com.hfg.xml.IndentedXMLOutputStream Maven / Gradle / Ivy

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com.hfg xml, html, svg, and bioinformatics utility library
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package com.hfg.xml;

import java.io.FilterOutputStream;
import java.io.OutputStream;


class IndentedXMLOutputStream extends FilterOutputStream
{
   private static enum State { IN_START_TAG, IN_END_TAG, IN_CONTENT }

   private int mIndentLevel = 0;
   private int mIndentSize  = 3;
   private byte[] mBuffer = new byte[16 * 1024];
   private int mBufferPtr = 0;
   private char mPreviousChar = (char)-1;
   private State   mState;

   private static byte[] ln  = System.getProperty("line.separator").getBytes();

   //---------------------------------------------------------------------------
   public IndentedXMLOutputStream(OutputStream outputStream)
   {
      super(outputStream);
   }

   //---------------------------------------------------------------------------
   @Override
   public void write(int i) throws java.io.IOException
   {
      if (mBufferPtr < mBuffer.length)
      {
         // Just add it to the buffer.
         mBuffer[mBufferPtr++] = (byte) i;
      }
      else
      {
         flush();
      }
   }

   //---------------------------------------------------------------------------
   // TODO: improve this simple implementation
   @Override
   public void write(byte[] bytes) throws java.io.IOException
   {
      for (int i = 0; i < bytes.length; i++)
      {
         write(bytes[i]);
      }
   }

   //---------------------------------------------------------------------------
   // TODO: improve this simple implementation
   @Override
   public void write(byte[] bytes, int i, int i1) throws java.io.IOException
   {
      for (int index = i; index - i < i1; index++)
      {
         write(bytes[i]);
      }
   }

   //---------------------------------------------------------------------------
   public void flush() throws java.io.IOException
   {
      for (int i = 0; i < mBufferPtr; i++)
      {
         if ((char) mBuffer[i] == '>')
         {
            if (mPreviousChar == '/')
            {
               // End of an empty tag. Return and indent at the current level
               out.write(ln);
               for (int j = 0; j < mIndentLevel * mIndentSize; j++) out.write((byte) ' ');
            }
            else if (mState == State.IN_END_TAG)
            {
               // End of an end tag. Return and decrease the indent level
               out.write(ln);

               for (int j = 0; j < mIndentLevel * mIndentSize; j++) out.write((byte) ' ');
            }
         }
         if ((char) mBuffer[i] == '<')
         {
            mState = State.IN_START_TAG;
         }
         else if ((char) mBuffer[i] == '/')
         {
            if (mPreviousChar == '<') mState = State.IN_END_TAG;
         }

         if (mPreviousChar == '>')
         out.write(mBuffer[i]);
         mPreviousChar = (char) mBuffer[i];
      }

      mBufferPtr = 0;
   }

   //---------------------------------------------------------------------------
   public void close() throws java.io.IOException
   {
   }
}