNodeVisitor(), Boolean.valueOf(verbose));
85  	}
86  
87  	public static void report(UsageGraph usageGraph, boolean verbose) {
88  		usageGraph.accept(new UsageNodeVisitor(), Boolean.valueOf(verbose));
89  	}
90  
91  	public static void main(String[] args) throws Exception {
92  		// 1) Directories
93  		List<File> directories = new ArrayList<>();
94  		directories.add(new File("C:/pmd/workspace/pmd-trunk/src"));
95  
96  		// Basic filter
97  		FilenameFilter javaFilter = new FilenameFilter() {
98  			public boolean accept(File dir, String name) {
99  				// Recurse on directories
100 				if (new File(dir, name).isDirectory()) {
101 					return true;
102 				} else {
103 					return name.endsWith(".java");
104 				}
105 			}
106 		};
107 
108 		// 2) Filename filters
109 		List<FilenameFilter> filters = new ArrayList<>();
110 		filters.add(javaFilter);
111 
112 		assert directories.size() == filters.size();
113 
114 		// Find all files, convert to class names
115 		List<String> classes = new ArrayList<>();
116 		for (int i = 0; i < directories.size(); i++) {
117 			File directory = directories.get(i);
118 			FilenameFilter filter = filters.get(i);
119 			List<File> files = new FileFinder().findFilesFrom(directory, filter, true);
120 			for (File file : files) {
121 				String name = file.getPath();
122 
123 				// Chop off directory
124 				name = name.substring(directory.getPath().length() + 1);
125 
126 				// Drop extension
127 				name = name.replaceAll("\\.java$", "");
128 
129 				// Trim path separators
130 				name = name.replace('\\', '.');
131 				name = name.replace('/', '.');
132 
133 				classes.add(name);
134 			}
135 		}
136 
137 		long start = System.currentTimeMillis();
138 
139 		// Define filter for "indirect users" and "dead code candidates".
140 		// TODO Need to support these are different concepts.
141 		List<String> includeRegexes = Arrays.asList(new String[] { "net\\.sourceforge\\.pmd\\.dcd.*", "us\\..*" });
142 		List<String> excludeRegexes = Arrays.asList(new String[] { "java\\..*", "javax\\..*", ".*\\.twa\\..*" });
143 		Filter<String> classFilter = Filters.buildRegexFilterExcludeOverInclude(includeRegexes, excludeRegexes);
144 		System.out.println("Class filter: " + classFilter);
145 
146 		// Index each of the "direct users"
147 		UsageGraphBuilder builder = new UsageGraphBuilder(classFilter);
148 		int total = 0;
149 		for (String clazz : classes) {
150 			System.out.println("indexing class: " + clazz);
151 			builder.index(clazz);
152 			total++;
153 			if (total % 20 == 0) {
154 				System.out.println(total + " : " + total / ((System.currentTimeMillis() - start) / 1000.0));
155 			}
156 		}
157 
158 		// Reporting
159 		boolean dump = true;
160 		boolean deadCode = true;
161 		UsageGraph usageGraph = builder.getUsageGraph();
162 		if (dump) {
163 			System.out.println("--- Dump ---");
164 			dump(usageGraph, true);
165 		}
166 		if (deadCode) {
167 			System.out.println("--- Dead Code ---");
168 			report(usageGraph, true);
169 		}
170 		long end = System.currentTimeMillis();
171 		System.out.println("Time: " + (end - start) / 1000.0);
172 	}
173 }