Github user hornn commented on a diff in the pull request:
https://github.com/apache/incubator-hawq/pull/972#discussion_r85472163
--- Diff:
pxf/pxf-jdbc/src/main/java/org/apache/hawq/pxf/plugins/jdbc/WhereSQLBuilder.java
---
@@ -0,0 +1,140 @@
+package org.apache.hawq.pxf.plugins.jdbc;
+/*
+ * 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.
+ */
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.apache.hawq.pxf.api.LogicalFilter;
+import org.apache.hawq.pxf.plugins.jdbc.utils.DbProduct;
+import org.apache.hawq.pxf.api.BasicFilter;
+import org.apache.hawq.pxf.api.FilterParser;
+import org.apache.hawq.pxf.api.io.DataType;
+import org.apache.hawq.pxf.api.utilities.ColumnDescriptor;
+import org.apache.hawq.pxf.api.utilities.InputData;
+
+/**
+ * Parse filter object generated by parent class {@link
org.apache.hawq.pxf.plugins.jdbc.JdbcFilterBuilder},
+ * and build WHERE statement.
+ * For Multiple filters , currently only support HDOP_AND .
+ * The unsupported Filter operation and LogicalOperation ,will return
null statement.
+ *
+ */
+public class WhereSQLBuilder extends JdbcFilterBuilder {
+ private InputData inputData;
+
+ public WhereSQLBuilder(InputData input) {
+ inputData = input;
+ }
+
+ /**
+ * 1.check for LogicalOperator, Jdbc currently only support HDOP_AND.
+ * 2.and convert to BasicFilter List.
+ */
+ private static List<BasicFilter> convertBasicFilterList(Object filter,
List<BasicFilter> returnList) throws UnsupportedFilterException {
+ if (returnList == null)
+ returnList = new ArrayList<>();
+ if (filter instanceof BasicFilter) {
+ returnList.add((BasicFilter) filter);
+ return returnList;
+ }
+ LogicalFilter lfilter = (LogicalFilter) filter;
+ if (lfilter.getOperator() !=
FilterParser.LogicalOperation.HDOP_AND)
+ throw new UnsupportedFilterException("unsupported
LogicalOperation : " + lfilter.getOperator());
+ for (Object f : lfilter.getFilterList()) {
+ returnList = convertBasicFilterList(f, returnList);
+ }
+ return returnList;
+ }
+
+ public String buildWhereSQL(String db_product) throws Exception {
+ if (!inputData.hasFilter()) return null;
+ List<BasicFilter> filters = null;
+ try {
+ String filterString = inputData.getFilterString();
+ Object filterobj = getFilterObject(filterString);
+
+ filters = convertBasicFilterList(filterobj, filters);
+ StringBuffer sb = new StringBuffer("1=1");
+ for (Object obj : filters) {
+ BasicFilter filter = (BasicFilter) obj;
+ sb.append(" AND ");
+
+ ColumnDescriptor column =
inputData.getColumn(filter.getColumn().index());
+ //the column name of filter
+ sb.append(column.columnName());
+
+ //the operation of filter
+ FilterParser.Operation op = filter.getOperation();
+ switch (op) {
+ case HDOP_LT:
+ sb.append("<");
+ break;
+ case HDOP_GT:
+ sb.append(">");
+ break;
+ case HDOP_LE:
+ sb.append("<=");
+ break;
+ case HDOP_GE:
+ sb.append(">=");
+ break;
+ case HDOP_EQ:
+ sb.append("=");
+ break;
+ default:
+ throw new UnsupportedFilterException("unsupported
Filter operation : " + op);
+ }
+ //
+ DbProduct dbProduct = DbProduct.getDbProduct(db_product);
+ Object val = filter.getConstant().constant();
+ switch (DataType.get(column.columnTypeCode())) {
+ case SMALLINT:
+ case INTEGER:
+ case BIGINT:
+ case FLOAT8:
+ case REAL:
+ case BOOLEAN:
+ sb.append(val.toString());
+ break;
+ case TEXT:
+ sb.append("'").append(val.toString()).append("'");
+ break;
+ case DATE:
+ //According to the database products, for the date
field for special treatment.
+ sb.append(dbProduct.wrapDate(val));
+ break;
+ default:
+ throw new UnsupportedFilterException("unsupported
column type for filtering : " + column.columnTypeCode());
+ }
+
+ sb.append("");
--- End diff --
why is it needed?
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