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| <a name="1" href="#1">1</a> <em class="jxr_comment">/*</em> |
| <a name="2" href="#2">2</a> <em class="jxr_comment"> * Licensed to the Apache Software Foundation (ASF) under one or more</em> |
| <a name="3" href="#3">3</a> <em class="jxr_comment"> * contributor license agreements. See the NOTICE file distributed with</em> |
| <a name="4" href="#4">4</a> <em class="jxr_comment"> * this work for additional information regarding copyright ownership.</em> |
| <a name="5" href="#5">5</a> <em class="jxr_comment"> * The ASF licenses this file to You under the Apache License, Version 2.0</em> |
| <a name="6" href="#6">6</a> <em class="jxr_comment"> * (the "License"); you may not use this file except in compliance with</em> |
| <a name="7" href="#7">7</a> <em class="jxr_comment"> * the License. You may obtain a copy of the License at</em> |
| <a name="8" href="#8">8</a> <em class="jxr_comment"> * </em> |
| <a name="9" href="#9">9</a> <em class="jxr_comment"> * <a href="http://www.apache.org/licenses/LICENSE-2.0" target="alexandria_uri">http://www.apache.org/licenses/LICENSE-2.0</a></em> |
| <a name="10" href="#10">10</a> <em class="jxr_comment"> * </em> |
| <a name="11" href="#11">11</a> <em class="jxr_comment"> * Unless required by applicable law or agreed to in writing, software</em> |
| <a name="12" href="#12">12</a> <em class="jxr_comment"> * distributed under the License is distributed on an "AS IS" BASIS,</em> |
| <a name="13" href="#13">13</a> <em class="jxr_comment"> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</em> |
| <a name="14" href="#14">14</a> <em class="jxr_comment"> * See the License for the specific language governing permissions and</em> |
| <a name="15" href="#15">15</a> <em class="jxr_comment"> * limitations under the License.</em> |
| <a name="16" href="#16">16</a> <em class="jxr_comment"> */</em> |
| <a name="17" href="#17">17</a> |
| <a name="18" href="#18">18</a> <em class="jxr_comment">// Contributors: Mathias Bogaert</em> |
| <a name="19" href="#19">19</a> <em class="jxr_comment">// joelr@viair.com</em> |
| <a name="20" href="#20">20</a> |
| <a name="21" href="#21">21</a> <strong class="jxr_keyword">package</strong> org.apache.log4j.helpers; |
| <a name="22" href="#22">22</a> |
| <a name="23" href="#23">23</a> <strong class="jxr_keyword">import</strong> org.apache.log4j.spi.LoggingEvent; |
| <a name="24" href="#24">24</a> |
| <a name="25" href="#25">25</a> <em class="jxr_javadoccomment">/**</em> |
| <a name="26" href="#26">26</a> <em class="jxr_javadoccomment"> <code>BoundedFIFO</code> serves as the bounded first-in-first-out</em> |
| <a name="27" href="#27">27</a> <em class="jxr_javadoccomment"> buffer heavily used by the {@link org.apache.log4j.AsyncAppender}.</em> |
| <a name="28" href="#28">28</a> <em class="jxr_javadoccomment"> </em> |
| <a name="29" href="#29">29</a> <em class="jxr_javadoccomment"> @author Ceki G&uuml;lc&uuml; </em> |
| <a name="30" href="#30">30</a> <em class="jxr_javadoccomment"> @since version 0.9.1 */</em> |
| <a name="31" href="#31">31</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">class</strong> <a href="../../../../org/apache/log4j/helpers/BoundedFIFO.html">BoundedFIFO</a> { |
| <a name="32" href="#32">32</a> |
| <a name="33" href="#33">33</a> <a href="../../../../org/apache/log4j/spi/LoggingEvent.html">LoggingEvent</a>[] buf; |
| <a name="34" href="#34">34</a> <strong class="jxr_keyword">int</strong> numElements = 0; |
| <a name="35" href="#35">35</a> <strong class="jxr_keyword">int</strong> first = 0; |
| <a name="36" href="#36">36</a> <strong class="jxr_keyword">int</strong> next = 0; |
| <a name="37" href="#37">37</a> <strong class="jxr_keyword">int</strong> maxSize; |
| <a name="38" href="#38">38</a> |
| <a name="39" href="#39">39</a> <em class="jxr_javadoccomment">/**</em> |
| <a name="40" href="#40">40</a> <em class="jxr_javadoccomment"> Instantiate a new BoundedFIFO with a maximum size passed as argument.</em> |
| <a name="41" href="#41">41</a> <em class="jxr_javadoccomment"> */</em> |
| <a name="42" href="#42">42</a> <strong class="jxr_keyword">public</strong> |
| <a name="43" href="#43">43</a> <a href="../../../../org/apache/log4j/helpers/BoundedFIFO.html">BoundedFIFO</a>(<strong class="jxr_keyword">int</strong> maxSize) { |
| <a name="44" href="#44">44</a> <strong class="jxr_keyword">if</strong>(maxSize < 1) { |
| <a name="45" href="#45">45</a> <strong class="jxr_keyword">throw</strong> <strong class="jxr_keyword">new</strong> IllegalArgumentException(<span class="jxr_string">"The maxSize argument ("</span>+maxSize+ |
| <a name="46" href="#46">46</a> <span class="jxr_string">") is not a positive integer."</span>); |
| <a name="47" href="#47">47</a> } |
| <a name="48" href="#48">48</a> <strong class="jxr_keyword">this</strong>.maxSize = maxSize; |
| <a name="49" href="#49">49</a> buf = <strong class="jxr_keyword">new</strong> <a href="../../../../org/apache/log4j/spi/LoggingEvent.html">LoggingEvent</a>[maxSize]; |
| <a name="50" href="#50">50</a> } |
| <a name="51" href="#51">51</a> |
| <a name="52" href="#52">52</a> <em class="jxr_javadoccomment">/**</em> |
| <a name="53" href="#53">53</a> <em class="jxr_javadoccomment"> Get the first element in the buffer. Returns <code>null</code> if</em> |
| <a name="54" href="#54">54</a> <em class="jxr_javadoccomment"> there are no elements in the buffer. */</em> |
| <a name="55" href="#55">55</a> <strong class="jxr_keyword">public</strong> |
| <a name="56" href="#56">56</a> <a href="../../../../org/apache/log4j/spi/LoggingEvent.html">LoggingEvent</a> get() { |
| <a name="57" href="#57">57</a> <strong class="jxr_keyword">if</strong>(numElements == 0) |
| <a name="58" href="#58">58</a> <strong class="jxr_keyword">return</strong> <strong class="jxr_keyword">null</strong>; |
| <a name="59" href="#59">59</a> |
| <a name="60" href="#60">60</a> <a href="../../../../org/apache/log4j/spi/LoggingEvent.html">LoggingEvent</a> r = buf[first]; |
| <a name="61" href="#61">61</a> buf[first] = <strong class="jxr_keyword">null</strong>; <em class="jxr_comment">// help garbage collection</em> |
| <a name="62" href="#62">62</a> |
| <a name="63" href="#63">63</a> <strong class="jxr_keyword">if</strong>(++first == maxSize) { |
| <a name="64" href="#64">64</a> first = 0; |
| <a name="65" href="#65">65</a> } |
| <a name="66" href="#66">66</a> numElements--; |
| <a name="67" href="#67">67</a> <strong class="jxr_keyword">return</strong> r; |
| <a name="68" href="#68">68</a> } |
| <a name="69" href="#69">69</a> |
| <a name="70" href="#70">70</a> <em class="jxr_javadoccomment">/**</em> |
| <a name="71" href="#71">71</a> <em class="jxr_javadoccomment"> Place a {@link LoggingEvent} in the buffer. If the buffer is full</em> |
| <a name="72" href="#72">72</a> <em class="jxr_javadoccomment"> then the event is <b>silently dropped</b>. It is the caller's</em> |
| <a name="73" href="#73">73</a> <em class="jxr_javadoccomment"> responsability to make sure that the buffer has free space. */</em> |
| <a name="74" href="#74">74</a> <strong class="jxr_keyword">public</strong> |
| <a name="75" href="#75">75</a> <strong class="jxr_keyword">void</strong> put(<a href="../../../../org/apache/log4j/spi/LoggingEvent.html">LoggingEvent</a> o) { |
| <a name="76" href="#76">76</a> <strong class="jxr_keyword">if</strong>(numElements != maxSize) { |
| <a name="77" href="#77">77</a> buf[next] = o; |
| <a name="78" href="#78">78</a> <strong class="jxr_keyword">if</strong>(++next == maxSize) { |
| <a name="79" href="#79">79</a> next = 0; |
| <a name="80" href="#80">80</a> } |
| <a name="81" href="#81">81</a> numElements++; |
| <a name="82" href="#82">82</a> } |
| <a name="83" href="#83">83</a> } |
| <a name="84" href="#84">84</a> |
| <a name="85" href="#85">85</a> <em class="jxr_javadoccomment">/**</em> |
| <a name="86" href="#86">86</a> <em class="jxr_javadoccomment"> Get the maximum size of the buffer.</em> |
| <a name="87" href="#87">87</a> <em class="jxr_javadoccomment"> */</em> |
| <a name="88" href="#88">88</a> <strong class="jxr_keyword">public</strong> |
| <a name="89" href="#89">89</a> <strong class="jxr_keyword">int</strong> getMaxSize() { |
| <a name="90" href="#90">90</a> <strong class="jxr_keyword">return</strong> maxSize; |
| <a name="91" href="#91">91</a> } |
| <a name="92" href="#92">92</a> |
| <a name="93" href="#93">93</a> <em class="jxr_javadoccomment">/**</em> |
| <a name="94" href="#94">94</a> <em class="jxr_javadoccomment"> Return <code>true</code> if the buffer is full, that is, whether</em> |
| <a name="95" href="#95">95</a> <em class="jxr_javadoccomment"> the number of elements in the buffer equals the buffer size. */</em> |
| <a name="96" href="#96">96</a> <strong class="jxr_keyword">public</strong> |
| <a name="97" href="#97">97</a> <strong class="jxr_keyword">boolean</strong> isFull() { |
| <a name="98" href="#98">98</a> <strong class="jxr_keyword">return</strong> numElements == maxSize; |
| <a name="99" href="#99">99</a> } |
| <a name="100" href="#100">100</a> |
| <a name="101" href="#101">101</a> <em class="jxr_javadoccomment">/**</em> |
| <a name="102" href="#102">102</a> <em class="jxr_javadoccomment"> Get the number of elements in the buffer. This number is</em> |
| <a name="103" href="#103">103</a> <em class="jxr_javadoccomment"> guaranteed to be in the range 0 to <code>maxSize</code></em> |
| <a name="104" href="#104">104</a> <em class="jxr_javadoccomment"> (inclusive).</em> |
| <a name="105" href="#105">105</a> <em class="jxr_javadoccomment"> */</em> |
| <a name="106" href="#106">106</a> <strong class="jxr_keyword">public</strong> |
| <a name="107" href="#107">107</a> <strong class="jxr_keyword">int</strong> length() { |
| <a name="108" href="#108">108</a> <strong class="jxr_keyword">return</strong> numElements; |
| <a name="109" href="#109">109</a> } |
| <a name="110" href="#110">110</a> |
| <a name="111" href="#111">111</a> |
| <a name="112" href="#112">112</a> <strong class="jxr_keyword">int</strong> min(<strong class="jxr_keyword">int</strong> a, <strong class="jxr_keyword">int</strong> b) { |
| <a name="113" href="#113">113</a> <strong class="jxr_keyword">return</strong> a < b ? a : b; |
| <a name="114" href="#114">114</a> } |
| <a name="115" href="#115">115</a> |
| <a name="116" href="#116">116</a> |
| <a name="117" href="#117">117</a> <em class="jxr_javadoccomment">/**</em> |
| <a name="118" href="#118">118</a> <em class="jxr_javadoccomment"> Resize the buffer to a new size. If the new size is smaller than</em> |
| <a name="119" href="#119">119</a> <em class="jxr_javadoccomment"> the old size events might be lost.</em> |
| <a name="120" href="#120">120</a> <em class="jxr_javadoccomment"> </em> |
| <a name="121" href="#121">121</a> <em class="jxr_javadoccomment"> @since 1.1</em> |
| <a name="122" href="#122">122</a> <em class="jxr_javadoccomment"> */</em> |
| <a name="123" href="#123">123</a> <strong class="jxr_keyword">synchronized</strong> |
| <a name="124" href="#124">124</a> <strong class="jxr_keyword">public</strong> |
| <a name="125" href="#125">125</a> <strong class="jxr_keyword">void</strong> resize(<strong class="jxr_keyword">int</strong> newSize) { |
| <a name="126" href="#126">126</a> <strong class="jxr_keyword">if</strong>(newSize == maxSize) |
| <a name="127" href="#127">127</a> <strong class="jxr_keyword">return</strong>; |
| <a name="128" href="#128">128</a> |
| <a name="129" href="#129">129</a> |
| <a name="130" href="#130">130</a> <a href="../../../../org/apache/log4j/spi/LoggingEvent.html">LoggingEvent</a>[] tmp = <strong class="jxr_keyword">new</strong> <a href="../../../../org/apache/log4j/spi/LoggingEvent.html">LoggingEvent</a>[newSize]; |
| <a name="131" href="#131">131</a> |
| <a name="132" href="#132">132</a> <em class="jxr_comment">// we should not copy beyond the buf array</em> |
| <a name="133" href="#133">133</a> <strong class="jxr_keyword">int</strong> len1 = maxSize - first; |
| <a name="134" href="#134">134</a> |
| <a name="135" href="#135">135</a> <em class="jxr_comment">// we should not copy beyond the tmp array</em> |
| <a name="136" href="#136">136</a> len1 = min(len1, newSize); |
| <a name="137" href="#137">137</a> |
| <a name="138" href="#138">138</a> <em class="jxr_comment">// er.. how much do we actually need to copy?</em> |
| <a name="139" href="#139">139</a> <em class="jxr_comment">// We should not copy more than the actual number of elements.</em> |
| <a name="140" href="#140">140</a> len1 = min(len1, numElements); |
| <a name="141" href="#141">141</a> |
| <a name="142" href="#142">142</a> <em class="jxr_comment">// Copy from buf starting a first, to tmp, starting at position 0, len1 elements.</em> |
| <a name="143" href="#143">143</a> System.arraycopy(buf, first, tmp, 0, len1); |
| <a name="144" href="#144">144</a> |
| <a name="145" href="#145">145</a> <em class="jxr_comment">// Are there any uncopied elements and is there still space in the new array?</em> |
| <a name="146" href="#146">146</a> <strong class="jxr_keyword">int</strong> len2 = 0; |
| <a name="147" href="#147">147</a> <strong class="jxr_keyword">if</strong>((len1 < numElements) && (len1 < newSize)) { |
| <a name="148" href="#148">148</a> len2 = numElements - len1; |
| <a name="149" href="#149">149</a> len2 = min(len2, newSize - len1); |
| <a name="150" href="#150">150</a> System.arraycopy(buf, 0, tmp, len1, len2); |
| <a name="151" href="#151">151</a> } |
| <a name="152" href="#152">152</a> |
| <a name="153" href="#153">153</a> <strong class="jxr_keyword">this</strong>.buf = tmp; |
| <a name="154" href="#154">154</a> <strong class="jxr_keyword">this</strong>.maxSize = newSize; |
| <a name="155" href="#155">155</a> <strong class="jxr_keyword">this</strong>.first=0; |
| <a name="156" href="#156">156</a> <strong class="jxr_keyword">this</strong>.numElements = len1+len2; |
| <a name="157" href="#157">157</a> <strong class="jxr_keyword">this</strong>.next = <strong class="jxr_keyword">this</strong>.numElements; |
| <a name="158" href="#158">158</a> <strong class="jxr_keyword">if</strong>(<strong class="jxr_keyword">this</strong>.next == <strong class="jxr_keyword">this</strong>.maxSize) <em class="jxr_comment">// this should never happen, but again, it just might.</em> |
| <a name="159" href="#159">159</a> <strong class="jxr_keyword">this</strong>.next = 0; |
| <a name="160" href="#160">160</a> } |
| <a name="161" href="#161">161</a> |
| <a name="162" href="#162">162</a> |
| <a name="163" href="#163">163</a> <em class="jxr_javadoccomment">/**</em> |
| <a name="164" href="#164">164</a> <em class="jxr_javadoccomment"> Returns <code>true</code> if there is just one element in the</em> |
| <a name="165" href="#165">165</a> <em class="jxr_javadoccomment"> buffer. In other words, if there were no elements before the last</em> |
| <a name="166" href="#166">166</a> <em class="jxr_javadoccomment"> {@link #put} operation completed. */</em> |
| <a name="167" href="#167">167</a> <strong class="jxr_keyword">public</strong> |
| <a name="168" href="#168">168</a> <strong class="jxr_keyword">boolean</strong> wasEmpty() { |
| <a name="169" href="#169">169</a> <strong class="jxr_keyword">return</strong> numElements == 1; |
| <a name="170" href="#170">170</a> } |
| <a name="171" href="#171">171</a> |
| <a name="172" href="#172">172</a> <em class="jxr_javadoccomment">/**</em> |
| <a name="173" href="#173">173</a> <em class="jxr_javadoccomment"> Returns <code>true</code> if the number of elements in the</em> |
| <a name="174" href="#174">174</a> <em class="jxr_javadoccomment"> buffer plus 1 equals the maximum buffer size, returns</em> |
| <a name="175" href="#175">175</a> <em class="jxr_javadoccomment"> <code>false</code> otherwise. */</em> |
| <a name="176" href="#176">176</a> <strong class="jxr_keyword">public</strong> |
| <a name="177" href="#177">177</a> <strong class="jxr_keyword">boolean</strong> wasFull() { |
| <a name="178" href="#178">178</a> <strong class="jxr_keyword">return</strong> (numElements+1 == maxSize); |
| <a name="179" href="#179">179</a> } |
| <a name="180" href="#180">180</a> |
| <a name="181" href="#181">181</a> } |
| </pre> |
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