001/*
002 * Copyright 2012-2015 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.boot.autoconfigure.condition;
018
019import java.lang.annotation.Documented;
020import java.lang.annotation.ElementType;
021import java.lang.annotation.Retention;
022import java.lang.annotation.RetentionPolicy;
023import java.lang.annotation.Target;
024
025import org.springframework.context.annotation.Conditional;
026import org.springframework.util.Assert;
027import org.springframework.util.ClassUtils;
028
029/**
030 * {@link Conditional} that matches based on the JVM version the application is running
031 * on.
032 *
033 * @author Oliver Gierke
034 * @author Phillip Webb
035 * @author Andy Wilkinson
036 * @since 1.1.0
037 */
038@Target({ ElementType.TYPE, ElementType.METHOD })
039@Retention(RetentionPolicy.RUNTIME)
040@Documented
041@Conditional(OnJavaCondition.class)
042public @interface ConditionalOnJava {
043
044        /**
045         * Configures whether the value configured in {@link #value()} shall be considered the
046         * upper exclusive or lower inclusive boundary. Defaults to
047         * {@link Range#EQUAL_OR_NEWER}.
048         * @return the range
049         */
050        Range range() default Range.EQUAL_OR_NEWER;
051
052        /**
053         * The {@link JavaVersion} to check for. Use {@link #range()} to specify whether the
054         * configured value is an upper-exclusive or lower-inclusive boundary.
055         * @return the java version
056         */
057        JavaVersion value();
058
059        /**
060         * Range options.
061         */
062        enum Range {
063
064                /**
065                 * Equal to, or newer than the specified {@link JavaVersion}.
066                 */
067                EQUAL_OR_NEWER,
068
069                /**
070                 * Older than the specified {@link JavaVersion}.
071                 */
072                OLDER_THAN
073
074        }
075
076        /**
077         * Java versions.
078         */
079        enum JavaVersion {
080
081                /**
082                 * Java 1.9.
083                 */
084                NINE(9, "1.9", "java.security.cert.URICertStoreParameters"),
085
086                /**
087                 * Java 1.8.
088                 */
089                EIGHT(8, "1.8", "java.util.function.Function"),
090
091                /**
092                 * Java 1.7.
093                 */
094                SEVEN(7, "1.7", "java.nio.file.Files"),
095
096                /**
097                 * Java 1.6.
098                 */
099                SIX(6, "1.6", "java.util.ServiceLoader");
100
101                private final int value;
102
103                private final String name;
104
105                private final boolean available;
106
107                JavaVersion(int value, String name, String className) {
108                        this.value = value;
109                        this.name = name;
110                        this.available = ClassUtils.isPresent(className, getClass().getClassLoader());
111                }
112
113                /**
114                 * Determines if this version is within the specified range of versions.
115                 * @param range the range
116                 * @param version the bounds of the range
117                 * @return if this version is within the specified range
118                 */
119                public boolean isWithin(Range range, JavaVersion version) {
120                        Assert.notNull(range, "Range must not be null");
121                        Assert.notNull(version, "Version must not be null");
122                        switch (range) {
123                        case EQUAL_OR_NEWER:
124                                return this.value >= version.value;
125                        case OLDER_THAN:
126                                return this.value < version.value;
127                        }
128                        throw new IllegalStateException("Unknown range " + range);
129                }
130
131                @Override
132                public String toString() {
133                        return this.name;
134                }
135
136                /**
137                 * Returns the {@link JavaVersion} of the current runtime.
138                 * @return the {@link JavaVersion}
139                 */
140                public static JavaVersion getJavaVersion() {
141                        for (JavaVersion candidate : JavaVersion.values()) {
142                                if (candidate.available) {
143                                        return candidate;
144                                }
145                        }
146                        return SIX;
147                }
148
149        }
150
151}