SettingTable.java
/*
* $Source$
* $Revision$
*
* Copyright (C) 2000 William Chesters
*
* Part of Melati (http://melati.org), a framework for the rapid
* development of clean, maintainable web applications.
*
* Melati is free software; Permission is granted to copy, distribute
* and/or modify this software under the terms either:
*
* a) 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,
*
* or
*
* b) any version of the Melati Software License, as published
* at http://melati.org
*
* You should have received a copy of the GNU General Public License and
* the Melati Software License along with this program;
* if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA to obtain the
* GNU General Public License and visit http://melati.org to obtain the
* Melati Software License.
*
* Feel free to contact the Developers of Melati (http://melati.org),
* if you would like to work out a different arrangement than the options
* outlined here. It is our intention to allow Melati to be used by as
* wide an audience as possible.
*
* 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.
*
* Contact details for copyright holder:
*
* William Chesters <williamc@paneris.org>
* http://paneris.org/~williamc
* Obrechtstraat 114, 2517VX Den Haag, The Netherlands
*/
package org.melati.poem;
import org.melati.poem.generated.SettingTableBase;
import java.util.Hashtable;
/**
* A {@link Table} which is used like a properties file.
*
* Every Melati DB has one.
*
* Extended from a Melati POEM generated stub.
*
* <p>
* Description:
* A configurable setting for the application.
* </p>
*
*
* <table>
* <caption>
* Field summary for SQL table <code>Setting</code>
* </caption>
* <tr><th>Name</th><th>Type</th><th>Description</th></tr>
* <tr><td> id </td><td> Integer </td><td> The Table Row Object ID </td></tr>
* <tr><td> name </td><td> String </td><td> A code name for this setting
* </td></tr>
* <tr><td> value </td><td> String </td><td> The value of this setting
* </td></tr>
* </table>
*
* See org.melati.poem.prepro.TableDef#generateTableMainJava
*/
public class SettingTable<T extends Setting> extends SettingTableBase<Setting> {
/**
* Constructor.
*
* See org.melati.poem.prepro.TableDef#generateTableMainJava
* @param database the POEM database we are using
* @param name the name of this <code>Table</code>
* @param definitionSource which definition is being used
* @throws PoemException if anything goes wrong
*/
public SettingTable(
Database database, String name,
DefinitionSource definitionSource) throws PoemException {
super(database, name, definitionSource);
}
// programmer's domain-specific code here
private static final Object nullEntry = new Object();
private Hashtable<String, Object> cache = null;
private long cacheSerial = 0L;
/**
* Get an object of the appropriate type by name.
*
* Note this has not worked prior to 25/10/2006,
* a new cache was created every time.
* Transactions are so fine grained that it is not clear that
* this cache serves any purpose.
*
* @param name the name field of this Setting object
* @return its value, cast to the appropriate type.
*/
public Object getCooked(String name) {
if (cache == null || cacheSerial != serial(PoemThread.transaction())) {
cacheSerial = serial(PoemThread.transaction());
cache = new Hashtable<String, Object>();
} else {
Object value = cache.get(name);
if (value == nullEntry)
return null;
else if (value != null)
return value;
}
Setting prop =
(Setting)getNameColumn().firstWhereEq(name);
if (prop == null) {
cache.put(name, nullEntry);
return null;
}
else {
Object propValue = prop.getCooked();
cache.put(name, propValue == null ? nullEntry : propValue);
return propValue;
}
}
/**
* Get the String representation of the setting.
* @param name the name field of the Setting object
* @return the value as a String or null
*/
public String get(String name) {
Object it = getCooked(name);
return it == null ? null : it.toString();
}
/**
* Thrown when a {@link Setting} requested has not been set.
*/
public static class UnsetException extends PoemException {
private static final long serialVersionUID = 1L;
/** The name of the requested setting. */
public String name;
/** Constructor. */
public UnsetException(String name) {
this.name = name;
}
/** @return The detail message. */
public String getMessage() {
return "The application's `" + name + "' parameter has not been set";
}
}
/**
* Get a set value.
*
* @param name the Setting's name field
* @return the Setting's value as an appropriate Object
*/
public Object getOrDie(String name) {
Object it = get(name);
if (it == null)
throw new UnsetException(name);
return it;
}
/**
* Make sure that a setting with this name exists, if not then create it.
* Note that only the name is checked for existence, the other parameters
* are only used for creation, so enabling the setting to be manually changed.
*
* @param name the name of the Setting to ensure
* @param typefactory what type to use
* @param value the value of this setting
* @param displayname a human readable name
* @param description the purpose of the setting
* @return the existing or newly created Setting
*/
public Setting ensure(String name, PoemTypeFactory typefactory, Object value,
String displayname, String description) {
Setting setting = (Setting)getNameColumn().firstWhereEq(name);
if (setting != null)
return setting;
else {
setting = (Setting)newPersistent();
setting.setName(name);
setting.setDisplayname(displayname);
setting.setDescription(description);
setting.setUsereditable(true);
setting.setWidth(20);
setting.setHeight(1);
setting.setPrecision(22);
setting.setScale(2);
setting.setNullable(true);
setting.setSize(-1);
setting.setTypefactory(typefactory);
setting.setRaw(value);
return (Setting)getNameColumn().ensure(setting);
}
}
/**
* Convenience method.
*
* @param name the name of the Setting to ensure
* @param value the value of this setting
* @param displayname a human readable name
* @param description the purpose of the setting
* @return the existing or newly created Setting
* @see #ensure(String, PoemTypeFactory, Object, String, String)
*/
public Setting ensure(String name, String value,
String displayname, String description) {
return ensure(name, PoemTypeFactory.STRING, value,
displayname, description);
}
/**
* Convenience method.
* @param name the name of the Setting to ensure
* @param value the value of this setting
* @param displayname a human readable name
* @param description the purpose of the setting
* @return the existing or newly created Setting
* @see #ensure(String, PoemTypeFactory, Object, String, String)
*/
public Setting ensure(String name, int value,
String displayname, String description) {
return ensure(name, PoemTypeFactory.INTEGER, new Integer(value),
displayname, description);
}
/**
* Convenience method.
* @param name the name of the Setting to ensure
* @param value the value of this setting
* @param displayname a human readable name
* @param description the purpose of the setting
* @return the existing or newly created Setting
* @see #ensure(String, PoemTypeFactory, Object, String, String)
*/
public Setting ensure(String name, boolean value,
String displayname, String description) {
return ensure(name, PoemTypeFactory.BOOLEAN,
value ? Boolean.TRUE : Boolean.FALSE,
displayname, description);
}
}