string.java

  @JRubyMethod(name = "delete_prefix")
  public IRubyObject delete_prefix(ThreadContext context, IRubyObject arg) {
      IRubyObject tmp = arg.checkStringType();
      if (tmp.isNil()) throw context.runtime.newTypeError("no implicit conversion of " + arg.getMetaClass().getName() + " into String");
      RubyString prefix = (RubyString)tmp;
      if (this.start_with_p(context, prefix).isTrue()) {
          RubyString result = (RubyString) substr19(context.runtime, prefix.strLength(), this.strLength() - prefix.strLength());
          return result.isEmpty() ? this : result;
      } else {
          return this;
      }
  }

  @JRubyMethod(name = "delete_suffix")
  public IRubyObject delete_suffix(ThreadContext context, IRubyObject arg) {
      IRubyObject tmp = arg.checkStringType();
      if (tmp.isNil()) throw context.runtime.newTypeError("no implicit conversion of " + arg.getMetaClass().getName() + " into String");
      RubyString suffix = (RubyString)tmp;
      if (this.end_with_p(context, suffix).isTrue()) {
          RubyString result = (RubyString) substr19(context.runtime, 0, this.strLength() - suffix.strLength());
          return result.isEmpty() ? this : result;
      } else {
          return this;
      }
  }