| /* |
| * 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; |
| |
| import org.apache.empire.commons.Unwrappable; |
| import org.apache.empire.data.DataType; |
| import org.apache.empire.db.DBColumn; |
| import org.apache.empire.db.DBColumnExpr; |
| import org.apache.empire.db.DBDatabase; |
| import org.w3c.dom.Element; |
| |
| /** |
| * This class allows column renaming in SQL. |
| * <P> |
| * There is no need to explicitly create instances of this class.<BR> |
| * Instead use {@link DBColumnExpr#as(String) } |
| */ |
| public class DBParenthesisExpr extends DBColumnExpr implements Unwrappable<DBColumnExpr> |
| { |
| // *Deprecated* private static final long serialVersionUID = 1L; |
| |
| private final DBColumnExpr wrapped; |
| |
| /** |
| * Constructs a DBAliasExpr object combine the DBColumnExpr object with the alias name. |
| * |
| * @param expr an DBColumnExpr object, one column |
| * @param alias the alias name of the column |
| */ |
| public DBParenthesisExpr(DBColumnExpr expr) |
| { |
| // Check whether already a AliasExpr |
| if (expr.getClass().equals(getClass())) |
| this.wrapped = ((DBParenthesisExpr) expr).wrapped; |
| else |
| this.wrapped = expr; |
| } |
| |
| /** |
| * Returns the current DBDatabase object. |
| * |
| * @return the current DBDatabase object |
| */ |
| @SuppressWarnings("unchecked") |
| @Override |
| public final DBDatabase getDatabase() |
| { |
| return wrapped.getDatabase(); |
| } |
| |
| /** |
| * Returns the data type of the DBColumnExpr object. |
| * |
| * @return the data type |
| */ |
| @Override |
| public DataType getDataType() |
| { |
| return wrapped.getDataType(); |
| } |
| |
| /** |
| * Returns the enum type of this Expression (if any) |
| * @return the enum type or null |
| */ |
| @Override |
| public Class<Enum<?>> getEnumType() |
| { |
| return wrapped.getEnumType(); |
| } |
| |
| /** |
| * This helper function returns the alias name. |
| * |
| * @return the alias name |
| */ |
| @Override |
| public String getName() |
| { |
| return wrapped.getName(); |
| } |
| |
| /** |
| * Returns the expression the source column. |
| */ |
| @Override |
| public DBColumn getSourceColumn() |
| { |
| return wrapped.getSourceColumn(); |
| } |
| |
| /** |
| * Returns the DBColunm object. |
| * |
| * @return the DBColunm object |
| */ |
| @Override |
| public DBColumn getUpdateColumn() |
| { |
| return wrapped.getUpdateColumn(); |
| } |
| |
| /** |
| * Indicates that we are actually an expression wrapper |
| * @return true |
| */ |
| @Override |
| public boolean isWrapper() |
| { // Yep |
| return true; |
| } |
| |
| /** |
| * Returns the underlying column expression. |
| * @return the underlying column expression |
| */ |
| @Override |
| public DBColumnExpr unwrap() |
| { |
| return wrapped; |
| } |
| |
| /** |
| * Forward to expression |
| * |
| * @return false |
| */ |
| @Override |
| public boolean isAggregate() |
| { |
| return wrapped.isAggregate(); |
| } |
| |
| /** |
| * Overrides the equals method |
| * @return true if alias name and expression match |
| */ |
| @Override |
| public boolean equals(Object other) |
| { |
| if (other==this) |
| return true; |
| // Check for another expression |
| if (other instanceof DBParenthesisExpr) |
| { // Compare expr |
| DBParenthesisExpr otherExpr = ((DBParenthesisExpr)other); |
| return wrapped.equals(otherExpr.wrapped); |
| } |
| return false; |
| } |
| |
| /** |
| * @see org.apache.empire.db.DBExpr#addReferencedColumns(Set) |
| */ |
| @Override |
| public void addReferencedColumns(Set<DBColumn> list) |
| { |
| wrapped.addReferencedColumns(list); |
| } |
| |
| /** |
| * Creates the SQL-Command adds the alias name to the SQL-Command. |
| * |
| * @param buf the SQL statment |
| * @param context the current SQL-Command context |
| */ |
| @Override |
| public void addSQL(StringBuilder buf, long context) |
| { // Append alias |
| buf.append("("); |
| wrapped.addSQL(buf, context); // |CTX_NOPARENTHESES |
| buf.append(")"); |
| } |
| |
| /** |
| * This function set the alias name to the XML tag. |
| * @return the XML tag (with the alias name) |
| */ |
| @Override |
| public Element addXml(Element parent, long flags) |
| { // Set name to Alias |
| Element field = wrapped.addXml(parent, flags); |
| field.setAttribute("parenthesis", String.valueOf(true)); |
| return field; |
| } |
| } |