//
// This file is part of the OpenNMS(R) Application.
//
// OpenNMS(R) is Copyright (C) 2002-2003 The OpenNMS Group, Inc. All rights reserved.
// OpenNMS(R) is a derivative work, containing both original code, included code and modified
// code that was published under the GNU General Public License. Copyrights for modified
// and included code are below.
//
// OpenNMS(R) is a registered trademark of The OpenNMS Group, Inc.
//
// Modifications:
//
// 2008 Jan 08: Use JOIN rather than WHERE to join tables, to allow outer joins
// 2007 Jul 03: Use Java 5 generics. - dj@opennms.org
//
// Copyright (C) 1999-2001 Oculan Corp. All rights reserved.
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
//
// For more information contact:
// OpenNMS Licensing <license@opennms.org>
// http://www.opennms.org/
// http://www.opennms.com/
//
// Tab Size = 8
//
package org.opennms.netmgt.config;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.io.Reader;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.exolab.castor.xml.MarshalException;
import org.exolab.castor.xml.Unmarshaller;
import org.exolab.castor.xml.ValidationException;
import org.opennms.netmgt.ConfigFileConstants;
import org.opennms.netmgt.config.filter.Column;
import org.opennms.netmgt.config.filter.DatabaseSchema;
import org.opennms.netmgt.config.filter.Join;
import org.opennms.netmgt.config.filter.Table;
/**
* This is the singleton class used to load the configuration for the OpenNMS
* database schema for the filters from the database-schema xml file.
*
* <strong>Note: </strong>Users of this class should make sure the
* <em>init()</em> is called before calling any other method to ensure the
* config is loaded before accessing other convenience methods.
*
* @author <a href="mailto:sowmya@opennms.org">Sowmya Nataraj </a>
* @author <a href="http://www.opennms.org/">OpenNMS </a>
*/
public final class DatabaseSchemaConfigFactory {
/**
* The singleton instance of this factory
*/
private static DatabaseSchemaConfigFactory m_singleton = null;
/**
* The config class loaded from the config file
*/
private DatabaseSchema m_config;
/**
* The set of tables that can be joined directly or indirectly to the
* primary table
*/
// FIXME: m_joinable is never read
//private Set m_joinable = null;
/**
* A map from a table to the join to use to get 'closer' to the primary
* table
*/
private Map<String, Join> m_primaryJoins = null;
/**
* This member is set to true if the configuration file has been loaded.
*/
private static boolean m_loaded = false;
/**
* Private constructor
*
* @exception java.io.IOException
* Thrown if the specified config file cannot be read
* @exception org.exolab.castor.xml.MarshalException
* Thrown if the file does not conform to the schema.
* @exception org.exolab.castor.xml.ValidationException
* Thrown if the contents do not match the required schema.
*/
private DatabaseSchemaConfigFactory(String configFile) throws IOException, MarshalException, ValidationException {
FileReader cfgIn = new FileReader(configFile);
parseXML(cfgIn);
cfgIn.close();
}
public DatabaseSchemaConfigFactory(Reader reader) throws IOException, MarshalException, ValidationException {
parseXML(reader);
}
private void parseXML(Reader rdr) throws IOException, MarshalException, ValidationException {
m_config = (DatabaseSchema) Unmarshaller.unmarshal(DatabaseSchema.class, rdr);
finishConstruction();
}
/**
* Load the config from the default config file and create the singleton
* instance of this factory.
*
* @exception java.io.IOException
* Thrown if the specified config file cannot be read
* @exception org.exolab.castor.xml.MarshalException
* Thrown if the file does not conform to the schema.
* @exception org.exolab.castor.xml.ValidationException
* Thrown if the contents do not match the required schema.
*/
public static synchronized void init() throws IOException, MarshalException, ValidationException {
if (m_loaded) {
// init already called - return
// to reload, reload() will need to be called
return;
}
File cfgFile = ConfigFileConstants.getFile(ConfigFileConstants.DB_SCHEMA_FILE_NAME);
m_singleton = new DatabaseSchemaConfigFactory(cfgFile.getPath());
m_loaded = true;
}
/**
* Reload the config from the default config file
*
* @exception java.io.IOException
* Thrown if the specified config file cannot be read/loaded
* @exception org.exolab.castor.xml.MarshalException
* Thrown if the file does not conform to the schema.
* @exception org.exolab.castor.xml.ValidationException
* Thrown if the contents do not match the required schema.
*/
public static synchronized void reload() throws IOException, MarshalException, ValidationException {
m_singleton = null;
m_loaded = false;
init();
}
/**
* Return the singleton instance of this factory.
*
* @return The current factory instance.
*
* @throws java.lang.IllegalStateException
* Thrown if the factory has not yet been initialized.
*/
public static synchronized DatabaseSchemaConfigFactory getInstance() {
if (!m_loaded)
throw new IllegalStateException("The factory has not been initialized");
return m_singleton;
}
public static synchronized void setInstance(DatabaseSchemaConfigFactory instance) {
m_singleton = instance;
m_loaded = true;
}
/**
* Return the database schema.
*
* @return the database schema
*/
public synchronized DatabaseSchema getDatabaseSchema() {
return m_config;
}
/**
* This method is used to find the table that should drive the construction
* of the join clauses between all table in the from clause. At least one
* table has to be designated as the driver table.
*
* @return The name of the driver table
*/
public Table getPrimaryTable() {
Enumeration<Table> e = getDatabaseSchema().enumerateTable();
while (e.hasMoreElements()) {
Table t = e.nextElement();
if (t.getVisible() == null || t.getVisible().equalsIgnoreCase("true")) {
if (t.getKey() != null && t.getKey().equals("primary")) {
return t;
}
}
}
return null;
}
/**
* Construct m_primaryJoins
*/
private void finishConstruction() {
Set<String> joinableSet = new HashSet<String>();
Map<String, Join> primaryJoins = new HashMap<String, Join>();
joinableSet.add(getPrimaryTable().getName());
// loop until we stop adding entries to the set
int joinableCount = 0;
while (joinableCount < joinableSet.size()) {
joinableCount = joinableSet.size();
Set<String> newSet = new HashSet<String>(joinableSet);
Enumeration<Table> e = getDatabaseSchema().enumerateTable();
// for each table not already in the set
while (e.hasMoreElements()) {
Table t = e.nextElement();
if (!joinableSet.contains(t.getName()) && (t.getVisible() == null || t.getVisible().equalsIgnoreCase("true"))) {
Enumeration<Join> ejoin = t.enumerateJoin();
// for each join does it join a table in the set?
while (ejoin.hasMoreElements()) {
Join j = ejoin.nextElement();
if (joinableSet.contains(j.getTable())) {
newSet.add(t.getName());
primaryJoins.put(t.getName(), j);
}
}
}
}
joinableSet = newSet;
}
// FIXME: m_joinable is never read
//m_joinable = Collections.synchronizedSet(joinableSet);
m_primaryJoins = Collections.synchronizedMap(primaryJoins);
}
/**
* Find a table using its name as the search key.
*
* @param name
* the name of the table to find
* @return the table if it is found, null otherwise.
*/
public Table getTableByName(String name) {
Enumeration<Table> e = getDatabaseSchema().enumerateTable();
while (e.hasMoreElements()) {
Table t = e.nextElement();
if (t.getVisible() == null || t.getVisible().equalsIgnoreCase("true")) {
if (t.getName() != null && t.getName().equals(name)) {
return t;
}
}
}
return null;
}
/**
* Find the table which has a visible column named 'colName'
*
* @param the
* name of the column to search for
* @return the table containing column 'colName', null if colName is not a
* valid column or if is not visible.
*
*/
public Table findTableByVisibleColumn(String colName) {
Table table = null;
Enumeration<Table> etbl = getDatabaseSchema().enumerateTable();
OUTER: while (etbl.hasMoreElements()) {
Table t = etbl.nextElement();
Enumeration<Column> ecol = t.enumerateColumn();
while (ecol.hasMoreElements()) {
Column col = ecol.nextElement();
if (col.getVisible() == null || col.getVisible().equalsIgnoreCase("true")) {
if (col.getName().equalsIgnoreCase(colName)) {
table = t;
break OUTER;
}
}
}
}
return table;
}
/**
* Return a count of the number of tables defined.
*
* @return the number of tables in the schema
*/
public int getTableCount() {
return getDatabaseSchema().getTableCount();
}
/**
* Return the sequence of tables necessary to join the primary table to the
* given tables.
*
* @param tables
* list of Tables to join
* @return a list of table names, starting with the primary table, going
* to each of the given tables, or a zero-length array if no join
* exists or only the primary table was specified
*/
public List<String> getJoinTables(List<Table> tables) {
List<String> joinedTables = new ArrayList<String>();
for (int i = 0; i < tables.size(); i++) {
int insertPosition = joinedTables.size();
String currentTable = tables.get(i).getName();
while (currentTable != null && !joinedTables.contains(currentTable)) {
joinedTables.add(insertPosition, currentTable);
Join next = m_primaryJoins.get(currentTable);
if (next != null) {
currentTable = next.getTable();
} else {
currentTable = null;
}
}
}
return joinedTables;
}
/**
* Construct a SQL FROM clause joining the given tables to the primary table.
*
* @param tables
* list of Tables to join
* @return an SQL FROM clause or "" if no expression is found
*/
public String constructJoinExprForTables(List<Table> tables) {
StringBuffer joinExpr = new StringBuffer();
List<String> joinTables = getJoinTables(tables);
joinExpr.append(joinTables.get(0));
for (int i = 1; i < joinTables.size(); i++) {
Join currentJoin = m_primaryJoins.get(joinTables.get(i));
if (currentJoin.getType() != null && !currentJoin.getType().equalsIgnoreCase("inner")) {
joinExpr.append(" " + currentJoin.getType().toUpperCase());
}
joinExpr.append(" JOIN " + joinTables.get(i) + " ON (");
joinExpr.append(currentJoin.getTable() + "." + currentJoin.getTableColumn() + " = ");
joinExpr.append(joinTables.get(i) + "." + currentJoin.getColumn() + ")");
}
if (joinExpr.length() > 0)
return "FROM " + joinExpr.toString();
return "";
}
}
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