Package org.teiid.core.types

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

/*
* 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.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.Reader;
import java.io.Writer;
import java.nio.charset.Charset;
import java.sql.Clob;
import java.sql.SQLException;

import javax.sql.rowset.serial.SerialClob;

import org.teiid.core.CorePlugin;
import org.teiid.core.util.ObjectConverterUtil;
import org.teiid.core.util.ReaderInputStream;
import org.teiid.core.util.SqlUtil;


/**
* This object holds a chunk of char data and implements the JDBC Clob interface.
* This object presents a streaming interface and provides a way to access partial
* of the Clob data. Connectors can use this object when dealing with large
* objects.
*/
public class ClobImpl extends BaseLob implements Clob {
   
  private final static class ClobStreamProvider implements
      LobSearchUtil.StreamProvider {
    private final Clob searchstr;

    private ClobStreamProvider(Clob searchstr) {
      this.searchstr = searchstr;
    }

    public InputStream getBinaryStream() throws SQLException {
      ReaderInputStream ris = new ReaderInputStream(searchstr.getCharacterStream(), Charset.forName("UTF-16")); //$NON-NLS-1$
      try {
        ris.skip(2);
        return ris;
      } catch (IOException e) {
        throw new SQLException(e);
      }
    }
  }

  private long len = -1;
 
  public ClobImpl() {
   
  }
 
  /**
   * Creates a new ClobImpl.  Note that the length is not taken from the {@link InputStreamFactory} since
   * it refers to bytes and not chars.
   * @param streamFactory
   * @param length
   */
    public ClobImpl(InputStreamFactory streamFactory, long length) {
    super(streamFactory);
    this.len = length;
  }

  /**
     * Gets the <code>CLOB</code> value designated by this <code>Clob</code>
     * object as a stream of Ascii bytes.
     * @return an ascii stream containing the <code>CLOB</code> data
     * @exception SQLException if there is an error accessing the
     * <code>CLOB</code> value
     */
    public InputStream getAsciiStream() throws SQLException {
      return new ReaderInputStream(getCharacterStream(), Charset.forName("US-ASCII")); //$NON-NLS-1$
    }

    /**
     * Returns a copy of the specified substring
     * in the <code>CLOB</code> value
     * designated by this <code>Clob</code> object.
     * The substring begins at position
     * <code>pos</code> and has up to <code>length</code> consecutive
     * characters.
     * @param pos the first character of the substring to be extracted.
     *            The first character is at position 1.
     * @param length the number of consecutive characters to be copied
     * @return a <code>String</code> that is the specified substring in
     *         the <code>CLOB</code> value designated by this <code>Clob</code> object
     * @exception SQLException if there is an error accessing the <code>CLOB</code>
     */
    public String getSubString(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.1", params)); //$NON-NLS-1$
        } else if ((pos+length) > length()) {
            length = (int)(length()-pos);
        }
        Reader in = getCharacterStream();
        try {
          try {
            long skipped = 0;
            while (pos > 0) {
              skipped = in.skip(pos);
              pos -= skipped;
            }
            return new String(ObjectConverterUtil.convertToCharArray(in, length));
          } finally {
            in.close();
          }
        } catch (IOException e) {
          throw new SQLException(e);
        }
    }

    /**
     * Returns the number of characters in the <code>CLOB</code> value
     * designated by this <code>Clob</code> object.
     * @return length of the <code>CLOB</code> in characters
     */
    public long length() throws SQLException {
      if (len == -1) {
        long length = 0;
        Reader r = new BufferedReader(getCharacterStream());
        try {
        while (r.read() != -1) {
          length++;
        }
      } catch (IOException e) {
        throw new SQLException(e);
      } finally {
        try {
          r.close();
        } catch (IOException e) {
        }
      }
        this.len = length;
      }
        return len;
    }

    /**
     * Determines the character position at which the specified
     * <code>Clob</code> object <code>searchstr</code> appears in this
     * <code>Clob</code> object.  The search begins at position
     * <code>start</code>.
     * @param searchstr the <code>Clob</code> object for which to search
     * @param start the position at which to begin searching; the first
     *              position is 1
     * @return the position at which the <code>Clob</code> object appears,
     * else -1; the first position is 1
     */
    public long position(final Clob searchstr, long start) throws SQLException {
        if (searchstr == null) {
            return -1;
        }
       
        return LobSearchUtil.position(new ClobStreamProvider(searchstr), searchstr.length(), new ClobStreamProvider(this), this.length(), start, 2);
    }
   
    /**
    * Determines the character position at which the specified substring
    * <code>searchstr</code> appears in the SQL <code>CLOB</code> value
    * represented by this <code>Clob</code> object.  The search
    * begins at position <code>start</code>.
    * @param searchstr the substring for which to search
    * @param start the position at which to begin searching; the first position
    *              is 1
    * @return the position at which the substring appears, else -1; the first
    *         position is 1
    * @exception SQLException if there is an error accessing the
    * <code>CLOB</code> value
    */
    public long position(String searchstr, long start) throws SQLException {
      if (searchstr == null) {
            return -1;
        }
      return position(new SerialClob(searchstr.toCharArray()), start);
    }
         
  public Reader getCharacterStream(long arg0, long arg1) throws SQLException {
    throw SqlUtil.createFeatureNotSupportedException();
  }

  public OutputStream setAsciiStream(long arg0) throws SQLException {
    throw SqlUtil.createFeatureNotSupportedException()
  }

  public Writer setCharacterStream(long arg0) throws SQLException {
    throw SqlUtil.createFeatureNotSupportedException()
  }

  public int setString(long arg0, String arg1) throws SQLException {
    throw SqlUtil.createFeatureNotSupportedException()
  }

  public int setString(long arg0, String arg1, int arg2, int arg3)
      throws SQLException {
    throw SqlUtil.createFeatureNotSupportedException()
  }

  public void truncate(long arg0) throws SQLException {
    throw SqlUtil.createFeatureNotSupportedException();
  }

}
TOP

Related Classes of org.teiid.core.types.ClobImpl

TOP
Copyright © 2018 www.massapi.com. All rights reserved.
All source code are property of their respective owners. Java is a trademark of Sun Microsystems, Inc and owned by ORACLE Inc. Contact coftware#gmail.com.