--- Martin Cooper <[EMAIL PROTECTED]> wrote: > > > > -----Original Message----- > > From: David Graham [mailto:[EMAIL PROTECTED] > > Sent: Sunday, February 15, 2004 1:01 PM > > To: Struts Developers List > > Subject: RE: string concatenation > > > > > > Struts has many dependencies already and I'd like to avoid adding one > with > > lang. Why not just size a large StringBuffer and trade memory for > speed? > > We already have a dependency on Lang, albeit indirectly, so why not take > advantage of it?
I don't believe that's correct. What component has a dependency on lang that we use? We need it for testing but it's not included in the Struts distro. > > Frankly, I disagree with the push I see from some folks (including Craig > on > commons-dev recently) to reduce dependencies between components by > duplicating functionality. The whole point of Commons is to avoid > duplication, so why are people pushing back against using the successful > components that we helped create here in Struts? In the cases I know of the usage of other components is very limited and not needed. Examples are Digester and BeanUtils using one class from collections in very few places when we would be better off dropping collections and using standard Java collections. David > > -- > Martin Cooper > > > > > > David > > > > --- Martin Cooper <[EMAIL PROTECTED]> wrote: > > > Rather than add a new string utility class to Struts, which isn't > really > > > where it should belong, I think we'd be better off just using this: > > > > > > > > http://jakarta.apache.org/commons/lang/api/org/apache/commons/lang > > /StringUti > > > ls.html#join(java.lang.Object[]) > > > > > > Alternatively, you could suggest (on the commons-dev list) adding a > > > variation of your StringHolder class, based on the join() method > above, > > > to > > > Commons Lang. > > > > > > -- > > > Martin Cooper > > > > > > > > > > -----Original Message----- > > > > From: nishant kumar [mailto:[EMAIL PROTECTED] > > > > Sent: Saturday, February 14, 2004 5:46 PM > > > > To: [EMAIL PROTECTED] > > > > Subject: string concatenation > > > > > > > > > > > > hi, > > > > I have a performance tuning suggestion which i think will greatly > > > > impact the performance of struts html tags. > > > > String concatenation using StringBuffer is definitely much > > > > better than > > > > using the plus operator but there are scenarios where there are > much > > > > better ways than using StringBuffers. Actually struts html tags > fall > > > in > > > > those scenarios. > > > > So let me give you an example. this is the code from > > > > renderFormStartElement method of FormTag. > > > > > > > > StringBuffer results = new StringBuffer(); > > > > results.append("<form"); > > > > results.append(" name=\""); > > > > results.append(beanName); > > > > results.append("\""); > > > > results.append(" method=\""); > > > > results.append(method == null ? "post" : method); > > > > results.append("\" action=\""); > > > > .... > > > > str = results.toString(); > > > > > > > > pageContext.getOut().write(str); > > > > > > > > Now lets list the issues with this. > > > > 1. first presizing this buffer is quite difficult (avoided in this > > > > case). here the buffer starts with size 16 and doubles each time > the > > > > size is exceeded. This causes unnecessary creation of new char > arrays > > > > and redundant copy of data whenever resizing happens. > > > > 2. whenever append is called data is copied from the passed string > to > > > > the end of stringbuffer. > > > > 3. finally the whole concatenated data is again copied into > another > > > > string. > > > > 4. and then in the end this string is written to a writer, another > > > copy, > > > > which is the only copy required. > > > > > > > > so even if you had presized the stringbuffer correctly, you have > > > copied > > > > the same data thrice instead of just once. And you also create two > NOT > > > > needed objects. > > > > > > > > so here is the solution i propose. have a class holding an array > of > > > > Strings and keep appending strings to this array and finally print > > > this > > > > array to the writer. something like this. > > > > > > > > private String[] data = new String[256]; > > > > private int size = 0; > > > > > > > > public StringHolder append(String str){ > > > > ensureCapacity(this.size + 1); > > > > this.data[this.size++] = str; > > > > return this; > > > > } > > > > > > > > public void writeTo(Writer out) throws IOException{ > > > > for (int i = 0; i < this.size; i++){ > > > > if (this.data[i] != null){ > > > > out.write(this.data[i]); > > > > } > > > > } > > > > } > > > > > > > > this way only the last copy takes place and you also avoid > creating so > > > > much garbage. > > > > > > > > i have attached StringHolder class which does the above task and > also > > > > the FormTag after making necessary modification to fit in this > class. > > > > >From the code of FormTag you can see that you need to make quite > few > > > > changes to get great benefit. > > > > > > > > i have also attached a better implementation of > > > > ResponseUtils.filter(String) method. the logic is on the same > lines as > > > > above. > > > > > > > > thanks, > > > > nishant > > > > > > > > -- > > > > nishant kumar <[EMAIL PROTECTED]> > > > > > > > > > > > > > > > > > --------------------------------------------------------------------- > > > To unsubscribe, e-mail: [EMAIL PROTECTED] > > > For additional commands, e-mail: [EMAIL PROTECTED] > > > > > > > > > __________________________________ > > Do you Yahoo!? > > Yahoo! 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