| package org.apache.commons.digester3.plugins.strategies; |
| |
| /* |
| * 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. |
| * <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 {@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. |
| * <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( final String propsAttr, final String falseval ) |
| { |
| this.propsAttr = propsAttr; |
| this.falseval = falseval; |
| } |
| |
| /** |
| * 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 behavior 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( final Digester d, final Class<?> pluginClass, final Properties p ) |
| throws PluginException |
| { |
| final 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(); |
| } |
| |
| } |