JarCastingConstant String
Constant String is a library for doing constant time string manipulation in Java.
CString cs = CString.create("foo")
.concat(CString.create("bar"))
.substring(3)
.concat(CString.create("bara"))
.delete(3,7)
.insert(0, CString.create("foo"));
cs.toString(); // foobar
Perhaps not the most useful thing in everyday programming, but still a fun exercise to implement.
Using
The artifacts are published on Maven Central, so trying it out is as simple as adding the dependency to you pom.xml or gradle file.
<dependency>
<groupId>us.klette</groupId>
<artifactId>constantstring</artifactId>
<version>2.0</version>
</dependency>
API
Constant String exposes a simple API via the CString-interface. The static method CString.create(...) allows you to quickly create a new instance of a (hidden) implementation of the interface. Some of the operations are similar to the ones found on the built-in Java String class, such as the substring method. On these we try hard to map the arguments and functionality as close as possible.
Operations
The following operations are supported by the API.
toString()
The toString()-method evaluates the graph of operations, and returns the final result as a String. This is done in a non-constant time.
Create
Create a new CString instance from a String.
Example
CString myStr = CString.create("The start of my text goes like this..")
Substring
Extracts a part of a String, either only by start index to the end of the string, or by a start index and an end index.
Examples
myStr.substring(4).toString() // "start of my text goes like this.."
myStr.substring(4,8).toString() // "start"
Concat
Appends a String at the end of the current value.
Example
CString.create("foo")
.concat(CString.create("ba"))
.concat("r")
.toString() // "foobar"
Delete
Delete part of a string specified by a start index and an end index.
Example
CString.create("foobar").delete(3,6).toString() // "foo"
Insert
Inserts a String at a given index.
Example
CString.create("foar").insert("o",2).insert(CString.create("b"), 3).toString() // "foobar"