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55  * by Daniel F. Savarese. We appreciate his contributions.
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57
58 import org.apache.oro.text.regex.*;
59
60 /**
61  * This is a test program demonstrating the difference between the
62  * matches() and contains() methods.
63  *
64  @author <a HREF="dfs@savarese.org">Daniel F. Savarese</a>
65  @version $Id: matchesContainsExample.java,v 1.1.1.1 2000/07/23 23:08:48 jon Exp $
66  */
67 public final class matchesContainsExample {
68
69   /**
70    * A common mistake is to confuse the behavior of the matches() and
71    * contains() methods. matches() tests to see if a string exactly
72    * matches a pattern whereas contains() searches for the first pattern
73    * match contained somewhere within the string. When used with a
74    * PatternMatcherInput instance, the contains() method allows you to
75    * search for every pattern match within a string by using a while loop.
76    */
77   public static final void main(String JavaDoc args[]) {
78     int matches = 0;
79     String JavaDoc numberExpression = "\\d+";
80     String JavaDoc exactMatch = "2010";
81     String JavaDoc containsMatches =
82    " 2001 was the movie before 2010, which takes place before 2069 the book ";
83     Pattern pattern = null;
84     PatternMatcherInput input;
85     PatternCompiler compiler;
86     PatternMatcher matcher;
87     MatchResult result;
88
89     // Create Perl5Compiler and Perl5Matcher instances.
90 compiler = new Perl5Compiler();
91     matcher = new Perl5Matcher();
92
93     // Attempt to compile the pattern. If the pattern is not valid,
94 // report the error and exit.
95 try {
96       pattern = compiler.compile(numberExpression);
97     } catch(MalformedPatternException e) {
98       System.err.println("Bad pattern.");
99       System.err.println(e.getMessage());
100       System.exit(1);
101     }
102
103     // Here we show the difference between the matches() and contains()
104 // methods(). Compile the program and study the output to reinforce
105 // in your mind what the methods do.
106
107     System.out.println("Input: " + exactMatch);
108
109     // The following should return true because exactMatch exactly matches
110 // numberExprssion.
111
112     if(matcher.matches(exactMatch, pattern))
113       System.out.println("matches() Result: TRUE, EXACT MATCH");
114     else
115       System.out.println("matches() Result: FALSE, NOT EXACT MATCH");
116
117     System.out.println("\nInput: " + containsMatches);
118
119     // The following should return false because containsMatches does not
120 // exactly match numberExpression even though its subparts do.
121
122     if(matcher.matches(containsMatches, pattern))
123       System.out.println("matches() Result: TRUE, EXACT MATCH");
124     else
125       System.out.println("matches() Result: FALSE, NOT EXACT MATCH");
126
127
128     // Now we call the contains() method. contains() should return true
129 // for both strings.
130
131     System.out.println("\nInput: " + exactMatch);
132
133     if(matcher.contains(exactMatch, pattern)) {
134       System.out.println("contains() Result: TRUE");
135
136       // Fetch match and print.
137 result = matcher.getMatch();
138       System.out.println("Match: " + result);
139     } else
140       System.out.println("contains() Result: FALSE");
141
142     System.out.println("\nInput: " + containsMatches);
143
144     if(matcher.contains(containsMatches, pattern)) {
145       System.out.println("contains() Result: TRUE");
146       // Fetch match and print.
147 result = matcher.getMatch();
148       System.out.println("Match: " + result);
149     } else
150       System.out.println("contains() Result: FALSE");
151
152
153     // In the previous example, notice how contains() will fetch only first
154 // match in a string. If you want to search a string for all of the
155 // matches it contains, you must create a PatternMatcherInput object
156 // to keep track of the position of the last match, so you can pick
157 // up a search where the last one left off.
158
159     input = new PatternMatcherInput(containsMatches);
160
161     System.out.println("\nPatternMatcherInput: " + input);
162     // Loop until there are no more matches left.
163 while(matcher.contains(input, pattern)) {
164       // Since we're still in the loop, fetch match that was found.
165 result = matcher.getMatch();
166
167       ++matches;
168
169       System.out.println("Match " + matches + ": " + result);
170     }
171   }
172 }
173
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