[core] Introduce View Support to HiveCatalog

paimon-core/src/main/java/org/apache/paimon/catalog/Catalog.java

@@ -25,6 +25,7 @@
 import org.apache.paimon.schema.Schema;
 import org.apache.paimon.schema.SchemaChange;
 import org.apache.paimon.table.Table;
+import org.apache.paimon.view.View;
 
 import java.io.Serializable;
 import java.util.Arrays;
@@ -299,6 +300,69 @@ default void alterTable(Identifier identifier, SchemaChange change, boolean igno
         alterTable(identifier, Collections.singletonList(change), ignoreIfNotExists);
     }
 
+    /**
+     * Check if a view exists in this catalog.
+     *
+     * @param identifier Path of the view
+     * @return true if the given view exists in the catalog false otherwise
+     */
+    default boolean viewExists(Identifier identifier) {
+        try {
+            return getView(identifier) != null;
+        } catch (ViewNotExistException e) {
+            return false;
+        }
+    }
+
+    /**
+     * Return a {@link View} identified by the given {@link Identifier}.
+     *
+     * @param identifier Path of the view
+     * @return The requested view
+     * @throws ViewNotExistException if the target does not exist
+     */
+    default View getView(Identifier identifier) throws ViewNotExistException {
+        throw new ViewNotExistException(identifier);
+    }
+
+    /**
+     * Drop a view.
+     *
+     * @param identifier Path of the view to be dropped
+     * @param ignoreIfNotExists Flag to specify behavior when the view does not exist: if set to
+     *     false, throw an exception, if set to true, do nothing.
+     * @throws ViewNotExistException if the view does not exist
+     */
+    default void dropView(Identifier identifier, boolean ignoreIfNotExists)
+            throws ViewNotExistException {
+        throw new UnsupportedOperationException();
+    }
+
+    /**
+     * Create a new view.
+     *
+     * @param identifier path of the view to be created
+     * @param view the view definition
+     * @param ignoreIfExists flag to specify behavior when a view already exists at the given path:
+     *     if set to false, it throws a ViewAlreadyExistException, if set to true, do nothing.
+     * @throws ViewAlreadyExistException if view already exists and ignoreIfExists is false
+     * @throws DatabaseNotExistException if the database in identifier doesn't exist
+     */
+    default void createView(Identifier identifier, View view, boolean ignoreIfExists)
+            throws ViewAlreadyExistException, DatabaseNotExistException {
+        throw new UnsupportedOperationException();
+    }
+
+    /**
+     * Get names of all views under this database. An empty list is returned if none exists.
+     *
+     * @return a list of the names of all views in this database
+     * @throws DatabaseNotExistException if the database does not exist
+     */
+    default List<String> listViews(String databaseName) throws DatabaseNotExistException {
+        return Collections.emptyList();
+    }
+
     /** Return a boolean that indicates whether this catalog allow upper case. */
     boolean allowUpperCase();
 
@@ -532,6 +596,48 @@ public String column() {
         }
     }
 
+    /** Exception for trying to create a view that already exists. */
+    class ViewAlreadyExistException extends Exception {
+
+        private static final String MSG = "View %s already exists.";
+
+        private final Identifier identifier;
+
+        public ViewAlreadyExistException(Identifier identifier) {
+            this(identifier, null);
+        }
+
+        public ViewAlreadyExistException(Identifier identifier, Throwable cause) {
+            super(String.format(MSG, identifier.getFullName()), cause);
+            this.identifier = identifier;
+        }
+
+        public Identifier identifier() {
+            return identifier;
+        }
+    }
+
+    /** Exception for trying to operate on a view that doesn't exist. */
+    class ViewNotExistException extends Exception {
+
+        private static final String MSG = "View %s does not exist.";
+
+        private final Identifier identifier;
+
+        public ViewNotExistException(Identifier identifier) {
+            this(identifier, null);
+        }
+
+        public ViewNotExistException(Identifier identifier, Throwable cause) {
+            super(String.format(MSG, identifier.getFullName()), cause);
+            this.identifier = identifier;
+        }
+
+        public Identifier identifier() {
+            return identifier;
+        }
+    }
+
     /** Loader of {@link Catalog}. */
     @FunctionalInterface
     interface Loader extends Serializable {

paimon-core/src/main/java/org/apache/paimon/catalog/DelegateCatalog.java

@@ -24,6 +24,7 @@
 import org.apache.paimon.schema.Schema;
 import org.apache.paimon.schema.SchemaChange;
 import org.apache.paimon.table.Table;
+import org.apache.paimon.view.View;
 
 import java.util.List;
 import java.util.Map;
@@ -135,6 +136,38 @@ public Table getTable(Identifier identifier) throws TableNotExistException {
         return wrapped.getTable(identifier);
     }
 
+    @Override
+    public boolean tableExists(Identifier identifier) {
+        return wrapped.tableExists(identifier);
+    }
+
+    @Override
+    public boolean viewExists(Identifier identifier) {
+        return wrapped.viewExists(identifier);
+    }
+
+    @Override
+    public View getView(Identifier identifier) throws ViewNotExistException {
+        return wrapped.getView(identifier);
+    }
+
+    @Override
+    public void dropView(Identifier identifier, boolean ignoreIfNotExists)
+            throws ViewNotExistException {
+        wrapped.dropView(identifier, ignoreIfNotExists);
+    }
+
+    @Override
+    public void createView(Identifier identifier, View view, boolean ignoreIfExists)
+            throws ViewAlreadyExistException, DatabaseNotExistException {
+        wrapped.createView(identifier, view, ignoreIfExists);
+    }
+
+    @Override
+    public List<String> listViews(String databaseName) throws DatabaseNotExistException {
+        return wrapped.listViews(databaseName);
+    }
+
     @Override
     public Path getTableLocation(Identifier identifier) {
         return wrapped.getTableLocation(identifier);

paimon-core/src/main/java/org/apache/paimon/view/View.java

@@ -0,0 +1,49 @@
+/*
+ * 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.paimon.view;
+
+import org.apache.paimon.types.RowType;
+
+import java.util.Map;
+import java.util.Optional;
+
+/** Interface for view definition. */
+public interface View {
+
+    /** A name to identify this view. */
+    String name();
+
+    /** Full name (including database) to identify this view. */
+    String fullName();
+
+    /** Returns the row type of this view. */
+    RowType rowType();
+
+    /** Returns the view representation. */
+    String query();
+
+    /** Optional comment of this view. */
+    Optional<String> comment();
+
+    /** Options of this view. */
+    Map<String, String> options();
+
+    /** Copy this view with adding dynamic options. */
+    View copy(Map<String, String> dynamicOptions);
+}

paimon-core/src/main/java/org/apache/paimon/view/ViewImpl.java

@@ -0,0 +1,110 @@
+/*
+ * 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.paimon.view;
+
+import org.apache.paimon.catalog.Identifier;
+import org.apache.paimon.types.RowType;
+
+import javax.annotation.Nullable;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Optional;
+
+/** Implementation of {@link View}. */
+public class ViewImpl implements View {
+
+    private final Identifier identifier;
+    private final RowType rowType;
+    private final String query;
+    @Nullable private final String comment;
+    private final Map<String, String> options;
+
+    public ViewImpl(
+            Identifier identifier,
+            RowType rowType,
+            String query,
+            @Nullable String comment,
+            Map<String, String> options) {
+        this.identifier = identifier;
+        this.rowType = rowType;
+        this.query = query;
+        this.comment = comment;
+        this.options = options;
+    }
+
+    @Override
+    public String name() {
+        return identifier.getObjectName();
+    }
+
+    @Override
+    public String fullName() {
+        return identifier.getFullName();
+    }
+
+    @Override
+    public RowType rowType() {
+        return rowType;
+    }
+
+    @Override
+    public String query() {
+        return query;
+    }
+
+    @Override
+    public Optional<String> comment() {
+        return Optional.ofNullable(comment);
+    }
+
+    @Override
+    public Map<String, String> options() {
+        return options;
+    }
+
+    @Override
+    public View copy(Map<String, String> dynamicOptions) {
+        Map<String, String> newOptions = new HashMap<>(options);
+        newOptions.putAll(dynamicOptions);
+        return new ViewImpl(identifier, rowType, query, comment, newOptions);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+        ViewImpl view = (ViewImpl) o;
+        return Objects.equals(identifier, view.identifier)
+                && Objects.equals(rowType, view.rowType)
+                && Objects.equals(query, view.query)
+                && Objects.equals(comment, view.comment)
+                && Objects.equals(options, view.options);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(identifier, rowType, query, comment, options);
+    }
+}