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Commons Beanutils example source code file (JDBCDynaClass.java)

This example Commons Beanutils source code file (JDBCDynaClass.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Commons Beanutils tags/keywords

arraylist, class, class, dynaproperty, dynaproperty, hashmap, illegalargumentexception, instantiationexception, io, jdbc, map, resultsetmetadata, sql, sqlexception, sqlexception, string, string, util

The Commons Beanutils JDBCDynaClass.java source code

/*
 * 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.commons.beanutils;

import java.io.Serializable;
import java.sql.Date;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Time;
import java.sql.Timestamp;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;

/**
 * <p>Provides common logic for JDBC implementations of {@link DynaClass}.

* * @author Craig R. McClanahan * @author George Franciscus * @version $Revision: 926529 $ $Date: 2010-03-23 11:44:24 +0000 (Tue, 23 Mar 2010) $ */ abstract class JDBCDynaClass implements DynaClass, Serializable { // ----------------------------------------------------- Instance Variables /** * <p>Flag defining whether column names should be lower cased when * converted to property names.</p> */ protected boolean lowerCase = true; /** * <p>Flag defining whether column names or labels should be used. */ private boolean useColumnLabel; /** * <p>The set of dynamic properties that are part of this * {@link DynaClass}.</p> */ protected DynaProperty[] properties = null; /** * <p>The set of dynamic properties that are part of this * {@link DynaClass}, keyed by the property name. Individual descriptor * instances will be the same instances as those in the * <code>properties list.

*/ protected Map propertiesMap = new HashMap(); /** * Cross Reference for column name --> dyna property name * (needed when lowerCase option is true) */ private Map columnNameXref; // ------------------------------------------------------ DynaClass Methods /** * <p>Return the name of this DynaClass (analogous to the * <code>getName() method of java.lang.Class implementation class to support * different dynamic classes, with different sets of properties.</p> */ public String getName() { return (this.getClass().getName()); } /** * <p>Return a property descriptor for the specified property, if it * exists; otherwise, return <code>null.

* * @param name Name of the dynamic property for which a descriptor * is requested * * @exception IllegalArgumentException if no property name is specified */ public DynaProperty getDynaProperty(String name) { if (name == null) { throw new IllegalArgumentException("No property name specified"); } return ((DynaProperty) propertiesMap.get(name)); } /** * <p>Return an array of ProperyDescriptors for the properties * currently defined in this DynaClass. If no properties are defined, a * zero-length array will be returned.</p> */ public DynaProperty[] getDynaProperties() { return (properties); } /** * <p>Instantiate and return a new DynaBean instance, associated * with this DynaClass. <strong>NOTE - This operation is not * supported, and throws an exception.</p> * * @exception IllegalAccessException if the Class or the appropriate * constructor is not accessible * @exception InstantiationException if this Class represents an abstract * class, an array class, a primitive type, or void; or if instantiation * fails for some other reason */ public DynaBean newInstance() throws IllegalAccessException, InstantiationException { throw new UnsupportedOperationException("newInstance() not supported"); } /** * Set whether the column label or name should be used for the property name. * * @param useColumnLabel true if the column label should be used, otherwise false */ public void setUseColumnLabel(boolean useColumnLabel) { this.useColumnLabel = useColumnLabel; } /** * <p>Loads and returns the Class of the given name. * By default, a load from the thread context class loader is attempted. * If there is no such class loader, the class loader used to load this * class will be utilized.</p> * * @param className The name of the class to load * @return The loaded class * @exception SQLException if an exception was thrown trying to load * the specified class */ protected Class loadClass(String className) throws SQLException { try { ClassLoader cl = Thread.currentThread().getContextClassLoader(); if (cl == null) { cl = this.getClass().getClassLoader(); } // use Class.forName() - see BEANUTILS-327 return Class.forName(className, false, cl); } catch (Exception e) { throw new SQLException( "Cannot load column class '" + className + "': " + e); } } /** * <p>Factory method to create a new DynaProperty for the given index * into the result set metadata.</p> * * @param metadata is the result set metadata * @param i is the column index in the metadata * @return the newly created DynaProperty instance * @throws SQLException If an error occurs accessing the SQL metadata */ protected DynaProperty createDynaProperty( ResultSetMetaData metadata, int i) throws SQLException { String columnName = null; if (useColumnLabel) { columnName = metadata.getColumnLabel(i); } if (columnName == null || columnName.trim().length() == 0) { columnName = metadata.getColumnName(i); } String name = lowerCase ? columnName.toLowerCase() : columnName; if (!name.equals(columnName)) { if (columnNameXref == null) { columnNameXref = new HashMap(); } columnNameXref.put(name, columnName); } String className = null; try { int sqlType = metadata.getColumnType(i); switch (sqlType) { case java.sql.Types.DATE: return new DynaProperty(name, java.sql.Date.class); case java.sql.Types.TIMESTAMP: return new DynaProperty(name, java.sql.Timestamp.class); case java.sql.Types.TIME: return new DynaProperty(name, java.sql.Time.class); default: className = metadata.getColumnClassName(i); } } catch (SQLException e) { // this is a patch for HsqlDb to ignore exceptions // thrown by its metadata implementation } // Default to Object type if no class name could be retrieved // from the metadata Class clazz = Object.class; if (className != null) { clazz = loadClass(className); } return new DynaProperty(name, clazz); } /** * <p>Introspect the metadata associated with our result set, and populate * the <code>properties and propertiesMap instance * variables.</p> * * @param resultSet The <code>resultSet whose metadata is to * be introspected * * @exception SQLException if an error is encountered processing the * result set metadata */ protected void introspect(ResultSet resultSet) throws SQLException { // Accumulate an ordered list of DynaProperties ArrayList list = new ArrayList(); ResultSetMetaData metadata = resultSet.getMetaData(); int n = metadata.getColumnCount(); for (int i = 1; i <= n; i++) { // JDBC is one-relative! DynaProperty dynaProperty = createDynaProperty(metadata, i); if (dynaProperty != null) { list.add(dynaProperty); } } // Convert this list into the internal data structures we need properties = (DynaProperty[]) list.toArray(new DynaProperty[list.size()]); for (int i = 0; i < properties.length; i++) { propertiesMap.put(properties[i].getName(), properties[i]); } } /** * Get a column value from a {@link ResultSet} for the specified name. * * @param resultSet The result set * @param name The property name * @return The value * @throws SQLException if an error occurs */ protected Object getObject(ResultSet resultSet, String name) throws SQLException { DynaProperty property = getDynaProperty(name); if (property == null) { throw new IllegalArgumentException("Invalid name '" + name + "'"); } String columnName = getColumnName(name); Class type = property.getType(); // java.sql.Date if (type.equals(Date.class)) { return resultSet.getDate(columnName); } // java.sql.Timestamp if (type.equals(Timestamp.class)) { return resultSet.getTimestamp(columnName); } // java.sql.Time if (type.equals(Time.class)) { return resultSet.getTime(columnName); } return resultSet.getObject(columnName); } /** * Get the table column name for the specified property name. * * @param name The property name * @return The column name (which can be different if the <i>lowerCase * option is used). */ protected String getColumnName(String name) { if (columnNameXref != null && columnNameXref.containsKey(name)) { return (String)columnNameXref.get(name); } else { return name; } } }

Other Commons Beanutils examples (source code examples)

Here is a short list of links related to this Commons Beanutils JDBCDynaClass.java source code file:

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