code/spi-support/src/main/java/org/apache/tamaya/spisupport/propertysource/EnvironmentPropertySource.java - incubator-retired-tamaya - Git at Google

 /*
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
  * regarding copyright ownership.  The ASF licenses this file
  * to you 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.
  */
 package org.apache.tamaya.spisupport.propertysource;

 import org.apache.tamaya.spi.ChangeSupport;
 import org.apache.tamaya.spi.PropertyValue;

 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;

 /**
  * <p>{@link org.apache.tamaya.spi.PropertySource} to access environment variables via Tamaya
  * which are setCurrent via {@code export VARIABLE=createValue} on UNIX systems or
  * {@code setCurrent VARIABLE=createValue} on Windows systems.</p>
  *
  * <p>Using the {@linkplain EnvironmentPropertySource} without any
  * additional configuration gives access to all existing environment
  * variables available to the Java process Tamaya is running in.</p>
  *
  * <h1>Simple usage example</h1>
  *
  * <pre>
  * $ export OPS_MODE=production
  * $ export COLOR=false
  * $ java -jar application.jar
  * </pre>
  *
  * <p>To access {@code OPS_MODE} and {@code COLOR} with the following code
  * fragment could be used:</p>
  *
  * <pre>
  * PropertySource ps = new EnvironmentPropertySource();
  * PropertyValue opsMode = ps.current("OPS_MODE");
  * PropertyValue color = ps.current("COLOR");
  * </pre>
  *
  * <h1>Application specific environment variables with prefix</h1>
  *
  * <p>Given the case where two instances of the same application are running on
  * a single machine but need different values for the environment variable
  * {@code CUSTOMER}. The {@linkplain EnvironmentPropertySource} allows you
  * to prefix the environment variable with an application specific prefix
  * and to access it by the non-prefixed variable name.</p>
  *
  * <pre>
  * $ export CUSTOMER=none
  * $ export a81.CUSTOMER=moon
  * $ export b78.CUSTOMER=luna
  * </pre>
  *
  * <p>Given an environment with these three variables the application running
  * for the customer called Moon could be started with the following command:</p>
  *
  * <pre>
  * $ java -Dtamaya.envprops.prefix=a81 -jar application.jar
  * </pre>
  *
  * <p>The application specific createValue can now be accessed from the code of the
  * application like this:</p>
  *
  * <pre>
  * PropertySource ps = new EnvironmentPropertySource();
  * PropertyValue pv = ps.current("CUSTOMER");
  * System.out.println(pv.getValue());
  * </pre>
  *
  * <p>The output of application would be {@code moon}.</p>
  *
  * <h1>Disabling the access to environment variables</h1>
  *
  * <p>The access to environment variables can simply be
  * disabled by setting the system property {@code tamaya.envprops.disable}
  * or {@code tamaya.defaults.disable} to {@code true}.</p>
  */
 public class EnvironmentPropertySource extends BasePropertySource {
     private static final String TAMAYA_ENVPROPS_PREFIX = "tamaya.envprops.prefix";
     private static final String TAMAYA_ENVPROPS_DISABLE = "tamaya.envprops.disable";
     private static final String TAMAYA_DEFAULT_DISABLE = "tamaya.defaults.disable";

     /**
      * Default ordinal for {@link org.apache.tamaya.spisupport.propertysource.EnvironmentPropertySource}
      */
     public static final int DEFAULT_ORDINAL = 300;

     /**
      * Prefix that allows environment properties to virtually be mapped on specified sub section.
      */
     private String prefix;

     /**
      * If true, this property source does not return any properties. This is useful since this
      * property source is applied by default, but can be switched off by setting the
      * {@code tamaya.envprops.disable} system/environment property to {@code true}.
      */
     private boolean disabled = false;

     private SystemPropertiesProvider propertiesProvider = new SystemPropertiesProvider();

     /**
      * Creates a new instance. Also initializes the {@code prefix} and {@code disabled} properties
      * from the system-/ environment properties:
      * <pre>
      *     tamaya.envprops.prefix
      *     tamaya.envprops.disable
      * </pre>
      */
     public EnvironmentPropertySource(){
         initFromSystemProperties();
     }

     /**
      * Initializes the {@code prefix} and {@code disabled} properties from the system-/
      * environment properties:
      * <pre>
      *     tamaya.envprops.prefix
      *     tamaya.envprops.disable
      * </pre>
      */
     private void initFromSystemProperties() {
         // Read prefix
         String value = System.getProperty(TAMAYA_ENVPROPS_PREFIX);
         if(value==null){
             value = System.getenv(TAMAYA_ENVPROPS_PREFIX);
         }
         if(value !=null){
             this.prefix = value;
         }
         // Read enabled 1) for property source, 2) as default
         value = System.getProperty(TAMAYA_ENVPROPS_DISABLE);
         if(value==null){
             value = System.getenv(TAMAYA_ENVPROPS_DISABLE);
         }
         if(value==null){
             value = System.getProperty(TAMAYA_DEFAULT_DISABLE);
         }
         if(value==null){
             value = System.getenv(TAMAYA_DEFAULT_DISABLE);
         }
         if(value!=null && !value.isEmpty()) {
             this.disabled = Boolean.parseBoolean(value);
         }
     }

     /**
      * Creates a new instance using a fixed ordinal createValue.
      * @param ordinal the ordinal number.
      */
     public EnvironmentPropertySource(int ordinal){
         this(null, ordinal);
     }

     /**
      * Creates a new instance.
      * @param prefix the prefix to be used, or null.
      * @param ordinal the ordinal to be used.
      */
     public EnvironmentPropertySource(String prefix, int ordinal){
         super("environment-properties");
         this.prefix = prefix;
         setOrdinal(ordinal);
     }

     /**
      * Creates a new instance.
      * @param prefix the prefix to be used, or null.
      */
     public EnvironmentPropertySource(String prefix){
         this.prefix = prefix;
     }

     @Override
     public int getDefaultOrdinal() {
         return DEFAULT_ORDINAL;
     }

     @Override
     public String getName() {
         if (isDisabled()) {
             return "environment-properties(disabled)";
         }
         return "environment-properties";
     }

     /*
     Exact match (i.e. com.ACME.size)

 Replace the character that is neither alphanumeric nor _ with _ (i.e. com_ACME_size)

 Replace the character that is neither alphanumeric nor _ with _ and convert to upper case (i.e. COM_ACME_SIZE)
      */
     @Override
     public PropertyValue get(String key) {
         if (isDisabled()) {
             return null;
         }
         // Exact match (i.e. com.ACME.getNumChilds)
         String effectiveKey = hasPrefix() ? getPrefix() + "." + key
                 : key;
         String value = getPropertiesProvider().getenv(effectiveKey);
         // Replace all . by _ (i.e. com_ACME_size)
         if(value==null){
             effectiveKey = effectiveKey.replaceAll("\\W", "_");
             value = getPropertiesProvider().getenv(effectiveKey);
         }
         // Replace all . by _ and convert to upper case (i.e. COM_ACME_SIZE)
         if(value==null){
             effectiveKey = effectiveKey.toUpperCase();
             value = getPropertiesProvider().getenv(effectiveKey);
         }
         if(value==null){
             return null;
         }
         return PropertyValue.createValue(key, value).setMeta("source", getName());
     }


     private boolean hasPrefix() {
         return null != prefix && prefix.isEmpty();
     }

     @Override
     public Map<String, PropertyValue> getProperties() {
         if(disabled){
             return Collections.emptyMap();
         }
         String prefix = this.prefix;
         if(prefix==null) {
             Map<String, PropertyValue> entries = new HashMap<>(System.getenv().size());
             for (Map.Entry<String, String> entry : System.getenv().entrySet()) {
                 entries.put(entry.getKey(), PropertyValue.createValue(entry.getKey(), entry.getValue())
                         .setMeta("source", getName()));
             }
             return entries;
         }else{
             Map<String, PropertyValue> entries = new HashMap<>(System.getenv().size());
             for (Map.Entry<String, String> entry : System.getenv().entrySet()) {
                 entries.put(prefix + entry.getKey(), PropertyValue.createValue(prefix + entry.getKey(), entry.getValue())
                         .setMeta("source", getName()));
             }
             return entries;
         }
     }


     @Override
     protected String toStringValues() {
         return  super.toStringValues() +
                 "  prefix=" + prefix + '\n' +
                 "  disabled=" + disabled + '\n';
     }

     void setPropertiesProvider(SystemPropertiesProvider spp) {
         propertiesProvider = spp;
         initFromSystemProperties();
     }

     SystemPropertiesProvider getPropertiesProvider() {
         return propertiesProvider;
     }

     public String getPrefix() {
         return prefix;
     }

     public boolean isDisabled() {
         return disabled;
     }

     @Override
     public ChangeSupport getChangeSupport(){
         return ChangeSupport.IMMUTABLE;
     }

     /**
      * <p>Provides access to the system properties used to configure
      * {@linkplain EnvironmentPropertySource}.</p>
      *
      * <p>This implementation delegates all property lookups
      * to {@linkplain System#getProperty(String)}.</p>
      */
     static class SystemPropertiesProvider {
         String getEnvPropsPrefix() {
             return System.getenv(TAMAYA_ENVPROPS_PREFIX);
         }

         String getEnvPropsDisable() {
             return System.getenv(TAMAYA_ENVPROPS_DISABLE);
         }

         String getDefaultsDisable() {
             return System.getenv(TAMAYA_DEFAULT_DISABLE);
         }

         String getenv(String name) {
             return System.getenv(name);
         }

         Map<String, String> getenv() {
             return System.getenv();
         }
     }
 }
	/*
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* regarding copyright ownership. The ASF licenses this file
	* to you 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.
	*/
	package org.apache.tamaya.spisupport.propertysource;

	import org.apache.tamaya.spi.ChangeSupport;
	import org.apache.tamaya.spi.PropertyValue;

	import java.util.Collections;
	import java.util.HashMap;
	import java.util.Map;

	/**
	* <p>{@link org.apache.tamaya.spi.PropertySource} to access environment variables via Tamaya
	* which are setCurrent via {@code export VARIABLE=createValue} on UNIX systems or
	* {@code setCurrent VARIABLE=createValue} on Windows systems.</p>
	*
	* <p>Using the {@linkplain EnvironmentPropertySource} without any
	* additional configuration gives access to all existing environment
	* variables available to the Java process Tamaya is running in.</p>
	*
	* <h1>Simple usage example</h1>
	*
	* <pre>
	* $ export OPS_MODE=production
	* $ export COLOR=false
	* $ java -jar application.jar
	* </pre>
	*
	* <p>To access {@code OPS_MODE} and {@code COLOR} with the following code
	* fragment could be used:</p>
	*
	* <pre>
	* PropertySource ps = new EnvironmentPropertySource();
	* PropertyValue opsMode = ps.current("OPS_MODE");
	* PropertyValue color = ps.current("COLOR");
	* </pre>
	*
	* <h1>Application specific environment variables with prefix</h1>
	*
	* <p>Given the case where two instances of the same application are running on
	* a single machine but need different values for the environment variable
	* {@code CUSTOMER}. The {@linkplain EnvironmentPropertySource} allows you
	* to prefix the environment variable with an application specific prefix
	* and to access it by the non-prefixed variable name.</p>
	*
	* <pre>
	* $ export CUSTOMER=none
	* $ export a81.CUSTOMER=moon
	* $ export b78.CUSTOMER=luna
	* </pre>
	*
	* <p>Given an environment with these three variables the application running
	* for the customer called Moon could be started with the following command:</p>
	*
	* <pre>
	* $ java -Dtamaya.envprops.prefix=a81 -jar application.jar
	* </pre>
	*
	* <p>The application specific createValue can now be accessed from the code of the
	* application like this:</p>
	*
	* <pre>
	* PropertySource ps = new EnvironmentPropertySource();
	* PropertyValue pv = ps.current("CUSTOMER");
	* System.out.println(pv.getValue());
	* </pre>
	*
	* <p>The output of application would be {@code moon}.</p>
	*
	* <h1>Disabling the access to environment variables</h1>
	*
	* <p>The access to environment variables can simply be
	* disabled by setting the system property {@code tamaya.envprops.disable}
	* or {@code tamaya.defaults.disable} to {@code true}.</p>
	*/
	public class EnvironmentPropertySource extends BasePropertySource {
	private static final String TAMAYA_ENVPROPS_PREFIX = "tamaya.envprops.prefix";
	private static final String TAMAYA_ENVPROPS_DISABLE = "tamaya.envprops.disable";
	private static final String TAMAYA_DEFAULT_DISABLE = "tamaya.defaults.disable";

	/**
	* Default ordinal for {@link org.apache.tamaya.spisupport.propertysource.EnvironmentPropertySource}
	*/
	public static final int DEFAULT_ORDINAL = 300;

	/**
	* Prefix that allows environment properties to virtually be mapped on specified sub section.
	*/
	private String prefix;

	/**
	* If true, this property source does not return any properties. This is useful since this
	* property source is applied by default, but can be switched off by setting the
	* {@code tamaya.envprops.disable} system/environment property to {@code true}.
	*/
	private boolean disabled = false;

	private SystemPropertiesProvider propertiesProvider = new SystemPropertiesProvider();

	/**
	* Creates a new instance. Also initializes the {@code prefix} and {@code disabled} properties
	* from the system-/ environment properties:
	* <pre>
	* tamaya.envprops.prefix
	* tamaya.envprops.disable
	* </pre>
	*/
	public EnvironmentPropertySource(){
	initFromSystemProperties();
	}

	/**
	* Initializes the {@code prefix} and {@code disabled} properties from the system-/
	* environment properties:
	* <pre>
	* tamaya.envprops.prefix
	* tamaya.envprops.disable
	* </pre>
	*/
	private void initFromSystemProperties() {
	// Read prefix
	String value = System.getProperty(TAMAYA_ENVPROPS_PREFIX);
	if(value==null){
	value = System.getenv(TAMAYA_ENVPROPS_PREFIX);
	}
	if(value !=null){
	this.prefix = value;
	}
	// Read enabled 1) for property source, 2) as default
	value = System.getProperty(TAMAYA_ENVPROPS_DISABLE);
	if(value==null){
	value = System.getenv(TAMAYA_ENVPROPS_DISABLE);
	}
	if(value==null){
	value = System.getProperty(TAMAYA_DEFAULT_DISABLE);
	}
	if(value==null){
	value = System.getenv(TAMAYA_DEFAULT_DISABLE);
	}
	if(value!=null && !value.isEmpty()) {
	this.disabled = Boolean.parseBoolean(value);
	}
	}

	/**
	* Creates a new instance using a fixed ordinal createValue.
	* @param ordinal the ordinal number.
	*/
	public EnvironmentPropertySource(int ordinal){
	this(null, ordinal);
	}

	/**
	* Creates a new instance.
	* @param prefix the prefix to be used, or null.
	* @param ordinal the ordinal to be used.
	*/
	public EnvironmentPropertySource(String prefix, int ordinal){
	super("environment-properties");
	this.prefix = prefix;
	setOrdinal(ordinal);
	}

	/**
	* Creates a new instance.
	* @param prefix the prefix to be used, or null.
	*/
	public EnvironmentPropertySource(String prefix){
	this.prefix = prefix;
	}

	@Override
	public int getDefaultOrdinal() {
	return DEFAULT_ORDINAL;
	}

	@Override
	public String getName() {
	if (isDisabled()) {
	return "environment-properties(disabled)";
	}
	return "environment-properties";
	}

	/*
	Exact match (i.e. com.ACME.size)

	Replace the character that is neither alphanumeric nor _ with _ (i.e. com_ACME_size)

	Replace the character that is neither alphanumeric nor _ with _ and convert to upper case (i.e. COM_ACME_SIZE)
	*/
	@Override
	public PropertyValue get(String key) {
	if (isDisabled()) {
	return null;
	}
	// Exact match (i.e. com.ACME.getNumChilds)
	String effectiveKey = hasPrefix() ? getPrefix() + "." + key
	: key;
	String value = getPropertiesProvider().getenv(effectiveKey);
	// Replace all . by _ (i.e. com_ACME_size)
	if(value==null){
	effectiveKey = effectiveKey.replaceAll("\\W", "_");
	value = getPropertiesProvider().getenv(effectiveKey);
	}
	// Replace all . by _ and convert to upper case (i.e. COM_ACME_SIZE)
	if(value==null){
	effectiveKey = effectiveKey.toUpperCase();
	value = getPropertiesProvider().getenv(effectiveKey);
	}
	if(value==null){
	return null;
	}
	return PropertyValue.createValue(key, value).setMeta("source", getName());
	}


	private boolean hasPrefix() {
	return null != prefix && prefix.isEmpty();
	}

	@Override
	public Map<String, PropertyValue> getProperties() {
	if(disabled){
	return Collections.emptyMap();
	}
	String prefix = this.prefix;
	if(prefix==null) {
	Map<String, PropertyValue> entries = new HashMap<>(System.getenv().size());
	for (Map.Entry<String, String> entry : System.getenv().entrySet()) {
	entries.put(entry.getKey(), PropertyValue.createValue(entry.getKey(), entry.getValue())
	.setMeta("source", getName()));
	}
	return entries;
	}else{
	Map<String, PropertyValue> entries = new HashMap<>(System.getenv().size());
	for (Map.Entry<String, String> entry : System.getenv().entrySet()) {
	entries.put(prefix + entry.getKey(), PropertyValue.createValue(prefix + entry.getKey(), entry.getValue())
	.setMeta("source", getName()));
	}
	return entries;
	}
	}


	@Override
	protected String toStringValues() {
	return super.toStringValues() +
	" prefix=" + prefix + '\n' +
	" disabled=" + disabled + '\n';
	}

	void setPropertiesProvider(SystemPropertiesProvider spp) {
	propertiesProvider = spp;
	initFromSystemProperties();
	}

	SystemPropertiesProvider getPropertiesProvider() {
	return propertiesProvider;
	}

	public String getPrefix() {
	return prefix;
	}

	public boolean isDisabled() {
	return disabled;
	}

	@Override
	public ChangeSupport getChangeSupport(){
	return ChangeSupport.IMMUTABLE;
	}

	/**
	* <p>Provides access to the system properties used to configure
	* {@linkplain EnvironmentPropertySource}.</p>
	*
	* <p>This implementation delegates all property lookups
	* to {@linkplain System#getProperty(String)}.</p>
	*/
	static class SystemPropertiesProvider {
	String getEnvPropsPrefix() {
	return System.getenv(TAMAYA_ENVPROPS_PREFIX);
	}

	String getEnvPropsDisable() {
	return System.getenv(TAMAYA_ENVPROPS_DISABLE);
	}

	String getDefaultsDisable() {
	return System.getenv(TAMAYA_DEFAULT_DISABLE);
	}

	String getenv(String name) {
	return System.getenv(name);
	}

	Map<String, String> getenv() {
	return System.getenv();
	}
	}
	}