write letFile etc.and byte helper class

ctalk/src/com/db/letdb/LetFile.java

@@ -0,0 +1,116 @@
+package com.db.letdb;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Hashtable;
+import java.util.Map;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import com.helper.ByteHelper;
+
+
+/**
+ * 
+ * @author chao
+ *
+ */
+public class LetFile {
+	private static final Log log = LogFactory.getLog(LetFile.class);
+	private static final String DB_DIR = "letdb";
+	private static final String LOCK_FILE = "letdb/.lock";
+	private static final String INDEX_FILE = "letdb/.index";
+	private static Map<Long,Index> indexMap = new Hashtable<Long,Index>();
+
+	public void init() throws IOException{
+		File file = new File(DB_DIR);
+		if (!file.exists() || !file.isDirectory()){
+			log.info("crate dir letdb/ ");
+			file.mkdir();
+		}else{
+			File indexFile = new File(INDEX_FILE);
+			if (!indexFile.exists()){
+				log.info("crate file .index ");
+				indexFile.createNewFile();
+			}
+			loadIndex();
+		}
+	}
+
+	/**
+	 * load index from .index file to indexMap in memory
+	 * @throws IOException
+	 */
+	private void loadIndex() throws IOException{
+		InputStream in = new FileInputStream(new File(INDEX_FILE));
+		log.debug(".index found");
+		int off = 0;
+		byte[] b = new byte[24];
+		while (in.read(b, off, 24) != -1){
+			Index index = Index.getInstance(b);
+			if (index != null){
+				indexMap.put(index.getId(),index);
+				off += 24;
+			}
+		}
+		log.debug("load index in map account: "+indexMap.size());
+	}
+
+
+}
+
+/**
+ * doc map index
+ * @author chao
+ * 
+ */
+class Index{
+	private long id = -1;       //doc id
+	private int state = 0;      //-1:this doc has been delete; 0:normal
+	private long pos = 0;       //doc start postion
+	private int len = 0;        //doc take size  
+	public static int INDEX_LEN = 24;
+
+	public static Index getInstance(byte[] content){
+		if (content.length == INDEX_LEN){
+			Index index = new Index();
+
+			index.setId(ByteHelper.getLong(content, 0));
+			index.setState(ByteHelper.getInt(content, 4));
+			index.setPos(ByteHelper.getLong(content, 12));
+			index.setLen(ByteHelper.getInt(content, 20));
+
+			return index;
+		}else{
+			return null;
+		}
+	}
+
+	public int getState() {
+		return state;
+	}
+	public void setState(int state) {
+		this.state = state;
+	}
+	public long getPos() {
+		return pos;
+	}
+	public void setPos(long pos) {
+		this.pos = pos;
+	}
+	public int getLen() {
+		return len;
+	}
+	public void setLen(int len) {
+		this.len = len;
+	}
+	public long getId() {
+		return id;
+	}
+	public void setId(long id) {
+		this.id = id;
+	}
+}

ctalk/src/com/db/letdb/Letdb.java

@@ -0,0 +1,18 @@
+package com.db.letdb;
+
+
+/**
+ * 
+ * @author chao
+ * Letdb is a simple database,only support localhost store,
+ * it's similar with nosql database ,data format is json
+ */
+public class Letdb {
+
+	;
+	;
+	;
+
+	;
+
+}

ctalk/src/com/helper/ByteHelper.java

@@ -0,0 +1,25 @@
+package com.helper;
+/**
+ * @created: 2011-11-7
+ * @author : jias chao<[email protected]>
+ */
+public class ByteHelper {
+
+	public static long getLong(byte[] bytes, int offset) {
+		long result = 0;
+		for (int i = offset; i < offset + 8; i++) {
+			result = (result << 8) | (0x00ff & bytes[i]);
+		}
+		return result;
+	}
+
+	public static int getInt(byte[] bytes, int begin) {
+		int result = 0;
+		for (int i = 0; i < 4; i++) {
+			result = result | (0x00ff & bytes[i + begin]) << ((3 - i) * 8);
+		}
+		return result;
+	}
+
+
+}