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    JAVA_9(9.0f, "9"),
087
088    /**
089     * The most recent java version. Mainly introduced to avoid to break when a new version of Java is used.
090     */
091    JAVA_RECENT(maxVersion(), Float.toString(maxVersion()));
092
093    /**
094     * The float value.
095     */
096    private final float value;
097    /**
098     * The standard name.
099     */
100    private final String name;
101
102    /**
103     * Constructor.
104     *
105     * @param value  the float value
106     * @param name  the standard name, not null
107     */
108    JavaVersion(final float value, final String name) {
109        this.value = value;
110        this.name = name;
111    }
112
113    //-----------------------------------------------------------------------
114    /**
115     * <p>Whether this version of Java is at least the version of Java passed in.</p>
116     *
117     * <p>For example:<br>
118     *  {@code myVersion.atLeast(JavaVersion.JAVA_1_4)}<p>
119     *
120     * @param requiredVersion  the version to check against, not null
121     * @return true if this version is equal to or greater than the specified version
122     */
123    public boolean atLeast(final JavaVersion requiredVersion) {
124        return this.value >= requiredVersion.value;
125    }
126
127    /**
128     * Transforms the given string with a Java version number to the
129     * corresponding constant of this enumeration class. This method is used
130     * internally.
131     *
132     * @param nom the Java version as string
133     * @return the corresponding enumeration constant or <b>null</b> if the
134     * version is unknown
135     */
136    // helper for static importing
137    static JavaVersion getJavaVersion(final String nom) {
138        return get(nom);
139    }
140
141    /**
142     * Transforms the given string with a Java version number to the
143     * corresponding constant of this enumeration class. This method is used
144     * internally.
145     *
146     * @param nom the Java version as string
147     * @return the corresponding enumeration constant or <b>null</b> if the
148     * version is unknown
149     */
150    static JavaVersion get(final String nom) {
151        if ("0.9".equals(nom)) {
152            return JAVA_0_9;
153        } else if ("1.1".equals(nom)) {
154            return JAVA_1_1;
155        } else if ("1.2".equals(nom)) {
156            return JAVA_1_2;
157        } else if ("1.3".equals(nom)) {
158            return JAVA_1_3;
159        } else if ("1.4".equals(nom)) {
160            return JAVA_1_4;
161        } else if ("1.5".equals(nom)) {
162            return JAVA_1_5;
163        } else if ("1.6".equals(nom)) {
164            return JAVA_1_6;
165        } else if ("1.7".equals(nom)) {
166            return JAVA_1_7;
167        } else if ("1.8".equals(nom)) {
168            return JAVA_1_8;
169        } else if ("9".equals(nom)) {
170            return JAVA_9;
171        }
172        if (nom == null) {
173            return null;
174        }
175        final float v = toFloatVersion(nom);
176        if ((v - 1.) < 1.) { // then we need to check decimals > .9
177            final int firstComma = Math.max(nom.indexOf('.'), nom.indexOf(','));
178            final int end = Math.max(nom.length(), nom.indexOf(',', firstComma));
179            if (Float.parseFloat(nom.substring(firstComma + 1, end)) > .9f) {
180                return JAVA_RECENT;
181            }
182        }
183        return null;
184    }
185
186    //-----------------------------------------------------------------------
187    /**
188     * <p>The string value is overridden to return the standard name.</p>
189     *
190     * <p>For example, <code>"1.5"</code>.</p>
191     *
192     * @return the name, not null
193     */
194    @Override
195    public String toString() {
196        return name;
197    }
198
199    /**
200     * Gets the Java Version from the system or 99.0 if the {@code java.specification.version} system property is not set.
201     *
202     * @return the value of {@code java.specification.version} system property or 99.0 if it is not set.
203     */
204    private static float maxVersion() {
205        final float v = toFloatVersion(System.getProperty("java.specification.version", "99.0"));
206        if (v > 0) {
207            return v;
208        }
209        return 99f;
210    }
211
212    /**
213     * Parses a float value from a String.
214     *
215     * @param value the String to parse.
216     * @return the float value represented by the string or -1 if the given String can not be parsed.
217     */
218    private static float toFloatVersion(final String value) {
219        final int defaultReturnValue = -1;
220        if (value.contains(".")) {
221            final String[] toParse = value.split("\\.");
222            if (toParse.length >= 2) {
223                return NumberUtils.toFloat(toParse[0] + '.' + toParse[1], defaultReturnValue);
224            }
225        } else {
226            return NumberUtils.toFloat(value, defaultReturnValue);
227        }
228        return defaultReturnValue;
229    }
230}