52 lines
2.4 KiB
Plaintext
52 lines
2.4 KiB
Plaintext
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Sample: XmlSort
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Category: cursor sample
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Author: Radu Preotiuc-Pietro
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Last Updated: Feb. 3, 2009
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Versions:
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xmlbeans-v2
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-----------------------------------------------------------------------------
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This is another practical sample on how to use XmlCursor. It sorts all the
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children elements of a given parent in (reverse) alphabetical order. It uses
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insertion sort to minimize the number of swaps (and because it is stable) and
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XmlCursor.moveXml() to perform the swaps.
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The algorithm works by conceptually separating the list of children into a
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sorted list and an unsorted list. Each list is represented by an XmlCursor
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positioned at the head of the list. At the beginning, the sorted list
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contains the first child and the unsorted list contains the rest of the
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children (if any). Then, each of the elements in the unsorted list is
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inserted in the already-sorted list in its appropriate place using the
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moveXml() method (the text following each element is then moved along with
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the element).
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To build this sample, call 'ant build' and to run it against the provided
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sample XML file, call 'ant run'.
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To run the sample from the command line using 'java', provide as the first
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parameter the name of the XML file to process and as the second argument
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(optional), an XPath pointing to the element whose children are to be sorted
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(by default, the children of the root element are sorted). The XPath must
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evaluate to an element and one element only, otherwise an error will be
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reported. The console output will mirror the input file, with the children
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of the given element sorted in ascending alphabetical order.
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This sample can also be used as a library routine by calling its main
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static method: XmlSort.sort(XmlObject, Comparator). The XmlObject whose
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children are to be sorted is passed directly as a parameter and the
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Comparator defines the order in which the elements are to be sorted. The
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parameters to the compare() method are two XmlCursors pointing to the
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two elements to be compared. The inner class XmlSort.QNameComparator
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implements comparison based on the QName of the elements (ascending or
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descending) but custom comparison methods (based for instance on the
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value of some attribute etc) can also be passed in.
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To try out this sample:
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1. Set XMLBEANS_HOME in your environment
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2. Ant must be on your PATH
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3. To compile the sample source, run "ant build"
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4. To execute the sample, run "ant run"
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