Sunday, January 4, 2015

Google Gauva API in a one glance: Splitter and Strings class

Splitter Class

@GwtCompatible(emulated=true)
public final class Splitter
extends Object
Extracts non-overlapping substrings from an input string, typically by recognizing appearances of a separator sequence. This separator can be specified as a single character, fixed stringregular expression or CharMatcher instance. Or, instead of using a separator at all, a splitter can extract adjacent substrings of a given fixed length.

work opposite to the joiner, Split string into the elements of collection using delimeter which can be sequence of chars,CharMatcher or a regex.
let's see how splitter work using sample code.
/**
 * 
 */
package com.rajkrrsingh.test.guava;

import java.util.Iterator;

import com.google.common.base.Splitter;

/**
 * @author rks
 * @04-Jan-2015
 */
public class GuavaSplitterDemo {

 public static void main(String[] args) {
  splitterDemo();
 }

 // Split a string into a collection of elements
 public static void splitterDemo(){
  Iterator<String> itr = Splitter.on("#").split("RKS#John#Harry#Tom").iterator();
  while(itr.hasNext()){
   System.out.println(itr.next());
  }
  // split on pattern
  Iterator<String> itr1 = Splitter.onPattern("\\d+").split("RKS1John2Harry3Tom").iterator();
  while(itr1.hasNext()){
   System.out.println(itr1.next());
  }
  // omit empty string
  Iterator<String> itr2 = Splitter.on("#").omitEmptyStrings().trimResults().split("RKS# #John#   #Harry#Tom").iterator();
  while(itr2.hasNext()){
   System.out.println(itr2.next());
  }
  // fixed length string extractor
  Iterator<String> itr3 = Splitter.fixedLength(3).split("RKS#John#Harry#Tom").iterator();
  while(itr3.hasNext()){
   System.out.println(itr3.next());
  }
 }
}


Strings Class

@GwtCompatible
public final class Strings
extends Object
Static utility methods pertaining to String or CharSequence instances.

lets see how splitter work using the following sample code.
/**
* 
*/
package com.rajkrrsingh.test.guava;

import com.google.common.base.Strings;

/**
* @author rks
* @04-Jan-2015
*/
public class GuavaStringsDemo {

public static void main(String[] args) {
stringHelper();
}

// helper class to String 
public static void stringHelper(){
String str = ""; 
if(Strings.isNullOrEmpty(str)){
System.out.println("String is null or empty");
}
System.out.println(Strings.nullToEmpty(str));
System.out.println(Strings.emptyToNull(Strings.nullToEmpty(str)));
//repeat a string 
System.out.println(Strings.repeat("RKS", 3));
// string padding
System.out.println(Strings.padEnd("RKS", 10, '*'));
System.out.println(Strings.padStart("RKS", 10, '*'));
}
}


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