org.apache.nutch.net.URLExemptionFilters Maven / Gradle / Ivy
/*
* 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.
*/
package org.apache.nutch.net;
import org.apache.hadoop.conf.Configuration;
import org.apache.nutch.plugin.Extension;
import org.apache.nutch.plugin.PluginRepository;
import org.apache.nutch.plugin.PluginRuntimeException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.lang.invoke.MethodHandles;
/** Creates and caches {@link URLExemptionFilter} implementing plugins. */
public class URLExemptionFilters {
private static final Logger LOG = LoggerFactory
.getLogger(MethodHandles.lookup().lookupClass());
private URLExemptionFilter[] filters;
public URLExemptionFilters(Configuration conf) {
Extension[] extensions = PluginRepository.get(conf)
.getExtensionPoint(URLExemptionFilter.X_POINT_ID).getExtensions();
filters = new URLExemptionFilter[extensions.length];
for (int i = 0; i < extensions.length; i++) {
try {
filters[i] = (URLExemptionFilter) extensions[i].getExtensionInstance();
} catch (PluginRuntimeException e) {
throw new IllegalStateException(e);
}
}
LOG.info("Found {} extensions at point:'{}'", filters.length,
URLExemptionFilter.X_POINT_ID);
}
/** Run all defined filters. Assume logical AND. */
public boolean isExempted(String fromUrl, String toUrl) {
if (filters.length < 1) {
//at least one filter should be on
return false;
}
//validate from, to and filters
boolean exempted = fromUrl != null && toUrl != null;
//An URL is exempted when all the filters accept it to pass through
for (int i = 0; i < this.filters.length && exempted; i++) {
exempted = this.filters[i].filter(fromUrl, toUrl);
}
return exempted;
}
}