com.discursive.jccook.collections.lazy.LazyMapExample.java Source code

Introduction

Here is the source code for com.discursive.jccook.collections.lazy.LazyMapExample.java

Source

/* 
 * ========================================================================
 * 
 * Copyright 2005 Tim O'Brien.
 *
 * 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 com.discursive.jccook.collections.lazy;

import java.net.URL;
import java.util.Map;

import org.apache.commons.collections.map.LRUMap;
import org.apache.commons.collections.map.LazyMap;

public class LazyMapExample {

    Map stockQuotes;

    public static void main(String[] args) throws Exception {
        LazyMapExample example = new LazyMapExample();
        example.start();
    }

    public void start() throws Exception {

        StockQuoteTransformer sqTransformer = new StockQuoteTransformer();
        sqTransformer.setQuoteURL(new URL("http://quotes.company.com"));
        sqTransformer.setTimeout(500);

        stockQuotes = new LRUMap(5);
        stockQuotes = LazyMap.decorate(stockQuotes, sqTransformer);

        // Now use some of the entries in the cache
        Float cscoPrice = (Float) stockQuotes.get("CSCO");
        Float msPrice = (Float) stockQuotes.get("MSFT");
        Float tscPrice = (Float) stockQuotes.get("TSC");
        Float luPrice = (Float) stockQuotes.get("LU");
        Float pPrice = (Float) stockQuotes.get("P");
        Float msPrice2 = (Float) stockQuotes.get("MSFT");

        // Add another price to the Map, this should kick out the LRU item.
        stockQuotes.put("AA", new Float(203.20));

        // CSCO was the first price requested, it is therefor the
        // least recently used.
        if (!stockQuotes.containsKey("CSCO")) {
            System.out.println("As expected CSCO was discarded");
        }
    }
}