In this article, we will discuss how to get length of StringBuffer object using StringBuffer’s length() method
1. StringBuffer’s length() method:
- This StringBuffer method is used to get length of the StringBuffer or character count
- That’s sequence of characters or number of characters appended/inserted into StringBuffer
Method Signature:
public int length();
Returns:
- Returns length i.e.; character count
2. Examples on length() method:
Generally, length() method of StringBuffer class is used for following purpose,
- To get length or character count
- for-loop: used to keep boundary condition, while iterating
- while-loop: used to keep boundary condition, while iterating
- do-while-loop: used to keep boundary condition, while iterating
- To create equivalent char[] array
Let’s see examples for each listed above cases:
2.1 To get length or character count of StringBuffer
StringBufferLengthMethod.java
package in.bench.resources.stringbuffer.methods;
public class StringBufferLengthMethod {
public static void main(String[] args) {
// StringBuffer object
StringBuffer sbUrl = new StringBuffer(
"BenchResources.Net");
// to check length of the StringBuffer
int length = sbUrl.length();
// print to console
System.out.println("The length of StringBuffer '"
+ sbUrl + "' is " + length);
}
}
Output:
The length of StringBuffer 'BenchResources.Net' is 18
2.2 Boundary condition for for-loop while iterating
StringBufferLengthForLoop.java
package in.bench.resources.stringbuffer.methods;
public class StringBufferLengthForLoop {
public static void main(String[] args) {
// StringBuffer object
StringBuffer sbUrl = new StringBuffer(
"BenchResources.Net");
// iterating using for-loop
for(int index = 0; index < sbUrl.length(); index++) {
System.out.println("StringBuffer character at "
+ index + "-position is : "
+ sbUrl.charAt(index));
}
}
}
Output:
StringBuffer character at 0-position is : B
StringBuffer character at 1-position is : e
StringBuffer character at 2-position is : n
StringBuffer character at 3-position is : c
StringBuffer character at 4-position is : h
StringBuffer character at 5-position is : R
StringBuffer character at 6-position is : e
StringBuffer character at 7-position is : s
StringBuffer character at 8-position is : o
StringBuffer character at 9-position is : u
StringBuffer character at 10-position is : r
StringBuffer character at 11-position is : c
StringBuffer character at 12-position is : e
StringBuffer character at 13-position is : s
StringBuffer character at 14-position is : .
StringBuffer character at 15-position is : N
StringBuffer character at 16-position is : e
StringBuffer character at 17-position is : t
2.3 Boundary condition for while-loop while iterating
StringBufferLengthWhileLoop.java
package in.bench.resources.stringbuffer.methods;
public class StringBufferLengthWhileLoop {
public static void main(String[] args) {
// StringBuffer object
StringBuffer sbUrl = new StringBuffer(
"BenchResources.Net");
// initialize index
int index = 0;
// get length
int length = sbUrl.length();
// iterating using while-loop
while(index < length){
// print to console
System.out.println("StringBuffer character at "
+ index + "-position is : "
+ sbUrl.charAt(index));
// increment index-value by 1
index++;
}
}
}
Output:
StringBuffer character at 0-position is : B
StringBuffer character at 1-position is : e
StringBuffer character at 2-position is : n
StringBuffer character at 3-position is : c
StringBuffer character at 4-position is : h
StringBuffer character at 5-position is : R
StringBuffer character at 6-position is : e
StringBuffer character at 7-position is : s
StringBuffer character at 8-position is : o
StringBuffer character at 9-position is : u
StringBuffer character at 10-position is : r
StringBuffer character at 11-position is : c
StringBuffer character at 12-position is : e
StringBuffer character at 13-position is : s
StringBuffer character at 14-position is : .
StringBuffer character at 15-position is : N
StringBuffer character at 16-position is : e
StringBuffer character at 17-position is : t
2.4 Boundary condition for do-while-loop while iterating
StringBufferLengthDoWhileLoop.java
package in.bench.resources.stringbuffer.methods;
public class StringBufferLengthDoWhileLoop {
public static void main(String[] args) {
// StringBuffer object
StringBuffer sbUrl = new StringBuffer(
"BenchResources.Net");
// initialize index
int index = 0;
// get length
int length = sbUrl.length();
// iterating using do-while-loop
do {
// print to console
System.out.println("StringBuffer character at "
+ index + "-position is : "
+ sbUrl.charAt(index));
// increment index-value by 1
index++;
} while(index < length);
}
}
Output:
StringBuffer character at 0-position is : B
StringBuffer character at 1-position is : e
StringBuffer character at 2-position is : n
StringBuffer character at 3-position is : c
StringBuffer character at 4-position is : h
StringBuffer character at 5-position is : R
StringBuffer character at 6-position is : e
StringBuffer character at 7-position is : s
StringBuffer character at 8-position is : o
StringBuffer character at 9-position is : u
StringBuffer character at 10-position is : r
StringBuffer character at 11-position is : c
StringBuffer character at 12-position is : e
StringBuffer character at 13-position is : s
StringBuffer character at 14-position is : .
StringBuffer character at 15-position is : N
StringBuffer character at 16-position is : e
StringBuffer character at 17-position is : t
Difference between while-loop and do-while-loop ?
- do-while-loop checks boundary condition, after 1st loop iteration (at least 1 iteration is possible)
- while-loop checks boundary condition even before 1st iteration (no iteration is possible without satisfying loop-entry condition)
2.5 To create equivalent char[] array
StringBufferLengthCreateCharArray.java
package in.bench.resources.stringbuffer.methods;
public class StringBufferLengthCreateCharArray {
public static void main(String[] args) {
// StringBuffer object
StringBuffer sbUrl = new StringBuffer(
"BenchResources.Net");
// get length
int length = sbUrl.length();
// create character array object
char[] chArray = new char[length];
// iterate using for-loop & store into char[] array
for (int index = 0; index < length ; index++) {
// store into char[] array
chArray[index] = sbUrl.charAt(index);
}
// print to console - this is demo purpose
System.out.println("The converted char[] array is : "
+ String.valueOf(chArray));
}
}
Output:
The converted char[] array is : BenchResources.Net
Related Articles:
- StringBuffer class
- StringBuffer append() method (13)
- StringBuffer capacity() method
- StringBuffer charAt(int index) method
- StringBuffer delete(int start, int end) method
- StringBuffer deleteCharAt(int index) method
- StringBuffer ensureCapacity(int minimumCapacity) method
- StringBuffer indexOf() method (2)
- StringBuffer insert() method (12)
- StringBuffer lastIndexOf() method (2)
- StringBuffer length() method
- StringBuffer replace(int start, int end, String str) method
- StringBuffer reverse() method
- StringBuffer substring(int start, int end) method
References:
- https://docs.oracle.com/javase/tutorial/essential/concurrency/immutable.html
- https://docs.oracle.com/javase/tutorial/essential/concurrency/imstrat.html
- https://docs.oracle.com/javase/tutorial/java/data/strings.html
- https://docs.oracle.com/javase/8/docs/api/java/lang/String.html
- https://docs.oracle.com/javase/8/docs/api/java/lang/class-use/String.html
- https://docs.oracle.com/javase/8/docs/api/java/lang/StringBuffer.html
- https://docs.oracle.com/javase/8/docs/api/java/lang/StringBuilder.html
Happy Coding !!
Happy Learning !!
