Package org.apache.lucene.store

Source Code of org.apache.lucene.store.Directory

package org.apache.lucene.store;

/**
* 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.
*/

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.Closeable;
import java.util.Collection;
import java.util.zip.CRC32;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.lucene.index.IndexFileNameFilter;
import org.apache.lucene.index.TermInfosWriter;
import org.apache.lucene.util.IOUtils;
import org.apache.lucene.util.cache.Cache;
import org.apache.lucene.util.cache.SimpleLRUCache;
import org.apache.solr.core.SolrCore;
import org.apache.solr.core.SolrResourceLoader.PartionKey;
import org.apache.solr.schema.IndexSchema;

import com.alimama.mdrill.buffer.CacheKeyBuffer;
import com.alimama.mdrill.hdfsDirectory.FileSystemDirectory;

/** A Directory is a flat list of files.  Files may be written once, when they
* are created.  Once a file is created it may only be opened for read, or
* deleted.  Random access is permitted both when reading and writing.
*
* <p> Java's i/o APIs not used directly, but rather all i/o is
* through this API.  This permits things such as: <ul>
* <li> implementation of RAM-based indices;
* <li> implementation indices stored in a database, via JDBC;
* <li> implementation of an index as a single file;
* </ul>
*
* Directory locking is implemented by an instance of {@link
* LockFactory}, and can be changed for each Directory
* instance using {@link #setLockFactory}.
*
*/
public abstract class Directory implements Closeable {
    private static final Log logger = LogFactory.getLog(Directory.class);

  public String dir_uuid=java.util.UUID.randomUUID().toString();
  private IndexSchema schema=null;
  private SolrCore core=null;
 
  private Cache<CacheKeyBuffer, String> CACHE_BUFFER = Cache.synchronizedCache(new SimpleLRUCache<CacheKeyBuffer, String>(64));

  public synchronized String  getCacheKey() {
    CacheKeyBuffer kkk = new CacheKeyBuffer(new String[0], this.dir_uuid,System.currentTimeMillis() / 600000l,this.getP());

    String rtn = CACHE_BUFFER.get(kkk);
    if (rtn == null) {
      String[] filelist = null;
      try {
        filelist = this.listAll();
      } catch (Throwable e) {
        logger.error("listAll", e);
      }

      rtn = getCacheKey(filelist);
      CACHE_BUFFER.put(kkk, rtn);
    }

    return rtn;
  }
 
 
  public synchronized String getCacheKey(String[] filelist)
    {
   
    CacheKeyBuffer kkk = new CacheKeyBuffer(filelist, this.dir_uuid,
        System.currentTimeMillis() / 600000l,this.getP());

    String rtn = CACHE_BUFFER.get(kkk);
    if (rtn == null) {
      StringBuffer buff=new StringBuffer();
      buff.append(this.getClass().getName()).append("_");
      buff.append(this.dir_uuid).append("_");
    CRC32 crc32 = new CRC32();
    crc32.update(0);
    long filesize=0;
      if(filelist!=null)
      {
        buff.append(filelist.length).append("_");
        for(String s:filelist)
        {
            crc32.update(new String(s).getBytes());
            try{
              filesize+=this.fileLength(s);
            }catch(Throwable e)
            {
              logger.error("filelength",e);
            }
        }
      }
    long crcvalue = crc32.getValue();
    buff.append(crcvalue).append("_");
    buff.append(filesize).append("_");
    rtn = buff.toString();
    CACHE_BUFFER.put(kkk, rtn);

  }

  return rtn;
    }
 
  private PartionKey p=null;
 
  public PartionKey getP() {
    return p;
  }

  public SolrCore getCore() {
    return core;
  }

  public void setCore(SolrCore core,PartionKey p) {
    this.core = core;
    this.p = p;

  }

  public IndexSchema getSchema() {
    return schema;
  }

  public  void setSchema(IndexSchema schema)
  {
    this.schema=schema;
  }
  volatile protected boolean isOpen = true;

  /** Holds the LockFactory instance (implements locking for
   * this Directory instance). */
  protected LockFactory lockFactory;

  /**
   * Returns an array of strings, one for each file in the directory.
   *
   * @throws NoSuchDirectoryException if the directory is not prepared for any
   *         write operations (such as {@link #createOutput(String)}).
   * @throws IOException in case of other IO errors
   */
  public abstract String[] listAll() throws IOException;

  /** Returns true iff a file with the given name exists. */
  public abstract boolean fileExists(String name)
       throws IOException;

  /** Returns the time the named file was last modified. */
  public abstract long fileModified(String name)
       throws IOException;

  /** Set the modified time of an existing file to now.
   *
   *  @deprecated Lucene never uses this API; it will be
   *  removed in 4.0. */
  @Deprecated
  public abstract void touchFile(String name)
       throws IOException;

  /** Removes an existing file in the directory. */
  public abstract void deleteFile(String name)
       throws IOException;

  /**
   * Returns the length of a file in the directory. This method follows the
   * following contract:
   * <ul>
   * <li>Throws {@link FileNotFoundException} if the file does not exist
   * <li>Returns a value &ge;0 if the file exists, which specifies its length.
   * </ul>
   *
   * @param name the name of the file for which to return the length.
   * @throws FileNotFoundException if the file does not exist.
   * @throws IOException if there was an IO error while retrieving the file's
   *         length.
   */
  public abstract long fileLength(String name) throws IOException;


  /** Creates a new, empty file in the directory with the given name.
      Returns a stream writing this file. */
  public abstract IndexOutput createOutput(String name)
       throws IOException;

  /**
   * Ensure that any writes to this file are moved to
   * stable storage.  Lucene uses this to properly commit
   * changes to the index, to prevent a machine/OS crash
   * from corrupting the index.
   * @deprecated use {@link #sync(Collection)} instead.
   * For easy migration you can change your code to call
   * sync(Collections.singleton(name))
   */
  @Deprecated
  public void sync(String name) throws IOException { // TODO 4.0 kill me
  }

  /**
   * Ensure that any writes to these files are moved to
   * stable storage.  Lucene uses this to properly commit
   * changes to the index, to prevent a machine/OS crash
   * from corrupting the index.<br/>
   * <br/>
   * NOTE: Clients may call this method for same files over
   * and over again, so some impls might optimize for that.
   * For other impls the operation can be a noop, for various
   * reasons.
   */
  public void sync(Collection<String> names) throws IOException { // TODO 4.0 make me abstract
    for (String name : names)
      sync(name);
  }

  /** Returns a stream reading an existing file. */
  public abstract IndexInput openInput(String name)
    throws IOException;

  /** Returns a stream reading an existing file, with the
   * specified read buffer size.  The particular Directory
   * implementation may ignore the buffer size.  Currently
   * the only Directory implementations that respect this
   * parameter are {@link FSDirectory} and {@link
   * org.apache.lucene.index.CompoundFileReader}.
  */
  public IndexInput openInput(String name, int bufferSize) throws IOException {
    return openInput(name);
  }

  /** Construct a {@link Lock}.
   * @param name the name of the lock file
   */
  public Lock makeLock(String name) {
      return lockFactory.makeLock(name);
  }
  /**
   * Attempt to clear (forcefully unlock and remove) the
   * specified lock.  Only call this at a time when you are
   * certain this lock is no longer in use.
   * @param name name of the lock to be cleared.
   */
  public void clearLock(String name) throws IOException {
    if (lockFactory != null) {
      lockFactory.clearLock(name);
    }
  }

  /** Closes the store. */
  public abstract void close()
       throws IOException;

  /**
   * Set the LockFactory that this Directory instance should
   * use for its locking implementation.  Each * instance of
   * LockFactory should only be used for one directory (ie,
   * do not share a single instance across multiple
   * Directories).
   *
   * @param lockFactory instance of {@link LockFactory}.
   */
  public void setLockFactory(LockFactory lockFactory) throws IOException {
    assert lockFactory != null;
    this.lockFactory = lockFactory;
    lockFactory.setLockPrefix(this.getLockID());
  }

  /**
   * Get the LockFactory that this Directory instance is
   * using for its locking implementation.  Note that this
   * may be null for Directory implementations that provide
   * their own locking implementation.
   */
  public LockFactory getLockFactory() {
      return this.lockFactory;
  }

  /**
   * Return a string identifier that uniquely differentiates
   * this Directory instance from other Directory instances.
   * This ID should be the same if two Directory instances
   * (even in different JVMs and/or on different machines)
   * are considered "the same index".  This is how locking
   * "scopes" to the right index.
   */
  public String getLockID() {
      return this.toString();
  }

  @Override
  public String toString() {
    return super.toString() + " lockFactory=" + getLockFactory();
  }

  /**
   * Copies the file <i>src</i> to {@link Directory} <i>to</i> under the new
   * file name <i>dest</i>.
   * <p>
   * If you want to copy the entire source directory to the destination one, you
   * can do so like this:
   *
   * <pre>
   * Directory to; // the directory to copy to
   * for (String file : dir.listAll()) {
   *   dir.copy(to, file, newFile); // newFile can be either file, or a new name
   * }
   * </pre>
   * <p>
   * <b>NOTE:</b> this method does not check whether <i>dest<i> exist and will
   * overwrite it if it does.
   */
  public void copy(Directory to, String src, String dest) throws IOException {
    IndexOutput os = null;
    IndexInput is = null;
    IOException priorException = null;
    try {
      os = to.createOutput(dest);
      is = openInput(src);
      is.copyBytes(os, is.length());
    } catch (IOException ioe) {
      priorException = ioe;
    } finally {
      IOUtils.closeWhileHandlingException(priorException, os, is);
    }
  }

  /**
   * Copy contents of a directory src to a directory dest. If a file in src
   * already exists in dest then the one in dest will be blindly overwritten.
   * <p>
   * <b>NOTE:</b> the source directory cannot change while this method is
   * running. Otherwise the results are undefined and you could easily hit a
   * FileNotFoundException.
   * <p>
   * <b>NOTE:</b> this method only copies files that look like index files (ie,
   * have extensions matching the known extensions of index files).
   *
   * @param src source directory
   * @param dest destination directory
   * @param closeDirSrc if <code>true</code>, call {@link #close()} method on
   *        source directory
   * @deprecated should be replaced with calls to
   *             {@link #copy(Directory, String, String)} for every file that
   *             needs copying. You can use the following code:
   *
   * <pre>
   * IndexFileNameFilter filter = IndexFileNameFilter.getFilter();
   * for (String file : src.listAll()) {
   *   if (filter.accept(null, file)) {
   *     src.copy(dest, file, file);
   *   }
   * }
   * </pre>
   */
  @Deprecated
  public static void copy(Directory src, Directory dest, boolean closeDirSrc) throws IOException {
    IndexFileNameFilter filter = IndexFileNameFilter.getFilter();
    for (String file : src.listAll()) {
      if (filter.accept(null, file)) {
        src.copy(dest, file, file);
      }
    }
    if (closeDirSrc) {
      src.close();
    }
  }

  /**
   * @throws AlreadyClosedException if this Directory is closed
   */
  protected final void ensureOpen() throws AlreadyClosedException {
    if (!isOpen)
      throw new AlreadyClosedException("this Directory is closed");
  }
}
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