Java tutorial
/* * $Header: /home/cvspublic/jakarta-commons/beanutils/src/java/org/apache/commons/beanutils/RowSetDynaClass.java,v 1.3 2003/01/15 21:59:39 rdonkin Exp $ * $Revision: 1.3 $ * $Date: 2003/01/15 21:59:39 $ * * ==================================================================== * * The Apache Software License, Version 1.1 * * Copyright (c) 1999-2003 The Apache Software Foundation. All rights * reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. 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For more * information on the Apache Software Foundation, please see * <http://www.apache.org/>. * */ package pe.com.mmh.sisgap.utils; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.SQLException; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import org.apache.commons.beanutils.DynaBean; import org.apache.commons.beanutils.DynaClass; import org.apache.commons.beanutils.DynaProperty; import org.apache.commons.lang.StringUtils; import org.displaytag.pagination.PaginatedList; import org.displaytag.properties.SortOrderEnum; /** * <p>Implementation of {@link DynaClass} that creates an in-memory collection * of {@link DynaBean}s representing the results of an SQL query. Once the * {@link DynaClass} instance has been created, the JDBC <code>ResultSet</code> * and <code>Statement</code> on which it is based can be closed, and the * underlying <code>Connection</code> can be returned to its connection pool * (if you are using one).</p> * * <p>The normal usage pattern is something like:</p> * <pre> * Connection conn = ...; // Acquire connection from pool * Statement stmt = conn.createStatement(); * ResultSet rs = stmt.executeQuery("SELECT ..."); * RowSetDynaClass rsdc = new RowSetDynaClass(rs); * r * stmt.close(); * ...; // Return connection to pool * List rows = rsdc.getRows(); * ...; // Process the rows as desired * </pre> * * <p>Each column in the result set will be represented as a {@link DynaBean} * property of the corresponding name (optionally forced to lower case * for portability). There will be one {@link DynaBean} in the * <code>List</code> returned by <code>getRows()</code> for each * row in the original <code>ResultSet</code>.</p> * * <p>In general, instances of {@link RowSetDynaClass} can be serialized * and deserialized, which will automatically include the list of * {@link DynaBean}s representing the data content. The only exception * to this rule would be when the underlying property values that were * copied from the <code>ResultSet</code> originally cannot themselves * be serialized. Therefore, a {@link RowSetDynaClass} makes a very * convenient mechanism for transporting data sets to remote Java-based * application components.</p> * * <p><strong>FIXME</strong> - This class shares a lot of behavior with * <code>ResultSetDynaClass</code>. We could not simply subclass it, * because the existence of the <code>resultSet</code> instance variable * would cause serializability problems. The common features should be * factored out so that they can be shared.</p> * * @author Craig R. McClanahan * @version $Revision: 1.3 $ $Date: 2003/01/15 21:59:39 $ */ public class RowSetDynaClass implements DynaClass, PaginatedList { // ----------------------------------------------------------- Constructors private Integer from = null; private Integer even = null; private int fullListSize = 0; private int objectsPerPage = 1; private int pageNumber = 1; private String sortCriterion; private SortOrderEnum sortDirection = null; private String dir; public int getPagesNumber() { if (fullListSize % objectsPerPage > 0) { return (int) (fullListSize / objectsPerPage) + 1; } else { return (int) (fullListSize / objectsPerPage); } } public int getPosicionInicialPrimerRegistro() { if (pageNumber != 1) { return objectsPerPage * (pageNumber - 1) + 1; } else { return 1; } } public int getFullListSize() { // TODO Auto-generated method stub //System.out.println("lee getFullListSize"); return fullListSize; } public List getList() { // TODO Auto-generated method stub //System.out.println("lee getList"); return (this.rows); } public int getObjectsPerPage() { //System.out.println("lee getObjectsPerPage"); // TODO Auto-generated method stub return objectsPerPage; } public int getPageNumber() { //System.out.println("lee getPageNumber"); // TODO Auto-generated method stub return pageNumber; } public String getSearchId() { // TODO Auto-generated method stub return null; } public String getSortCriterion() { // TODO Auto-generated method stub if (StringUtils.isEmpty(sortCriterion)) return null; return sortCriterion; } public SortOrderEnum getSortDirection() { // TODO Auto-generated method stub return sortDirection; } /** * <p>Construct a new {@link RowSetDynaClass} for the specified * <code>ResultSet</code>. The property names corresponding * to column names in the result set will be lower cased.</p> * * @param resultSet The result set to be wrapped * * @exception NullPointerException if <code>resultSet</code> * is <code>null</code> * @exception SQLException if the metadata for this result set * cannot be introspected */ public RowSetDynaClass(ResultSet resultSet, Integer from, Integer even) throws SQLException { this.from = from; this.even = even; if (resultSet == null) { throw new NullPointerException(); } this.lowerCase = true; introspect(resultSet); copy(resultSet); } /** * <p>Construct a new {@link RowSetDynaClass} for the specified * <code>ResultSet</code>. The property names corresponding * to column names in the result set will be lower cased.</p> * * @param resultSet The result set to be wrapped * * @exception NullPointerException if <code>resultSet</code> * is <code>null</code> * @exception SQLException if the metadata for this result set * cannot be introspected */ public RowSetDynaClass(ResultSet resultSet) throws SQLException { this(resultSet, true); } public RowSetDynaClass() throws SQLException { } /** * <p>Construct a new {@link RowSetDynaClass} for the specified * <code>ResultSet</code>. The property names corresponding * to the column names in the result set will be lower cased or not, * depending on the specified <code>lowerCase</code> value.</p> * * <p><strong>WARNING</strong> - If you specify <code>false</code> * for <code>lowerCase</code>, the returned property names will * exactly match the column names returned by your JDBC driver. * Because different drivers might return column names in different * cases, the property names seen by your application will vary * depending on which JDBC driver you are using.</p> * * @param resultSet The result set to be wrapped * @param lowerCase Should property names be lower cased? * * @exception NullPointerException if <code>resultSet</code> * is <code>null</code> * @exception SQLException if the metadata for this result set * cannot be introspected */ public RowSetDynaClass(ResultSet resultSet, boolean lowerCase) throws SQLException { if (resultSet == null) { throw new NullPointerException(); } this.lowerCase = lowerCase; introspect(resultSet); copy(resultSet); } // ----------------------------------------------------- Instance Variables /** * <p>Flag defining whether column names should be lower cased when * converted to property names.</p> */ protected boolean lowerCase = true; /** * <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</code> list.</p> */ protected Map propertiesMap = new HashMap(); /** * <p>The list of {@link DynaBean}s representing the contents of * the original <code>ResultSet</code> on which this * {@link RowSetDynaClass} was based.</p> */ protected List rows = new ArrayList(); // ------------------------------------------------------ DynaClass Methods /** * <p>Return the name of this DynaClass (analogous to the * <code>getName()</code> method of <code>java.lang.Class</code), which * allows the same <code>DynaClass</code> 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</code>.</p> * * @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 <code>ProperyDescriptors</code> 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</strong> - 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"); } // --------------------------------------------------------- Public Methods /** * <p>Return a <code>List</code> containing the {@link DynaBean}s that * represent the contents of each <code>Row</code> from the * <code>ResultSet</code> that was the basis of this * {@link RowSetDynaClass} instance. These {@link DynaBean}s are * disconnected from the database itself, so there is no problem with * modifying the contents of the list, or the values of the properties * of these {@link DynaBean}s. However, it is the application's * responsibility to persist any such changes back to the database, * if it so desires.</p> */ public List getRows() { return (this.rows); } // ------------------------------------------------------ Protected Methods /** * <p>Copy the column values for each row in the specified * <code>ResultSet</code> into a newly created {@link DynaBean}, and add * this bean to the list of {@link DynaBean}s that will later by * returned by a call to <code>getRows()</code>.</p> * * @param resultSet The <code>ResultSet</code> whose data is to be * copied * * @exception SQLException if an error is encountered copying the data */ protected void copy(ResultSet resultSet) throws SQLException { int cont = 0; while (resultSet.next()) { cont++; DynaBean bean = new BasicDynaBean(this); for (int i = 0; i < properties.length; i++) { String name = properties[i].getName(); bean.set(name, resultSet.getObject(name)); } //System.out.println(from + " "+even); if (from != null && even != null) { //System.out.println(cont); if (cont > even) break; if (cont < from) continue; } rows.add(bean); } } /** * <p>Introspect the metadata associated with our result set, and populate * the <code>properties</code> and <code>propertiesMap</code> instance * variables.</p> * * @param resultSet The <code>resultSet</code> 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]); } } /** * <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 */ protected DynaProperty createDynaProperty(ResultSetMetaData metadata, int i) throws SQLException { String name = null; if (lowerCase) { name = metadata.getColumnName(i).toLowerCase(); } else { name = metadata.getColumnName(i); } String className = null; try { 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>Loads and returns the <code>Class</code> 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> * * @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(); } return (cl.loadClass(className)); } catch (Exception e) { throw new SQLException("Cannot load column class '" + className + "': " + e); } } public void setFullListSize(int fullListSize) { this.fullListSize = fullListSize; } public void setObjectsPerPage(int objectsPerPage) { this.objectsPerPage = objectsPerPage; } public void setPageNumber(int pageNumber) { this.pageNumber = pageNumber; } public void setSortCriterion(String sortCriterion) { this.sortCriterion = sortCriterion; } public void setSortDirection(SortOrderEnum sortDirection) { this.sortDirection = sortDirection; } public String getDir() { return dir; } public void setDir(String dir) { this.dir = dir; if (!StringUtils.isEmpty(dir)) { if (dir.equals("asc")) sortDirection = SortOrderEnum.ASCENDING; if (dir.equals("des")) sortDirection = SortOrderEnum.DESCENDING; } } }