Package org.apache.derby.impl.store.raw.data

Source Code of org.apache.derby.impl.store.raw.data.InitPageOperation

/*

   Derby - Class org.apache.derby.impl.store.raw.data.InitPageOperation

   Licensed to the Apache Software Foundation (ASF) under one or more
   contributor license agreements.  See the NOTICE file distributed with
   this work for additional information regarding copyright ownership.
   The ASF licenses this file to you under the Apache License, Version 2.0
   (the "License"); you may not use this file except in compliance with
   the License.  You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

*/

package org.apache.derby.impl.store.raw.data;

import org.apache.derby.impl.store.raw.data.BasePage;

import org.apache.derby.iapi.services.sanity.SanityManager;
import org.apache.derby.iapi.services.io.FormatIdUtil;
import org.apache.derby.iapi.services.io.StoredFormatIds;

import org.apache.derby.iapi.error.StandardException;

import org.apache.derby.iapi.store.raw.RecordHandle;
import org.apache.derby.iapi.store.raw.Page;
import org.apache.derby.iapi.store.raw.Transaction;

import org.apache.derby.iapi.store.raw.log.LogInstant;

import org.apache.derby.iapi.services.io.CompressedNumber;

import java.io.OutputStream;
import java.io.ObjectOutput;
import java.io.ObjectInput;
import java.io.IOException;
import org.apache.derby.iapi.services.io.LimitObjectInput;

/**
  This operation initializes the page that is being allocated,
  this operation does not change the alloc page information.

  <PRE>
  @format_id  LOGOP_INIT_PAGE
    the formatId is written by FormatIdOutputStream when this object is
    written out by writeObject
  @purpose  initialized a page
  @upgrade
  @disk_layout
    PhysicalPageOperation the superclass
    nextRecordId(CompressedInt)  the next recordId this page should give out
    initFlag(CompressedInt)    initialization flag: reuse, overflow
    pageformat(int)        the page's formatId

    OptionalData  none
  @end_format
  </PRE>
*/
public final class InitPageOperation extends PhysicalPageOperation
{
  protected int  nextRecordId; // next recordId
  protected int  initFlag;
  protected int  pageFormatId;
  protected long  pageOffset;

  protected boolean reuse;  // is this page being initialize for reuse, or for first time
  protected boolean overflowPage; // is this page an overflow page

  public InitPageOperation(BasePage page, int flag, int formatid,
               long offset)
     throws StandardException
  {
    super(page);

    initFlag = flag;
    pageFormatId = formatid;
    pageOffset = offset;

    // unless we specified recordId should be reusable, when we reuse a
    // page, we keep incrementing the existing recordId
    if ((initFlag & BasePage.INIT_PAGE_REUSE_RECORDID) == 0)
      nextRecordId = page.newRecordId();
    else
      nextRecordId = RecordHandle.FIRST_RECORD_ID;
  }

  /*
   * Formatable methods
   */

  // no-arg constructor, required by Formatable
  public InitPageOperation() { super(); }

  /**
    Write this out.
    @exception IOException error writing to log stream
  */
  public void writeExternal(ObjectOutput out) throws IOException
  {
    super.writeExternal(out);
    CompressedNumber.writeInt(out, nextRecordId);
    CompressedNumber.writeInt(out, initFlag);
    CompressedNumber.writeLong(out, pageOffset);
    out.writeInt(pageFormatId);
  }

  /**
    Read this in
    @exception IOException error reading from log stream
    @exception ClassNotFoundException log stream corrupted
  */
  public void readExternal(ObjectInput in)
     throws IOException, ClassNotFoundException
  {
    super.readExternal(in);
    nextRecordId = CompressedNumber.readInt(in);
    initFlag = CompressedNumber.readInt(in);
    pageOffset = CompressedNumber.readLong(in);
    pageFormatId = in.readInt();
  }

  /**
    Return my format identifier.
  */
  public int getTypeFormatId() {
    return StoredFormatIds.LOGOP_INIT_PAGE;
  }
  /*
   * Loggable methods
   */
  /**
    Mark the page as valid, and clear out any crud from the page

    @exception IOException Can be thrown by any of the methods of ObjectInput.
    @exception StandardException Standard Derby policy.

    @see org.apache.derby.iapi.store.raw.Loggable#doMe
  */
  public void doMe(Transaction xact, LogInstant instant, LimitObjectInput in)
     throws StandardException, IOException
  {
    boolean overflowPage = ((initFlag & BasePage.INIT_PAGE_OVERFLOW) != 0);
    boolean reuse = ((initFlag & BasePage.INIT_PAGE_REUSE) != 0);

    this.page.initPage(instant,
               BasePage.VALID_PAGE,
               nextRecordId,
               overflowPage, reuse);
  }

  /*
   * Override PageBasicOperation's getPageForRedoRecovery
   */
  /**
    If we are in load tran, this page may not exist for the container yet.
    We need to create it first.

    This routine is called as the last resort of find page, the container
    handle has already been found and it is not dropped.

    @exception StandardException Standard Derby policy.
  */
  protected BasePage getPageForRedoRecovery(Transaction xact)
     throws StandardException
  {
    BasePage p = super.getPageForRedoRecovery(xact);
    if (p != null)
      return p;

    // create the page
    // RESOLVE: we need the page format to properly recreate an Alloc page
    // NEED TO UPGRADE this log record.
    p = (BasePage)containerHdl.reCreatePageForRedoRecovery(
            pageFormatId,                  
            getPageId().getPageNumber(),
            pageOffset);
    return p;
  }
 

  /*
   * PhysicalPageOperation method
   */

  /**
    Mark the page as free

    @exception StandardException Thrown by methods I call
    @exception IOException Thrown by methods I call

    @see PhysicalPageOperation#undoMe
  */
  public void undoMe(Transaction xact, BasePage undoPage, LogInstant CLRInstant,
             LimitObjectInput in)
     throws StandardException, IOException
  {
    undoPage.setPageStatus(CLRInstant, BasePage.INVALID_PAGE);
    // only set the page to invalid, cannot wipe out the page to zero's
    // becuase recovery may need to redo some operations that depend on the
    // content of the page.

    undoPage.setAuxObject(null);
  }


  /*
   * PageBasicOperation methods
   */
 
  /**
   * restore the before image of the page
   *
   * @exception StandardException Standard Derby Error Policy
   * @exception IOException problem reading the complete log record from the
   * input stream
   */
  public void restoreMe(Transaction xact, BasePage undoPage,
             LogInstant CLRInstant, LimitObjectInput in)
     throws StandardException, IOException
  {
    undoMe(xact, undoPage, CLRInstant, in);
  }

  public String toString()
  {
    if (SanityManager.DEBUG)
    {
      boolean overflowPage = ((initFlag & BasePage.INIT_PAGE_OVERFLOW) != 0);
      boolean reuse = ((initFlag & BasePage.INIT_PAGE_REUSE) != 0);

      return super.toString() + "Init Page.  Overflow = "
        + overflowPage + " reuse " + reuse + " nextRecordId " + nextRecordId;
    }
    else
      return null;
  }

}
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