umagesh     02/02/23 18:35:50

  Added:       
proposal/sandbox/filterreaders/src/main/org/apache/tools/ant/filters
                        StripLineComments.java
  Log:
  Filter Reader that strips out those lines that begin with a comment tag.
  
  Revision  Changes    Path
  1.1                  
jakarta-ant/proposal/sandbox/filterreaders/src/main/org/apache/tools/ant/filters/StripLineComments.java
  
  Index: StripLineComments.java
  ===================================================================
  package org.apache.tools.ant.filters;
  
  import java.io.FilterReader;
  import java.io.IOException;
  import java.io.Reader;
  import java.util.Vector;
  
  import org.apache.tools.ant.types.Parameter;
  import org.apache.tools.ant.types.Parameterizable;
  
  /**
   * This is a line comment stripper reader
   *
   * Example:
   * =======
   *
   * <filterreader classname="org.apache.tools.ant.filters.StripLineComments">
   *    <param name="comment" value="#"/>
   *    <param name="comment" value="--"/>
   *    <param name="comment" value="REM "/>
   *    <param name="comment" value="rem "/>
   *    <param name="comment" value="//"/>
   * </filterreader>
   *
   * @author <a href="mailto:[EMAIL PROTECTED]">Magesh Umasankar</a>
   */
  public final class StripLineComments
      extends FilterReader
      implements Parameterizable
  {
      private static final String COMMENTS_KEY = "comment";
  
      private Parameter[] parameters;
  
      private boolean initialized = false;
  
      private final Vector comments = new Vector();
  
      private int commentsSize = 0;
  
      private String line = null;
  
      /**
       * Create a new filtered reader.
       *
       * @param in  a Reader object providing the underlying stream.
       */
      public StripLineComments(final Reader in) {
          super(in);
      }
  
      public final int read() throws IOException {
          if (!initialized) {
              initialize();
              initialized = true;
          }
  
          int ch = -1;
  
          if (line != null) {
              ch = line.charAt(0);
              if (line.length() == 1) {
                  line = null;
              } else {
                  line = line.substring(1);
              }
          } else {
              ch = in.read();
              while (ch != -1) {
                  if (line == null) {
                      line = "";
                  }
                  line = line + (char) ch;
                  if (ch == '\n') {
                      break;
                  }
                  ch = in.read();
              }
  
              if (line != null) {
                  for (int i = 0; i < commentsSize; i++) {
                      String comment = (String) comments.elementAt(i);
                      if (line.startsWith(comment)) {
                          line = null;
                          break;
                      }
                  }
                  return read();
              }
          }
  
          return ch;
      }
  
      public final int read(final char cbuf[], final int off,
                            final int len) throws IOException {
          for (int i = 0; i < len; i++) {
              final int ch = read();
              if (ch == -1) {
                  if (i == 0) {
                      return -1;
                  } else {
                      return i;
                  }
              }
              cbuf[off + i] = (char) ch;
          }
          return len;
      }
  
      public final long skip(final long n) throws IOException {
          for (long i = 0; i < n; i++) {
              if (in.read() == -1) return i;
          }
          return n;
      }
  
      /**
       * Set Parameters
       */
      public final void setParameters(final Parameter[] parameters) {
          this.parameters = parameters;
          initialized = false;
      }
  
      private final void initialize() {
          if (parameters != null) {
              for (int i = 0; i < parameters.length; i++) {
                  if (COMMENTS_KEY.equals(parameters[i].getName())) {
                      comments.addElement(parameters[i].getValue());
                  }
              }
              commentsSize = comments.size();
          }
      }
  }
  
  
  

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