We have to deal with properties in almost every projects that we write. Properties<\/a> class, which we use in these cases, is just mapping key to value. Sometimes it is fine, but in many cases properties look like tree. Example of properties file is shown below:<\/p>\n Here we have simple properties like systemName and also complex endpoints definition (all properties which start with endpoint<\/i>) and single endpoints definition (each endpoint properties starts with endpoint.<ENDPOINT_NAME><\/i>).<\/p>\n How simple could it be to treat this properties like a tree and simply extract subset of them?<\/p>\n The answer is using ConfigSlurper<\/a>.<\/p>\n To use ConfigSlurper just parse properties object:<\/p>\n <\/p>\n Parse method returns ConfigObject<\/a> which is just very clever map Map<\/a>.<\/p>\n Now you could get property using dot notation:<\/p>\n But there is a deal. If you use ConfigObject then you cannot use it like normal Properties and get property with dots.<\/p>\n <\/p>\n ConfigObject allows you to extract subtree as Properties:<\/p>\n and even:<\/p>\n If you want to know how many endpoint you have and how they are named you could use keySet method:<\/p>\n <\/p>\n ConfigSlurper do not return null even if property is not found, so you could get nested property without fear:<\/p>\n You have only to be careful, when have property named like begining of another property:<\/p>\n fromProperties.endpoint.first.port<\/i> returns String and do not have test property.<\/p>\n You could also print properties from ConfigObject:<\/p>\n The output looks like this:<\/p>\n Hmm… It looks like DSL. Why do not keep your configuration in this manner?<\/p>\n Your configuration could be a groovy script.<\/p>\n You could pass such configuration as resource stream or file content:<\/p>\n What interesting all your properties do not have to be strings. It could be any object: String, long, int, etc.<\/p>\n You could deal with properties like simple Map, but why if you could instead use it like tree of properties?<\/p>\nsystemName=test\r\nendpoint.first.protocol=http\r\nendpoint.first.address=localhost\r\nendpoint.first.port=8080\r\nendpoint.first.path=test\r\nendpoint.second.protocol=ftp\r\nendpoint.second.address=localhost\r\nendpoint.second.port=21\r\nendpoint.second.user=admin\r\nendpoint.second.password=pass\r\n<\/pre>\n
ConfigSlurper from properties<\/h1>\n
def 'should import configuration from properties'() {\r\n given: Properties p = new Properties()\r\n p.load(ConfigSlurperTest.getResourceAsStream('\/configuration.properties'))\r\n expect: new ConfigSlurper().parse(p).systemName as String == 'test'\r\n}<\/pre>\ndef 'should get nested property'() {\r\n expect:\r\n fromProperties.endpoint.first.protocol == 'http'\r\n}<\/pre>\ndef 'should not used nested property as one string'() {\r\n expect:\r\n fromProperties.'endpoint.first.protocol' != 'http'\r\n}<\/pre>\ndef 'should get first endpoint info from properties'() {\r\n expect:\r\n fromProperties.endpoint.first.toProperties() == [\r\n protocol: 'http',\r\n address : 'localhost',\r\n port : '8080',\r\n path : 'test'\r\n ]\r\n}<\/pre>\ndef 'should allow for nested property as one string when toProperties called'() {\r\n expect: fromProperties.endpoint.toProperties()['first.protocol'] == 'http'\r\n}<\/pre>\ndef 'should get list of endpoints'() {\r\n expect: fromProperties.endpoint.keySet() == ['first', 'second'] as Set\r\n}<\/pre>\ndef 'should not throw exception when missing property'() {\r\n expect: fromProperties.endpoint.third.port.toProperties() == [: ] as Properties\r\n}<\/pre>\ndef 'should throw exception when asking for too nested property'() {\r\n when:\r\n fromProperties.endpoint.first.port.test\r\n then:\r\n thrown(MissingPropertyException)\r\n}<\/pre>\nprintln fromProperties.prettyPrint()<\/pre>\n
endpoint {\r\n first {\r\n path='test'\r\n port='8080'\r\n protocol='http'\r\n address='localhost'\r\n }\r\n second {\r\n password='pass'\r\n protocol='ftp'\r\n address='localhost'\r\n port='21'\r\n user='admin'\r\n }\r\n}\r\nsystemName='test'<\/pre>\nConfigSlurper from script<\/h1>\n
systemName = 'test'\r\nendpoint {\r\n first {\r\n path = 'test'\r\n port = 8080\r\n protocol = 'http'\r\n address = 'localhost'\r\n }\r\n second {\r\n password = 'pass'\r\n protocol = 'ftp'\r\n address = 'localhost'\r\n port = 21\r\n user = 'admin'\r\n }\r\n}\r\ntest.key = ['really': 'nested?'] as Properties<\/pre>\ndef 'should get config from script as url'() {\r\n given: ConfigObject config = new ConfigSlurper().parse(ConfigSlurperTest.getResource('\/configuration.groovy'))\r\n expect: config.systemName == 'test'\r\n}<\/pre>\ndef 'should get nested properties from script as int'() {\r\n expect: fromScript.endpoint.first.port == 8080\r\n}<\/pre>\nConclusion<\/h1>\n