{"id":52580,"date":"2016-02-18T07:00:08","date_gmt":"2016-02-18T05:00:08","guid":{"rendered":"http:\/\/www.javacodegeeks.com\/?p=52580"},"modified":"2016-02-17T13:59:25","modified_gmt":"2016-02-17T11:59:25","slug":"creating-custom-springboot-starter-twitter4j","status":"publish","type":"post","link":"https:\/\/www.javacodegeeks.com\/2016\/02\/creating-custom-springboot-starter-twitter4j.html","title":{"rendered":"Creating Custom SpringBoot Starter for Twitter4j"},"content":{"rendered":"

SpringBoot <\/b>provides lot of starter modules to get up and running quickly. SpringBoot\u2019s auto-configure mechanism takes care of configuring SpringBeans on our behalf based on various criteria.<\/p>\n

In addition to the springboot starters that comes out-of-the-box provided by Core Spring Team, we can also create our own starter modules.<\/p>\n

In this post we will look into how to create a custom SpringBoot starter. To demonstrate it we are going to create twitter4j-spring-boot-starter<\/b> which will auto-configure Twitter4J beans.<\/p>\n

To accomplish this, we are going to create:<\/p>\n

    \n
  1. \u00a0twitter4j-spring-boot-autoconfigure<\/b> module which contains Twitter4J AutoConfiguration bean definitions<\/li>\n
  2. twitter4j-spring-boot-starter<\/b> module which pulls in twitter4j-spring-boot-autoconfigure<\/b> and twitter4j-core<\/b> dependencies<\/li>\n
  3. Sample application which uses twitter4j-spring-boot-starter<\/b><\/li>\n<\/ol>\n

    Create Parent Module spring-boot-starter-twitter4j<\/h2>\n

    First we are going to create a parent pom type module to define dependency versions and sub-modules.<\/p>\n

    <?xml version=\"1.0\" encoding=\"UTF-8\"?>\r\n<project xmlns=\"http:\/\/maven.apache.org\/POM\/4.0.0\"\r\n    xmlns:xsi=\"http:\/\/www.w3.org\/2001\/XMLSchema-instance\"\r\n    xsi:schemaLocation=\"http:\/\/maven.apache.org\/POM\/4.0.0\r\n                        http:\/\/maven.apache.org\/maven-v4_0_0.xsd\">\r\n    <modelVersion>4.0.0<\/modelVersion>\r\n\r\n    <groupId>com.sivalabs<\/groupId>\r\n    <artifactId>spring-boot-starter-twitter4j<\/artifactId>\r\n    <packaging>pom<\/packaging>\r\n    <version>1.0-SNAPSHOT<\/version>\r\n    <name>spring-boot-starter-twitter4j<\/name>\r\n\r\n    <properties>\r\n        <project.build.sourceEncoding>UTF-8<\/project.build.sourceEncoding>\r\n        <twitter4j.version>4.0.3<\/twitter4j.version>\r\n        <spring-boot.version>1.3.2.RELEASE<\/spring-boot.version>\r\n    <\/properties>\r\n\r\n    <modules>\r\n        <module>twitter4j-spring-boot-autoconfigure<\/module>\r\n        <module>twitter4j-spring-boot-starter<\/module>\r\n        <module>twitter4j-spring-boot-sample<\/module>\r\n    <\/modules>\r\n\r\n    <dependencyManagement>\r\n        <dependencies>\r\n            <dependency>\r\n                <groupId>org.springframework.boot<\/groupId>\r\n                <artifactId>spring-boot-dependencies<\/artifactId>\r\n                <version>${spring-boot.version}<\/version>\r\n                <type>pom<\/type>\r\n                <scope>import<\/scope>\r\n            <\/dependency>\r\n\r\n            <dependency>\r\n                <groupId>org.twitter4j<\/groupId>\r\n                <artifactId>twitter4j-core<\/artifactId>\r\n                <version>${twitter4j.version}<\/version>\r\n            <\/dependency>\r\n        <\/dependencies>\r\n    <\/dependencyManagement>\r\n\r\n<\/project><\/pre>\n
    In this pom.xml<\/b> we are defining the SpringBoot and Twitter4j versions in section so that we don\u2019t need to specify versions all over the places.<\/p>\n
    Create twitter4j-spring-boot-autoconfigure module<\/p>\n
    Create a child module with name twitter4j-spring-boot-autoconfigure<\/b> in our parent maven module spring-boot-starter-twitter4j<\/b>.<\/p>\n
    Add the maven dependencies such as spring-boot, spring-boot-autoconfigure<\/b>, twitter4j-core<\/b> and junit <\/b>as follows:<\/p>\n
    <?xml version=\"1.0\" encoding=\"UTF-8\"?>\r\n<project xmlns=\"http:\/\/maven.apache.org\/POM\/4.0.0\" \r\n    xmlns:xsi=\"http:\/\/www.w3.org\/2001\/XMLSchema-instance\"\r\n    xsi:schemaLocation=\"http:\/\/maven.apache.org\/POM\/4.0.0\r\n               http:\/\/maven.apache.org\/maven-v4_0_0.xsd\">\r\n    <modelVersion>4.0.0<\/modelVersion>\r\n    <groupId>com.sivalabs<\/groupId>\r\n    <artifactId>twitter4j-spring-boot-autoconfigure<\/artifactId>\r\n    <packaging>jar<\/packaging>\r\n    <version>1.0-SNAPSHOT<\/version>\r\n\r\n    <parent>\r\n        <groupId>com.sivalabs<\/groupId>\r\n        <artifactId>spring-boot-starter-twitter4j<\/artifactId>\r\n        <version>1.0-SNAPSHOT<\/version>\r\n    <\/parent>\r\n\r\n    <properties>\r\n        <project.build.sourceEncoding>UTF-8<\/project.build.sourceEncoding>\r\n    <\/properties>\r\n\r\n    <dependencies>\r\n        <dependency>\r\n            <groupId>org.springframework.boot<\/groupId>\r\n            <artifactId>spring-boot<\/artifactId>\r\n        <\/dependency>\r\n        <dependency>\r\n            <groupId>org.springframework.boot<\/groupId>\r\n            <artifactId>spring-boot-autoconfigure<\/artifactId>\r\n        <\/dependency>\r\n        <dependency>\r\n            <groupId>org.springframework.boot<\/groupId>\r\n            <artifactId>spring-boot-configuration-processor<\/artifactId>\r\n            <optional>true<\/optional>\r\n        <\/dependency>\r\n        <dependency>\r\n            <groupId>junit<\/groupId>\r\n            <artifactId>junit<\/artifactId>\r\n            <scope>test<\/scope>\r\n        <\/dependency>\r\n        <dependency>\r\n            <groupId>org.twitter4j<\/groupId>\r\n            <artifactId>twitter4j-core<\/artifactId>\r\n            <optional>true<\/optional>\r\n        <\/dependency>\r\n    <\/dependencies>\r\n<\/project><\/pre>\n
    Note that we have specified twitter4j-core<\/b> as optional <\/b>dependency because twitter4j-core<\/b> should be added to the project only when twitter4j-spring-boot-starter<\/b> is added to the project.<\/p>\n
    Create Twitter4jProperties to hold the Twitter4J config parameters<\/h2>\n
    Create Twitter4jProperties.java <\/b>to hold the Twitter4J OAuth config parameters.
     
    <\/div> <\/div><\/p>\n
    package com.sivalabs.spring.boot.autoconfigure;\r\n\r\nimport org.springframework.boot.context.properties.ConfigurationProperties;\r\nimport org.springframework.boot.context.properties.NestedConfigurationProperty;\r\n\r\n@ConfigurationProperties(prefix= Twitter4jProperties.TWITTER4J_PREFIX)\r\npublic class Twitter4jProperties {\r\n\r\n    public static final String TWITTER4J_PREFIX = \"twitter4j\";\r\n\r\n    private Boolean debug = false;\r\n\r\n    @NestedConfigurationProperty\r\n    private OAuth oauth = new OAuth();\r\n\r\n    public Boolean getDebug() {\r\n        return debug;\r\n    }\r\n\r\n    public void setDebug(Boolean debug) {\r\n        this.debug = debug;\r\n    }\r\n\r\n    public OAuth getOauth() {\r\n        return oauth;\r\n    }\r\n\r\n    public void setOauth(OAuth oauth) {\r\n        this.oauth = oauth;\r\n    }\r\n\r\n    public static class OAuth {\r\n\r\n        private String consumerKey;\r\n        private String consumerSecret;\r\n        private String accessToken;\r\n        private String accessTokenSecret;\r\n\r\n        public String getConsumerKey() {\r\n            return consumerKey;\r\n        }\r\n        public void setConsumerKey(String consumerKey) {\r\n            this.consumerKey = consumerKey;\r\n        }\r\n        public String getConsumerSecret() {\r\n            return consumerSecret;\r\n        }\r\n        public void setConsumerSecret(String consumerSecret) {\r\n            this.consumerSecret = consumerSecret;\r\n        }\r\n        public String getAccessToken() {\r\n            return accessToken;\r\n        }\r\n        public void setAccessToken(String accessToken) {\r\n            this.accessToken = accessToken;\r\n        }\r\n        public String getAccessTokenSecret() {\r\n            return accessTokenSecret;\r\n        }\r\n        public void setAccessTokenSecret(String accessTokenSecret) {\r\n            this.accessTokenSecret = accessTokenSecret;\r\n        }\r\n    }\r\n}<\/pre>\n
    With this configuration object we can configure the twitter4j properties in application.properties<\/b> as follows:<\/p>\n
    twitter4j.debug=true\r\ntwitter4j.oauth.consumer-key=your-consumer-key-here\r\ntwitter4j.oauth.consumer-secret=your-consumer-secret-here\r\ntwitter4j.oauth.access-token=your-access-token-here\r\ntwitter4j.oauth.access-token-secret=your-access-token-secret-here<\/pre>\n
    Create Twitter4jAutoConfiguration to auto-configure Twitter4J<\/h2>\n
    Here comes the key part of our starter.<\/p>\n
    Twitter4jAutoConfiguration <\/b>configuration class contains the bean definitions that will be automatically configured based on some criteria.<\/p>\n
    What is that criteria?<\/p>\n