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apache / logging-log4j-site / 9755b12b39efbc0142688f9b1a11ec68db89f97b / . / 2.13.2 / log4j-core / apidocs / src-html / org / apache / logging / log4j / core / util / Assert.html
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<pre><span class="sourceLineNo">001</span>/*<a name="line.1"></a>
<span class="sourceLineNo">002</span> * Licensed to the Apache Software Foundation (ASF) under one or more<a name="line.2"></a>
<span class="sourceLineNo">003</span> * contributor license agreements. See the NOTICE file distributed with<a name="line.3"></a>
<span class="sourceLineNo">004</span> * this work for additional information regarding copyright ownership.<a name="line.4"></a>
<span class="sourceLineNo">005</span> * The ASF licenses this file to You under the Apache license, Version 2.0<a name="line.5"></a>
<span class="sourceLineNo">006</span> * (the "License"); you may not use this file except in compliance with<a name="line.6"></a>
<span class="sourceLineNo">007</span> * the License. You may obtain a copy of the License at<a name="line.7"></a>
<span class="sourceLineNo">008</span> *<a name="line.8"></a>
<span class="sourceLineNo">009</span> * http://www.apache.org/licenses/LICENSE-2.0<a name="line.9"></a>
<span class="sourceLineNo">010</span> *<a name="line.10"></a>
<span class="sourceLineNo">011</span> * Unless required by applicable law or agreed to in writing, software<a name="line.11"></a>
<span class="sourceLineNo">012</span> * distributed under the License is distributed on an "AS IS" BASIS,<a name="line.12"></a>
<span class="sourceLineNo">013</span> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<a name="line.13"></a>
<span class="sourceLineNo">014</span> * See the license for the specific language governing permissions and<a name="line.14"></a>
<span class="sourceLineNo">015</span> * limitations under the license.<a name="line.15"></a>
<span class="sourceLineNo">016</span> */<a name="line.16"></a>
<span class="sourceLineNo">017</span>package org.apache.logging.log4j.core.util;<a name="line.17"></a>
<span class="sourceLineNo">018</span><a name="line.18"></a>
<span class="sourceLineNo">019</span>import java.util.Collection;<a name="line.19"></a>
<span class="sourceLineNo">020</span>import java.util.Map;<a name="line.20"></a>
<span class="sourceLineNo">021</span><a name="line.21"></a>
<span class="sourceLineNo">022</span>/**<a name="line.22"></a>
<span class="sourceLineNo">023</span> * Utility class providing common validation logic.<a name="line.23"></a>
<span class="sourceLineNo">024</span> */<a name="line.24"></a>
<span class="sourceLineNo">025</span>public final class Assert {<a name="line.25"></a>
<span class="sourceLineNo">026</span> private Assert() {<a name="line.26"></a>
<span class="sourceLineNo">027</span> }<a name="line.27"></a>
<span class="sourceLineNo">028</span><a name="line.28"></a>
<span class="sourceLineNo">029</span> /**<a name="line.29"></a>
<span class="sourceLineNo">030</span> * Checks if an object has empty semantics. The following scenarios are considered empty:<a name="line.30"></a>
<span class="sourceLineNo">031</span> * &lt;ul&gt;<a name="line.31"></a>
<span class="sourceLineNo">032</span> * &lt;li&gt;{@code null}&lt;/li&gt;<a name="line.32"></a>
<span class="sourceLineNo">033</span> * &lt;li&gt;empty {@link CharSequence}&lt;/li&gt;<a name="line.33"></a>
<span class="sourceLineNo">034</span> * &lt;li&gt;empty array&lt;/li&gt;<a name="line.34"></a>
<span class="sourceLineNo">035</span> * &lt;li&gt;empty {@link Iterable}&lt;/li&gt;<a name="line.35"></a>
<span class="sourceLineNo">036</span> * &lt;li&gt;empty {@link Map}&lt;/li&gt;<a name="line.36"></a>
<span class="sourceLineNo">037</span> * &lt;/ul&gt;<a name="line.37"></a>
<span class="sourceLineNo">038</span> *<a name="line.38"></a>
<span class="sourceLineNo">039</span> * @param o value to check for emptiness<a name="line.39"></a>
<span class="sourceLineNo">040</span> * @return true if the value is empty, false otherwise<a name="line.40"></a>
<span class="sourceLineNo">041</span> * @since 2.8<a name="line.41"></a>
<span class="sourceLineNo">042</span> */<a name="line.42"></a>
<span class="sourceLineNo">043</span> public static boolean isEmpty(final Object o) {<a name="line.43"></a>
<span class="sourceLineNo">044</span> if (o == null) {<a name="line.44"></a>
<span class="sourceLineNo">045</span> return true;<a name="line.45"></a>
<span class="sourceLineNo">046</span> }<a name="line.46"></a>
<span class="sourceLineNo">047</span> if (o instanceof CharSequence) {<a name="line.47"></a>
<span class="sourceLineNo">048</span> return ((CharSequence) o).length() == 0;<a name="line.48"></a>
<span class="sourceLineNo">049</span> }<a name="line.49"></a>
<span class="sourceLineNo">050</span> if (o.getClass().isArray()) {<a name="line.50"></a>
<span class="sourceLineNo">051</span> return ((Object[]) o).length == 0;<a name="line.51"></a>
<span class="sourceLineNo">052</span> }<a name="line.52"></a>
<span class="sourceLineNo">053</span> if (o instanceof Collection) {<a name="line.53"></a>
<span class="sourceLineNo">054</span> return ((Collection&lt;?&gt;) o).isEmpty();<a name="line.54"></a>
<span class="sourceLineNo">055</span> }<a name="line.55"></a>
<span class="sourceLineNo">056</span> if (o instanceof Map) {<a name="line.56"></a>
<span class="sourceLineNo">057</span> return ((Map&lt;?, ?&gt;) o).isEmpty();<a name="line.57"></a>
<span class="sourceLineNo">058</span> }<a name="line.58"></a>
<span class="sourceLineNo">059</span> return false;<a name="line.59"></a>
<span class="sourceLineNo">060</span> }<a name="line.60"></a>
<span class="sourceLineNo">061</span><a name="line.61"></a>
<span class="sourceLineNo">062</span> /**<a name="line.62"></a>
<span class="sourceLineNo">063</span> * Opposite of {@link #isEmpty(Object)}.<a name="line.63"></a>
<span class="sourceLineNo">064</span> *<a name="line.64"></a>
<span class="sourceLineNo">065</span> * @param o value to check for non-emptiness<a name="line.65"></a>
<span class="sourceLineNo">066</span> * @return true if the value is non-empty, false otherwise<a name="line.66"></a>
<span class="sourceLineNo">067</span> * @since 2.8<a name="line.67"></a>
<span class="sourceLineNo">068</span> */<a name="line.68"></a>
<span class="sourceLineNo">069</span> public static boolean isNonEmpty(final Object o) {<a name="line.69"></a>
<span class="sourceLineNo">070</span> return !isEmpty(o);<a name="line.70"></a>
<span class="sourceLineNo">071</span> }<a name="line.71"></a>
<span class="sourceLineNo">072</span><a name="line.72"></a>
<span class="sourceLineNo">073</span> /**<a name="line.73"></a>
<span class="sourceLineNo">074</span> * Checks a value for emptiness and throws an IllegalArgumentException if it's empty.<a name="line.74"></a>
<span class="sourceLineNo">075</span> *<a name="line.75"></a>
<span class="sourceLineNo">076</span> * @param value value to check for emptiness<a name="line.76"></a>
<span class="sourceLineNo">077</span> * @param &lt;T&gt; type of value<a name="line.77"></a>
<span class="sourceLineNo">078</span> * @return the provided value if non-empty<a name="line.78"></a>
<span class="sourceLineNo">079</span> * @since 2.8<a name="line.79"></a>
<span class="sourceLineNo">080</span> */<a name="line.80"></a>
<span class="sourceLineNo">081</span> public static &lt;T&gt; T requireNonEmpty(final T value) {<a name="line.81"></a>
<span class="sourceLineNo">082</span> return requireNonEmpty(value, "");<a name="line.82"></a>
<span class="sourceLineNo">083</span> }<a name="line.83"></a>
<span class="sourceLineNo">084</span><a name="line.84"></a>
<span class="sourceLineNo">085</span> /**<a name="line.85"></a>
<span class="sourceLineNo">086</span> * Checks a value for emptiness and throws an IllegalArgumentException if it's empty.<a name="line.86"></a>
<span class="sourceLineNo">087</span> *<a name="line.87"></a>
<span class="sourceLineNo">088</span> * @param value value to check for emptiness<a name="line.88"></a>
<span class="sourceLineNo">089</span> * @param message message to provide in exception<a name="line.89"></a>
<span class="sourceLineNo">090</span> * @param &lt;T&gt; type of value<a name="line.90"></a>
<span class="sourceLineNo">091</span> * @return the provided value if non-empty<a name="line.91"></a>
<span class="sourceLineNo">092</span> * @since 2.8<a name="line.92"></a>
<span class="sourceLineNo">093</span> */<a name="line.93"></a>
<span class="sourceLineNo">094</span> public static &lt;T&gt; T requireNonEmpty(final T value, final String message) {<a name="line.94"></a>
<span class="sourceLineNo">095</span> if (isEmpty(value)) {<a name="line.95"></a>
<span class="sourceLineNo">096</span> throw new IllegalArgumentException(message);<a name="line.96"></a>
<span class="sourceLineNo">097</span> }<a name="line.97"></a>
<span class="sourceLineNo">098</span> return value;<a name="line.98"></a>
<span class="sourceLineNo">099</span> }<a name="line.99"></a>
<span class="sourceLineNo">100</span><a name="line.100"></a>
<span class="sourceLineNo">101</span> public static int valueIsAtLeast(final int value, final int minValue) {<a name="line.101"></a>
<span class="sourceLineNo">102</span> if (value &lt; minValue) {<a name="line.102"></a>
<span class="sourceLineNo">103</span> throw new IllegalArgumentException("Value should be at least " + minValue + " but was " + value);<a name="line.103"></a>
<span class="sourceLineNo">104</span> }<a name="line.104"></a>
<span class="sourceLineNo">105</span> return value;<a name="line.105"></a>
<span class="sourceLineNo">106</span> }<a name="line.106"></a>
<span class="sourceLineNo">107</span>}<a name="line.107"></a>
</pre>
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