gerrit.onap Code Review - sandbox-2.git/blob - rosetta/src/main/java/org/onap/rosetta/Ladder.java

1 /*******************************************************************************\r

2 * ============LICENSE_START====================================================\r

3 * * org.onap.aaf\r

4 * * ===========================================================================\r

6 * * ===========================================================================\r

7 * * Licensed under the Apache License, Version 2.0 (the "License");\r

8 * * you may not use this file except in compliance with the License.\r

9 * * You may obtain a copy of the License at\r

10 * * \r

11 * * http://www.apache.org/licenses/LICENSE-2.0\r

12 * * \r

13 * * Unless required by applicable law or agreed to in writing, software\r

14 * * distributed under the License is distributed on an "AS IS" BASIS,\r

15 * * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\r

16 * * See the License for the specific language governing permissions and\r

17 * * limitations under the License.\r

18 * * ============LICENSE_END====================================================\r

19 * *\r

20 * * ECOMP is a trademark and service mark of AT&T Intellectual Property.\r

21 * *\r

22 ******************************************************************************/\r

23 package org.onap.rosetta;\r

24 \r

25 \r

26 /**\r

27 * A Ladder is a Stack like Storage Class, but where you can ascend and descend while\r

28 * the elements exists.\r

29 * \r

30 * Like an extension ladder, you can make taller as you go\r

31 * \r

32 *\r

33 */\r

34 public class Ladder<T> {\r

35 public static final int DEFAULT_INIT_SIZE=8;\r

36 private final int init_size;\r

37 private int rung; // as in ladder\r

38 private Object[] struts;\r

39 \r

40 public Ladder() {\r

41 rung=0;\r

42 init_size = DEFAULT_INIT_SIZE;\r

43 struts=new Object[init_size];\r

44 }\r

45 \r

46 public Ladder(int initSize) {\r

47 rung=0;\r

48 init_size = initSize;\r

49 struts=new Object[init_size];\r

50 }\r

51 \r

52 public void bottom() {\r

53 rung = 0;\r

54 }\r

55 \r

56 public void top() {\r

57 rung = struts.length-1;\r

58 while(rung>0 && struts[rung]==null)--rung;\r

59 }\r

60 \r

61 public int howHigh() {\r

62 return rung;\r

63 }\r

64 \r

65 public void jumpTo(int rung) {\r

66 if(rung>=struts.length) {\r

67 Object[] temp = new Object[init_size*((rung/init_size)+1)];\r

68 System.arraycopy(struts, 0, temp, 0, struts.length);\r

69 struts = temp;\r

70 }\r

71 this.rung = rung;\r

72 }\r

73 \r

74 public int height() {\r

75 return struts.length;\r

76 }\r

77 \r

78 public void cutTo(int rungs) {\r

79 Object[] temp = new Object[rungs];\r

80 System.arraycopy(struts, 0, temp, 0, Math.min(rungs, struts.length));\r

81 struts = temp;\r

82 }\r

83 \r

84 public void ascend() {\r

85 ++rung;\r

86 if(rung>=struts.length) {\r

87 Object[] temp = new Object[struts.length+init_size];\r

88 System.arraycopy(struts, 0, temp, 0, struts.length);\r

89 struts = temp;\r

90 }\r

91 }\r

92 \r

93 public void descend() {\r

94 --rung;\r

95 }\r

96 \r

97 @SuppressWarnings("unchecked")\r

98 public T peek() {\r

99 return (T)struts[rung];\r

100 }\r

101 \r

102 public void push(T t) {\r

103 struts[rung]=t;\r

104 }\r

105 \r

106 @SuppressWarnings("unchecked")\r

107 public T pop() {\r

108 T t = (T)struts[rung];\r

109 struts[rung]=null;\r

110 return t;\r

111 }\r

112 \r

113 }\r