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diff --git a/appc-common/src/main/java/org/onap/appc/configuration/package.html b/appc-common/src/main/java/org/onap/appc/configuration/package.html deleted file mode 100644 index c6889da9a..000000000 --- a/appc-common/src/main/java/org/onap/appc/configuration/package.html +++ /dev/null @@ -1,174 +0,0 @@ -<!-- - ============LICENSE_START======================================================= - ONAP : APPC - ================================================================================ - Copyright (C) 2017 AT&T Intellectual Property. All rights reserved. - ================================================================================ - Copyright (C) 2017 Amdocs - ============================================================================= - Licensed under the Apache License, Version 2.0 (the "License"); - you may not use this file except in compliance with the License. - You may obtain a copy of the License at - - http://www.apache.org/licenses/LICENSE-2.0 - - Unless required by applicable law or agreed to in writing, software - distributed under the License is distributed on an "AS IS" BASIS, - WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. - See the License for the specific language governing permissions and - limitations under the License. - - ECOMP is a trademark and service mark of AT&T Intellectual Property. - ============LICENSE_END========================================================= - --> - -<html> -<head> -<title>Configuration</title> -</head> - -<body> - <p style="margin-left: 30.0px;"> - CDP Configuration support is provided by a common framework to load - and manage configuration properties from multiple sources. The basic - concept is to load a set of default properties from a known resource - file located on the class path, and then override these defaults - with optional settings that can be provided by a user through either - additional property files or via the command line (as VM arguments). - The loading of defaults from a resource property file (named <strong>com/att/cdp/default.properties</strong>) - ensures that values are defined for properties the application needs - in order to operate. - </p> - <p style="margin-left: 30.0px;"> - One of these default values that can be set is the name of the - property file that allows the user to supply settings, as well as - the path where the file can be found. In general, the default name - of the property file will be "<strong>cdp.properties</strong>", - and the path that will be searched is "<strong>${user.home};etc;../etc</strong>". - However, these values can be changed through the use of the - default.properties resource file. The property that specifies the - property file name is named <strong>com.att.cdp.bootstrap.file</strong>, - while the property named <strong>com.att.cdp.bootstrap.path</strong> - specifies the search path. - </p> - <p style="margin-left: 30.0px;"> - After the default.properties are loaded, but prior to searching for - the application configuration file, the configuration factory checks - for properties <strong>com.att.cdp.bootstrap.path</strong> and <strong>com.att.cdp.bootstrap.file - </strong>in the System properties object (meaning they were set by the - command line). If these values are defined in the system properties - object, they are used. If not, these values are obtained from the - default properties just loaded. This allows the specification of - either the file name or path, or both, to be overridden during start - up by using command-line arguments. - </p> - <p style="margin-left: 30.0px;">The search path is scanned for the - first occurrence of the specified property file. The first - occurrence is loaded and scanning is stopped at that point. The - configuration factory does not load all occurrences it finds, only - the first occurrence it finds.</p> - <p style="margin-left: 30.0px;">The configuration properties are - loaded and processed according to a defined precedence order, such - that properties defined with a higher precedence override the same - property at a lower precedence. The precedence order is defined as - follows:</p> - <h2>Precedence Order</h2> - <ol> - <li>Default properties are initially loaded into the - configuration. These default properties are the lowest level - precedence, and will be overridden by any properties specified at - higher levels. These are loaded from resources that are packaged - as part of the various application components. Each component - (Server, Coordinator, EPM, or CLI) may have different default - properties. The default properties are loaded from a resource - named <strong>com/att/cdp/default.properties</strong>. The default - properties can specify the name of the application property file - to be used to configure the application, as well as the path to - search. Additionally, these properties can be supplied via the - command line to override the default settings if needed.<br /> <br /> - </li> - <li>The configuration factory allows for the application to - supply an initial properties object to initialize the - configuration. This properties object could be loaded or created - in any way necessary for the application. This is totally up to - the application to define, if it is needed. If no - application-specific property object is supplied, this step is - skipped. If a property object is supplied, it is used to replace - or set any properties that may have been defined by the defaults.<br /> - <br /> - </li> - <li>The configuration factory will then search for a bootstrap - file on a bootstrap path. The actual bootstrap file name and path - can be specified as properties on the command line, or will - default to a file name of <strong>cdp.properties</strong> and a - path of <strong>${user.home};etc;../etc</strong>. If desired, the - user can specify the exact name of the property file to be loaded - as well as the path using <strong>-Dcom.att.cdp.bootstrap.file=<filename></strong> - and <strong>-Dcom.att.cdp.bootstrap.path=<path></strong>. - These properties are set to default values by the default - properties loaded in step #1 above. The first occurrence of a - property file is the file loaded and used. Any other occurrences - are not processed.<br /> <br /> - </li> - <li>The System properties are then merged into the - configuration. This allows the highest level of precedence, - command-line VM arguments (-D<strong>name=value</strong>) to be - merged into the configuration property object. These settings - override all lower level settings of the same name, as well as - merge all system properties into the configuration object. - </li> - </ol> - <h2>Variables</h2> - <p style="margin-left: 30.0px;"> - The configuration support allows for variables to be inserted into - any property that is defined. Variables are named using the format <strong>${name}</strong>, - where the "name" is the name of a property that is defined - in the configuration, or a system property (such as <strong>user.home</strong>). - Variables can nest, such that a variable can be replaced with - another variable, which is then reevaluated to obtain the value. - This allows for indirection as well as variable substitution, if - needed. - </p> - <h2>Using the Configuration Support</h2> - <p style="margin-left: 30.0px;"> - The configuration support was designed to be easy to use. The - configuration implementation is abstracted away from the application - so that it could be changed easily in the future if needed, or if we - needed to load different implementations for different reasons. This - means that the application always accesses the configuration through - an interface, named <strong>Configuration</strong>. The - implementation of that configuration interface is obtained by a - static method on the <strong>ConfigurationFactory</strong> class. - The configuration factory will both create the configuration if not - already created on the first access, as well as return the current - configuration if already created. Additionally, the - ConfigurationFactory provides mechanisms to recreate the - configuration after the application is initialized should the need - arise to update its configuration. - </p> - <p style="margin-left: 30.0px;">An example of the code needed to - obtain access to the configuration is:</p> - <pre style="margin-left: 30.0px;">Configuration config = ConfigurationFactory.getConfiguration();</pre> - <p style="margin-left: 30.0px;">Please refer to the javadoc or the - source code in cdp-common for other ways that the configuration and - configuration factory can be used.</p> - <h2>Reloading Properties</h2> - <p style="margin-left: 30.0px;">The configuration support allows - for properties to be re-loaded and re-evaluated after the - application is running. This is designed to allow a configuration to - be refreshed should the need arise. This could allow on-demand - refresh (via a command, for example), or automatically based on - sensing a change in the configuration file.</p> - <p style="margin-left: 30.0px;"> - When the <strong>ConfigurationFactory</strong> method <strong>getConfiguration(Propert</strong><strong>ies)</strong> - is called, the current configuration is cleared and rebuilt using - the process defined above. The supplied property object is used in - step #2 of the process. While the properties are being re-built, no - access to the properties are allowed. Any attempt to access - properties while the re-build operation is in effect will block the - caller until completed. This is accomplished using read and write - shared locks. - </p> -</body> -</html> ->>>>>>> app-controller/master:appc-common/src/main/java/org/onap/appc/configuration/package.html |