btreemultifieldindex.java

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package org.garret.perst.impl;
import  org.garret.perst.*;

import java.lang.reflect.*;
import java.util.*;
import java.util.ArrayList;

class BtreeMultiFieldIndex extends Btree implements FieldIndex { 
    String   className;
    String[] fieldName;
    int[]    types;

    transient Class   cls;
    transient Field[] fld;

    BtreeMultiFieldIndex() {}
    
    BtreeMultiFieldIndex(Class cls, String[] fieldName, boolean unique) {
        this.cls = cls;
        this.unique = unique;
        this.fieldName = fieldName;        
        this.className = ClassDescriptor.getClassName(cls);
        locateFields();
        type = ClassDescriptor.tpArrayOfByte;        
        types = new int[fieldName.length];
        for (int i = 0; i < types.length; i++) {
            types[i] = checkType(fld[i].getType());
        }
    }

    private final void locateFields() 
    {
        fld = new Field[fieldName.length];
        for (int i = 0; i < fieldName.length; i++) {
            fld[i] = ClassDescriptor.locateField(cls, fieldName[i]);
            if (fld[i] == null) { 
                throw new StorageError(StorageError.INDEXED_FIELD_NOT_FOUND, className + "." + fieldName[i]);
            }
        }
    }

    public Class getIndexedClass() { 
        return cls;
    }

    public Field[] getKeyFields() { 
        return fld;
    }

    public void onLoad()
    {
        cls = ClassDescriptor.loadClass(getStorage(), className);
        locateFields();
    }

    int compareByteArrays(byte[] key, byte[] item, int offs, int lengtn) { 
        int o1 = 0;
        int o2 = offs;
        byte[] a1 = key;
        byte[] a2 = item;
        for (int i = 0; i < fld.length && o1 < key.length; i++) {
            int diff = 0;
            switch (types[i]) { 
              case ClassDescriptor.tpBoolean:
              case ClassDescriptor.tpByte:
                diff = a1[o1++] - a2[o2++];
                break;
              case ClassDescriptor.tpShort:
                diff = Bytes.unpack2(a1, o1) - Bytes.unpack2(a2, o2);
                o1 += 2;
                o2 += 2;
                break;
              case ClassDescriptor.tpChar:
                diff = (char)Bytes.unpack2(a1, o1) - (char)Bytes.unpack2(a2, o2);
                o1 += 2;
                o2 += 2;
                break;
              case ClassDescriptor.tpInt:
              case ClassDescriptor.tpObject:
              {
                  int i1 = Bytes.unpack4(a1, o1);
                  int i2 = Bytes.unpack4(a2, o2);
                  diff = i1 < i2 ? -1 : i1 == i2 ? 0 : 1;
                  o1 += 4;
                  o2 += 4;
                  break;
              }
              case ClassDescriptor.tpLong:
              case ClassDescriptor.tpDate:
              {
                  long l1 = Bytes.unpack8(a1, o1);
                  long l2 = Bytes.unpack8(a2, o2);
                  diff = l1 < l2 ? -1 : l1 == l2 ? 0 : 1;
                  o1 += 8;
                  o2 += 8;
                  break;
              }
              case ClassDescriptor.tpFloat:
              {
                  float f1 = Float.intBitsToFloat(Bytes.unpack4(a1, o1));
                  float f2 = Float.intBitsToFloat(Bytes.unpack4(a2, o2));
                  diff = f1 < f2 ? -1 : f1 == f2 ? 0 : 1;
                  o1 += 4;
                  o2 += 4;
                  break;
              }
              case ClassDescriptor.tpDouble:
              {
                  double d1 = Double.longBitsToDouble(Bytes.unpack8(a1, o1));
                  double d2 = Double.longBitsToDouble(Bytes.unpack8(a2, o2));
                  diff = d1 < d2 ? -1 : d1 == d2 ? 0 : 1;
                  o1 += 8;
                  o2 += 8;
                  break;
              }
              case ClassDescriptor.tpString:
              {
                  int len1 = Bytes.unpack4(a1, o1);
                  int len2 = Bytes.unpack4(a2, o2);
                  o1 += 4;
                  o2 += 4;
                  int len = len1 < len2 ? len1 : len2;
                  while (--len >= 0) { 
                      diff = (char)Bytes.unpack2(a1, o1) - (char)Bytes.unpack2(a2, o2);
                      if (diff != 0) { 
                          return diff;
                      }
                      o1 += 2;
                      o2 += 2;
                  }
                  diff = len1 - len2;
                  break;
              }
              case ClassDescriptor.tpArrayOfByte:
              {
                  int len1 = Bytes.unpack4(a1, o1);
                  int len2 = Bytes.unpack4(a2, o2);
                  o1 += 4;
                  o2 += 4;
                  int len = len1 < len2 ? len1 : len2;
                  while (--len >= 0) { 
                      diff = a1[o1++] - a2[o2++];
                      if (diff != 0) { 
                          return diff;
                      }
                  }
                  diff = len1 - len2;
                  break;
              }
              default:
                Assert.failed("Invalid type");
            }
            if (diff != 0) { 
                return diff;
            }
        }
        return 0;
    }

    Object unpackByteArrayKey(Page pg, int pos) {
        int offs = BtreePage.firstKeyOffs + BtreePage.getKeyStrOffs(pg, pos);
        byte[] data = pg.data;
        Object values[] = new Object[fld.length];

        for (int i = 0; i < fld.length; i++) {
            Object v = null;
            switch (types[i]) { 
              case ClassDescriptor.tpBoolean:
                v = Boolean.valueOf(data[offs++] != 0);
                break;
              case ClassDescriptor.tpByte:
                v = new Byte(data[offs++]);
                break;
              case ClassDescriptor.tpShort:
                v = new Short(Bytes.unpack2(data, offs));
                offs += 2;
                break;
              case ClassDescriptor.tpChar:
                v = new Character((char)Bytes.unpack2(data, offs));
                offs += 2;
                break;
              case ClassDescriptor.tpInt:
                v = new Integer(Bytes.unpack4(data, offs));
                offs += 4;
                break;
              case ClassDescriptor.tpObject:
              {
                  int oid = Bytes.unpack4(data, offs);
                  v = oid == 0 ? null : ((StorageImpl)getStorage()).lookupObject(oid, null);
                  offs += 4;
                  break;
              }
              case ClassDescriptor.tpLong:
                v = new Long(Bytes.unpack8(data, offs));
                offs += 8;
                break;
              case ClassDescriptor.tpDate:
              {
                  long msec = Bytes.unpack8(data, offs);
                  v = msec == -1 ? null : new Date(msec);
                  offs += 8;
                  break;
              }
              case ClassDescriptor.tpFloat:
                v = new Float(Float.intBitsToFloat(Bytes.unpack4(data, offs)));
                offs += 4;
                break;
              case ClassDescriptor.tpDouble:
                v = new Double(Double.longBitsToDouble(Bytes.unpack8(data, offs)));
                offs += 8;
                break;
              case ClassDescriptor.tpString:
              {
                  int len = Bytes.unpack4(data, offs);
                  offs += 4;
                  char[] sval = new char[len];
                  for (int j = 0; j < len; j++) { 
                      sval[j] = (char)Bytes.unpack2(data, offs);
                      offs += 2;
                  }
                  v = new String(sval);
                  break;
              }
              case ClassDescriptor.tpArrayOfByte:
              {
                  int len = Bytes.unpack4(data, offs);
                  offs += 4;
                  byte[] bval = new byte[len];
                  System.arraycopy(data, offs, bval, 0, len);
                  offs += len;
                  break;
              }
              default:
                Assert.failed("Invalid type");
            }
            values[i] = v;
        }
        return values;
    }


    private Key extractKey(IPersistent obj) { 
        try { 
            ByteBuffer buf = new ByteBuffer();
            int dst = 0;
            for (int i = 0; i < fld.length; i++) { 
                Field f = (Field)fld[i];
                switch (types[i]) {
                  case ClassDescriptor.tpBoolean:
                    buf.extend(dst+1);
                    buf.arr[dst++] = (byte)(f.getBoolean(obj) ? 1 : 0);
                    break;
                  case ClassDescriptor.tpByte:
                    buf.extend(dst+1);
                    buf.arr[dst++] = f.getByte(obj);
                    break;
                  case ClassDescriptor.tpShort:
                    buf.extend(dst+2);
                    Bytes.pack2(buf.arr, dst, f.getShort(obj));
                    dst += 2;
                    break;
                  case ClassDescriptor.tpChar:
                    buf.extend(dst+2);
                    Bytes.pack2(buf.arr, dst, (short)f.getChar(obj));
                    dst += 2;
                    break;
                  case ClassDescriptor.tpInt:
                    buf.extend(dst+4);
                    Bytes.pack4(buf.arr, dst, f.getInt(obj));
                    dst += 4;
                    break;
                  case ClassDescriptor.tpObject:
                  {
                      IPersistent p = (IPersistent)f.get(obj);