bplustree.java

R树与B树的混合树

package NET.sourceforge.BplusJ.BplusJ;

	/// <summary>
	/// Tree index mapping Strings to Strings.
	/// </summary>
	public class BplusTree implements IStringTree
	{
		/// <summary>
		/// Internal tree mapping Strings to bytes (for conversion to Strings).
		/// </summary>
		public ITreeIndex tree;
		public BplusTree(ITreeIndex tree)
		{
//			if (!(tree is BplusTreeBytes) && this.checkTree()) 
//			{
//				throw new BplusTreeException("Bplustree (superclass) can only wrap BplusTreeBytes, not other ITreeIndex implementations");
//			}
			this.tree = tree;
		}
		
//		public boolean checkTree() 
//		{
//			// this is to prevent accidental misuse with the wrong ITreeIndex implementation,
//			// but to also allow subclasses to override the behaviour... (there must be a better way...)
//			return true;
//		}

		public static BplusTree Initialize(String treefileName, String blockfileName, int KeyLength, int CultureId,
			int nodesize, int buffersize) 
			throws Exception
		{
			BplusTreeBytes tree = BplusTreeBytes.Initialize(treefileName, blockfileName, KeyLength, CultureId, nodesize, buffersize);
			return new BplusTree(tree);
		}
		public static BplusTree Initialize(String treefileName, String blockfileName, int KeyLength, int CultureId) 
			throws Exception
		{
			BplusTreeBytes tree = BplusTreeBytes.Initialize(treefileName, blockfileName, KeyLength, CultureId);
			return new BplusTree(tree);
		}
		public static BplusTree Initialize(String treefileName, String blockfileName, int KeyLength) 
			throws Exception
		{
			BplusTreeBytes tree = BplusTreeBytes.Initialize(treefileName, blockfileName, KeyLength);
			return new BplusTree(tree);
		}
		
		public static BplusTree Initialize(java.io.RandomAccessFile treefile, java.io.RandomAccessFile blockfile, int KeyLength, int CultureId,
			int nodesize, int buffersize) throws Exception
		{
			BplusTreeBytes tree = BplusTreeBytes.Initialize(treefile, blockfile, KeyLength, CultureId, nodesize, buffersize);
			return new BplusTree(tree);
		}
		public static BplusTree Initialize(java.io.RandomAccessFile treefile, java.io.RandomAccessFile blockfile, int KeyLength, int CultureId) 
			throws Exception
		{
			BplusTreeBytes tree = BplusTreeBytes.Initialize(treefile, blockfile, KeyLength, CultureId);
			return new BplusTree(tree);
		}
		public static BplusTree Initialize(java.io.RandomAccessFile treefile, java.io.RandomAccessFile blockfile, int KeyLength)
			throws Exception
		{
			BplusTreeBytes tree = BplusTreeBytes.Initialize(treefile, blockfile, KeyLength);
			return new BplusTree(tree);
		}
		
		public static BplusTree ReOpen(java.io.RandomAccessFile treefile, java.io.RandomAccessFile blockfile) throws Exception
		{
			BplusTreeBytes tree = BplusTreeBytes.ReOpen(treefile, blockfile);
			return new BplusTree(tree);
		}
		public static BplusTree ReOpen(String treefileName, String blockfileName) throws Exception
		{
			BplusTreeBytes tree = BplusTreeBytes.ReOpen(treefileName, blockfileName);
			return new BplusTree(tree);
		}
		public static BplusTree ReadOnly(String treefileName, String blockfileName) throws Exception
		{
			BplusTreeBytes tree = BplusTreeBytes.ReadOnly(treefileName, blockfileName);
			return new BplusTree(tree);
		}

		//#region ITreeIndex Members

		public void Recover(boolean CorrectErrors) throws Exception
		{
			this.tree.Recover(CorrectErrors);
		}

		public void RemoveKey(String key) throws Exception
		{
			this.tree.RemoveKey(key);
		}

		public String FirstKey() throws Exception
		{
			return this.tree.FirstKey();
		}

		public String NextKey(String AfterThisKey) throws Exception
		{
			return this.tree.NextKey(AfterThisKey);
		}

		public boolean ContainsKey(String key) throws Exception
		{
			return this.tree.ContainsKey(key);
		}

		public Object Get(String key, Object defaultValue) throws Exception
		{
			Object test = this.tree.Get(key, null);
			if (test != null) 
			{
				return BytesToString((byte[]) test);
			}
			return defaultValue;
		}

		public void Set(String key, Object map) throws Exception
		{
//			if (!(map is String)) 
//			{
//				throw new BplusTreeException("BplusTree only stores Strings as values");
//			}
			String theString = (String) map;
			byte[] bytes = StringToBytes(theString);
			//this.tree[key] = bytes;
			this.tree.Set(key, bytes);
		}

		public void Commit() throws Exception
		{
			this.tree.Commit();
		}

		public void Abort() throws Exception
		{
			this.tree.Abort();
		}

		
		public void SetFootPrintLimit(int limit) throws Exception
		{
			this.tree.SetFootPrintLimit(limit);
		}
		
		public void Shutdown() throws Exception
		{
			this.tree.Shutdown();
		}
		
		public int Compare(String left, String right) throws Exception
		{
			return this.tree.Compare(left, right);
		}

		//#endregion
		public String get(String key) throws Exception
		{
			Object theGet = this.tree.Get(key, null);
			if (theGet!=null)
			{
				byte[] bytes = (byte[]) theGet;
				return BytesToString(bytes);
			}
			//System.Diagnostics.Debug.WriteLine(this.toHtml());
			throw new BplusTreeKeyMissing("key not found "+key);
		}
		public void set(String key, String value) throws Exception
		{
			byte[] bytes = StringToBytes(value);
			//this.tree[key] = bytes;
			this.tree.Set(key, bytes);
		}
		public static String BytesToString(byte[] bytes) throws Exception
		{
			return new String(bytes, 0, bytes.length, "UTF-8");
//			System.Text.Decoder decode = System.Text.Encoding.UTF8.GetDecoder();
//			long length = decode.GetCharCount(bytes, 0, bytes.Length);
//			char[] chars = new char[length];
//			decode.GetChars(bytes, 0, bytes.Length, chars, 0);
//			String result = new String(chars);
//			return result;
		}
		public static byte[] StringToBytes(String theString) throws Exception
		{
			return theString.getBytes("UTF-8");
//			System.Text.Encoder encode = System.Text.Encoding.UTF8.GetEncoder();
//			char[] chars = theString.ToCharArray();
//			long length = encode.GetByteCount(chars, 0, chars.Length, true);
//			byte[] bytes = new byte[length];
//			encode.GetBytes(chars, 0, chars.Length,bytes, 0, true);
//			return bytes;
		}
//		public virtual String toHtml() 
//		{
//			return ((BplusTreeBytes) this.tree).toHtml();
//		}
	}