/**
    *
    * 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.hadoop.hbase;
  
  import java.io.DataInput;
  import java.io.DataOutput;
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  import java.util.TreeMap;
  import java.util.TreeSet;
  import java.util.regex.Matcher;
  
  import org.apache.hadoop.classification.InterfaceAudience;
  import org.apache.hadoop.classification.InterfaceStability;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.hbase.exceptions.DeserializationException;
  import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
  import org.apache.hadoop.hbase.protobuf.ProtobufUtil;
  import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.BytesBytesPair;
  import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.ColumnFamilySchema;
  import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.NameStringPair;
  import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.TableSchema;
  import org.apache.hadoop.hbase.regionserver.BloomType;
  import org.apache.hadoop.hbase.security.User;
  import org.apache.hadoop.hbase.util.Bytes;
  import org.apache.hadoop.hbase.util.Writables;
  import org.apache.hadoop.io.WritableComparable;
  
  import com.google.protobuf.ByteString;
  import com.google.protobuf.InvalidProtocolBufferException;
  
  /**
   * HTableDescriptor contains the details about an HBase table  such as the descriptors of
   * all the column families, is the table a catalog table, <code> -ROOT- </code> or
   * <code> .META. </code>, if the table is read only, the maximum size of the memstore,
   * when the region split should occur, coprocessors associated with it etc...
   */
  @InterfaceAudience.Public
  @InterfaceStability.Evolving
  public class HTableDescriptor implements WritableComparable<HTableDescriptor> {
  
    /**
     *  Changes prior to version 3 were not recorded here.
     *  Version 3 adds metadata as a map where keys and values are byte[].
     *  Version 4 adds indexes
     *  Version 5 removed transactional pollution -- e.g. indexes
     *  Version 6 changed metadata to BytesBytesPair in PB
     *  Version 7 adds table-level configuration
     */
    private static final byte TABLE_DESCRIPTOR_VERSION = 7;
  
    private byte [] name = HConstants.EMPTY_BYTE_ARRAY;
  
    private String nameAsString = "";
  
    /**
     * A map which holds the metadata information of the table. This metadata
     * includes values like IS_ROOT, IS_META, DEFERRED_LOG_FLUSH, SPLIT_POLICY,
     * MAX_FILE_SIZE, READONLY, MEMSTORE_FLUSHSIZE etc...
     */
    private final Map<ImmutableBytesWritable, ImmutableBytesWritable> values =
      new HashMap<ImmutableBytesWritable, ImmutableBytesWritable>();
  
    /**
     * A map which holds the configuration specific to the table.
     * The keys of the map have the same names as config keys and override the defaults with
     * table-specific settings. Example usage may be for compactions, etc.
     */
    private final Map<String, String> configuration = new HashMap<String, String>();
  
    public static final String SPLIT_POLICY = "SPLIT_POLICY";
  
    /**
     * <em>INTERNAL</em> Used by HBase Shell interface to access this metadata
     * attribute which denotes the maximum size of the store file after which
    * a region split occurs
    *
    * @see #getMaxFileSize()
    */
   public static final String MAX_FILESIZE = "MAX_FILESIZE";
   private static final ImmutableBytesWritable MAX_FILESIZE_KEY =
     new ImmutableBytesWritable(Bytes.toBytes(MAX_FILESIZE));
 
   public static final String OWNER = "OWNER";
   public static final ImmutableBytesWritable OWNER_KEY =
     new ImmutableBytesWritable(Bytes.toBytes(OWNER));
 
   /**
    * <em>INTERNAL</em> Used by rest interface to access this metadata
    * attribute which denotes if the table is Read Only
    *
    * @see #isReadOnly()
    */
   public static final String READONLY = "READONLY";
   private static final ImmutableBytesWritable READONLY_KEY =
     new ImmutableBytesWritable(Bytes.toBytes(READONLY));
 
   /**
    * <em>INTERNAL</em> Used by HBase Shell interface to access this metadata
    * attribute which represents the maximum size of the memstore after which
    * its contents are flushed onto the disk
    *
    * @see #getMemStoreFlushSize()
    */
   public static final String MEMSTORE_FLUSHSIZE = "MEMSTORE_FLUSHSIZE";
   private static final ImmutableBytesWritable MEMSTORE_FLUSHSIZE_KEY =
     new ImmutableBytesWritable(Bytes.toBytes(MEMSTORE_FLUSHSIZE));
 
   /**
    * <em>INTERNAL</em> Used by rest interface to access this metadata
    * attribute which denotes if the table is a -ROOT- region or not
    *
    * @see #isRootRegion()
    */
   public static final String IS_ROOT = "IS_ROOT";
   private static final ImmutableBytesWritable IS_ROOT_KEY =
     new ImmutableBytesWritable(Bytes.toBytes(IS_ROOT));
 
   /**
    * <em>INTERNAL</em> Used by rest interface to access this metadata
    * attribute which denotes if it is a catalog table, either
    * <code> .META. </code> or <code> -ROOT- </code>
    *
    * @see #isMetaRegion()
    */
   public static final String IS_META = "IS_META";
   private static final ImmutableBytesWritable IS_META_KEY =
     new ImmutableBytesWritable(Bytes.toBytes(IS_META));
 
   /**
    * <em>INTERNAL</em> Used by HBase Shell interface to access this metadata
    * attribute which denotes if the deferred log flush option is enabled
    */
   public static final String DEFERRED_LOG_FLUSH = "DEFERRED_LOG_FLUSH";
   private static final ImmutableBytesWritable DEFERRED_LOG_FLUSH_KEY =
     new ImmutableBytesWritable(Bytes.toBytes(DEFERRED_LOG_FLUSH));
 
   /*
    *  The below are ugly but better than creating them each time till we
    *  replace booleans being saved as Strings with plain booleans.  Need a
    *  migration script to do this.  TODO.
    */
   private static final ImmutableBytesWritable FALSE =
     new ImmutableBytesWritable(Bytes.toBytes(Boolean.FALSE.toString()));
 
   private static final ImmutableBytesWritable TRUE =
     new ImmutableBytesWritable(Bytes.toBytes(Boolean.TRUE.toString()));
 
   private static final boolean DEFAULT_DEFERRED_LOG_FLUSH = false;
 
   /**
    * Constant that denotes whether the table is READONLY by default and is false
    */
   public static final boolean DEFAULT_READONLY = false;
 
   /**
    * Constant that denotes the maximum default size of the memstore after which
    * the contents are flushed to the store files
    */
   public static final long DEFAULT_MEMSTORE_FLUSH_SIZE = 1024*1024*128L;
 
   private final static Map<String, String> DEFAULT_VALUES
     = new HashMap<String, String>();
   private final static Set<ImmutableBytesWritable> RESERVED_KEYWORDS
     = new HashSet<ImmutableBytesWritable>();
   static {
     DEFAULT_VALUES.put(MAX_FILESIZE,
         String.valueOf(HConstants.DEFAULT_MAX_FILE_SIZE));
     DEFAULT_VALUES.put(READONLY, String.valueOf(DEFAULT_READONLY));
     DEFAULT_VALUES.put(MEMSTORE_FLUSHSIZE,
         String.valueOf(DEFAULT_MEMSTORE_FLUSH_SIZE));
     DEFAULT_VALUES.put(DEFERRED_LOG_FLUSH,
         String.valueOf(DEFAULT_DEFERRED_LOG_FLUSH));
     for (String s : DEFAULT_VALUES.keySet()) {
       RESERVED_KEYWORDS.add(new ImmutableBytesWritable(Bytes.toBytes(s)));
     }
     RESERVED_KEYWORDS.add(IS_ROOT_KEY);
     RESERVED_KEYWORDS.add(IS_META_KEY);
   }
 
   /**
    * Cache of whether this is a meta table or not.
    */
   private volatile Boolean meta = null;
   /**
    * Cache of whether this is root table or not.
    */
   private volatile Boolean root = null;
   /**
    * Cache of whether deferred logging set.
    */
   private Boolean deferredLog = null;
 
   /**
    * Maps column family name to the respective HColumnDescriptors
    */
   private final Map<byte [], HColumnDescriptor> families =
     new TreeMap<byte [], HColumnDescriptor>(Bytes.BYTES_RAWCOMPARATOR);
 
   /**
    * <em> INTERNAL </em> Private constructor used internally creating table descriptors for
    * catalog tables, <code>.META.</code> and <code>-ROOT-</code>.
    */
   protected HTableDescriptor(final byte [] name, HColumnDescriptor[] families) {
     this.name = name.clone();
     this.nameAsString = Bytes.toString(this.name);
     setMetaFlags(name);
     for(HColumnDescriptor descriptor : families) {
       this.families.put(descriptor.getName(), descriptor);
     }
   }
 
   /**
    * <em> INTERNAL </em>Private constructor used internally creating table descriptors for
    * catalog tables, <code>.META.</code> and <code>-ROOT-</code>.
    */
   protected HTableDescriptor(final byte [] name, HColumnDescriptor[] families,
       Map<ImmutableBytesWritable,ImmutableBytesWritable> values) {
     this.name = name.clone();
     this.nameAsString = Bytes.toString(this.name);
     setMetaFlags(name);
     for(HColumnDescriptor descriptor : families) {
       this.families.put(descriptor.getName(), descriptor);
     }
     for (Map.Entry<ImmutableBytesWritable, ImmutableBytesWritable> entry:
         values.entrySet()) {
       setValue(entry.getKey(), entry.getValue());
     }
   }
 
   /**
    * Default constructor which constructs an empty object.
    * For deserializing an HTableDescriptor instance only.
    * @see #HTableDescriptor(byte[])
    * @deprecated Used by Writables and Writables are going away.
    */
   @Deprecated
   public HTableDescriptor() {
     super();
   }
 
   /**
    * Construct a table descriptor specifying table name.
    * @param name Table name.
    * @throws IllegalArgumentException if passed a table name
    * that is made of other than 'word' characters, underscore or period: i.e.
    * <code>[a-zA-Z_0-9.].
    * @see <a href="HADOOP-1581">HADOOP-1581 HBASE: Un-openable tablename bug</a>
    */
   public HTableDescriptor(final String name) {
     this(Bytes.toBytes(name));
   }
 
   /**
    * Construct a table descriptor specifying a byte array table name
    * @param name - Table name as a byte array.
    * @throws IllegalArgumentException if passed a table name
    * that is made of other than 'word' characters, underscore or period: i.e.
    * <code>[a-zA-Z_0-9-.].
    * @see <a href="HADOOP-1581">HADOOP-1581 HBASE: Un-openable tablename bug</a>
    */
   public HTableDescriptor(final byte [] name) {
     super();
     setMetaFlags(this.name);
     this.name = this.isMetaRegion()? name: isLegalTableName(name);
     this.nameAsString = Bytes.toString(this.name);
   }
 
   /**
    * Construct a table descriptor by cloning the descriptor passed as a parameter.
    * <p>
    * Makes a deep copy of the supplied descriptor.
    * Can make a modifiable descriptor from an UnmodifyableHTableDescriptor.
    * @param desc The descriptor.
    */
   public HTableDescriptor(final HTableDescriptor desc) {
     super();
     this.name = desc.name.clone();
     this.nameAsString = Bytes.toString(this.name);
     setMetaFlags(this.name);
     for (HColumnDescriptor c: desc.families.values()) {
       this.families.put(c.getName(), new HColumnDescriptor(c));
     }
     for (Map.Entry<ImmutableBytesWritable, ImmutableBytesWritable> e:
         desc.values.entrySet()) {
       setValue(e.getKey(), e.getValue());
     }
     for (Map.Entry<String, String> e : desc.configuration.entrySet()) {
       this.configuration.put(e.getKey(), e.getValue());
     }
   }
 
   /*
    * Set meta flags on this table.
    * IS_ROOT_KEY is set if its a -ROOT- table
    * IS_META_KEY is set either if its a -ROOT- or a .META. table
    * Called by constructors.
    * @param name
    */
   private void setMetaFlags(final byte [] name) {
     setRootRegion(Bytes.equals(name, HConstants.ROOT_TABLE_NAME));
     setMetaRegion(isRootRegion() ||
       Bytes.equals(name, HConstants.META_TABLE_NAME));
   }
 
   /**
    * Check if the descriptor represents a <code> -ROOT- </code> region.
    *
    * @return true if this is a <code> -ROOT- </code> region
    */
   public boolean isRootRegion() {
     if (this.root == null) {
       this.root = isSomething(IS_ROOT_KEY, false)? Boolean.TRUE: Boolean.FALSE;
     }
     return this.root.booleanValue();
   }
 
   /**
    * <em> INTERNAL </em> Used to denote if the current table represents
    * <code> -ROOT- </code> region. This is used internally by the
    * HTableDescriptor constructors
    *
    * @param isRoot true if this is the <code> -ROOT- </code> region
    */
   protected void setRootRegion(boolean isRoot) {
     // TODO: Make the value a boolean rather than String of boolean.
     setValue(IS_ROOT_KEY, isRoot? TRUE: FALSE);
   }
 
   /**
    * Checks if this table is either <code> -ROOT- </code> or <code> .META. </code>
    * region.
    *
    * @return true if this is either a <code> -ROOT- </code> or <code> .META. </code>
    * region
    */
   public boolean isMetaRegion() {
     if (this.meta == null) {
       this.meta = calculateIsMetaRegion();
     }
     return this.meta.booleanValue();
   }
 
   private synchronized Boolean calculateIsMetaRegion() {
     byte [] value = getValue(IS_META_KEY);
     return (value != null)? Boolean.valueOf(Bytes.toString(value)): Boolean.FALSE;
   }
 
   private boolean isSomething(final ImmutableBytesWritable key,
       final boolean valueIfNull) {
     byte [] value = getValue(key);
     if (value != null) {
       // TODO: Make value be a boolean rather than String of boolean.
       return Boolean.valueOf(Bytes.toString(value));
     }
     return valueIfNull;
   }
 
   /**
    * <em> INTERNAL </em> Used to denote if the current table represents
    * <code> -ROOT- </code> or <code> .META. </code> region. This is used
    * internally by the HTableDescriptor constructors
    *
    * @param isMeta true if its either <code> -ROOT- </code> or
    * <code> .META. </code> region
    */
   protected void setMetaRegion(boolean isMeta) {
     setValue(IS_META_KEY, isMeta? TRUE: FALSE);
   }
 
   /**
    * Checks if the table is a <code>.META.</code> table
    *
    * @return true if table is <code> .META. </code> region.
    */
   public boolean isMetaTable() {
     return isMetaRegion() && !isRootRegion();
   }
 
   /**
    * Checks of the tableName being passed represents either
    * <code > -ROOT- </code> or <code> .META. </code>
    *
    * @return true if a tablesName is either <code> -ROOT- </code>
    * or <code> .META. </code>
    */
   public static boolean isMetaTable(final byte [] tableName) {
     return Bytes.equals(tableName, HConstants.ROOT_TABLE_NAME) ||
       Bytes.equals(tableName, HConstants.META_TABLE_NAME);
   }
 
   // A non-capture group so that this can be embedded.
   public static final String VALID_USER_TABLE_REGEX = "(?:[a-zA-Z_0-9][a-zA-Z_0-9.-]*)";
 
   /**
    * Check passed byte buffer, "tableName", is legal user-space table name.
    * @return Returns passed <code>tableName</code> param
    * @throws NullPointerException If passed <code>tableName</code> is null
    * @throws IllegalArgumentException if passed a tableName
    * that is made of other than 'word' characters or underscores: i.e.
    * <code>[a-zA-Z_0-9].
    */
   public static byte [] isLegalTableName(final byte [] tableName) {
     if (tableName == null || tableName.length <= 0) {
       throw new IllegalArgumentException("Name is null or empty");
     }
     if (tableName[0] == '.' || tableName[0] == '-') {
       throw new IllegalArgumentException("Illegal first character <" + tableName[0] +
           "> at 0. User-space table names can only start with 'word " +
           "characters': i.e. [a-zA-Z_0-9]: " + Bytes.toString(tableName));
     }
     if (HConstants.CLUSTER_ID_FILE_NAME.equalsIgnoreCase(Bytes
         .toString(tableName))
         || HConstants.SPLIT_LOGDIR_NAME.equalsIgnoreCase(Bytes
             .toString(tableName))
         || HConstants.VERSION_FILE_NAME.equalsIgnoreCase(Bytes
             .toString(tableName))) {
       throw new IllegalArgumentException(Bytes.toString(tableName)
           + " conflicted with system reserved words");
     }
     for (int i = 0; i < tableName.length; i++) {
       if (Character.isLetterOrDigit(tableName[i]) || tableName[i] == '_' ||
     		  tableName[i] == '-' || tableName[i] == '.') {
         continue;
       }
       throw new IllegalArgumentException("Illegal character <" + tableName[i] +
         "> at " + i + ". User-space table names can only contain " +
         "'word characters': i.e. [a-zA-Z_0-9-.]: " + Bytes.toString(tableName));
     }
     return tableName;
   }
 
   /**
    * Getter for accessing the metadata associated with the key
    *
    * @param key The key.
    * @return The value.
    * @see #values
    */
   public byte[] getValue(byte[] key) {
     return getValue(new ImmutableBytesWritable(key));
   }
 
   private byte[] getValue(final ImmutableBytesWritable key) {
     ImmutableBytesWritable ibw = values.get(key);
     if (ibw == null)
       return null;
     return ibw.get();
   }
 
   /**
    * Getter for accessing the metadata associated with the key
    *
    * @param key The key.
    * @return The value.
    * @see #values
    */
   public String getValue(String key) {
     byte[] value = getValue(Bytes.toBytes(key));
     if (value == null)
       return null;
     return Bytes.toString(value);
   }
 
   /**
    * Getter for fetching an unmodifiable {@link #values} map.
    *
    * @return unmodifiable map {@link #values}.
    * @see #values
    */
   public Map<ImmutableBytesWritable,ImmutableBytesWritable> getValues() {
     // shallow pointer copy
     return Collections.unmodifiableMap(values);
   }
 
   /**
    * Setter for storing metadata as a (key, value) pair in {@link #values} map
    *
    * @param key The key.
    * @param value The value.
    * @see #values
    */
   public void setValue(byte[] key, byte[] value) {
     setValue(new ImmutableBytesWritable(key), new ImmutableBytesWritable(value));
   }
 
   /*
    * @param key The key.
    * @param value The value.
    */
   private void setValue(final ImmutableBytesWritable key,
       final String value) {
     setValue(key, new ImmutableBytesWritable(Bytes.toBytes(value)));
   }
 
   /*
    * @param key The key.
    * @param value The value.
    */
   private void setValue(final ImmutableBytesWritable key,
       final ImmutableBytesWritable value) {
     values.put(key, value);
   }
 
   /**
    * Setter for storing metadata as a (key, value) pair in {@link #values} map
    *
    * @param key The key.
    * @param value The value.
    * @see #values
    */
   public void setValue(String key, String value) {
     if (value == null) {
       remove(key);
     } else {
       setValue(Bytes.toBytes(key), Bytes.toBytes(value));
     }
   }
 
   /**
    * Remove metadata represented by the key from the {@link #values} map
    *
    * @param key Key whose key and value we're to remove from HTableDescriptor
    * parameters.
    */
   public void remove(final String key) {
     remove(new ImmutableBytesWritable(Bytes.toBytes(key)));
   }
 
   /**
    * Remove metadata represented by the key from the {@link #values} map
    *
    * @param key Key whose key and value we're to remove from HTableDescriptor
    * parameters.
    */
   public void remove(ImmutableBytesWritable key) {
     values.remove(key);
   }
 
   /**
    * Check if the readOnly flag of the table is set. If the readOnly flag is
    * set then the contents of the table can only be read from but not modified.
    *
    * @return true if all columns in the table should be read only
    */
   public boolean isReadOnly() {
     return isSomething(READONLY_KEY, DEFAULT_READONLY);
   }
 
   /**
    * Setting the table as read only sets all the columns in the table as read
    * only. By default all tables are modifiable, but if the readOnly flag is
    * set to true then the contents of the table can only be read but not modified.
    *
    * @param readOnly True if all of the columns in the table should be read
    * only.
    */
   public void setReadOnly(final boolean readOnly) {
     setValue(READONLY_KEY, readOnly? TRUE: FALSE);
   }
 
   /**
    * Check if deferred log edits are enabled on the table.
    *
    * @return true if that deferred log flush is enabled on the table
    *
    * @see #setDeferredLogFlush(boolean)
    */
   public synchronized boolean isDeferredLogFlush() {
     if(this.deferredLog == null) {
       this.deferredLog =
           isSomething(DEFERRED_LOG_FLUSH_KEY, DEFAULT_DEFERRED_LOG_FLUSH);
     }
     return this.deferredLog;
   }
 
   /**
    * This is used to defer the log edits syncing to the file system. Everytime
    * an edit is sent to the server it is first sync'd to the file system by the
    * log writer. This sync is an expensive operation and thus can be deferred so
    * that the edits are kept in memory for a specified period of time as represented
    * by <code> hbase.regionserver.optionallogflushinterval </code> and not flushed
    * for every edit.
    * <p>
    * NOTE:- This option might result in data loss if the region server crashes
    * before these deferred edits in memory are flushed onto the filesystem.
    * </p>
    *
    * @param isDeferredLogFlush
    */
   public synchronized void setDeferredLogFlush(final boolean isDeferredLogFlush) {
     setValue(DEFERRED_LOG_FLUSH_KEY, isDeferredLogFlush? TRUE: FALSE);
     this.deferredLog = isDeferredLogFlush;
   }
 
   /**
    * Get the name of the table as a byte array.
    *
    * @return name of table
    */
   public byte [] getName() {
     return name;
   }
 
   /**
    * Get the name of the table as a String
    *
    * @return name of table as a String
    */
   public String getNameAsString() {
     return this.nameAsString;
   }
 
   /**
    * This get the class associated with the region split policy which
    * determines when a region split should occur.  The class used by
    * default is defined in {@link org.apache.hadoop.hbase.regionserver.RegionSplitPolicy}
    *
    * @return the class name of the region split policy for this table.
    * If this returns null, the default split policy is used.
    */
    public String getRegionSplitPolicyClassName() {
     return getValue(SPLIT_POLICY);
   }
 
   /**
    * Set the name of the table.
    *
    * @param name name of table
    */
   public void setName(byte[] name) {
     this.name = name;
     this.nameAsString = Bytes.toString(this.name);
     setMetaFlags(this.name);
   }
 
   /**
    * Returns the maximum size upto which a region can grow to after which a region
    * split is triggered. The region size is represented by the size of the biggest
    * store file in that region.
    *
    * @return max hregion size for table, -1 if not set.
    *
    * @see #setMaxFileSize(long)
    */
   public long getMaxFileSize() {
     byte [] value = getValue(MAX_FILESIZE_KEY);
     if (value != null) {
       return Long.parseLong(Bytes.toString(value));
     }
     return -1;
   }
 
   /**
    * Sets the maximum size upto which a region can grow to after which a region
    * split is triggered. The region size is represented by the size of the biggest
    * store file in that region, i.e. If the biggest store file grows beyond the
    * maxFileSize, then the region split is triggered. This defaults to a value of
    * 256 MB.
    * <p>
    * This is not an absolute value and might vary. Assume that a single row exceeds
    * the maxFileSize then the storeFileSize will be greater than maxFileSize since
    * a single row cannot be split across multiple regions
    * </p>
    *
    * @param maxFileSize The maximum file size that a store file can grow to
    * before a split is triggered.
    */
   public void setMaxFileSize(long maxFileSize) {
     setValue(MAX_FILESIZE_KEY, Long.toString(maxFileSize));
   }
 
   /**
    * Returns the size of the memstore after which a flush to filesystem is triggered.
    *
    * @return memory cache flush size for each hregion, -1 if not set.
    *
    * @see #setMemStoreFlushSize(long)
    */
   public long getMemStoreFlushSize() {
     byte [] value = getValue(MEMSTORE_FLUSHSIZE_KEY);
     if (value != null) {
       return Long.parseLong(Bytes.toString(value));
     }
     return -1;
   }
 
   /**
    * Represents the maximum size of the memstore after which the contents of the
    * memstore are flushed to the filesystem. This defaults to a size of 64 MB.
    *
    * @param memstoreFlushSize memory cache flush size for each hregion
    */
   public void setMemStoreFlushSize(long memstoreFlushSize) {
     setValue(MEMSTORE_FLUSHSIZE_KEY, Long.toString(memstoreFlushSize));
   }
 
   /**
    * Adds a column family.
    * @param family HColumnDescriptor of family to add.
    */
   public void addFamily(final HColumnDescriptor family) {
     if (family.getName() == null || family.getName().length <= 0) {
       throw new NullPointerException("Family name cannot be null or empty");
     }
     this.families.put(family.getName(), family);
   }
 
   /**
    * Checks to see if this table contains the given column family
    * @param familyName Family name or column name.
    * @return true if the table contains the specified family name
    */
   public boolean hasFamily(final byte [] familyName) {
     return families.containsKey(familyName);
   }
 
   /**
    * @return Name of this table and then a map of all of the column family
    * descriptors.
    * @see #getNameAsString()
    */
   @Override
   public String toString() {
     StringBuilder s = new StringBuilder();
     s.append('\'').append(Bytes.toString(name)).append('\'');
     s.append(getValues(true));
     for (HColumnDescriptor f : families.values()) {
       s.append(", ").append(f);
     }
     return s.toString();
   }
 
   /**
    * @return Name of this table and then a map of all of the column family
    * descriptors (with only the non-default column family attributes)
    */
   public String toStringCustomizedValues() {
     StringBuilder s = new StringBuilder();
     s.append('\'').append(Bytes.toString(name)).append('\'');
     s.append(getValues(false));
     for(HColumnDescriptor hcd : families.values()) {
       s.append(", ").append(hcd.toStringCustomizedValues());
     }
     return s.toString();
   }
 
   private StringBuilder getValues(boolean printDefaults) {
     StringBuilder s = new StringBuilder();
 
     // step 1: set partitioning and pruning
     Set<ImmutableBytesWritable> reservedKeys = new TreeSet<ImmutableBytesWritable>();
     Set<ImmutableBytesWritable> userKeys = new TreeSet<ImmutableBytesWritable>();
     for (ImmutableBytesWritable k : values.keySet()) {
       if (k == null || k.get() == null) continue;
       String key = Bytes.toString(k.get());
       // in this section, print out reserved keywords + coprocessor info
       if (!RESERVED_KEYWORDS.contains(k) && !key.startsWith("coprocessor$")) {
         userKeys.add(k);
         continue;
       }
       // only print out IS_ROOT/IS_META if true
       String value = Bytes.toString(values.get(k).get());
       if (key.equalsIgnoreCase(IS_ROOT) || key.equalsIgnoreCase(IS_META)) {
         if (Boolean.valueOf(value) == false) continue;
       }
       // see if a reserved key is a default value. may not want to print it out
       if (printDefaults
           || !DEFAULT_VALUES.containsKey(key)
           || !DEFAULT_VALUES.get(key).equalsIgnoreCase(value)) {
         reservedKeys.add(k);
       }
     }
 
     // early exit optimization
     boolean hasAttributes = !reservedKeys.isEmpty() || !userKeys.isEmpty();
     if (!hasAttributes && configuration.isEmpty()) return s;
 
     s.append(", {");
     // step 2: printing attributes
     if (hasAttributes) {
       s.append("TABLE_ATTRIBUTES => {");
 
       // print all reserved keys first
       boolean printCommaForAttr = false;
       for (ImmutableBytesWritable k : reservedKeys) {
         String key = Bytes.toString(k.get());
         String value = Bytes.toString(values.get(k).get());
         if (printCommaForAttr) s.append(", ");
         printCommaForAttr = true;
         s.append(key);
         s.append(" => ");
         s.append('\'').append(value).append('\'');
       }
 
       if (!userKeys.isEmpty()) {
         // print all non-reserved, advanced config keys as a separate subset
         if (printCommaForAttr) s.append(", ");
         printCommaForAttr = true;
         s.append(HConstants.METADATA).append(" => ");
         s.append("{");
         boolean printCommaForCfg = false;
         for (ImmutableBytesWritable k : userKeys) {
           String key = Bytes.toString(k.get());
           String value = Bytes.toString(values.get(k).get());
           if (printCommaForCfg) s.append(", ");
           printCommaForCfg = true;
           s.append('\'').append(key).append('\'');
           s.append(" => ");
           s.append('\'').append(value).append('\'');
         }
         s.append("}");
       }
     }
 
     // step 3: printing all configuration:
     if (!configuration.isEmpty()) {
       if (hasAttributes) {
         s.append(", ");
       }
       s.append(HConstants.CONFIGURATION).append(" => ");
       s.append('{');
       boolean printCommaForConfig = false;
       for (Map.Entry<String, String> e : configuration.entrySet()) {
         if (printCommaForConfig) s.append(", ");
         printCommaForConfig = true;
         s.append('\'').append(e.getKey()).append('\'');
         s.append(" => ");
         s.append('\'').append(e.getValue()).append('\'');
       }
       s.append("}");
     }
     s.append("}"); // end METHOD
     return s;
   }
 
   /**
    * Compare the contents of the descriptor with another one passed as a parameter.
    * Checks if the obj passed is an instance of HTableDescriptor, if yes then the
    * contents of the descriptors are compared.
    *
    * @return true if the contents of the the two descriptors exactly match
    *
    * @see java.lang.Object#equals(java.lang.Object)
    */
   @Override
   public boolean equals(Object obj) {
     if (this == obj) {
       return true;
     }
     if (obj == null) {
       return false;
     }
     if (!(obj instanceof HTableDescriptor)) {
       return false;
     }
     return compareTo((HTableDescriptor)obj) == 0;
   }
 
   /**
    * @see java.lang.Object#hashCode()
    */
   @Override
   public int hashCode() {
     int result = Bytes.hashCode(this.name);
     result ^= Byte.valueOf(TABLE_DESCRIPTOR_VERSION).hashCode();
     if (this.families != null && this.families.size() > 0) {
       for (HColumnDescriptor e: this.families.values()) {
         result ^= e.hashCode();
       }
     }
     result ^= values.hashCode();
     result ^= configuration.hashCode();
     return result;
   }
 
   /**
    * <em> INTERNAL </em> This method is a part of {@link WritableComparable} interface
    * and is used for de-serialization of the HTableDescriptor over RPC
    * @deprecated Writables are going away.  Use pb {@link #parseFrom(byte[])} instead.
    */
   @Deprecated
   @Override
   public void readFields(DataInput in) throws IOException {
     int version = in.readInt();
     if (version < 3)
       throw new IOException("versions < 3 are not supported (and never existed!?)");
     // version 3+
     name = Bytes.readByteArray(in);
     nameAsString = Bytes.toString(this.name);
     setRootRegion(in.readBoolean());
     setMetaRegion(in.readBoolean());
     values.clear();
     configuration.clear();
     int numVals = in.readInt();
     for (int i = 0; i < numVals; i++) {
       ImmutableBytesWritable key = new ImmutableBytesWritable();
       ImmutableBytesWritable value = new ImmutableBytesWritable();
       key.readFields(in);
       value.readFields(in);
       setValue(key, value);
     }
     families.clear();
     int numFamilies = in.readInt();
     for (int i = 0; i < numFamilies; i++) {
       HColumnDescriptor c = new HColumnDescriptor();
       c.readFields(in);
       families.put(c.getName(), c);
     }
     if (version >= 7) {
       int numConfigs = in.readInt();
       for (int i = 0; i < numConfigs; i++) {
         ImmutableBytesWritable key = new ImmutableBytesWritable();
         ImmutableBytesWritable value = new ImmutableBytesWritable();
         key.readFields(in);
         value.readFields(in);
         configuration.put(
           Bytes.toString(key.get(), key.getOffset(), key.getLength()),
           Bytes.toString(value.get(), value.getOffset(), value.getLength()));
       }
     }
   }
 
   /**
    * <em> INTERNAL </em> This method is a part of {@link WritableComparable} interface
    * and is used for serialization of the HTableDescriptor over RPC
    * @deprecated Writables are going away.
    * Use {@link com.google.protobuf.MessageLite#toByteArray} instead.
    */
   @Deprecated
   @Override
   public void write(DataOutput out) throws IOException {
 	out.writeInt(TABLE_DESCRIPTOR_VERSION);
     Bytes.writeByteArray(out, name);
     out.writeBoolean(isRootRegion());
     out.writeBoolean(isMetaRegion());
     out.writeInt(values.size());
     for (Map.Entry<ImmutableBytesWritable, ImmutableBytesWritable> e:
         values.entrySet()) {
       e.getKey().write(out);
       e.getValue().write(out);
     }
     out.writeInt(families.size());
     for(Iterator<HColumnDescriptor> it = families.values().iterator();
         it.hasNext(); ) {
       HColumnDescriptor family = it.next();
       family.write(out);
     }
     out.writeInt(configuration.size());
     for (Map.Entry<String, String> e : configuration.entrySet()) {
       new ImmutableBytesWritable(Bytes.toBytes(e.getKey())).write(out);
       new ImmutableBytesWritable(Bytes.toBytes(e.getValue())).write(out);
     }
   }
 
   // Comparable
 
   /**
    * Compares the descriptor with another descriptor which is passed as a parameter.
    * This compares the content of the two descriptors and not the reference.
    *
    * @return 0 if the contents of the descriptors are exactly matching,
    * 		 1 if there is a mismatch in the contents
    */
   @Override
   public int compareTo(final HTableDescriptor other) {
     int result = Bytes.compareTo(this.name, other.name);
     if (result == 0) {
       result = families.size() - other.families.size();
     }
     if (result == 0 && families.size() != other.families.size()) {
       result = Integer.valueOf(families.size()).compareTo(
           Integer.valueOf(other.families.size()));
     }
     if (result == 0) {
       for (Iterator<HColumnDescriptor> it = families.values().iterator(),
           it2 = other.families.values().iterator(); it.hasNext(); ) {
         result = it.next().compareTo(it2.next());
         if (result != 0) {
           break;
         }
       }
     }
     if (result == 0) {
       // punt on comparison for ordering, just calculate difference
       result = this.values.hashCode() - other.values.hashCode();
       if (result < 0)
         result = -1;
       else if (result > 0)
         result = 1;
     }
     if (result == 0) {
       result = this.configuration.hashCode() - other.configuration.hashCode();
       if (result < 0)
         result = -1;
       else if (result > 0)
         result = 1;
     }
     return result;
   }
 
   /**
    * Returns an unmodifiable collection of all the {@link HColumnDescriptor}
    * of all the column families of the table.
    *
    * @return Immutable collection of {@link HColumnDescriptor} of all the
    * column families.
    */
   public Collection<HColumnDescriptor> getFamilies() {
     return Collections.unmodifiableCollection(this.families.values());
   }
 
   /**
    * Returns all the column family names of the current table. The map of
    * HTableDescriptor contains mapping of family name to HColumnDescriptors.
    * This returns all the keys of the family map which represents the column
    * family names of the table.
    *
    * @return Immutable sorted set of the keys of the families.
    */
   public Set<byte[]> getFamiliesKeys() {
     return Collections.unmodifiableSet(this.families.keySet());
   }
 
   /**
    * Returns an array all the {@link HColumnDescriptor} of the column families
    * of the table.
    *
    * @return Array of all the HColumnDescriptors of the current table
    *
    * @see #getFamilies()
    */
   public HColumnDescriptor[] getColumnFamilies() {
     Collection<HColumnDescriptor> hColumnDescriptors = getFamilies();
     return hColumnDescriptors.toArray(new HColumnDescriptor[hColumnDescriptors.size()]);
   }
 
 
   /**
    * Returns the HColumnDescriptor for a specific column family with name as
    * specified by the parameter column.
    *
    * @param column Column family name
    * @return Column descriptor for the passed family name or the family on
    * passed in column.
    */
   public HColumnDescriptor getFamily(final byte [] column) {
     return this.families.get(column);
   }
 
 
   /**
    * Removes the HColumnDescriptor with name specified by the parameter column
    * from the table descriptor
    *
    * @param column Name of the column family to be removed.
    * @return Column descriptor for the passed family name or the family on
    * passed in column.
    */
   public HColumnDescriptor removeFamily(final byte [] column) {
     return this.families.remove(column);
   }
 
 
   /**
    * Add a table coprocessor to this table. The coprocessor
    * type must be {@link org.apache.hadoop.hbase.coprocessor.RegionObserver}
    * or Endpoint.
    * It won't check if the class can be loaded or not.
    * Whether a coprocessor is loadable or not will be determined when
    * a region is opened.
    * @param className Full class name.
    * @throws IOException
    */
   public void addCoprocessor(String className) throws IOException {
     addCoprocessor(className, null, Coprocessor.PRIORITY_USER, null);
   }
 
 
   /**
    * Add a table coprocessor to this table. The coprocessor
    * type must be {@link org.apache.hadoop.hbase.coprocessor.RegionObserver}
    * or Endpoint.
    * It won't check if the class can be loaded or not.
    * Whether a coprocessor is loadable or not will be determined when
    * a region is opened.
    * @param jarFilePath Path of the jar file. If it's null, the class will be
    * loaded from default classloader.
    * @param className Full class name.
    * @param priority Priority
    * @param kvs Arbitrary key-value parameter pairs passed into the coprocessor.
    * @throws IOException
    */
   public void addCoprocessor(String className, Path jarFilePath,
                              int priority, final Map<String, String> kvs)
   throws IOException {
     if (hasCoprocessor(className)) {
       throw new IOException("Coprocessor " + className + " already exists.");
     }
     // validate parameter kvs
     StringBuilder kvString = new StringBuilder();
     if (kvs != null) {
       for (Map.Entry<String, String> e: kvs.entrySet()) {
         if (!e.getKey().matches(HConstants.CP_HTD_ATTR_VALUE_PARAM_KEY_PATTERN)) {
           throw new IOException("Illegal parameter key = " + e.getKey());
         }
         if (!e.getValue().matches(HConstants.CP_HTD_ATTR_VALUE_PARAM_VALUE_PATTERN)) {
           throw new IOException("Illegal parameter (" + e.getKey() +
               ") value = " + e.getValue());
         }
         if (kvString.length() != 0) {
           kvString.append(',');
         }
         kvString.append(e.getKey());
         kvString.append('=');
         kvString.append(e.getValue());
       }
     }
 
     // generate a coprocessor key
     int maxCoprocessorNumber = 0;
     Matcher keyMatcher;
     for (Map.Entry<ImmutableBytesWritable, ImmutableBytesWritable> e:
         this.values.entrySet()) {
       keyMatcher =
           HConstants.CP_HTD_ATTR_KEY_PATTERN.matcher(
               Bytes.toString(e.getKey().get()));
       if (!keyMatcher.matches()) {
         continue;
       }
       maxCoprocessorNumber = Math.max(Integer.parseInt(keyMatcher.group(1)),
           maxCoprocessorNumber);
     }
     maxCoprocessorNumber++;
 
     String key = "coprocessor$" + Integer.toString(maxCoprocessorNumber);
     String value = ((jarFilePath == null)? "" : jarFilePath.toString()) +
         "|" + className + "|" + Integer.toString(priority) + "|" +
         kvString.toString();
     setValue(key, value);
   }
 
 
   /**
    * Check if the table has an attached co-processor represented by the name className
    *
    * @param className - Class name of the co-processor
    * @return true of the table has a co-processor className
    */
   public boolean hasCoprocessor(String className) {
     Matcher keyMatcher;
     Matcher valueMatcher;
     for (Map.Entry<ImmutableBytesWritable, ImmutableBytesWritable> e:
         this.values.entrySet()) {
       keyMatcher =
           HConstants.CP_HTD_ATTR_KEY_PATTERN.matcher(
               Bytes.toString(e.getKey().get()));
       if (!keyMatcher.matches()) {
         continue;
       }
       valueMatcher =
         HConstants.CP_HTD_ATTR_VALUE_PATTERN.matcher(
             Bytes.toString(e.getValue().get()));
       if (!valueMatcher.matches()) {
         continue;
       }
       // get className and compare
       String clazz = valueMatcher.group(2).trim(); // classname is the 2nd field
       if (clazz.equals(className.trim())) {
         return true;
       }
     }
     return false;
   }
 
   /**
    * Return the list of attached co-processor represented by their name className
    *
    * @return The list of co-processors classNames
    */
   public List<String> getCoprocessors() {
     List<String> result = new ArrayList<String>();
     Matcher keyMatcher;
     Matcher valueMatcher;
     for (Map.Entry<ImmutableBytesWritable, ImmutableBytesWritable> e : this.values.entrySet()) {
       keyMatcher = HConstants.CP_HTD_ATTR_KEY_PATTERN.matcher(Bytes.toString(e.getKey().get()));
       if (!keyMatcher.matches()) {
         continue;
       }
       valueMatcher = HConstants.CP_HTD_ATTR_VALUE_PATTERN.matcher(Bytes
           .toString(e.getValue().get()));
       if (!valueMatcher.matches()) {
         continue;
       }
       result.add(valueMatcher.group(2).trim()); // classname is the 2nd field
     }
     return result;
   }
 
   /**
    * Remove a coprocessor from those set on the table
    * @param className Class name of the co-processor
    */
   public void removeCoprocessor(String className) {
     ImmutableBytesWritable match = null;
     Matcher keyMatcher;
     Matcher valueMatcher;
     for (Map.Entry<ImmutableBytesWritable, ImmutableBytesWritable> e : this.values
         .entrySet()) {
       keyMatcher = HConstants.CP_HTD_ATTR_KEY_PATTERN.matcher(Bytes.toString(e
           .getKey().get()));
       if (!keyMatcher.matches()) {
         continue;
       }
       valueMatcher = HConstants.CP_HTD_ATTR_VALUE_PATTERN.matcher(Bytes
           .toString(e.getValue().get()));
       if (!valueMatcher.matches()) {
         continue;
       }
       // get className and compare
       String clazz = valueMatcher.group(2).trim(); // classname is the 2nd field
       // remove the CP if it is present
       if (clazz.equals(className.trim())) {
         match = e.getKey();
         break;
       }
     }
     // if we found a match, remove it
     if (match != null)
       remove(match);
   }
 
   /**
    * Returns the {@link Path} object representing the table directory under
    * path rootdir
    *
    * @param rootdir qualified path of HBase root directory
    * @param tableName name of table
    * @return {@link Path} for table
    */
   public static Path getTableDir(Path rootdir, final byte [] tableName) {
     return new Path(rootdir, Bytes.toString(tableName));
   }
 
   /** Table descriptor for <core>-ROOT-</code> catalog table */
   public static final HTableDescriptor ROOT_TABLEDESC = new HTableDescriptor(
       HConstants.ROOT_TABLE_NAME,
       new HColumnDescriptor[] {
           new HColumnDescriptor(HConstants.CATALOG_FAMILY)
               // Ten is arbitrary number.  Keep versions to help debugging.
               .setMaxVersions(10)
               .setInMemory(true)
               .setBlocksize(8 * 1024)
               .setTimeToLive(HConstants.FOREVER)
               .setScope(HConstants.REPLICATION_SCOPE_LOCAL)
       });
 
   /** Table descriptor for <code>.META.</code> catalog table */
   public static final HTableDescriptor META_TABLEDESC = new HTableDescriptor(
       HConstants.META_TABLE_NAME, new HColumnDescriptor[] {
           new HColumnDescriptor(HConstants.CATALOG_FAMILY)
               // Ten is arbitrary number.  Keep versions to help debugging.
               .setMaxVersions(10)
               .setInMemory(true)
               .setBlocksize(8 * 1024)
               .setScope(HConstants.REPLICATION_SCOPE_LOCAL)
               // Disable blooms for meta.  Needs work.  Seems to mess w/ getClosestOrBefore.
               .setBloomFilterType(BloomType.NONE)
       });
 
   static {
     try {
       META_TABLEDESC.addCoprocessor(
           "org.apache.hadoop.hbase.coprocessor.MultiRowMutationEndpoint",
           null, Coprocessor.PRIORITY_SYSTEM, null);
     } catch (IOException ex) {
       //LOG.warn("exception in loading coprocessor for the META table");
       throw new RuntimeException(ex);
     }
   }
 
 
   @Deprecated
   public void setOwner(User owner) {
     setOwnerString(owner != null ? owner.getShortName() : null);
   }
 
   // used by admin.rb:alter(table_name,*args) to update owner.
   @Deprecated
   public void setOwnerString(String ownerString) {
     if (ownerString != null) {
       setValue(OWNER_KEY, ownerString);
     } else {
       remove(OWNER_KEY);
     }
   }
 
   @Deprecated
   public String getOwnerString() {
     if (getValue(OWNER_KEY) != null) {
       return Bytes.toString(getValue(OWNER_KEY));
     }
     // Note that every table should have an owner (i.e. should have OWNER_KEY set).
     // .META. and -ROOT- should return system user as owner, not null (see
     // MasterFileSystem.java:bootstrap()).
     return null;
   }
 
   /**
    * @return This instance serialized with pb with pb magic prefix
    * @see #parseFrom(byte[])
    */
   public byte [] toByteArray() {
     return ProtobufUtil.prependPBMagic(convert().toByteArray());
   }
 
   /**
    * @param bytes A pb serialized {@link HTableDescriptor} instance with pb magic prefix
    * @return An instance of {@link HTableDescriptor} made from <code>bytes</code>
    * @throws DeserializationException
    * @throws IOException
    * @see #toByteArray()
    */
   public static HTableDescriptor parseFrom(final byte [] bytes)
   throws DeserializationException, IOException {
     if (!ProtobufUtil.isPBMagicPrefix(bytes)) {
       return (HTableDescriptor)Writables.getWritable(bytes, new HTableDescriptor());
     }
     int pblen = ProtobufUtil.lengthOfPBMagic();
     TableSchema.Builder builder = TableSchema.newBuilder();
     TableSchema ts;
     try {
       ts = builder.mergeFrom(bytes, pblen, bytes.length - pblen).build();
     } catch (InvalidProtocolBufferException e) {
       throw new DeserializationException(e);
     }
     return convert(ts);
   }
 
   /**
    * @return Convert the current {@link HTableDescriptor} into a pb TableSchema instance.
    */
   public TableSchema convert() {
     TableSchema.Builder builder = TableSchema.newBuilder();
     builder.setName(ByteString.copyFrom(getName()));
     for (Map.Entry<ImmutableBytesWritable, ImmutableBytesWritable> e: this.values.entrySet()) {
       BytesBytesPair.Builder aBuilder = BytesBytesPair.newBuilder();
       aBuilder.setFirst(ByteString.copyFrom(e.getKey().get()));
       aBuilder.setSecond(ByteString.copyFrom(e.getValue().get()));
       builder.addAttributes(aBuilder.build());
     }
     for (HColumnDescriptor hcd: getColumnFamilies()) {
       builder.addColumnFamilies(hcd.convert());
     }
     for (Map.Entry<String, String> e : this.configuration.entrySet()) {
       NameStringPair.Builder aBuilder = NameStringPair.newBuilder();
       aBuilder.setName(e.getKey());
       aBuilder.setValue(e.getValue());
       builder.addConfiguration(aBuilder.build());
     }
     return builder.build();
   }
 
   /**
    * @param ts A pb TableSchema instance.
    * @return An {@link HTableDescriptor} made from the passed in pb <code>ts</code>.
    */
   public static HTableDescriptor convert(final TableSchema ts) {
     List<ColumnFamilySchema> list = ts.getColumnFamiliesList();
     HColumnDescriptor [] hcds = new HColumnDescriptor[list.size()];
     int index = 0;
     for (ColumnFamilySchema cfs: list) {
       hcds[index++] = HColumnDescriptor.convert(cfs);
     }
     HTableDescriptor htd = new HTableDescriptor(ts.getName().toByteArray(), hcds);
     for (BytesBytesPair a: ts.getAttributesList()) {
       htd.setValue(a.getFirst().toByteArray(), a.getSecond().toByteArray());
     }
     for (NameStringPair a: ts.getConfigurationList()) {
       htd.setConfiguration(a.getName(), a.getValue());
     }
     return htd;
   }
 
   /**
    * Getter for accessing the configuration value by key
    */
   public String getConfigurationValue(String key) {
     return configuration.get(key);
   }
 
   /**
    * Getter for fetching an unmodifiable {@link #configuration} map.
    */
   public Map<String, String> getConfiguration() {
     // shallow pointer copy
     return Collections.unmodifiableMap(configuration);
   }
 
   /**
    * Setter for storing a configuration setting in {@link #configuration} map.
    * @param key Config key. Same as XML config key e.g. hbase.something.or.other.
    * @param value String value. If null, removes the setting.
    */
   public void setConfiguration(String key, String value) {
     if (value == null) {
       removeConfiguration(key);
     } else {
       configuration.put(key, value);
     }
   }
 
   /**
    * Remove a config setting represented by the key from the {@link #configuration} map
    */
   public void removeConfiguration(final String key) {
     configuration.remove(key);
   }
 }