tapestry/tapestry-examples/VlibBeans/src/java/org/apache/tapestry/vlib/ejb/impl/BookQueryBean.java - tapestry4 - Git at Google

 // Copyright 2004, 2005 The Apache Software Foundation
 //
 // Licensed 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.tapestry.vlib.ejb.impl;

 import java.sql.Connection;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.List;

 import org.apache.tapestry.contrib.ejb.XEJBException;
 import org.apache.tapestry.contrib.jdbc.IStatement;
 import org.apache.tapestry.contrib.jdbc.StatementAssembly;
 import org.apache.tapestry.vlib.ejb.Book;
 import org.apache.tapestry.vlib.ejb.MasterQueryParameters;
 import org.apache.tapestry.vlib.ejb.SortOrdering;

 /**
  * Implementation of a stateful session bean used to query the
  * {@link org.apache.tapestry.vlib.ejb.IBook} entity and cache the results. It can then download the
  * results, in chunks, to the client ... this is used to support clients that which to display the
  * results a page at a time (with random access to the pages of results).
  * <p>
  * To avoid a lot of duplicate code for things like finding the JDBC {@link Connection} and querying
  * the IBook entity, we subclass from {@link OperationsBean}.
  *
  * @see org.apache.tapestry.vlib.ejb.IBookQuery
  * @see org.apache.tapestry.vlib.ejb.IBookQueryHome
  * @author Howard Lewis Ship
  */

 public class BookQueryBean extends OperationsBean
 {
     private static final long serialVersionUID = 8782046868254488388L;

     /**
      * Stores the results from the most recent query.
      */

     private Book[] _results;

     /**
      * Releases any results.
      */

     public void ejbRemove()
     {
         _results = null;
     }

     // Business methods

     /**
      * Returns the number of results from the most recent query.
      */

     public int getResultCount()
     {
         if (_results == null)
             return 0;

         return _results.length;
     }

     /**
      * Gets a subset of the results from the query.
      */

     public Book[] get(int offset, int length)
     {
         Book[] result;

         if (offset < 0)
             return null;

         int finalLength = Math.min(length, _results.length - offset);

         if (finalLength < 0)
             return null;

         // Create a new array and copy the requested
         // results into it.

         result = new Book[finalLength];
         System.arraycopy(_results, offset, result, 0, finalLength);

         return result;
     }

     /**
      * The master query is for querying by some mixture of title, author and publisher.
      */

     public int masterQuery(MasterQueryParameters parameters, SortOrdering sortOrdering)
     {
         IStatement statement = null;
         Connection connection = null;

         // Forget any current results.

         _results = null;

         try
         {
             connection = getConnection();

             try
             {
                 statement = buildMasterQuery(connection, parameters, sortOrdering);
             }
             catch (SQLException ex)
             {
                 throw new XEJBException("Unable to create query statement.", ex);
             }

             processQuery(statement);

         }
         finally
         {
             close(connection, statement, null);
         }

         return getResultCount();
     }

     /**
      * Queries on books owned by a given person, sorted by title.
      */

     public int ownerQuery(Integer ownerId, SortOrdering sortOrdering)
     {
         IStatement statement = null;
         Connection connection = null;

         // Forget any current results.

         _results = null;

         try
         {
             connection = getConnection();

             try
             {
                 statement = buildPersonQuery(connection, "owner.PERSON_ID", ownerId, sortOrdering);
             }
             catch (SQLException ex)
             {
                 throw new XEJBException("Unable to create query statement.", ex);
             }

             processQuery(statement);

         }
         finally
         {
             close(connection, statement, null);
         }

         return getResultCount();
     }

     /**
      * Queries on books held (borrowed) by a given person, sorted by title.
      */

     public int holderQuery(Integer holderId, SortOrdering sortOrdering)
     {
         IStatement statement = null;
         Connection connection = null;

         // Forget any current results.

         _results = null;

         try
         {
             connection = getConnection();

             try
             {
                 statement = buildPersonQuery(connection, "holder.PERSON_ID", holderId, sortOrdering);
             }
             catch (SQLException ex)
             {
                 throw new XEJBException("Unable to create query statement.", ex);
             }

             processQuery(statement);

         }
         finally
         {
             close(connection, statement, null);
         }

         return getResultCount();
     }

     public int borrowerQuery(Integer borrowerId, SortOrdering sortOrdering)
     {
         IStatement statement = null;
         Connection connection = null;

         // Forget any current results.

         _results = null;

         try
         {
             connection = getConnection();

             try
             {
                 statement = buildBorrowerQuery(connection, borrowerId, sortOrdering);
             }
             catch (SQLException ex)
             {
                 throw new XEJBException("Unable to create query statement.", ex);
             }

             processQuery(statement);

         }
         finally
         {
             close(connection, statement, null);
         }

         return getResultCount();
     }

     private void processQuery(IStatement statement)
     {
         ResultSet set = null;

         try
         {
             set = statement.executeQuery();
         }
         catch (SQLException ex)
         {
             throw new XEJBException("Unable to execute query.", ex);
         }

         try
         {
             processQueryResults(set);
         }
         catch (SQLException ex)
         {
             throw new XEJBException("Unable to process query results.", ex);
         }
         finally
         {
             close(null, null, set);
         }
     }

     private void processQueryResults(ResultSet set) throws SQLException
     {
         List list = new ArrayList();
         Object[] columns = new Object[Book.NUM_COLUMNS];

         while (set.next())
         {
             Book book = convertRowToBook(set, columns);

             list.add(book);
         }

         _results = new Book[list.size()];
         _results = (Book[]) list.toArray(_results);
     }

     private IStatement buildMasterQuery(Connection connection, MasterQueryParameters parameters,
             SortOrdering ordering) throws SQLException
     {
         String title = parameters.getTitle();
         String author = parameters.getAuthor();
         Integer publisherId = parameters.getPublisherId();
         Integer ownerId = parameters.getOwnerId();

         StatementAssembly assembly = buildBaseBookQuery();

         addSubstringSearch(assembly, "book.TITLE", title);
         addSubstringSearch(assembly, "book.AUTHOR", author);

         // Hide books that are not visible to the master query.

         assembly.addSep(" AND ");
         assembly.add("book.HIDDEN = 0");

         if (publisherId != null)
         {
             assembly.addSep(" AND ");
             assembly.add("book.PUBLISHER_ID = ");
             assembly.addParameter(publisherId);
         }

         if (ownerId != null)
         {
             assembly.addSep(" AND ");
             assembly.add("book.OWNER_ID = ");
             assembly.addParameter(ownerId);
         }

         addSortOrdering(assembly, ordering);

         return assembly.createStatement(connection);
     }

     private IStatement buildPersonQuery(Connection connection, String personColumn,
             Integer personId, SortOrdering sortOrdering) throws SQLException
     {
         StatementAssembly assembly = buildBaseBookQuery();

         assembly.addSep(" AND ");
         assembly.add(personColumn);
         assembly.add(" = ");
         assembly.addParameter(personId);

         addSortOrdering(assembly, sortOrdering);

         return assembly.createStatement(connection);
     }

     private IStatement buildBorrowerQuery(Connection connection, Integer borrowerId,
             SortOrdering sortOrdering) throws SQLException
     {
         StatementAssembly assembly = buildBaseBookQuery();

         // Get books held by the borrower but not owned by the borrower.

         assembly.addSep(" AND ");
         assembly.add("book.HOLDER_ID = ");
         assembly.addParameter(borrowerId);
         assembly.addSep(" AND ");
         assembly.add("book.HOLDER_ID <> book.OWNER_ID");

         addSortOrdering(assembly, sortOrdering);

         return assembly.createStatement(connection);
     }

 }
	// Copyright 2004, 2005 The Apache Software Foundation
	//
	// Licensed 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.tapestry.vlib.ejb.impl;

	import java.sql.Connection;
	import java.sql.ResultSet;
	import java.sql.SQLException;
	import java.util.ArrayList;
	import java.util.List;

	import org.apache.tapestry.contrib.ejb.XEJBException;
	import org.apache.tapestry.contrib.jdbc.IStatement;
	import org.apache.tapestry.contrib.jdbc.StatementAssembly;
	import org.apache.tapestry.vlib.ejb.Book;
	import org.apache.tapestry.vlib.ejb.MasterQueryParameters;
	import org.apache.tapestry.vlib.ejb.SortOrdering;

	/**
	* Implementation of a stateful session bean used to query the
	* {@link org.apache.tapestry.vlib.ejb.IBook} entity and cache the results. It can then download the
	* results, in chunks, to the client ... this is used to support clients that which to display the
	* results a page at a time (with random access to the pages of results).
	* <p>
	* To avoid a lot of duplicate code for things like finding the JDBC {@link Connection} and querying
	* the IBook entity, we subclass from {@link OperationsBean}.
	*
	* @see org.apache.tapestry.vlib.ejb.IBookQuery
	* @see org.apache.tapestry.vlib.ejb.IBookQueryHome
	* @author Howard Lewis Ship
	*/

	public class BookQueryBean extends OperationsBean
	{
	private static final long serialVersionUID = 8782046868254488388L;

	/**
	* Stores the results from the most recent query.
	*/

	private Book[] _results;

	/**
	* Releases any results.
	*/

	public void ejbRemove()
	{
	_results = null;
	}

	// Business methods

	/**
	* Returns the number of results from the most recent query.
	*/

	public int getResultCount()
	{
	if (_results == null)
	return 0;

	return _results.length;
	}

	/**
	* Gets a subset of the results from the query.
	*/

	public Book[] get(int offset, int length)
	{
	Book[] result;

	if (offset < 0)
	return null;

	int finalLength = Math.min(length, _results.length - offset);

	if (finalLength < 0)
	return null;

	// Create a new array and copy the requested
	// results into it.

	result = new Book[finalLength];
	System.arraycopy(_results, offset, result, 0, finalLength);

	return result;
	}

	/**
	* The master query is for querying by some mixture of title, author and publisher.
	*/

	public int masterQuery(MasterQueryParameters parameters, SortOrdering sortOrdering)
	{
	IStatement statement = null;
	Connection connection = null;

	// Forget any current results.

	_results = null;

	try
	{
	connection = getConnection();

	try
	{
	statement = buildMasterQuery(connection, parameters, sortOrdering);
	}
	catch (SQLException ex)
	{
	throw new XEJBException("Unable to create query statement.", ex);
	}

	processQuery(statement);

	}
	finally
	{
	close(connection, statement, null);
	}

	return getResultCount();
	}

	/**
	* Queries on books owned by a given person, sorted by title.
	*/

	public int ownerQuery(Integer ownerId, SortOrdering sortOrdering)
	{
	IStatement statement = null;
	Connection connection = null;

	// Forget any current results.

	_results = null;

	try
	{
	connection = getConnection();

	try
	{
	statement = buildPersonQuery(connection, "owner.PERSON_ID", ownerId, sortOrdering);
	}
	catch (SQLException ex)
	{
	throw new XEJBException("Unable to create query statement.", ex);
	}

	processQuery(statement);

	}
	finally
	{
	close(connection, statement, null);
	}

	return getResultCount();
	}

	/**
	* Queries on books held (borrowed) by a given person, sorted by title.
	*/

	public int holderQuery(Integer holderId, SortOrdering sortOrdering)
	{
	IStatement statement = null;
	Connection connection = null;

	// Forget any current results.

	_results = null;

	try
	{
	connection = getConnection();

	try
	{
	statement = buildPersonQuery(connection, "holder.PERSON_ID", holderId, sortOrdering);
	}
	catch (SQLException ex)
	{
	throw new XEJBException("Unable to create query statement.", ex);
	}

	processQuery(statement);

	}
	finally
	{
	close(connection, statement, null);
	}

	return getResultCount();
	}

	public int borrowerQuery(Integer borrowerId, SortOrdering sortOrdering)
	{
	IStatement statement = null;
	Connection connection = null;

	// Forget any current results.

	_results = null;

	try
	{
	connection = getConnection();

	try
	{
	statement = buildBorrowerQuery(connection, borrowerId, sortOrdering);
	}
	catch (SQLException ex)
	{
	throw new XEJBException("Unable to create query statement.", ex);
	}

	processQuery(statement);

	}
	finally
	{
	close(connection, statement, null);
	}

	return getResultCount();
	}

	private void processQuery(IStatement statement)
	{
	ResultSet set = null;

	try
	{
	set = statement.executeQuery();
	}
	catch (SQLException ex)
	{
	throw new XEJBException("Unable to execute query.", ex);
	}

	try
	{
	processQueryResults(set);
	}
	catch (SQLException ex)
	{
	throw new XEJBException("Unable to process query results.", ex);
	}
	finally
	{
	close(null, null, set);
	}
	}

	private void processQueryResults(ResultSet set) throws SQLException
	{
	List list = new ArrayList();
	Object[] columns = new Object[Book.NUM_COLUMNS];

	while (set.next())
	{
	Book book = convertRowToBook(set, columns);

	list.add(book);
	}

	_results = new Book[list.size()];
	_results = (Book[]) list.toArray(_results);
	}

	private IStatement buildMasterQuery(Connection connection, MasterQueryParameters parameters,
	SortOrdering ordering) throws SQLException
	{
	String title = parameters.getTitle();
	String author = parameters.getAuthor();
	Integer publisherId = parameters.getPublisherId();
	Integer ownerId = parameters.getOwnerId();

	StatementAssembly assembly = buildBaseBookQuery();

	addSubstringSearch(assembly, "book.TITLE", title);
	addSubstringSearch(assembly, "book.AUTHOR", author);

	// Hide books that are not visible to the master query.

	assembly.addSep(" AND ");
	assembly.add("book.HIDDEN = 0");

	if (publisherId != null)
	{
	assembly.addSep(" AND ");
	assembly.add("book.PUBLISHER_ID = ");
	assembly.addParameter(publisherId);
	}

	if (ownerId != null)
	{
	assembly.addSep(" AND ");
	assembly.add("book.OWNER_ID = ");
	assembly.addParameter(ownerId);
	}

	addSortOrdering(assembly, ordering);

	return assembly.createStatement(connection);
	}

	private IStatement buildPersonQuery(Connection connection, String personColumn,
	Integer personId, SortOrdering sortOrdering) throws SQLException
	{
	StatementAssembly assembly = buildBaseBookQuery();

	assembly.addSep(" AND ");
	assembly.add(personColumn);
	assembly.add(" = ");
	assembly.addParameter(personId);

	addSortOrdering(assembly, sortOrdering);

	return assembly.createStatement(connection);
	}

	private IStatement buildBorrowerQuery(Connection connection, Integer borrowerId,
	SortOrdering sortOrdering) throws SQLException
	{
	StatementAssembly assembly = buildBaseBookQuery();

	// Get books held by the borrower but not owned by the borrower.

	assembly.addSep(" AND ");
	assembly.add("book.HOLDER_ID = ");
	assembly.addParameter(borrowerId);
	assembly.addSep(" AND ");
	assembly.add("book.HOLDER_ID <> book.OWNER_ID");

	addSortOrdering(assembly, sortOrdering);

	return assembly.createStatement(connection);
	}

	}