Package org.teiid.core.types

Source Code of org.teiid.core.types.BlobImpl

/*
* JBoss, Home of Professional Open Source.
* See the COPYRIGHT.txt file distributed with this work for information
* regarding copyright ownership.  Some portions may be licensed
* to Red Hat, Inc. under one or more contributor license agreements.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301 USA.
*/

package org.teiid.core.types;

import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.sql.Blob;
import java.sql.SQLException;

import javax.sql.rowset.serial.SerialBlob;

import org.teiid.core.CorePlugin;
import org.teiid.core.types.LobSearchUtil.StreamProvider;
import org.teiid.core.util.ObjectConverterUtil;
import org.teiid.core.util.SqlUtil;


/**
* This object holds a chunk of binary data and implements the JDBC Blob interface.
* It presents a streaming interface and provides a way to access partial
* of the blob data. Connectors can use this object when dealing with large
* objects.
*/
public class BlobImpl extends BaseLob implements Blob, StreamProvider {
   
  public BlobImpl() {
   
  }
 
    /**
     * Creates a MMBlob object with the <code>valueID</code>.
     * @param valueID reference to value chunk in data source.
     */
    public BlobImpl(InputStreamFactory streamFactory) {
      super(streamFactory);
    }

    /**
     * Returns as an array of bytes, part or all of the <code>BLOB</code>
     * value that this <code>Blob</code> object designates.  The byte
     * array contains up to <code>length</code> consecutive bytes
     * starting at position <code>pos</code>.
     * @param pos the ordinal position of the first byte in the
     * <code>BLOB</code> value to be extracted; the first byte is at
     * position 1
     * @param length the number of consecutive bytes to be copied
     * @return a byte array containing up to <code>length</code>
     * consecutive bytes from the <code>BLOB</code> value designated
     * by this <code>Blob</code> object, starting with the
     * byte at position <code>pos</code>
     * @exception SQLException if there is an error accessing the
     * <code>BLOB</code>
     */
    public byte[] getBytes(long pos, int length) throws SQLException {
        if (pos < 1) {
            Object[] params = new Object[] {new Long(pos)};
            throw new SQLException(CorePlugin.Util.getString("MMClob_MMBlob.0", params)); //$NON-NLS-1$
        }
        else if (pos > length()) {
            return null;
        }
        pos = pos - 1;
       
        if (length < 0) {
            Object[] params = new Object[] {new Integer( length)};
            throw new SQLException(CorePlugin.Util.getString("MMClob_MMBlob.3", params)); //$NON-NLS-1$
        }
        else if (pos + length > length()) {
            length = (int)(length() - pos);
        }
        InputStream in = getBinaryStream();
        try {
          long skipped = 0;
          while (pos > 0) {
            skipped = in.skip(pos);
            pos -= skipped;
          }
          return ObjectConverterUtil.convertToByteArray(in, length);
        } catch (IOException e) {
          throw new SQLException(e);
        } finally {
          try {
        in.close();
      } catch (IOException e) {
      }
        }
    }

    /**
     * Returns the number of bytes in the <code>BLOB</code> value
     * designated by this <code>Blob</code> object.
     * @return length of the <code>BLOB</code> in bytes
     */
    public long length() throws SQLException{
      if (getStreamFactory().getLength() == -1) {
        InputStream is = new BufferedInputStream(getBinaryStream());
      try {
          long length = 0;
          while (is.read() != -1) {
            length++;
          }
        getStreamFactory().setLength(length);
      } catch (IOException e) {
        throw new SQLException(e);
      } finally {
        try {
          is.close();
        } catch (IOException e) {
        }
      }
      }
        return getStreamFactory().getLength();
    }

    /**
     * Determines the byte position in the <code>BLOB</code> value
     * designated by this <code>Blob</code> object at which
     * <code>pattern</code> begins.  The search begins at position
     * <code>start</code>.
     * @param pattern the <code>Blob</code> object designating
     * the <code>BLOB</code> value for which to search
     * @param start the position in the <code>BLOB</code> value
     *        at which to begin searching; the first position is 1
     * @return the position at which the pattern begins, else -1
     * @exception SQLException if there is an error accessing the
     * <code>BLOB</code>
     */
    public long position(final Blob pattern, long start) throws SQLException {
        if (pattern == null) {
            return -1;
        }
       
        return LobSearchUtil.position(new LobSearchUtil.StreamProvider() {
          public InputStream getBinaryStream() throws SQLException {
            return pattern.getBinaryStream();
          }
        }, pattern.length(), this, this.length(), start, 1);
    }
   
    /**
     * Determines the byte position at which the specified byte
     * <code>pattern</code> begins within the <code>BLOB</code>
     * value that this <code>Blob</code> object represents.  The
     * search for <code>pattern</code> begins at position
     * <code>start</code>.
     * @param pattern the byte array for which to search
     * @param start the position at which to begin searching; the
     *        first position is 1
     * @return the position at which the pattern appears, else -1
     * @exception SQLException if there is an error accessing the
     * <code>BLOB</code>
     */
    public long position(byte[] pattern, long start) throws SQLException {
      if (pattern == null) {
        return -1;
      }
        return position(new SerialBlob(pattern), start);
    }
       
  public InputStream getBinaryStream(long arg0, long arg1)
      throws SQLException {
    throw SqlUtil.createFeatureNotSupportedException();
  }


  /**
   * @see java.sql.Blob#setBytes(long, byte[])
   */
  public int setBytes(long pos, byte[] bytes) throws SQLException {
    throw SqlUtil.createFeatureNotSupportedException();
  }

  /**
   * @see java.sql.Blob#setBytes(long, byte[], int, int)
   */
  public int setBytes(long pos, byte[] bytes, int offset, int len) throws SQLException {
    throw SqlUtil.createFeatureNotSupportedException();
  }

  /**
   * @see java.sql.Blob#setBinaryStream(long)
   */
  public OutputStream setBinaryStream(long pos) throws SQLException {
    throw SqlUtil.createFeatureNotSupportedException();
  }

  /**
   * @see java.sql.Blob#truncate(long)
   */
  public void truncate(long len) throws SQLException {
    throw SqlUtil.createFeatureNotSupportedException();
  }
}
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