Pattern\matcher Combination of Java Basics

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Pattern:

Pattern
   
     
    

     
      
    Extends Object
   
     
    
   
     
    

     
      
    Implements Serializable
   
     
    

The compiled representation of the regular expression.

A regular expression that is specified as a string must first be compiled into an instance of this class. The resulting pattern can then be used to create an Matcher object that, according to the regular expression, can match any sequence of characters . All the states involved in performing a match reside in the match, so multiple matches can share the same pattern.

Therefore, the typical invocation order is

Pattern p = pattern. compile ("A*b"); Matcher m = p. matcher ("Aaaaab"); Boolean b = M. matches ();

This class is a convenient way to define a method when you use only one regular expression matches . This method compiles an expression and matches the input sequence in a single call. Statement

Boolean B = pattern.matches ("A*b", "Aaaaab");

is equivalent to the three statements above, although it is inefficient for duplicate matches because it does not allow the reuse of compiled schemas.

Matcher:

Matcher
   
     
    

     
      
    Extends Object
   
     
    
   
     
    

     
      
    Implements Matchresult
   
     
    

By explaining Pattern the engine that performs the matching operation on the character sequence.

Creates a match from a pattern by invoking the mode's matcher method. After you create a match, you can use it to perform three different matching operations:

• matchesMethod attempts to match the entire input sequence to the pattern.

• lookingAtAttempts to match the input sequence to the pattern from the beginning.

• findmethod to scan the input sequence to find the next subsequence that matches the pattern.

Each method returns a Boolean value that represents success or failure. You can get more information about a successful match by querying the status of the match.

Typical uses are:

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Pattern\matcher Combination of Java Basics