Package org.apache.tools.ant.filters

Class SortFilter

java.lang.Object
java.io.Reader
java.io.FilterReader
org.apache.tools.ant.filters.BaseFilterReader
org.apache.tools.ant.filters.BaseParamFilterReader
org.apache.tools.ant.filters.SortFilter
All Implemented Interfaces:
Closeable, AutoCloseable, Readable, ChainableReader, Parameterizable
public final class SortFilter extends BaseParamFilterReader implements ChainableReader

Sort a file before and/or after the file.

Examples: 

   <copy todir="build">
       <fileset dir="input" includes="*.txt"/>
       <filterchain>
           <sortfilter/>
       </filterchain>
   </copy>

Sort all files *.txt from src location and copy them into build location. The lines of each file are sorted in ascendant order comparing the lines via the String.compareTo(Object o) method. 

   <copy todir="build">
       <fileset dir="input" includes="*.txt"/>
       <filterchain>
           <sortfilter reverse="true"/>
       </filterchain>
   </copy>

Sort all files *.txt from src location into reverse order and copy them into build location. If reverse parameter has value true (default value), then the output line of the files will be in ascendant order. 

   <copy todir="build">
       <fileset dir="input" includes="*.txt"/>
       <filterchain>
           <filterreader classname="org.apache.tools.ant.filters.SortFilter">
             <param name="comparator" value="org.apache.tools.ant.filters.EvenFirstCmp"/>
           </filterreader>
       </filterchain>
   </copy>

Sort all files *.txt from src location using as sorting criterion EvenFirstCmp class, that sorts the file lines putting even lines first then odd lines for example. The modified files are copied into build location. The EvenFirstCmp, has to an instantiable class via Class.newInstance(), therefore in case of inner class has to be static. It also has to implement java.util.Comparator interface, for example: 

         package org.apache.tools.ant.filters;
         ...(omitted)
           public final class EvenFirstCmp implements <b>Comparator</b> {
             public int compare(Object o1, Object o2) {
             ...(omitted)
             }
           }

The example above is equivalent to:

   <componentdef name="evenfirst"
                 classname="org.apache.tools.ant.filters.EvenFirstCmp"/>
   <copy todir="build">
       <fileset dir="input" includes="*.txt"/>
       <filterchain>
           <sortfilter>
               <evenfirst/>
           </sortfilter>
       </filterchain>
   </copy>

If parameter comparator is present, then reverse parameter will not be taken into account.

Since:
Ant 1.8.0

  • Constructor Details

    • SortFilter

      public SortFilter()
      Constructor for "dummy" instances.
      See Also:

    • SortFilter

      public SortFilter(Reader in)
      Creates a new filtered reader.
      Parameters:
      in - A Reader object providing the underlying stream. Must not be null.

  • Method Details

    • read

      public int read() throws IOException
      Returns the next character in the filtered stream. If the desired number of lines have already been read, the resulting stream is effectively at an end. Otherwise, the next character from the underlying stream is read and returned.
      Overrides:
      read in class FilterReader
      Returns:
      the next character in the resulting stream, or -1 if the end of the resulting stream has been reached
      Throws:
      IOException - if the underlying stream throws an IOException during reading

    • chain

      public Reader chain(Reader rdr)
      Creates a new SortReader using the passed in Reader for instantiation.
      Specified by:
      chain in interface ChainableReader
      Parameters:
      rdr - A Reader object providing the underlying stream. Must not be null.
      Returns:
      a new filter based on this configuration, but filtering the specified reader

    • isReverse

      public boolean isReverse()
      Returns true if the sorting process will be in reverse order, otherwise the sorting process will be in ascendant order.
      Returns:
      true if the sorting process will be in reverse order, otherwise the sorting process will be in ascendant order.

    • setReverse

      public void setReverse(boolean reverse)
      Sets the sorting process will be in ascendant (reverse=false) or to descendant (reverse=true).
      Parameters:
      reverse - Boolean representing reverse ordering process.

    • getComparator

      public Comparator<? super String> getComparator()
      Returns the comparator to be used for sorting.
      Returns:
      the comparator

    • setComparator

      public void setComparator(Comparator<? super String> comparator)
      Set the comparator to be used as sorting criterion.
      Parameters:
      comparator - the comparator to set

    • add

      public void add(Comparator<? super String> comparator)
      Set the comparator to be used as sorting criterion as nested element.
      Parameters:
      comparator - the comparator to set