content: /*
   *  Licensed to the Apache Software Foundation (ASF) under one or more
   *  contributor license agreements.  See the NOTICE file distributed with
   *  this work for additional information regarding copyright ownership.
   *  The ASF licenses this file to You under the Apache License, Version 2.0
   *  (the "License"); you may not use this file except in compliance with
   *  the License.  You may obtain a copy of the License at
   *
   *      https://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS,
   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   *
   */
  
  package org.apache.tools.ant.types.mappers;
  
  import java.io.Reader;
  import java.io.StringReader;
  import java.util.Vector;
  
  import org.apache.tools.ant.BuildException;
  import org.apache.tools.ant.UnsupportedAttributeException;
  import org.apache.tools.ant.filters.util.ChainReaderHelper;
  import org.apache.tools.ant.types.FilterChain;
  import org.apache.tools.ant.util.FileNameMapper;
  import org.apache.tools.ant.util.FileUtils;
  
  /**
   * This is a FileNameMapper based on a FilterChain.
   */
  public class FilterMapper extends FilterChain implements FileNameMapper {
  
      private static final int BUFFER_SIZE = 8192;
  
      /**
       * From attribute not supported.
       * @param from a string
       * @throws BuildException always
       */
      @Override
      public void setFrom(String from) {
          throw new UnsupportedAttributeException(
              "filtermapper doesn't support the \"from\" attribute.", "from");
      }
  
      /**
       * From attribute not supported.
       * @param to a string
       * @throws BuildException always
       */
      @Override
      public void setTo(String to) {
          throw new UnsupportedAttributeException(
              "filtermapper doesn't support the \"to\" attribute.", "to");
      }
  
      /**
       * Return the result of the filters on the sourcefilename.
       * @param sourceFileName the filename to map
       * @return  a one-element array of converted filenames, or null if
       *          the filterchain returns an empty string.
       */
      @Override
      public String[] mapFileName(String sourceFileName) {
          if (sourceFileName == null) {
              return null;
          }
          try {
              Reader stringReader = new StringReader(sourceFileName);
              ChainReaderHelper helper = new ChainReaderHelper();
              helper.setBufferSize(BUFFER_SIZE);
              helper.setPrimaryReader(stringReader);
              helper.setProject(getProject());
              Vector<FilterChain> filterChains = new Vector<>();
              filterChains.add(this);
              helper.setFilterChains(filterChains);
              String result = FileUtils.safeReadFully(helper.getAssembledReader());
              if (result.isEmpty()) {
                  return null;
              }
              return new String[] {result};
          } catch (BuildException ex) {
              throw ex;
          } catch (Exception ex) {
              throw new BuildException(ex);
          }
      }
  }
  