Merge pull request Azure#22 from jianghaolu/master

Updates from Java SDK

azure-client-authentication/src/main/java/com/microsoft/azure/credentials/ApplicationTokenCredentials.java

@@ -113,13 +113,14 @@ public ApplicationTokenCredentials withDefaultSubscriptionId(String subscription
      *
      * @param credentialsFile A  file with credentials, using the standard Java properties format.
      * and the following keys:
-         *     subscription=<subscription-id>
-         *     tenant=<tenant-id>
-         *     client=<client-id>
-         *     key=<client-key>
-         *     managementURI=<management-URI>
-         *     baseURL=<base-URL>
-         *     authURL=<authentication-URL>
+     *     subscription=&lt;subscription-id&gt;
+     *     tenant=&lt;tenant-id&gt;
+     *     client=&lt;client-id&gt;
+     *     key=&lt;client-key&gt;
+     *     managementURI=&lt;management-URI&gt;
+     *     baseURL=&lt;base-URL&gt;
+     *     authURL=&lt;authentication-URL&gt;
+     *
      * @return The credentials based on the file.
      * @throws IOException exception thrown from file access errors.
      */

azure-client-runtime/src/main/java/com/microsoft/azure/AzureEnvironment.java

@@ -68,7 +68,25 @@ public AzureEnvironment(
             "https://login.chinacloudapi.cn/",
             "https://management.core.chinacloudapi.cn/",
             true,
-            "https://management.chinacloudapi.cn");
+            "https://management.chinacloudapi.cn/");
+
+    /**
+     * Provides the settings for authentication with Azure US Government.
+     */
+    public static final AzureEnvironment AZURE_US_GOVERNMENT = new AzureEnvironment(
+            "https://login.microsoftonline.com/",
+            "https://management.core.usgovcloudapi.net/",
+            true,
+            "https://management.usgovcloudapi.net/");
+
+    /**
+     * Provides the settings for authentication with Azure Germany.
+     */
+    public static final AzureEnvironment AZURE_GERMANY = new AzureEnvironment(
+            "https://login.microsoftonline.de/",
+            "https://management.core.cloudapi.de/",
+            true,
+            "https://management.microsoftazure.de/");
 
     /**
      * Gets the base URL of the management service.

azure-client-runtime/src/main/java/com/microsoft/azure/DAGNode.java

@@ -8,6 +8,7 @@
 package com.microsoft.azure;
 
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 
 /**
@@ -18,6 +19,7 @@
 public class DAGNode<T> extends Node<T> {
     private List<String> dependentKeys;
     private int toBeResolved;
+    private boolean isPreparer;
 
     /**
      * Creates a DAG node.
@@ -34,11 +36,11 @@ public DAGNode(String key, T data) {
      * @return a list of keys of nodes in {@link DAGraph} those are dependents on this node
      */
     List<String> dependentKeys() {
-        return this.dependentKeys;
+        return Collections.unmodifiableList(this.dependentKeys);
     }
 
     /**
-     * mark the node identified by the given key as dependent of this node.
+     * Mark the node identified by the given key as dependent of this node.
      *
      * @param key the id of the dependent node
      */
@@ -54,12 +56,11 @@ public List<String> dependencyKeys() {
     }
 
     /**
-     * mark the node identified by the given key as this node's dependency.
+     * Mark the node identified by the given key as this node's dependency.
      *
      * @param dependencyKey the id of the dependency node
      */
     public void addDependency(String dependencyKey) {
-        toBeResolved++;
         super.addChild(dependencyKey);
     }
 
@@ -70,6 +71,30 @@ public boolean hasDependencies() {
         return this.hasChildren();
     }
 
+    /**
+     * Mark or un-mark this node as preparer.
+     *
+     * @param isPreparer <tt>true</tt> if this node needs to be marked as preparer, <tt>false</tt> otherwise.
+     */
+    public void setPreparer(boolean isPreparer) {
+        this.isPreparer = isPreparer;
+    }
+
+    /**
+     * @return <tt>true</tt> if this node is marked as preparer
+     */
+    public boolean isPreparer() {
+        return isPreparer;
+    }
+
+    /**
+     * Initialize the node so that traversal can be performed on the parent DAG.
+     */
+    public void initialize() {
+        this.toBeResolved = this.dependencyKeys().size();
+        this.dependentKeys.clear();
+    }
+
     /**
      * @return <tt>true</tt> if all dependencies of this node are ready to be consumed
      */

azure-client-runtime/src/main/java/com/microsoft/azure/DAGraph.java

@@ -32,6 +32,7 @@ public class DAGraph<T, U extends DAGNode<T>> extends Graph<T, U> {
     public DAGraph(U rootNode) {
         this.rootNode = rootNode;
         this.queue = new ArrayDeque<>();
+        this.rootNode.setPreparer(true);
         this.addNode(rootNode);
     }
 
@@ -52,18 +53,25 @@ public boolean isRootNode(U node) {
         return this.rootNode == node;
     }
 
+    /**
+     * @return <tt>true</tt> if this dag is the preparer responsible for
+     * preparing the DAG for traversal.
+     */
+    public boolean isPreparer() {
+        return this.rootNode.isPreparer();
+    }
+
     /**
      * Merge this DAG with another DAG.
      * <p>
-     * this will mark this DAG as a child DAG, the dependencies of nodes in this DAG will be merged
+     * This will mark this DAG as a child DAG, the dependencies of nodes in this DAG will be merged
      * with (copied to) the parent DAG
      *
      * @param parent the parent DAG
      */
     public void merge(DAGraph<T, U> parent) {
         this.hasParent = true;
         parent.rootNode.addDependency(this.rootNode.key());
-        this.rootNode.addDependent(parent.rootNode.key());
         for (Map.Entry<String, U> entry: graph.entrySet()) {
             String key = entry.getKey();
             if (!parent.graph.containsKey(key)) {
@@ -77,19 +85,25 @@ public void merge(DAGraph<T, U> parent) {
      * in the DAG with no dependencies.
      */
     public void prepare() {
-        initializeQueue();
-        if (queue.isEmpty()) {
-            throw new RuntimeException("Found circular dependency");
+        if (isPreparer()) {
+            for (U node : graph.values()) {
+                // Prepare each node for traversal
+                node.initialize();
+                if (!this.isRootNode(node)) {
+                    // Mark other sub-DAGs as non-preparer
+                    node.setPreparer(false);
+                }
+            }
+            initializeDependentKeys();
+            initializeQueue();
         }
     }
 
     /**
      * Gets next node in the DAG which has no dependency or all of it's dependencies are resolved and
      * ready to be consumed.
-     * <p>
-     * null will be returned when all the nodes are explored
      *
-     * @return next node
+     * @return next node or null if all the nodes have been explored
      */
     public U getNext() {
         return graph.get(queue.poll());
@@ -111,6 +125,7 @@ public T getNodeData(String key) {
      * @param completed the node ready to be consumed
      */
     public void reportedCompleted(U completed) {
+        completed.setPreparer(true);
         String dependency = completed.key();
         for (String dependentKey : graph.get(dependency).dependentKeys()) {
             DAGNode<T> dependent = graph.get(dependentKey);
@@ -122,27 +137,25 @@ public void reportedCompleted(U completed) {
     }
 
     /**
-     * populate dependents of all nodes.
+     * Initializes dependents of all nodes.
      * <p>
-     * the DAG will be explored in DFS order and all node's dependents will be identified,
+     * The DAG will be explored in DFS order and all node's dependents will be identified,
      * this prepares the DAG for traversal using getNext method, each call to getNext returns next node
      * in the DAG with no dependencies.
      */
-    public void populateDependentKeys() {
-        this.queue.clear();
+    private void initializeDependentKeys() {
         visit(new Visitor<U>() {
+            // This 'visit' will be called only once per each node.
             @Override
             public void visit(U node) {
                 if (node.dependencyKeys().isEmpty()) {
-                    queue.add(node.key());
                     return;
                 }
 
                 String dependentKey = node.key();
                 for (String dependencyKey : node.dependencyKeys()) {
                     graph.get(dependencyKey)
-                            .dependentKeys()
-                            .add(dependentKey);
+                            .addDependent(dependentKey);
                 }
             }
         });
@@ -159,5 +172,8 @@ private void initializeQueue() {
                 this.queue.add(entry.getKey());
             }
         }
+        if (queue.isEmpty()) {
+            throw new RuntimeException("Found circular dependency");
+        }
     }
 }

azure-client-runtime/src/main/java/com/microsoft/azure/Graph.java

@@ -15,7 +15,7 @@
 /**
  * Type representing a directed graph data structure.
  * <p>
- * each node in a graph is represented by {@link Node}
+ * Each node in a graph is represented by {@link Node}
  *
  * @param <T> the type of the data stored in the graph's nodes
  * @param <U> the type of the nodes in the graph

azure-client-runtime/src/main/java/com/microsoft/azure/Node.java

@@ -8,6 +8,7 @@
 package com.microsoft.azure;
 
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 
 /**
@@ -57,7 +58,7 @@ public boolean hasChildren() {
      * @return children (neighbours) of this node
      */
     public List<String> children() {
-        return this.children;
+        return Collections.unmodifiableList(this.children);
     }
 
     /**

azure-client-runtime/src/main/java/com/microsoft/azure/ResourceGetExponentialBackoffRetryStrategy.java

@@ -0,0 +1,48 @@
+/**
+ *
+ * Copyright (c) Microsoft Corporation. All rights reserved.
+ * Licensed under the MIT License. See License.txt in the project root for license information.
+ *
+ */
+
+package com.microsoft.azure;
+
+import com.microsoft.rest.retry.RetryStrategy;
+import okhttp3.Response;
+
+/**
+ * A retry strategy with backoff parameters for calculating the exponential
+ * delay between retries for 404s from GET calls.
+ */
+public class ResourceGetExponentialBackoffRetryStrategy extends RetryStrategy {
+    /**
+     * Represents the default number of retries.
+     */
+    private static final int DEFAULT_NUMBER_OF_ATTEMPTS = 3;
+
+    /**
+     * Creates an instance of the retry strategy.
+     */
+    public ResourceGetExponentialBackoffRetryStrategy() {
+        this(null, DEFAULT_FIRST_FAST_RETRY);
+    }
+
+    /**
+     * Initializes a new instance of the {@link RetryStrategy} class.
+     *
+     * @param name           The name of the retry strategy.
+     * @param firstFastRetry true to immediately retry in the first attempt; otherwise, false.
+     */
+    private ResourceGetExponentialBackoffRetryStrategy(String name, boolean firstFastRetry) {
+        super(name, firstFastRetry);
+    }
+
+    @Override
+    public boolean shouldRetry(int retryCount, Response response) {
+        int code = response.code();
+        //CHECKSTYLE IGNORE MagicNumber FOR NEXT 2 LINES
+        return retryCount < DEFAULT_NUMBER_OF_ATTEMPTS
+                && code == 404
+                && response.request().method().equalsIgnoreCase("GET");
+    }
+}