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Android example source code file (HashMapPerfTest.java)

This example Android source code file (HashMapPerfTest.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" TM.

Java - Android tags/keywords

android, exception, hashmap, hashmapperftest, iters, largetest, num_elts, os, random, string, stringthing, test, testcase, util

The HashMapPerfTest.java Android example source code

/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * 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 android.core;

import android.os.SystemClock;
import android.test.suitebuilder.annotation.LargeTest;
import junit.framework.TestCase;

import java.util.HashMap;
import java.util.Random;

/**
 * Tests basic functionality of HashMaps and prints the time needed to System.out
 */
public class HashMapPerfTest extends TestCase {

    private static final Random sRandom = new Random(1);

    class StringThing {

        String mId;

        public StringThing() {
            int len = sRandom.nextInt(20) + 1;
            char[] chars = new char[len];
            chars[0] = 't';
            for (int i = 1; i < len; i++) {
                chars[i] = (char) ('q' + sRandom.nextInt(4));
            }
            mId = new String(chars, 0, len);
        }

        public String getId() {
            return mId;
        }
    }

    private static final int NUM_ELTS = 1000;
    private static final int ITERS = 100;

    String[] keyCopies = new String[NUM_ELTS];

    private static final boolean lookupByOriginals = false;

    @LargeTest
    public void testHashMapPerformance() throws Exception {
        StringThing[] st = new StringThing[NUM_ELTS];
        for (int i = 0; i < NUM_ELTS; i++) {
            st[i] = new StringThing();
            keyCopies[i] = st[i].getId();
        }

        // android.os.Debug.startMethodTracing();
        long start = SystemClock.uptimeMillis();
        for (int i = 0; i < ITERS; i++) {
            HashMap<String, StringThing> map = new HashMap();
            for (int j = 0; j < NUM_ELTS; j++) {
                StringThing s = st[i];
                map.put(s.getId(), s);
            }
            for (int j = 0; j < NUM_ELTS; j++) {
                if (lookupByOriginals) {
                    StringThing s = st[i];
                    map.get(s.getId());
                } else {
                    map.get(keyCopies[j]);
                }
            }
        }
        long finish = SystemClock.uptimeMillis();
        // android.os.Debug.stopMethodTracing();

        // This should be an assertion instead
        
//        System.out.println("time (" + NUM_ELTS +
//                ", elts, " + ITERS +
//                " iters) = " + (finish - start));
    }
}

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