sonu gupta | 1bb37b8 | 2016-11-11 16:51:18 +0530 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2016-present Open Networking Laboratory |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package org.onosproject.yms.app.ydt; |
| 18 | |
| 19 | |
| 20 | import org.onosproject.yms.app.utils.TraversalType; |
| 21 | import org.onosproject.yms.ydt.YdtContext; |
| 22 | import org.onosproject.yms.ydt.YdtListener; |
| 23 | |
| 24 | import static org.onosproject.yms.app.utils.TraversalType.CHILD; |
| 25 | import static org.onosproject.yms.app.utils.TraversalType.PARENT; |
| 26 | import static org.onosproject.yms.app.utils.TraversalType.ROOT; |
| 27 | import static org.onosproject.yms.app.utils.TraversalType.SIBLING; |
| 28 | |
| 29 | /** |
| 30 | * Represents implementation of YDT walker, which walks the YDT. |
| 31 | */ |
| 32 | public class DefaultYdtWalker implements YdtExtendedWalker { |
| 33 | |
| 34 | @Override |
| 35 | public void walk(YdtListener ydtListener, YdtContext rootNode) { |
| 36 | walkTree(ydtListener, rootNode, false); |
| 37 | } |
| 38 | |
| 39 | /** |
| 40 | * Walks the YANG data tree till the node provided by the user. |
| 41 | * Protocols implements YDT listener and YDT Extended Listener and |
| 42 | * walks YDT tree with input as implemented object. |
| 43 | * YDT walker provides call backs to implemented methods. |
| 44 | * |
| 45 | * @param ydtListener YDT listener implemented by the protocol |
| 46 | * @param rootNode root node of YDT |
| 47 | * @param isExtended flag denotes the call type |
| 48 | */ |
| 49 | private void walkTree(YdtListener ydtListener, YdtContext rootNode, |
| 50 | boolean isExtended) { |
| 51 | YdtContext curNode = rootNode; |
| 52 | TraversalType curTraversal = ROOT; |
| 53 | |
| 54 | while (curNode != null) { |
| 55 | if (curTraversal != PARENT) { |
| 56 | |
| 57 | // Visit (curNode) for entry callback |
| 58 | if (isExtended) { |
| 59 | ((YdtExtendedListener) ydtListener) |
| 60 | .enterYdtNode((YdtExtendedContext) curNode); |
| 61 | } else { |
| 62 | ydtListener.enterYdtNode(curNode); |
| 63 | } |
| 64 | } |
| 65 | if (curTraversal != PARENT && |
| 66 | curNode.getFirstChild() != null) { |
| 67 | curTraversal = CHILD; |
| 68 | curNode = curNode.getFirstChild(); |
| 69 | } else if (curNode.getNextSibling() != null) { |
| 70 | // Revisit (curNode) for exit callback |
| 71 | exitCallBack(ydtListener, curNode, isExtended); |
| 72 | |
| 73 | /* |
| 74 | *Stop traversing the tree , tree need to be traversed |
| 75 | * till user requested node |
| 76 | */ |
| 77 | if (curNode.equals(rootNode)) { |
| 78 | return; |
| 79 | } |
| 80 | curTraversal = SIBLING; |
| 81 | curNode = curNode.getNextSibling(); |
| 82 | } else { |
| 83 | // Revisit (curNode) for exit callback |
| 84 | exitCallBack(ydtListener, curNode, isExtended); |
| 85 | |
| 86 | /* |
| 87 | *Stop traversing the tree , tree need to be traversed |
| 88 | * till user requested node |
| 89 | */ |
| 90 | if (curNode.equals(rootNode)) { |
| 91 | return; |
| 92 | } |
| 93 | |
| 94 | curTraversal = PARENT; |
| 95 | curNode = curNode.getParent(); |
| 96 | } |
| 97 | } |
| 98 | } |
| 99 | |
| 100 | /** |
| 101 | * Provides exit call back per node on the basis of extended flag, |
| 102 | * If isExtended set then YdtExtendedListener exit node call back will |
| 103 | * be provided else YdtListener with respective type of context |
| 104 | * (YdtContext/YdtExtendedContext). |
| 105 | * |
| 106 | * @param ydtListener YDT listener implemented by the protocol |
| 107 | * @param curNode current node of YDT |
| 108 | * @param isExtended flag denotes the call type |
| 109 | */ |
| 110 | private void exitCallBack(YdtListener ydtListener, YdtContext curNode, |
| 111 | boolean isExtended) { |
| 112 | if (isExtended) { |
| 113 | ((YdtExtendedListener) ydtListener) |
| 114 | .exitYdtNode((YdtExtendedContext) curNode); |
| 115 | } else { |
| 116 | ydtListener.exitYdtNode(curNode); |
| 117 | } |
| 118 | } |
| 119 | |
| 120 | @Override |
| 121 | public void walk(YdtExtendedListener ydtExtendedListener, |
| 122 | YdtExtendedContext rootNode) { |
| 123 | walkTree(ydtExtendedListener, rootNode, true); |
| 124 | } |
| 125 | } |