/* Copyright (c) 2006 Google Inc.
*
* 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 sample.gbase.cmdline;
import com.google.api.gbase.client.AttributeHistogram;
import com.google.api.gbase.client.GoogleBaseEntry;
import com.google.api.gbase.client.GoogleBaseFeed;
import com.google.api.gbase.client.GoogleBaseQuery;
import com.google.api.gbase.client.MetadataEntryExtension;
import com.google.api.gbase.client.AttributeHistogram.UniqueValue;
import com.google.gdata.util.ServiceException;
import java.io.IOException;
import java.net.URL;
/**
* This class demonstrates how to retrieve Google Base metadata
* using the client library of the Google Base data API.
*
* The tool implemented by this class will connect to Google Base,
* run the request and display some results.
*/
public class MetadataExample extends Example {
/**
* Runs the example.
*/
public static void main(String[] args) throws IOException, ServiceException {
String queryString = null;
args = init(args, "Google-MetadataExample-1.0");
// Process command-line arguments
if (args.length == 1) {
queryString = args[0];
} else {
System.err.println("Invalid argument count.");
System.err.println("Expected one argument:");
System.err.println(" query");
System.exit(1);
}
queryMetadata(queryString);
}
/**
* Retrieves and prints the list of the most used attributes used by
* the items that match a query.
*
* @param queryString a Google Base Query Language query
*/
private static void queryMetadata(String queryString)
throws IOException, ServiceException {
// Create a query URL from the given arguments
URL url = urlFactory.getAttributesFeedURL();
GoogleBaseQuery query = new GoogleBaseQuery(url);
query.setGoogleBaseQuery(queryString);
// Display the URL generated by the API
System.out.println("Sending request to: " + query.getUrl());
try {
GoogleBaseFeed feed = service.query(query);
// Print the items
printMetadataFeed(feed);
} catch (ServiceException e) {
printServiceException(e);
}
}
/**
* Prints each metadata item in the feed to the output.
* Uses {@link #printMetadataEntry(GoogleBaseEntry)}.
*
* @param feed a Google Base data API metadata feed
*/
private static void printMetadataFeed(GoogleBaseFeed feed) {
if (feed.getTotalResults() == 0) {
System.out.println("No matches.");
return;
}
for (GoogleBaseEntry entry : feed.getEntries()) {
printMetadataEntry(entry);
}
}
/**
* Prints a few relevant attributes and the values of the attribute histogram
* of a metadata GoogleBaseEntry item.
*
* @param entry a Google Base data API metadata entry
*/
private static void printMetadataEntry(GoogleBaseEntry entry) {
MetadataEntryExtension metadata = entry.getGoogleBaseMetadata();
AttributeHistogram attributeHistogram = metadata.getAttributeHistogram();
System.out.println(attributeHistogram.getAttributeName() +
" (" + attributeHistogram.getAttributeType().getName() + "): " +
"valueCount=" + attributeHistogram.getTotalValueCount() + " - " +
entry.getId());
for (UniqueValue value : attributeHistogram.getValues()) {
System.out.println(value.getValueAsString() +
" count=" + value.getCount());
}
}
}