Builder-pattern

Test.java

public class Test {
    private String text;

    public String getText() {
        return text;
    }
    
    public class Builder {
        boolean isBuilt = false;

        public Builder withText(String text) {
            Test.this.text = text;
            return this;
        }

        public Test build() {
            if (isBuilt) {
                throw new IllegalArgumentException("Can only be built once");
            }
            isBuilt = true;
            return Test.this;
        }
    }
    
    public static Builder getBuilder() {
        return new Test().new Builder();
    }
}