package org.apache.commons.digester3.plugins.strategies;
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* 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.
*/
import java.util.Properties;
import org.apache.commons.digester3.Digester;
import org.apache.commons.digester3.plugins.PluginException;
import org.apache.commons.digester3.plugins.RuleFinder;
import org.apache.commons.digester3.plugins.RuleLoader;
A rule-finding algorithm which expects the user to specify whether "automatic property setting" is desired. If this
class discovers that this is in fact the case for a declaration, then a RuleLoader is returned which, when invoked,
adds a single SetPropertiesRule instance to the digester.
This allows ordinary JavaBean classes to be used as plugins, and have xml attributes be mapped to bean properties of
the same name, without any custom plugin rules being created for them.
This RuleFinder is typically used as the last RuleFinder, so that automatic property setting only occurs if
there is no other source of custom rules available.
Since: 1.6
/**
* A rule-finding algorithm which expects the user to specify whether "automatic property setting" is desired. If this
* class discovers that this is in fact the case for a declaration, then a RuleLoader is returned which, when invoked,
* adds a single SetPropertiesRule instance to the digester.
* <p>
* This allows ordinary JavaBean classes to be used as plugins, and have xml attributes be mapped to bean properties of
* the same name, without any custom plugin rules being created for them.
* <p>
* This RuleFinder is typically used as the <i>last</i> RuleFinder, so that automatic property setting only occurs if
* there is no other source of custom rules available.
*
* @since 1.6
*/
public class FinderSetProperties
extends RuleFinder
{
private static final String DFLT_PROPS_ATTR = "setprops";
private static final String DFLT_FALSEVAL = "false";
private final String propsAttr;
private final String falseval;
See findLoader. /** See {@link #findLoader}. */
public FinderSetProperties()
{
this( DFLT_PROPS_ATTR, DFLT_FALSEVAL );
}
Create a rule-finder which will arrange for a SetPropertiesRule to be defined for each instance of a plugin, so
that xml attributes map to bean properties.
Param falseval will commonly be the string "false" for config files written in English.
Params: - propsAttr – must be non-null.
- falseval – must be non-null.
/**
* Create a rule-finder which will arrange for a SetPropertiesRule to be defined for each instance of a plugin, so
* that xml attributes map to bean properties.
* <p>
* Param falseval will commonly be the string "false" for config files written in English.
*
* @param propsAttr must be non-null.
* @param falseval must be non-null.
*/
public FinderSetProperties( String propsAttr, String falseval )
{
this.propsAttr = propsAttr;
this.falseval = falseval;
}
Returns a RuleLoader unless the properties contain an entry with the name matching constructor param
propsAttr, and the value matching what is in falseval.
If no custom source of rules for a plugin is found, then the user almost always wants xml attributes to map to
java bean properties, so this is the default behaviour unless the user explicitly indicates that they do
not want a SetPropertiesRule to be provided for the plugged-in class.
The returned object (when non-null) will add a SetPropertiesRule to the digester whenever its addRules method is
invoked.
Params: - d – The digester instance where locating plugin classes
- pluginClass – The plugin Java class
- p – The properties object that holds any xml attributes the user may have specified on the plugin
declaration in order to indicate how to locate the plugin rules.
Throws: - PluginException – if the algorithm finds a source of rules, but there is something invalid
about that source.
Returns: a source of digester rules for the specified plugin class.
/**
* Returns a RuleLoader <i>unless</i> the properties contain an entry with the name matching constructor param
* propsAttr, and the value matching what is in falseval.
* <p>
* If no custom source of rules for a plugin is found, then the user almost always wants xml attributes to map to
* java bean properties, so this is the default behaviour unless the user explicitly indicates that they do
* <i>not</i> want a SetPropertiesRule to be provided for the plugged-in class.
* <p>
* The returned object (when non-null) will add a SetPropertiesRule to the digester whenever its addRules method is
* invoked.
*
* @param d The digester instance where locating plugin classes
* @param pluginClass The plugin Java class
* @param p The properties object that holds any xml attributes the user may have specified on the plugin
* declaration in order to indicate how to locate the plugin rules.
* @return a source of digester rules for the specified plugin class.
* @throws PluginException if the algorithm finds a source of rules, but there is something invalid
* about that source.
*/
@Override
public RuleLoader findLoader( Digester d, Class<?> pluginClass, Properties p )
throws PluginException
{
String state = p.getProperty( propsAttr );
if ( ( state != null ) && state.equals( falseval ) )
{
// user has explicitly disabled automatic setting of properties.
// this is not expected to be common, but allowed.
return null;
}
return new LoaderSetProperties();
}
}