- /* $Id: FinderFromFile.java,v 1.5 2004/05/10 06:34:01 skitching Exp $
- *
- * Copyright 2004 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.commons.digester.plugins.strategies;
-
- import java.util.Properties;
- import java.io.InputStream;
- import java.io.FileInputStream;
- import java.io.IOException;
-
- import org.apache.commons.digester.Digester;
- import org.apache.commons.digester.plugins.RuleFinder;
- import org.apache.commons.digester.plugins.RuleLoader;
- import org.apache.commons.digester.plugins.PluginException;
-
- /**
- * A rule-finding algorithm which expects the user to specify an absolute
- * or relative path in the plugin declaration.
- * <p>
- * The file is expected to contain Digester rules in xmlrules format.
- *
- * @since 1.6
- */
-
- public class FinderFromFile extends RuleFinder {
- /**
- * Xml attribute that needs to be present on a plugin declaration
- * in order to specify the file to load rules from.
- */
- public static String DFLT_FILENAME_ATTR = "file";
-
- /** See {@link #findLoader}. */
- private String filenameAttr;
-
- /** See {@link #findLoader}. */
- public FinderFromFile() {
- this(DFLT_FILENAME_ATTR);
- }
-
- /** See {@link #findLoader}. */
- public FinderFromFile(String filenameAttr) {
- this.filenameAttr = filenameAttr;
- }
-
- /**
- * If there exists a property with the name specified in the constructor,
- * then load that file, run it through the xmlrules module and return an
- * object encapsulating those rules.
- * <p>
- * If there is no matching property provided, then just return null.
- * <p>
- * The returned object (when non-null) will add the selected rules to
- * the digester whenever its addRules method is invoked.
- */
- public RuleLoader findLoader(Digester d, Class pluginClass, Properties p)
- throws PluginException {
-
- String rulesFileName = p.getProperty(filenameAttr);
- if (rulesFileName == null) {
- // nope, user hasn't requested dynamic rules to be loaded
- // from a specific file.
- return null;
- }
-
- InputStream is = null;
- try {
- is = new FileInputStream(rulesFileName);
- } catch(IOException ioe) {
- throw new PluginException(
- "Unable to process file [" + rulesFileName + "]", ioe);
- }
-
- try {
- RuleLoader loader = new LoaderFromStream(is);
- return loader;
- } catch(Exception e) {
- throw new PluginException(
- "Unable to load xmlrules from file [" +
- rulesFileName + "]", e);
- } finally {
- try {
- is.close();
- } catch(java.io.IOException ioe) {
- throw new PluginException(
- "Unable to close stream for file [" +
- rulesFileName + "]", ioe);
- }
- }
- }
- }
-