001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.lang3;
018
019import org.apache.commons.lang3.math.NumberUtils;
020
021/**
022 * <p>An enum representing all the versions of the Java specification.
023 * This is intended to mirror available values from the
024 * <em>java.specification.version</em> System property. </p>
025 *
026 * @since 3.0
027 */
028public enum JavaVersion {
029
030    /**
031     * The Java version reported by Android. This is not an official Java version number.
032     */
033    JAVA_0_9(1.5f, "0.9"),
034
035    /**
036     * Java 1.1.
037     */
038    JAVA_1_1(1.1f, "1.1"),
039
040    /**
041     * Java 1.2.
042     */
043    JAVA_1_2(1.2f, "1.2"),
044
045    /**
046     * Java 1.3.
047     */
048    JAVA_1_3(1.3f, "1.3"),
049
050    /**
051     * Java 1.4.
052     */
053    JAVA_1_4(1.4f, "1.4"),
054
055    /**
056     * Java 1.5.
057     */
058    JAVA_1_5(1.5f, "1.5"),
059
060    /**
061     * Java 1.6.
062     */
063    JAVA_1_6(1.6f, "1.6"),
064
065    /**
066     * Java 1.7.
067     */
068    JAVA_1_7(1.7f, "1.7"),
069
070    /**
071     * Java 1.8.
072     */
073    JAVA_1_8(1.8f, "1.8"),
074
075    /**
076     * Java 1.9.
077     *
078     * @deprecated As of release 3.5, replaced by {@link #JAVA_9}
079     */
080    @Deprecated
081    JAVA_1_9(9.0f, "9"),
082
083    /**
084     * Java 9
085     *
086     * @since 3.5
087     */
088    JAVA_9(9.0f, "9"),
089
090    /**
091     * Java 10
092     *
093     * @since 3.7
094     */
095    JAVA_10(10.0f, "10"),
096
097    /**
098     * The most recent java version. Mainly introduced to avoid to break when a new version of Java is used.
099     */
100    JAVA_RECENT(maxVersion(), Float.toString(maxVersion()));
101
102    /**
103     * The float value.
104     */
105    private final float value;
106
107    /**
108     * The standard name.
109     */
110    private final String name;
111
112    /**
113     * Constructor.
114     *
115     * @param value  the float value
116     * @param name  the standard name, not null
117     */
118    JavaVersion(final float value, final String name) {
119        this.value = value;
120        this.name = name;
121    }
122
123    //-----------------------------------------------------------------------
124    /**
125     * <p>Whether this version of Java is at least the version of Java passed in.</p>
126     *
127     * <p>For example:<br>
128     *  {@code myVersion.atLeast(JavaVersion.JAVA_1_4)}<p>
129     *
130     * @param requiredVersion  the version to check against, not null
131     * @return true if this version is equal to or greater than the specified version
132     */
133    public boolean atLeast(final JavaVersion requiredVersion) {
134        return this.value >= requiredVersion.value;
135    }
136
137    /**
138     * Transforms the given string with a Java version number to the
139     * corresponding constant of this enumeration class. This method is used
140     * internally.
141     *
142     * @param nom the Java version as string
143     * @return the corresponding enumeration constant or <b>null</b> if the
144     * version is unknown
145     */
146    // helper for static importing
147    static JavaVersion getJavaVersion(final String nom) {
148        return get(nom);
149    }
150
151    /**
152     * Transforms the given string with a Java version number to the
153     * corresponding constant of this enumeration class. This method is used
154     * internally.
155     *
156     * @param nom the Java version as string
157     * @return the corresponding enumeration constant or <b>null</b> if the
158     * version is unknown
159     */
160    static JavaVersion get(final String nom) {
161        if ("0.9".equals(nom)) {
162            return JAVA_0_9;
163        } else if ("1.1".equals(nom)) {
164            return JAVA_1_1;
165        } else if ("1.2".equals(nom)) {
166            return JAVA_1_2;
167        } else if ("1.3".equals(nom)) {
168            return JAVA_1_3;
169        } else if ("1.4".equals(nom)) {
170            return JAVA_1_4;
171        } else if ("1.5".equals(nom)) {
172            return JAVA_1_5;
173        } else if ("1.6".equals(nom)) {
174            return JAVA_1_6;
175        } else if ("1.7".equals(nom)) {
176            return JAVA_1_7;
177        } else if ("1.8".equals(nom)) {
178            return JAVA_1_8;
179        } else if ("9".equals(nom)) {
180            return JAVA_9;
181        } else if ("10".equals(nom)) {
182            return JAVA_10;
183        }
184        if (nom == null) {
185            return null;
186        }
187        final float v = toFloatVersion(nom);
188        if ((v - 1.) < 1.) { // then we need to check decimals > .9
189            final int firstComma = Math.max(nom.indexOf('.'), nom.indexOf(','));
190            final int end = Math.max(nom.length(), nom.indexOf(',', firstComma));
191            if (Float.parseFloat(nom.substring(firstComma + 1, end)) > .9f) {
192                return JAVA_RECENT;
193            }
194        }
195        return null;
196    }
197
198    //-----------------------------------------------------------------------
199    /**
200     * <p>The string value is overridden to return the standard name.</p>
201     *
202     * <p>For example, <code>"1.5"</code>.</p>
203     *
204     * @return the name, not null
205     */
206    @Override
207    public String toString() {
208        return name;
209    }
210
211    /**
212     * Gets the Java Version from the system or 99.0 if the {@code java.specification.version} system property is not set.
213     *
214     * @return the value of {@code java.specification.version} system property or 99.0 if it is not set.
215     */
216    private static float maxVersion() {
217        final float v = toFloatVersion(System.getProperty("java.specification.version", "99.0"));
218        if (v > 0) {
219            return v;
220        }
221        return 99f;
222    }
223
224    /**
225     * Parses a float value from a String.
226     *
227     * @param value the String to parse.
228     * @return the float value represented by the string or -1 if the given String can not be parsed.
229     */
230    private static float toFloatVersion(final String value) {
231        final int defaultReturnValue = -1;
232        if (value.contains(".")) {
233            final String[] toParse = value.split("\\.");
234            if (toParse.length >= 2) {
235                return NumberUtils.toFloat(toParse[0] + '.' + toParse[1], defaultReturnValue);
236            }
237        } else {
238            return NumberUtils.toFloat(value, defaultReturnValue);
239        }
240        return defaultReturnValue;
241    }
242}