diff --git a/gcloud-java-examples/pom.xml b/gcloud-java-examples/pom.xml index e8f00852d079..642f8fb0fff0 100644 --- a/gcloud-java-examples/pom.xml +++ b/gcloud-java-examples/pom.xml @@ -63,6 +63,10 @@ com.google.cloud.examples.nio.Stat Stat + + com.google.cloud.examples.nio.CountBytes + CountBytes + com.google.cloud.examples.resourcemanager.ResourceManagerExample diff --git a/gcloud-java-examples/src/main/java/com/google/cloud/examples/nio/CountBytes.java b/gcloud-java-examples/src/main/java/com/google/cloud/examples/nio/CountBytes.java new file mode 100644 index 000000000000..50ad77d72f24 --- /dev/null +++ b/gcloud-java-examples/src/main/java/com/google/cloud/examples/nio/CountBytes.java @@ -0,0 +1,102 @@ +/* + * Copyright 2016 Google Inc. All Rights Reserved. + * + * 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.google.cloud.examples.nio; + +import com.google.common.base.Stopwatch; + +import java.io.IOException; +import java.net.URI; +import java.nio.ByteBuffer; +import java.nio.channels.SeekableByteChannel; +import java.nio.file.Files; +import java.nio.file.Path; +import java.nio.file.Paths; +import java.util.concurrent.TimeUnit; + +/** + * CountBytes will read through the whole file given as input. + * + *

This example shows how to read a file size using NIO. + * File.size returns the size of the file as saved in Storage metadata. + * This class also shows how to read all of the file's contents using NIO, + * and reports how long it took. + * + *

See the README for compilation instructions. Run this code with + * {@code target/appassembler/bin/CountBytes } + */ +public class CountBytes { + + /** + * See the class documentation. + */ + public static void main(String[] args) throws IOException { + if (args.length == 0 || args[0].equals("--help")) { + help(); + return; + } + for (String a : args) { + countFile(a); + } + } + + /** + * Print the length of the indicated file. + * + *

This uses the normal Java NIO Api, so it can take advantage of any installed + * NIO Filesystem provider without any extra effort. + */ + private static void countFile(String fname) { + // large buffers pay off + final int bufSize = 50 * 1024 * 1024; + try { + Path path = Paths.get(new URI(fname)); + long size = Files.size(path); + System.out.println(fname + ": " + size + " bytes."); + ByteBuffer buf = ByteBuffer.allocate(bufSize); + System.out.println("Reading the whole file..."); + Stopwatch sw = Stopwatch.createStarted(); + SeekableByteChannel chan = Files.newByteChannel(path); + long total = 0; + int readCalls = 0; + while (chan.read(buf) > 0) { + readCalls++; + total += buf.position(); + buf.flip(); + } + readCalls++; // We must count the last call + long elapsed = sw.elapsed(TimeUnit.SECONDS); + System.out.println("Read all " + total + " bytes in " + elapsed + "s. " + + "(" + readCalls +" calls to chan.read)"); + if (total != size) { + System.out.println("Wait, this doesn't match! We saw " + total + " bytes, " + + "yet the file size is listed at " + size + " bytes."); + } + } catch (Exception ex) { + System.out.println(fname + ": " + ex.toString()); + } + } + + private static void help() { + String[] help = + {"The argument is a ", + "and we show the length of that file." + }; + for (String s : help) { + System.out.println(s); + } + } +} diff --git a/gcloud-java-examples/src/main/java/com/google/cloud/examples/nio/Stat.java b/gcloud-java-examples/src/main/java/com/google/cloud/examples/nio/Stat.java index ee9c4387a71a..b8d018f8f738 100644 --- a/gcloud-java-examples/src/main/java/com/google/cloud/examples/nio/Stat.java +++ b/gcloud-java-examples/src/main/java/com/google/cloud/examples/nio/Stat.java @@ -1,3 +1,19 @@ +/* + * Copyright 2016 Google Inc. All Rights Reserved. + * + * 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.google.cloud.examples.nio; import java.io.IOException;