7. A flow description document processing apparatus comprising: an extracting unit constructed to extract, from a first flow description document, a first description which specifies services to be invoked by the first flow description document, and extract, from a second flow description document, a second description which specifies services to be invoked by the second flow description document; a detection unit constructed to detect a common part between the first description of the first flow description document and the second description of the second flow description document, wherein services specified by the first description extracted from the first flow description document include one or more services among services specified by the second description extracted from the second flow description document; and a rewrite unit constructed to rewrite the common part in the second flow description document into a reference to the common part in the first flow description document, wherein the reference includes identification information of the first flow description document, and information which specifies a start tag and end tag of the common part.
7. A flow description document processing apparatus comprising: an extracting unit constructed to extract, from a first flow description document, a first description which specifies services to be invoked by the first flow description document, and extract, from a second flow description document, a second description which specifies services to be invoked by the second flow description document; a detection unit constructed to detect a common part between the first description of the first flow description document and the second description of the second flow description document, wherein services specified by the first description extracted from the first flow description document include one or more services among services specified by the second description extracted from the second flow description document; and a rewrite unit constructed to rewrite the common part in the second flow description document into a reference to the common part in the first flow description document, wherein the reference includes identification information of the first flow description document, and information which specifies a start tag and end tag of the common part. 8. The apparatus according to claim 7 , wherein said rewrite unit stores, in a memory in an executable format, the first flow description document and the second flow description document whose common part has been rewritten into the reference to the common part in the first flow description document.