# Use StringBuilder::append
# Description
Replaces the infix operator + over String concatenations with at least three operands by StringBuilder::append. When possible, unwraps the parenthesized expressions.
# Benefits
Improves the performance of the String concatenations.
# Tags
# Code Changes
# Concatenating strings in infix expressions
Pre
String value = "prefix" + "value" + "suffix";
Post
String value = new StringBuilder().append("prefix")
.append("value")
.append("suffix")
.toString();
# Resolving types of arithmetic expressions
Pre
String value = "prefix" + 2 * 3 + ("value" + 2 + 3) + (4 + 5) + "suffix";
Post
String value = new StringBuilder().append("prefix")
.append(2*3)
.append("value")
.append(2)
.append(3)
.append(4 + 5)
.append("suffix")
.toString();
# Resolving types of numeric literals
Pre
String value = 5 + " (five) = " + 3 + " (three) + " + 2 + " (two).";
Post
String value = new StringBuilder().append(5)
.append(" (five) = ")
.append(3)
.append(" (three) + ")
.append(2)
.append(" (two).")
.toString();
# Limitations
If at least two of the first operands of the expression are numeric additions then the expression is evaluated by Java as numeric expression rather than String expression. Therefore, the transformation is not performed. E.g.:
Pre
String value = 2 + 3 + "";
Use a Java Refactoring Tool
No license required
You can review this refactoring on your code without a license by installing jSparrow to your Eclipse IDE. Install the plug-in from Eclipse IDE: Eclipse Marketplace.
System-wide Refactoring
Do you want to automate this refactoring (and many more) to your system-wide code? The automatic application of this system-wide refactoring can be unlocked by acquiring your jSparrow license.
