# IndentingWriter.java

    /*
    ** Module   : IndentingWriter.java
    ** Abstract : allows caller-controlled indenting of output
    **
    ** Copyright (c) 2008-2017, Golden Code Development Corporation.
    **
    ** -#- -I- --Date-- -T- --JPRM-- ----------------Description-----------------
    ** 001 GES 20080309 NEW   @37540 Created initial version which allows
    **                               caller-controlled indenting of output.
    */
    /*
    ** This program is free software: you can redistribute it and/or modify
    ** it under the terms of the GNU Affero General Public License as
    ** published by the Free Software Foundation, either version 3 of the
    ** License, or (at your option) any later version.
    **
    ** This program is distributed in the hope that it will be useful,
    ** but WITHOUT ANY WARRANTY; without even the implied warranty of
    ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    ** GNU Affero General Public License for more details.
    **
    ** You may find a copy of the GNU Affero GPL version 3 at the following
    ** location: https://www.gnu.org/licenses/agpl-3.0.en.html
    **
    ** Additional terms under GNU Affero GPL version 3 section 7:
    **
    **   Under Section 7 of the GNU Affero GPL version 3, the following additional
    **   terms apply to the works covered under the License.  These additional terms
    **   are non-permissive additional terms allowed under Section 7 of the GNU
    **   Affero GPL version 3 and may not be removed by you.
    **
    **   0. Attribution Requirement.
    **
    **     You must preserve all legal notices or author attributions in the covered
    **     work or Appropriate Legal Notices displayed by works containing the covered
    **     work.  You may not remove from the covered work any author or developer
    **     credit already included within the covered work.
    **
    **   1. No License To Use Trademarks.
    **
    **     This license does not grant any license or rights to use the trademarks
    **     Golden Code, FWD, any Golden Code or FWD logo, or any other trademarks
    **     of Golden Code Development Corporation. You are not authorized to use the
    **     name Golden Code, FWD, or the names of any author or contributor, for
    **     publicity purposes without written authorization.
    **
    **   2. No Misrepresentation of Affiliation.
    **
    **     You may not represent yourself as Golden Code Development Corporation or FWD.
    **
    **     You may not represent yourself for publicity purposes as associated with
    **     Golden Code Development Corporation, FWD, or any author or contributor to
    **     the covered work, without written authorization.
    **
    **   3. No Misrepresentation of Source or Origin.
    **
    **     You may not represent the covered work as solely your work.  All modified
    **     versions of the covered work must be marked in a reasonable way to make it
    **     clear that the modified work is not originating from Golden Code Development
    **     Corporation or FWD.  All modified versions must contain the notices of
    **     attribution required in this license.
    */

    package com.goldencode.p2j.io;

    import java.io.*;

    /**
     * Provides <code>Writer</code> semantics with caller-controlled
     * indenting.  An indent is written (inserted) between each newline and any
     * subsequent (non-newline) characters that are written.
     * <p>
     * This class is not thread-safe.
     *
     * @author    GES
     */
    public class IndentingWriter
    extends FilterWriter
    implements Indentable
    {
       /** Indent state manager. */
       private Indentable indent = new IndentHandler();

       /** The last byte written to the stream. */
       private char last = '\n';

       /**
        * Creates an instance with the associated writer as the base and
        * a default 0 indent level.
        *
        * @param    out
        *           The writer on which we filter.
        */
       public IndentingWriter(Writer out)
       {
          super(out);
       }

       /**
        * Creates an instance with the associated writer as the base.
        *
        * @param    out
        *           The writer on which we filter.
        * @param    indent
        *           The initial indent level.
        */
       public IndentingWriter(Writer out, int indent)
       {
          this(out);
          this.indent.setIndent(indent);
       }

       /**
        * Accesses the current indent level.
        *
        * @return   Indent level.
        */
       public int getIndent()
       {
          return indent.getIndent();
       }

       /**
        * Sets the current indent level.
        *
        * @param    indent
        *           New indent level.
        */
       public void setIndent(int indent)
       {
          this.indent.setIndent(indent);
       }

       /**
        * Increments the indent level by 1.
        */
       public void increment()
       {
          indent.increment();
       }

       /**
        * Decrements the indent level by 1.
        */
       public void decrement()
       {
          indent.decrement();
       }

       /**
        * Accesses the number of spaces in a single indent level.
        *
        * @return   Width of each indent level.
        */
       public int getWidth()
       {
          return indent.getWidth();
       }

       /**
        * Sets the number of spaces in a single indent level.
        *
        * @param    width
        *           New indent width.
        */
       public void setWidth(int width)
       {
          indent.setWidth(width);
       }

       /**
        * Sets both the indent level and the number of spaces in a single indent
        * level. This is a convenience function to avoid 2 separate calls and
        * the small amount of shared overhead that would have been incurred in
        * those calls.
        *
        * @param    indent
        *           New indent level.
        * @param    width
        *           New indent width.
        */
       public void setPad(int indent, int width)
       {
          this.indent.setPad(indent, width);
       }

       /**
        * Get the current pad.
        *
        * @return   The pad string for the next line of output.
        */
       public String getPad()
       {
          return indent.getPad();
       }

       /**
        * Writes the specified character to this writer (only the low order 16
        * bits are written, the high order 16 bits are ignored).
        * <p>
        * The current pad is inserted into the stream between all newline
        * characters and any subsequent non-newline characters.
        *
        * @param    ch
        *           The character to write.
        *
        * @throws   IOException
        *           if an I/O error occurs. In particular, an IOException may be
        *           thrown if the writer has been closed.
        */
       public void write(int ch)
       throws IOException
       {
          write(new char[] { (char) ch });
       }

       /**
        * Writes <code>len</code> characters from the specified string starting
        * at offset <code>off</code> in this writer. Element <code>off</code> is
        * the first character written and <code>off+len-1</code> is the last
        * character written.
        * <p>
        * The current pad is inserted into the stream between all newline
        * characters and any subsequent non-newline characters.
        *
        * @param    str
        *           The string to write.
        * @param    off
        *           The start offset in the string.
        * @param    len
        *           The number of characters to write.
        *
        * @throws   IOException
        *           If an I/O error occurs. In particular, an IOException may be
        *           thrown if the writer has been closed.
        *
        * @throws   NullPointerException
        *           If the string is <code>null</code>.
        * @throws   IndexOutOfBoundsException
        *           If the offset or length are negative, or if offset + length
        *           is larger than the length of the string.
        */
       public void write(String str, int off, int len)
       throws IOException,
              NullPointerException,
              IndexOutOfBoundsException
       {
          write(str.toCharArray(), off, len);
       }

       /**
        * Writes <code>len</code> characters from the specified character array
        * starting at offset <code>off</code> in this writer. Element ch[off] is
        * the first character written and ch[off+len-1] is the last character
        * written.
        * <p>
        * The current pad is inserted into the stream between all newline
        * characters and any subsequent non-newline characters.
        *
        * @param    ch
        *           The array of characters to write.
        * @param    off
        *           The start offset in the array.
        * @param    len
        *           The number of characters to write.
        *
        * @throws   IOException
        *           If an I/O error occurs. In particular, an IOException may be
        *           thrown if the writer has been closed.
        *
        * @throws   NullPointerException
        *           If the array is <code>null</code>.
        * @throws   IndexOutOfBoundsException
        *           If the offset or length are negative, or if offset + length
        *           is larger than the length of the array.
        */
       public void write(char[] ch, int off, int len)
       throws IOException,
              NullPointerException,
              IndexOutOfBoundsException
       {
          boolean empty = (indent.getIndent() == 0 && indent.getWidth() == 0);

          if (empty)
          {
             // no identing needed, use faster approach
             out.write(ch, off, len);

             // remember the last char
             last = ch[off + len - 1];
          }
          else
          {
             // indent needed, process one byte at a time
             for (int i = 0; i < len; i++)
             {
                char next = ch[i + off];

                // look for an output of a non-newline that follows a newline
                if (last == '\n' && next != '\n')
                {
                   // insert the indent
                   out.write(indent.getPad().toCharArray());
                }

                // write the current character
                out.write(next);

                // update the last character
                last = next;
             }
          }
       }
    }