Cancel a running or queued Call with OkHttp3

Example.java

// ...
		Request request = new Request.Builder()
			.url(url)
			.tag(TAG)
			.build();

        // Cancel previous call(s) if they are running or queued
        OkHttpUtils.cancelCallWithTag(client, TAG);    
        
        // New call
        Response response = client.newCall(request).execute();
// ...

OkHttpTest.java

package com.package.utils;

import com.package.utils.OkHttpUtils;

import org.junit.Test;

import java.io.IOException;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;

import static org.junit.Assert.fail;

public class OkHttpProviderTest {
    public final static String TAG = "tag";
    private final ScheduledExecutorService executor = Executors.newScheduledThreadPool(1);
    private final OkHttpClient client = new OkHttpClient();

    @Test
    public void cancelRequestWithTag() throws Exception {
        Request request = new Request.Builder()
                .url("http://httpbin.org/delay/2") // This URL is served with a 2 second delay.
                .tag(TAG)
                .build();

        final long startNanos = System.nanoTime();

        // Schedule a job to cancel the call in 1 second.
        executor.schedule(new Runnable() {
            @Override public void run() {
                System.out.printf("%.2f Canceling call.%n", (System.nanoTime() - startNanos) / 1e9f);
                OkHttpUtils.cancelCallWithTag(client, TAG);
                System.out.printf("%.2f Canceled call.%n", (System.nanoTime() - startNanos) / 1e9f);
            }
        }, 1, TimeUnit.SECONDS);

        try {
            System.out.printf("%.2f Executing call.%n", (System.nanoTime() - startNanos) / 1e9f);
            Response response = client.newCall(request).execute(); // Synchronous
            System.out.printf("%.2f Call was expected to fail, but completed: %s%n",
                    (System.nanoTime() - startNanos) / 1e9f, response);
            fail();
        } catch (IOException e) {
            System.out.printf("%.2f Call failed as expected: %s%n",
                    (System.nanoTime() - startNanos) / 1e9f, e);
        }
    }
}

OkHttpUtils.java

package com.package.utils;

import okhttp3.Call;
import okhttp3.OkHttpClient;

public class OkHttpUtils {
    public static void cancelCallWithTag(OkHttpClient client, String tag) {
        for(Call call : client.dispatcher().queuedCalls()) {
            if(call.request().tag().equals(tag))
                call.cancel();
        }
        for(Call call : client.dispatcher().runningCalls()) {
            if(call.request().tag().equals(tag))
                call.cancel();
        }
    }
}

For better handling of NPE we suggest to put the tag first when string comparison

public class OkHttpUtils {
    public static void cancelCallWithTag(OkHttpClient client, String tag) {
        for(Call call : client.dispatcher().queuedCalls()) {
            if(tag.equals(call.request().tag()))
                call.cancel();
        }
        for(Call call : client.dispatcher().runningCalls()) {
            if(tag.equals(call.request().tag()))
                call.cancel();
        }
    }
}