1 /* Copyright (C) 2003 Vladimir Roubtsov. All rights reserved. 2 * 3 * This program and the accompanying materials are made available under 4 * the terms of the Common Public License v1.0 which accompanies this distribution, 5 * and is available at http://www.eclipse.org/legal/cpl-v10.html 6 * 7 * $Id: IJREVersion.java,v 1.1.1.1.2.1 2004/07/10 03:34:52 vlad_r Exp $ 8 */ 9 package com.vladium.util; 10 11 // ---------------------------------------------------------------------------- 12 /** 13 * A constant collection to detect the current JRE version. Note that this code 14 * is more sophisticated then a mere check of "java.version" or "java.class.version" 15 * and similar system properties because some JVMs allow overriding those 16 * by the user (e.g., from the command line). This implementation relies on 17 * the core classes only and tries to minimize the number of security-sensitive 18 * methods it uses.<P> 19 * 20 * This interface is supported in Java 1.1+ and should be compiled with class 21 * version stamp 45.3 (-target 1.1). 22 * 23 * @author Vlad Roubtsov, (C) 2003 24 */ 25 public 26 interface IJREVersion 27 { 28 // public: ................................................................ 29 30 /** 'true' iff the current runtime version is 1.2 or later */ 31 boolean JRE_1_2_PLUS = _JREVersion._JRE_1_2_PLUS; // static final but not inlinable 32 /** 'true' iff the current runtime version is 1.3 or later */ 33 boolean JRE_1_3_PLUS = _JREVersion._JRE_1_3_PLUS; // static final but not inlinable 34 /** 'true' iff the current runtime version is 1.4 or later */ 35 boolean JRE_1_4_PLUS = _JREVersion._JRE_1_4_PLUS; // static final but not inlinable 36 37 // supporting Java 1.5 is trivial... 38 39 boolean JRE_SUN_SIGNAL_COMPATIBLE = _JREVersion._JRE_SUN_SIGNAL_COMPATIBLE; 40 41 /* 42 * Use a dummy nested class to fake a static initializer for the outer 43 * interface (I want IJREVersion as an interface and not a class so that 44 * all JRE_XXX constants could be imported via "implements"). 45 */ 46 abstract class _JREVersion 47 { 48 static final boolean _JRE_1_2_PLUS; // set in <clinit> 49 static final boolean _JRE_1_3_PLUS; // set in <clinit> 50 static final boolean _JRE_1_4_PLUS; // set in <clinit> 51 52 static final boolean _JRE_SUN_SIGNAL_COMPATIBLE; // set in <clinit> 53 _JREVersion()54 private _JREVersion () {} // prevent subclassing 55 56 static 57 { 58 _JRE_1_2_PLUS = ((SecurityManager.class.getModifiers () & 0x0400) == 0); 59 60 boolean temp = false; 61 if (_JRE_1_2_PLUS) 62 { 63 try 64 { 65 StrictMath.abs (1.0); 66 temp = true; 67 } 68 catch (Error ignore) {} 69 } 70 _JRE_1_3_PLUS = temp; 71 72 if (temp) 73 { 74 temp = false; 75 try 76 { 77 " ".subSequence (0, 0); 78 temp = true; 79 } 80 catch (NoSuchMethodError ignore) {} 81 } 82 _JRE_1_4_PLUS = temp; 83 84 temp = false; 85 86 _JRE_SUN_SIGNAL_COMPATIBLE = temp; 87 } 88 89 } // end of nested class 90 91 } // end of interface 92 // ---------------------------------------------------------------------------- 93 94