Use hierarchical layer to process NodePath

mode/core/src/main/java/org/apache/shardingsphere/mode/metadata/manager/rule/DatabaseRuleItemManager.java

@@ -57,7 +57,7 @@ public void alter(final DatabaseRuleNodePath databaseRuleNodePath) throws SQLExc
         RuleItemConfigurationChangedProcessor processor = TypedSPILoader.getService(RuleItemConfigurationChangedProcessor.class,
                 new RuleChangedItemType(databaseRuleNodePath.getRuleType(), databaseRuleNodePath.getDatabaseRuleItem().getType()));
         String yamlContent = metaDataPersistFacade.getMetaDataVersionService().loadContent(new VersionNodePath(databaseRuleNodePath));
-        String databaseName = databaseRuleNodePath.getDatabaseName();
+        String databaseName = databaseRuleNodePath.getDatabase().getDatabaseName();
         RuleConfiguration currentRuleConfig = processor.findRuleConfiguration(metaDataContexts.getMetaData().getDatabase(databaseName));
         String itemName = databaseRuleNodePath.getDatabaseRuleItem().getName();
         synchronized (this) {
@@ -74,7 +74,7 @@ public void alter(final DatabaseRuleNodePath databaseRuleNodePath) throws SQLExc
      */
     @SuppressWarnings({"rawtypes", "unchecked"})
     public void drop(final DatabaseRuleNodePath databaseRuleNodePath) throws SQLException {
-        String databaseName = databaseRuleNodePath.getDatabaseName();
+        String databaseName = databaseRuleNodePath.getDatabase().getDatabaseName();
         Preconditions.checkState(metaDataContexts.getMetaData().containsDatabase(databaseName), "No database '%s' exists.", databaseName);
         RuleItemConfigurationChangedProcessor processor = TypedSPILoader.getService(RuleItemConfigurationChangedProcessor.class,
                 new RuleChangedItemType(databaseRuleNodePath.getRuleType(), databaseRuleNodePath.getDatabaseRuleItem().getType()));

mode/core/src/main/java/org/apache/shardingsphere/mode/metadata/persist/metadata/service/DatabaseMetaDataPersistService.java

@@ -19,7 +19,7 @@
 
 import lombok.RequiredArgsConstructor;
 import org.apache.shardingsphere.mode.node.path.engine.generator.NodePathGenerator;
-import org.apache.shardingsphere.mode.node.path.type.database.metadata.schema.TableMetadataNodePath;
+import org.apache.shardingsphere.mode.node.path.type.database.metadata.DatabaseMetaDataNodePath;
 import org.apache.shardingsphere.mode.spi.repository.PersistRepository;
 
 import java.util.Collection;
@@ -38,7 +38,7 @@ public final class DatabaseMetaDataPersistService {
      * @param databaseName to be added database name
      */
     public void add(final String databaseName) {
-        repository.persist(NodePathGenerator.toPath(new TableMetadataNodePath(databaseName, null, null), true), "");
+        repository.persist(NodePathGenerator.toPath(new DatabaseMetaDataNodePath(databaseName), false), "");
     }
 
     /**
@@ -47,7 +47,7 @@ public void add(final String databaseName) {
      * @param databaseName to be dropped database name
      */
     public void drop(final String databaseName) {
-        repository.delete(NodePathGenerator.toPath(new TableMetadataNodePath(databaseName, null, null), true));
+        repository.delete(NodePathGenerator.toPath(new DatabaseMetaDataNodePath(databaseName), false));
     }
 
     /**
@@ -56,6 +56,6 @@ public void drop(final String databaseName) {
      * @return loaded database names
      */
     public Collection<String> loadAllDatabaseNames() {
-        return repository.getChildrenKeys(NodePathGenerator.toPath(new TableMetadataNodePath(null, null, null), false));
+        return repository.getChildrenKeys(NodePathGenerator.toPath(new DatabaseMetaDataNodePath(null), false));
     }
 }

mode/core/src/main/java/org/apache/shardingsphere/mode/metadata/persist/metadata/service/SchemaMetaDataPersistService.java

@@ -21,6 +21,7 @@
 import org.apache.shardingsphere.infra.metadata.database.schema.model.ShardingSphereSchema;
 import org.apache.shardingsphere.mode.metadata.persist.version.VersionPersistService;
 import org.apache.shardingsphere.mode.node.path.engine.generator.NodePathGenerator;
+import org.apache.shardingsphere.mode.node.path.type.database.metadata.schema.SchemaMetadataNodePath;
 import org.apache.shardingsphere.mode.node.path.type.database.metadata.schema.TableMetadataNodePath;
 import org.apache.shardingsphere.mode.spi.repository.PersistRepository;
 
@@ -62,7 +63,7 @@ public void add(final String databaseName, final String schemaName) {
      * @param schemaName to be dropped schema name
      */
     public void drop(final String databaseName, final String schemaName) {
-        repository.delete(NodePathGenerator.toPath(new TableMetadataNodePath(databaseName, schemaName, null), true));
+        repository.delete(NodePathGenerator.toPath(new SchemaMetadataNodePath(databaseName, schemaName), false));
     }
 
     /**
@@ -112,7 +113,7 @@ public void alterByRuleDropped(final String databaseName, final ShardingSphereSc
      * @return schemas
      */
     public Collection<ShardingSphereSchema> load(final String databaseName) {
-        return repository.getChildrenKeys(NodePathGenerator.toPath(new TableMetadataNodePath(databaseName, null, null), false)).stream()
+        return repository.getChildrenKeys(NodePathGenerator.toPath(new SchemaMetadataNodePath(databaseName, null), false)).stream()
                 .map(each -> new ShardingSphereSchema(each, tableMetaDataPersistService.load(databaseName, each), viewMetaDataPersistService.load(databaseName, each))).collect(Collectors.toList());
     }
 }

mode/core/src/main/java/org/apache/shardingsphere/mode/metadata/persist/metadata/service/TableRowDataPersistService.java

@@ -26,6 +26,7 @@
 import org.apache.shardingsphere.infra.yaml.data.swapper.YamlRowStatisticsSwapper;
 import org.apache.shardingsphere.mode.node.path.engine.generator.NodePathGenerator;
 import org.apache.shardingsphere.mode.node.path.type.database.statistics.StatisticsDataNodePath;
+import org.apache.shardingsphere.mode.node.path.type.database.statistics.StatisticsTableNodePath;
 import org.apache.shardingsphere.mode.spi.repository.PersistRepository;
 
 import java.util.ArrayList;
@@ -49,7 +50,7 @@ public final class TableRowDataPersistService {
      */
     public void persist(final String databaseName, final String schemaName, final String tableName, final Collection<YamlRowStatistics> rows) {
         if (rows.isEmpty()) {
-            repository.persist(NodePathGenerator.toPath(new StatisticsDataNodePath(databaseName, schemaName, tableName.toLowerCase(), null), false), "");
+            repository.persist(NodePathGenerator.toPath(new StatisticsTableNodePath(databaseName, schemaName, tableName.toLowerCase()), false), "");
         } else {
             rows.forEach(each -> repository.persist(NodePathGenerator.toPath(new StatisticsDataNodePath(databaseName, schemaName, tableName.toLowerCase(), each.getUniqueKey()), false),
                     YamlEngine.marshal(each)));
@@ -79,7 +80,7 @@ public void delete(final String databaseName, final String schemaName, final Str
     public TableStatistics load(final String databaseName, final String schemaName, final ShardingSphereTable table) {
         TableStatistics result = new TableStatistics(table.getName());
         YamlRowStatisticsSwapper swapper = new YamlRowStatisticsSwapper(new ArrayList<>(table.getAllColumns()));
-        for (String each : repository.getChildrenKeys(NodePathGenerator.toPath(new StatisticsDataNodePath(databaseName, schemaName, table.getName(), null), false))) {
+        for (String each : repository.getChildrenKeys(NodePathGenerator.toPath(new StatisticsTableNodePath(databaseName, schemaName, table.getName()), false))) {
             String yamlRow = repository.query(NodePathGenerator.toPath(new StatisticsDataNodePath(databaseName, schemaName, table.getName(), each), false));
             if (!Strings.isNullOrEmpty(yamlRow)) {
                 result.getRows().add(swapper.swapToObject(YamlEngine.unmarshal(yamlRow, YamlRowStatistics.class)));

mode/core/src/main/java/org/apache/shardingsphere/mode/metadata/persist/statistics/StatisticsPersistService.java

@@ -28,7 +28,9 @@
 import org.apache.shardingsphere.infra.yaml.data.swapper.YamlRowStatisticsSwapper;
 import org.apache.shardingsphere.mode.metadata.persist.metadata.service.TableRowDataPersistService;
 import org.apache.shardingsphere.mode.node.path.engine.generator.NodePathGenerator;
-import org.apache.shardingsphere.mode.node.path.type.database.statistics.StatisticsDataNodePath;
+import org.apache.shardingsphere.mode.node.path.type.database.statistics.StatisticsDatabaseNodePath;
+import org.apache.shardingsphere.mode.node.path.type.database.statistics.StatisticsSchemaNodePath;
+import org.apache.shardingsphere.mode.node.path.type.database.statistics.StatisticsTableNodePath;
 import org.apache.shardingsphere.mode.spi.repository.PersistRepository;
 
 import java.util.ArrayList;
@@ -57,7 +59,7 @@ public StatisticsPersistService(final PersistRepository repository) {
      * @return statistics
      */
     public ShardingSphereStatistics load(final ShardingSphereMetaData metaData) {
-        Collection<String> databaseNames = repository.getChildrenKeys(NodePathGenerator.toPath(new StatisticsDataNodePath(null, null, null, null), false));
+        Collection<String> databaseNames = repository.getChildrenKeys(NodePathGenerator.toPath(new StatisticsDatabaseNodePath(null), false));
         if (databaseNames.isEmpty()) {
             return new ShardingSphereStatistics();
         }
@@ -70,7 +72,7 @@ public ShardingSphereStatistics load(final ShardingSphereMetaData metaData) {
 
     private DatabaseStatistics load(final ShardingSphereDatabase database) {
         DatabaseStatistics result = new DatabaseStatistics();
-        for (String each : repository.getChildrenKeys(NodePathGenerator.toPath(new StatisticsDataNodePath(database.getName(), null, null, null), false)).stream()
+        for (String each : repository.getChildrenKeys(NodePathGenerator.toPath(new StatisticsSchemaNodePath(database.getName(), null), false)).stream()
                 .filter(database::containsSchema).collect(Collectors.toList())) {
             result.putSchemaStatistics(each, load(database.getName(), database.getSchema(each)));
         }
@@ -79,7 +81,7 @@ private DatabaseStatistics load(final ShardingSphereDatabase database) {
 
     private SchemaStatistics load(final String databaseName, final ShardingSphereSchema schema) {
         SchemaStatistics result = new SchemaStatistics();
-        for (String each : repository.getChildrenKeys(NodePathGenerator.toPath(new StatisticsDataNodePath("foo_db", "foo_schema", null, null), false)).stream()
+        for (String each : repository.getChildrenKeys(NodePathGenerator.toPath(new StatisticsTableNodePath(databaseName, schema.getName(), null), false)).stream()
                 .filter(schema::containsTable).collect(Collectors.toList())) {
             result.putTableStatistics(each, tableRowDataPersistService.load(databaseName, schema.getName(), schema.getTable(each)));
 
@@ -102,7 +104,7 @@ public void persist(final ShardingSphereDatabase database, final String schemaNa
     }
 
     private void persistSchema(final String databaseName, final String schemaName) {
-        repository.persist(NodePathGenerator.toPath(new StatisticsDataNodePath(databaseName, schemaName, null, null), true), "");
+        repository.persist(NodePathGenerator.toPath(new StatisticsSchemaNodePath(databaseName, schemaName), false), "");
     }
 
     private void persistTableData(final ShardingSphereDatabase database, final String schemaName, final SchemaStatistics schemaStatistics) {
@@ -139,6 +141,6 @@ public void update(final AlteredDatabaseStatistics alteredDatabaseStatistics) {
      * @param databaseName database name
      */
     public void delete(final String databaseName) {
-        repository.delete(NodePathGenerator.toPath(new StatisticsDataNodePath(databaseName, null, null, null), true));
+        repository.delete(NodePathGenerator.toPath(new StatisticsDatabaseNodePath(databaseName), false));
     }
 }

mode/node/src/main/java/org/apache/shardingsphere/mode/node/path/engine/generator/NodePathGenerator.java

@@ -45,7 +45,7 @@ public static String toPath(final NodePath nodePath, final boolean trimEmptyNode
         String templatePath = Objects.requireNonNull(nodePath.getClass().getAnnotation(NodePathEntity.class), "NodePathEntity annotation is missing").value();
         LinkedList<String> nodeSegments = new LinkedList<>();
         for (String each : templatePath.split(PATH_DELIMITER)) {
-            Optional<String> segmentLiteral = new NodePathSegment(each).getLiteral(nodePath);
+            Optional<String> segmentLiteral = new NodePathSegment(each, trimEmptyNode).getLiteral(nodePath);
             if (segmentLiteral.isPresent()) {
                 nodeSegments.add(segmentLiteral.get());
                 continue;

mode/node/src/main/java/org/apache/shardingsphere/mode/node/path/engine/generator/NodePathSegment.java

@@ -31,6 +31,8 @@ public final class NodePathSegment {
 
     private final String input;
 
+    private final boolean trimEmptyNode;
+
     /**
      * Get segment literal.
      *
@@ -41,7 +43,13 @@ public Optional<String> getLiteral(final NodePath nodePath) {
         Optional<String> variableName = new NodePathVariable(input).findVariableName();
         if (variableName.isPresent()) {
             Object variableValue = ReflectionUtils.getFieldValue(nodePath, variableName.get()).orElse(null);
-            return null == variableValue ? Optional.empty() : Optional.of(variableValue.toString());
+            if (null == variableValue) {
+                return Optional.empty();
+            }
+            if (variableValue instanceof NodePath) {
+                return Optional.of(NodePathGenerator.toPath((NodePath) variableValue, trimEmptyNode));
+            }
+            return Optional.of(variableValue.toString());
         }
         return Optional.of(input);
     }

mode/node/src/main/java/org/apache/shardingsphere/mode/node/path/type/database/metadata/DatabaseMetaDataNodePath.java

@@ -0,0 +1,45 @@
+/*
+ * 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.shardingsphere.mode.node.path.type.database.metadata;
+
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+import org.apache.shardingsphere.mode.node.path.NodePath;
+import org.apache.shardingsphere.mode.node.path.NodePathEntity;
+import org.apache.shardingsphere.mode.node.path.engine.searcher.NodePathPattern;
+import org.apache.shardingsphere.mode.node.path.engine.searcher.NodePathSearchCriteria;
+
+/**
+ * Database metadata node path.
+ */
+@NodePathEntity("/metadata/${databaseName}")
+@RequiredArgsConstructor
+@Getter
+public final class DatabaseMetaDataNodePath implements NodePath {
+
+    private final String databaseName;
+
+    /**
+     * Create database search criteria.
+     *
+     * @return created search criteria
+     */
+    public static NodePathSearchCriteria createDatabaseSearchCriteria() {
+        return new NodePathSearchCriteria(new DatabaseMetaDataNodePath(NodePathPattern.IDENTIFIER), false, true, 1);
+    }
+}

mode/node/src/main/java/org/apache/shardingsphere/mode/node/path/type/database/metadata/datasource/StorageNodeNodePath.java

@@ -18,24 +18,28 @@
 package org.apache.shardingsphere.mode.node.path.type.database.metadata.datasource;
 
 import lombok.Getter;
-import lombok.RequiredArgsConstructor;
 import org.apache.shardingsphere.mode.node.path.NodePath;
 import org.apache.shardingsphere.mode.node.path.NodePathEntity;
 import org.apache.shardingsphere.mode.node.path.engine.searcher.NodePathPattern;
 import org.apache.shardingsphere.mode.node.path.engine.searcher.NodePathSearchCriteria;
+import org.apache.shardingsphere.mode.node.path.type.database.metadata.DatabaseMetaDataNodePath;
 
 /**
  * Storage node node path.
  */
-@NodePathEntity("/metadata/${databaseName}/data_sources/nodes/${storageNodeName}")
-@RequiredArgsConstructor
+@NodePathEntity("${database}/data_sources/nodes/${storageNodeName}")
 @Getter
 public final class StorageNodeNodePath implements NodePath {
 
-    private final String databaseName;
+    private final DatabaseMetaDataNodePath database;
 
     private final String storageNodeName;
 
+    public StorageNodeNodePath(final String databaseName, final String storageNodeName) {
+        database = new DatabaseMetaDataNodePath(databaseName);
+        this.storageNodeName = storageNodeName;
+    }
+
     /**
      * Create storage node search criteria.
      *

mode/node/src/main/java/org/apache/shardingsphere/mode/node/path/type/database/metadata/datasource/StorageUnitNodePath.java

@@ -18,24 +18,28 @@
 package org.apache.shardingsphere.mode.node.path.type.database.metadata.datasource;
 
 import lombok.Getter;
-import lombok.RequiredArgsConstructor;
 import org.apache.shardingsphere.mode.node.path.NodePath;
 import org.apache.shardingsphere.mode.node.path.NodePathEntity;
 import org.apache.shardingsphere.mode.node.path.engine.searcher.NodePathPattern;
 import org.apache.shardingsphere.mode.node.path.engine.searcher.NodePathSearchCriteria;
+import org.apache.shardingsphere.mode.node.path.type.database.metadata.DatabaseMetaDataNodePath;
 
 /**
  * Storage unit node path.
  */
-@NodePathEntity("/metadata/${databaseName}/data_sources/units/${storageUnitName}")
-@RequiredArgsConstructor
+@NodePathEntity("${database}/data_sources/units/${storageUnitName}")
 @Getter
 public final class StorageUnitNodePath implements NodePath {
 
-    private final String databaseName;
+    private final DatabaseMetaDataNodePath database;
 
     private final String storageUnitName;
 
+    public StorageUnitNodePath(final String databaseName, final String storageUnitName) {
+        database = new DatabaseMetaDataNodePath(databaseName);
+        this.storageUnitName = storageUnitName;
+    }
+
     /**
      * Create storage unit search criteria.
      *

mode/node/src/main/java/org/apache/shardingsphere/mode/node/path/type/database/metadata/rule/DatabaseRuleNodePath.java

@@ -18,26 +18,31 @@
 package org.apache.shardingsphere.mode.node.path.type.database.metadata.rule;
 
 import lombok.Getter;
-import lombok.RequiredArgsConstructor;
 import org.apache.shardingsphere.mode.node.path.NodePath;
 import org.apache.shardingsphere.mode.node.path.NodePathEntity;
 import org.apache.shardingsphere.mode.node.path.engine.searcher.NodePathPattern;
 import org.apache.shardingsphere.mode.node.path.engine.searcher.NodePathSearchCriteria;
+import org.apache.shardingsphere.mode.node.path.type.database.metadata.DatabaseMetaDataNodePath;
 
 /**
  * Database rule node path.
  */
-@NodePathEntity("/metadata/${databaseName}/rules/${ruleType}/${databaseRuleItem}")
-@RequiredArgsConstructor
+@NodePathEntity("${database}/rules/${ruleType}/${databaseRuleItem}")
 @Getter
 public final class DatabaseRuleNodePath implements NodePath {
 
-    private final String databaseName;
+    private final DatabaseMetaDataNodePath database;
 
     private final String ruleType;
 
     private final DatabaseRuleItem databaseRuleItem;
 
+    public DatabaseRuleNodePath(final String databaseName, final String ruleType, final DatabaseRuleItem databaseRuleItem) {
+        database = new DatabaseMetaDataNodePath(databaseName);
+        this.ruleType = ruleType;
+        this.databaseRuleItem = databaseRuleItem;
+    }
+
     /**
      * Create rule type search criteria.
      *