| /* |
| * 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.empire.db.expr.column; |
| |
| import java.util.Set; |
| |
| // Java |
| import org.apache.empire.data.DataType; |
| import org.apache.empire.db.DBColumn; |
| import org.apache.empire.db.DBColumnExpr; |
| import org.apache.empire.db.DBExpr; |
| import org.apache.empire.dbms.DBSqlPhrase; |
| |
| |
| /** |
| * This class is used for performing various SQL functions on a column or column expression. |
| * <P> |
| * There is no need to explicitly create instances of this class.<BR> |
| * Instead use any of the following functions:<BR> |
| * {@link DBColumnExpr#abs() }, {@link DBColumnExpr#coalesce(Object) }, {@link DBColumnExpr#convertTo(DataType) }, |
| * {@link DBColumnExpr#decode(java.util.Map, Object) }, {@link DBColumnExpr#lower() }, {@link DBColumnExpr#min() }, |
| * {@link DBColumnExpr#max() }, {@link DBColumnExpr#month() }, {@link DBColumnExpr#sum() }, |
| * {@link DBColumnExpr#trim() }, {@link DBColumnExpr#upper() }, {@link DBColumnExpr#year() } |
| * <P> |
| * |
| */ |
| public class DBFuncExpr extends DBAbstractFuncExpr |
| { |
| // *Deprecated* private static final long serialVersionUID = 1L; |
| |
| protected final DBSqlPhrase phrase; |
| protected final Object[] params; |
| protected String template; |
| |
| /** |
| * Constructs a new DBFuncExpr object set the specified parameters to this object. |
| * Do not use directly - use any of the DBColumnExpr.??? factory functions instead! |
| * |
| * The sql function string is built from a string template. |
| * The template string is identified by the phrase param and obtained from the dbms. |
| * |
| * @param expr the DBColumnExpr object |
| * @param phrase the SQL-phrase |
| * @param params an array of params which will be replaced in the template |
| * @param updateColumn optional update column if any. This parameter may be null |
| * @param isAggregate indicates whether the function is an aggregate function (sum, min, max, avg, ...) |
| * @param dataType indicates the data type of the function result |
| */ |
| public DBFuncExpr(DBColumnExpr expr, DBSqlPhrase phrase, Object[] params, DBColumn updateColumn, boolean isAggregate, DataType dataType) |
| { |
| super(expr, updateColumn, isAggregate, dataType); |
| // Set Phrase and Params |
| this.phrase = phrase; |
| this.params = params; |
| this.template = null; |
| // check |
| if (phrase==DBSqlPhrase.SQL_FUNC_COALESCE) |
| log.warn("DBFuncExpr should not be used for SQL_FUNC_COALESCE. Use DBCoalesceExpr instead."); |
| } |
| |
| /** |
| * Constructs a new DBFuncExpr object set the specified parameters to this object. |
| * |
| * The sql function string is built from a string template. |
| * The template string must contain a ? which is a placeholder for the column expression. |
| * |
| * @param expr the DBColumnExpr object |
| * @param template specifies a template for the expression. The template must contain a ? placeholder for the column expression |
| * @param params an array of params which will be replaced in the template |
| * @param updateColumn optional update column if any. This parameter may be null |
| * @param isAggregate indicates whether the function is an aggregate function (sum, min, max, avg, ...) |
| * @param dataType indicates the data type of the function result |
| */ |
| public DBFuncExpr(DBColumnExpr expr, String template, Object[] params, DBColumn updateColumn, boolean isAggregate, DataType dataType) |
| { |
| super(expr, updateColumn, isAggregate, dataType); |
| // Set Phrase and Params |
| this.phrase = null; |
| this.params = params; |
| this.template = template; |
| } |
| |
| @Override |
| protected String getFunctionName() |
| { |
| // Get the template |
| if (phrase!=null) |
| { // from phrase |
| int end = phrase.name().lastIndexOf('_'); |
| if (end>0) |
| return phrase.name().substring(end+1); |
| // the phrase |
| return phrase.name(); |
| } |
| // Get the first word |
| if (template!=null) |
| { String s = template.trim(); |
| int i=0; |
| for (; i<s.length(); i++) |
| if (s.charAt(i)<'A') |
| break; |
| // return name |
| if (i>0) |
| return s.substring(0,i); |
| } |
| return "FUNC"; |
| } |
| |
| @Override |
| public Class<Enum<?>> getEnumType() |
| { |
| // check for functions which preserve the enumType |
| if (phrase==DBSqlPhrase.SQL_FUNC_COALESCE) |
| return expr.getEnumType(); |
| // Check SQL-Phrase |
| return super.getEnumType(); |
| } |
| |
| /** |
| * @see org.apache.empire.db.DBExpr#addReferencedColumns(Set) |
| */ |
| @Override |
| public void addReferencedColumns(Set<DBColumn> list) |
| { |
| super.addReferencedColumns(list); |
| if (this.params==null) |
| return; |
| // Check params |
| for (int i=0; i<this.params.length; i++) |
| { // add referenced columns |
| if (params[i] instanceof DBExpr) |
| ((DBExpr)params[i]).addReferencedColumns(list); |
| } |
| } |
| |
| /** |
| * Creates the SQL-Command adds a function to the SQL-Command. |
| * |
| * @param sql the SQL-Command |
| * @param context the current SQL-Command context |
| */ |
| @Override |
| public void addSQL(StringBuilder sql, long context) |
| { |
| // Get the template |
| if (template==null) |
| template = getDbms().getSQLPhrase(phrase); |
| // Add SQL |
| super.addSQL(sql, template, params, context); |
| } |
| |
| } |