Added indexed tree of folders downloading anything

[pub/Android/ownCloud.git] / src / com / owncloud / android / files / services / IndexedForest.java

diff --git a/src/com/owncloud/android/files/services/IndexedForest.java b/src/com/owncloud/android/files/services/IndexedForest.java
new file mode 100644 (file)
index 0000000..daf46a5
--- /dev/null
+++ b/src/com/owncloud/android/files/services/IndexedForest.java
@@ -0,0 +1,179 @@
+/* ownCloud Android client application
+ *   Copyright (C) 2015 ownCloud Inc.
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License version 2,
+ *   as published by the Free Software Foundation.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+package com.owncloud.android.files.services;
+
+import android.accounts.Account;
+
+import com.owncloud.android.datamodel.OCFile;
+
+import java.io.File;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+
+/**
+ *  Helper structure to keep the trees of folders containing any file downloading or synchronizing.
+ *
+ *  A map provides the indexation based in hashing.
+ *
+ *  A tree is created per account.
+ *
+ * @author David A. Velasco
+ */
+public class IndexedForest<V> {
+
+    private ConcurrentMap<String, Node<V>> mMap = new ConcurrentHashMap<String, Node<V>>();
+
+    private class Node<V> {
+        String mKey = null;
+        Node<V> mParent = null;
+        Set<Node<V>> mChildren = new HashSet<Node<V>>();    // TODO be careful with hash()
+        V mPayload = null;
+
+        // payload is optional
+        public Node(String key, V payload) {
+            if (key == null) {
+                throw new IllegalArgumentException("Argument key MUST NOT be null");
+            }
+            mKey = key;
+            mPayload = payload;
+        }
+
+        public Node<V> getParent() {
+            return mParent;
+        };
+
+        public Set<Node<V>> getChildren() {
+            return mChildren;
+        }
+
+        public String getKey() {
+            return mKey;
+        }
+
+        public V getPayload() {
+            return mPayload;
+        }
+
+        public void addChild(Node<V> child) {
+            mChildren.add(child);
+            child.setParent(this);
+        }
+
+        private void setParent(Node<V> parent) {
+            mParent = parent;
+        }
+
+        public boolean hasChildren() {
+            return mChildren.size() > 0;
+        }
+
+        public void removeChild(Node<V> removed) {
+            mChildren.remove(removed);
+        }
+    }
+
+
+    public /* synchronized */ String putIfAbsent(Account account, String remotePath, V value) {
+        String targetKey = buildKey(account, remotePath);
+        Node<V> valuedNode = new Node(targetKey, value);
+        mMap.putIfAbsent(
+                targetKey,
+                valuedNode
+        );
+
+        String currentPath = remotePath, parentPath = null, parentKey = null;
+        Node<V> currentNode = valuedNode, parentNode = null;
+        boolean linked = false;
+        while (!OCFile.ROOT_PATH.equals(currentPath) && !linked) {
+            parentPath = new File(currentPath).getParent();
+            if (!parentPath.endsWith(OCFile.PATH_SEPARATOR)) {
+                parentPath += OCFile.PATH_SEPARATOR;
+            }
+            parentKey = buildKey(account, parentPath);
+            parentNode = mMap.get(parentKey);
+            if (parentNode == null) {
+                parentNode = new Node(parentKey, null);
+                parentNode.addChild(currentNode);
+                mMap.put(parentKey, parentNode);
+            } else {
+                parentNode.addChild(currentNode);
+                linked = true;
+            }
+            currentPath = parentPath;
+            currentNode = parentNode;
+        }
+
+        return targetKey;
+    };
+
+    public /* synchronized */ V remove(Account account, String remotePath) {
+        String targetKey = buildKey(account, remotePath);
+        Node<V> firstRemoved = mMap.remove(targetKey);
+
+        if (firstRemoved != null) {
+            Node<V> removed = firstRemoved;
+            Node<V> parent = removed.getParent();
+            while (parent != null) {
+                parent.removeChild(removed);
+                if (!parent.hasChildren()) {
+                    removed = mMap.remove(parent.getKey());
+                    parent = removed.getParent();
+                } else {
+                    parent = null;
+                }
+            }
+        }
+
+        if (firstRemoved != null) {
+            return firstRemoved.getPayload();
+        } else {
+            return null;
+        }
+
+    }
+
+    public boolean contains(Account account, String remotePath) {
+        String targetKey = buildKey(account, remotePath);
+        return mMap.containsKey(targetKey);
+    }
+
+    public /* synchronized */ V get(String key) {
+        Node<V> node = mMap.get(key);
+        if (node != null) {
+            return node.getPayload();
+        } else {
+            return null;
+        }
+    }
+
+
+    /**
+     * Builds a key to index files
+     *
+     * @param account       Account where the file to download is stored
+     * @param remotePath    Path of the file in the server
+     */
+    private String buildKey(Account account, String remotePath) {
+        return account.name + remotePath;
+    }
+
+
+
+}