调用ModelProperty的相应方法时得到合适的CHILD DAO，这样应用层可以只使用XXX.dao在多线程情况下安全的执行任何操作

lealone-orm/src/main/java/org/lealone/orm/ExpressionBuilder.java

@@ -101,7 +101,7 @@ public ExpressionBuilder<T> set(String propertyName, Value value) {
         return this;
     }
 
-    public ExpressionBuilder<T> eq(String propertyName, ModelProperty<?> p) {
+    public ExpressionBuilder<T> eq(String propertyName, ModelProperty<?, ?> p) {
         ExpressionColumn left = model.getExpressionColumn(propertyName);
         ExpressionColumn right = Model.getExpressionColumn(p);
         Comparison c = new Comparison(getTable().getSession(), Comparison.EQUAL, left, right);

lealone-orm/src/main/java/org/lealone/orm/Model.java

@@ -74,7 +74,7 @@ public abstract class Model<T> {
 
     private static final ConcurrentSkipListMap<Long, ServerSession> currentSessions = new ConcurrentSkipListMap<>();
 
-    public class PRowId extends PBaseNumber<T, Long> {
+    public class PRowId extends PBaseNumber<T, Long, PRowId> {
 
         private long value;
 
@@ -178,6 +178,7 @@ public boolean equals(Object obj) {
     private ArrayStack<ExpressionBuilder<T>> expressionBuilderStack;
 
     private ArrayStack<TableFilter> tableFilterStack;
+    private HashMap<String, ModelProperty> modelPropertiesMap;
 
     ModelProperty[] modelProperties;
     // 0: regular model; 1: root dao; 2: child dao
@@ -198,6 +199,14 @@ public boolean isDao() {
 
     protected void setModelProperties(ModelProperty[] modelProperties) {
         this.modelProperties = modelProperties;
+        modelPropertiesMap = new HashMap<>(modelProperties.length);
+        for (ModelProperty p : modelProperties) {
+            modelPropertiesMap.put(p.getName(), p);
+        }
+    }
+
+    ModelProperty getModelProperty(String name) {
+        return modelPropertiesMap.get(name);
     }
 
     /**
@@ -251,13 +260,13 @@ public String getTableName() {
     }
 
     @SafeVarargs
-    public final T select(ModelProperty<?>... properties) {
+    public final T select(ModelProperty<?, ?>... properties) {
         Model<T> m = maybeCopy();
         if (m != this) {
             return m.select(properties);
         }
         selectExpressions = new ArrayList<>();
-        for (ModelProperty<?> p : properties) {
+        for (ModelProperty<?, ?> p : properties) {
             ExpressionColumn c = getExpressionColumn(p);
             selectExpressions.add(c);
         }
@@ -275,20 +284,20 @@ public T orderBy() {
     }
 
     @SafeVarargs
-    public final T groupBy(ModelProperty<?>... properties) {
+    public final T groupBy(ModelProperty<?, ?>... properties) {
         Model<T> m = maybeCopy();
         if (m != this) {
             return m.groupBy(properties);
         }
         groupExpressions = new ArrayList<>();
-        for (ModelProperty<?> p : properties) {
+        for (ModelProperty<?, ?> p : properties) {
             ExpressionColumn c = getExpressionColumn(p);
             groupExpressions.add(c);
         }
         return root;
     }
 
-    static ExpressionColumn getExpressionColumn(ModelProperty<?> p) {
+    static ExpressionColumn getExpressionColumn(ModelProperty<?, ?> p) {
         return new ExpressionColumn(p.getDatabaseName(), p.getSchemaName(), p.getTableName(), p.getName());
     }
 
@@ -622,21 +631,14 @@ private boolean isRootDao() {
     }
 
     @SuppressWarnings("unchecked")
-    private Model<T> maybeCopy() {
+    Model<T> maybeCopy() {
         if (isRootDao()) {
-            Model m = newInstance(modelTable.copy(), CHILD_DAO);
-            return m;
+            return newInstance(modelTable.copy(), CHILD_DAO);
         } else {
             return this;
         }
     }
 
-    // 支持并发
-    public T fork() {
-        checkDao("for");
-        return maybeCopy().root;
-    }
-
     private void maybeCreateWhereExpression(Table dbTable) {
         // 没有指定where条件时，如果存在ROWID，则用ROWID当where条件
         if (_rowid_.get() != 0) {

lealone-orm/src/main/java/org/lealone/orm/ModelProperty.java

@@ -32,7 +32,8 @@
  *
  * @param <R> The type of the owning root bean
  */
-public abstract class ModelProperty<R> {
+@SuppressWarnings("unchecked")
+public abstract class ModelProperty<R, P> {
 
     protected final String name;
     protected final R root;
@@ -72,8 +73,12 @@ public String toString() {
         return name;
     }
 
-    private Model<?> getModel() {
-        return ((Model<?>) root);
+    protected Model<?> getModel() {
+        return ((Model<?>) root).maybeCopy();
+    }
+
+    protected P getModelProperty(Model<?> model) {
+        return (P) model.getModelProperty(name);
     }
 
     /**
@@ -87,6 +92,10 @@ protected ExpressionBuilder<?> expr() {
      * Is null.
      */
     public R isNull() {
+        Model<?> model = getModel();
+        if (model != root) {
+            return ((ModelProperty<R, P>) getModelProperty(model)).isNull();
+        }
         expr().isNull(name);
         return root;
     }
@@ -95,6 +104,10 @@ public R isNull() {
      * Is not null.
      */
     public R isNotNull() {
+        Model<?> model = getModel();
+        if (model != root) {
+            return ((ModelProperty<R, P>) getModelProperty(model)).isNotNull();
+        }
         expr().isNotNull(name);
         return root;
     }
@@ -103,6 +116,10 @@ public R isNotNull() {
      * Order by ascending on this property.
      */
     public R asc() {
+        Model<?> model = getModel();
+        if (model != root) {
+            return ((ModelProperty<R, P>) getModelProperty(model)).asc();
+        }
         expr().orderBy(name, false);
         return root;
     }
@@ -111,6 +128,10 @@ public R asc() {
      * Order by descending on this property.
      */
     public R desc() {
+        Model<?> model = getModel();
+        if (model != root) {
+            return ((ModelProperty<R, P>) getModelProperty(model)).desc();
+        }
         expr().orderBy(name, true);
         return root;
     }
@@ -122,14 +143,20 @@ public String getName() {
         return name;
     }
 
-    public final R eq(ModelProperty<?> p) {
+    public final R eq(ModelProperty<?, ?> p) {
+        Model<?> model = getModel();
+        if (model != root) {
+            return ((ModelProperty<R, P>) getModelProperty(model)).eq(p);
+        }
         expr().eq(name, p);
         return root;
     }
 
-    // public abstract R set(Object value);
-
     public R set(Object value) {
+        Model<?> model = getModel();
+        if (model != root) {
+            return ((ModelProperty<R, P>) getModelProperty(model)).set(value);
+        }
         return root;
     }
 
@@ -156,7 +183,7 @@ protected JsonNode getJsonNode(JsonNode node) {
     /**
      * Helper method to check if two objects are equal.
      */
-    @SuppressWarnings({ "unchecked", "rawtypes" })
+    @SuppressWarnings({ "rawtypes" })
     protected static boolean areEqual(Object obj1, Object obj2) {
         if (obj1 == null) {
             return (obj2 == null);

lealone-orm/src/main/java/org/lealone/orm/property/PArray.java

@@ -24,7 +24,7 @@
  *
  * @param <R> the root model bean type
  */
-public class PArray<R> extends ModelProperty<R> {
+public class PArray<R> extends ModelProperty<R, PArray<R>> {
 
     /**
      * Construct with a property name and root instance.

lealone-orm/src/main/java/org/lealone/orm/property/PBaseComparable.java

@@ -24,7 +24,7 @@
  * @param <T> the type of the scalar property
  */
 @SuppressWarnings("rawtypes")
-public abstract class PBaseComparable<R, T extends Comparable> extends PBaseValueEqual<R, T> {
+public abstract class PBaseComparable<R, T extends Comparable, P> extends PBaseValueEqual<R, T, P> {
 
     /**
      * Construct with a property name and root instance.

lealone-orm/src/main/java/org/lealone/orm/property/PBaseDate.java

@@ -24,7 +24,7 @@
  * @param <D> the date time type
  */
 @SuppressWarnings("rawtypes")
-public abstract class PBaseDate<R, D extends Comparable> extends PBaseComparable<R, D> {
+public abstract class PBaseDate<R, D extends Comparable, P> extends PBaseComparable<R, D, P> {
 
     /**
      * Construct with a property name and root instance.

lealone-orm/src/main/java/org/lealone/orm/property/PBaseNumber.java

@@ -24,7 +24,7 @@
  * @param <T> the number type
  */
 @SuppressWarnings("rawtypes")
-public abstract class PBaseNumber<R, T extends Comparable> extends PBaseComparable<R, T> {
+public abstract class PBaseNumber<R, T extends Comparable, P> extends PBaseComparable<R, T, P> {
 
     /**
      * Construct with a property name and root instance.

lealone-orm/src/main/java/org/lealone/orm/property/PBaseValueEqual.java

@@ -27,7 +27,7 @@
  * @param <R> the root model bean type
  * @param <T> the number type
  */
-public abstract class PBaseValueEqual<R, T> extends ModelProperty<R> {
+public abstract class PBaseValueEqual<R, T, P> extends ModelProperty<R, P> {
 
     /**
      * Construct with a property name and root instance.

lealone-orm/src/main/java/org/lealone/orm/property/PBigDecimal.java

@@ -23,7 +23,7 @@
  * BigDecimal property.
  * @param <R> the root model bean type
  */
-public class PBigDecimal<R> extends PBaseNumber<R, BigDecimal> {
+public class PBigDecimal<R> extends PBaseNumber<R, BigDecimal, PBigDecimal<R>> {
 
     /**
      * Construct with a property name and root instance.

lealone-orm/src/main/java/org/lealone/orm/property/PBlob.java

@@ -19,7 +19,7 @@
 
 import org.lealone.orm.ModelProperty;
 
-public class PBlob<R> extends ModelProperty<R> {
+public class PBlob<R> extends ModelProperty<R, PBlob<R>> {
 
     public PBlob(String name, R root) {
         super(name, root);

lealone-orm/src/main/java/org/lealone/orm/property/PBoolean.java

@@ -22,7 +22,7 @@
  *
  * @param <R> the root model bean type
  */
-public class PBoolean<R> extends PBaseValueEqual<R, Boolean> {
+public class PBoolean<R> extends PBaseValueEqual<R, Boolean, PBoolean<R>> {
 
     /**
      * Construct with a property name and root instance.

lealone-orm/src/main/java/org/lealone/orm/property/PByte.java

@@ -22,7 +22,7 @@
  *
  * @param <R> the root model bean type
  */
-public class PByte<R> extends PBaseNumber<R, Byte> {
+public class PByte<R> extends PBaseNumber<R, Byte, PByte<R>> {
 
     /**
      * Construct with a property name and root instance.

lealone-orm/src/main/java/org/lealone/orm/property/PBytes.java

@@ -24,7 +24,7 @@
  *
  * @param <R> the root model bean type
  */
-public class PBytes<R> extends ModelProperty<R> {
+public class PBytes<R> extends ModelProperty<R, PBytes<R>> {
 
     /**
      * Construct with a property name and root instance.

lealone-orm/src/main/java/org/lealone/orm/property/PClob.java

@@ -19,7 +19,7 @@
 
 import org.lealone.orm.ModelProperty;
 
-public class PClob<R> extends ModelProperty<R> {
+public class PClob<R> extends ModelProperty<R, PClob<R>> {
 
     public PClob(String name, R root) {
         super(name, root);

lealone-orm/src/main/java/org/lealone/orm/property/PDate.java

@@ -24,7 +24,7 @@
  *
  * @param <R> the root model bean type
  */
-public class PDate<R> extends PBaseDate<R, Date> {
+public class PDate<R> extends PBaseDate<R, Date, PDate<R>> {
 
     /**
      * Construct with a property name and root instance.

lealone-orm/src/main/java/org/lealone/orm/property/PDouble.java

@@ -22,7 +22,7 @@
  *
  * @param <R> the root model bean type
  */
-public class PDouble<R> extends PBaseNumber<R, Double> {
+public class PDouble<R> extends PBaseNumber<R, Double, PDouble<R>> {
 
     /**
      * Construct with a property name and root instance.

lealone-orm/src/main/java/org/lealone/orm/property/PFloat.java

@@ -22,7 +22,7 @@
  *
  * @param <R> the root model bean type
  */
-public class PFloat<R> extends PBaseNumber<R, Float> {
+public class PFloat<R> extends PBaseNumber<R, Float, PFloat<R>> {
 
     /**
      * Construct with a property name and root instance.

lealone-orm/src/main/java/org/lealone/orm/property/PInteger.java

@@ -22,6 +22,7 @@
 
 import org.lealone.db.value.Value;
 import org.lealone.db.value.ValueInt;
+import org.lealone.orm.Model;
 
 import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.databind.JsonNode;
@@ -32,7 +33,7 @@
  *
  * @param <R> the root model bean type
  */
-public class PInteger<R> extends PBaseNumber<R, Integer> {
+public class PInteger<R> extends PBaseNumber<R, Integer, PInteger<R>> {
 
     private int value;
 
@@ -54,11 +55,13 @@ public PInteger(String name, R root, String prefix) {
     }
 
     public final R set(int value) {
+        Model<?> model = getModel();
+        if (model != root) {
+            return getModelProperty(model).set(value);
+        }
         if (!areEqual(this.value, value)) {
             this.value = value;
-            // if (isReady()) {
             expr().set(name, ValueInt.get(value));
-            // }
         }
         return root;
     }
@@ -69,6 +72,10 @@ public R set(Object value) {
     }
 
     public final int get() {
+        Model<?> model = getModel();
+        if (model != root) {
+            return getModelProperty(model).get();
+        }
         return value;
     }