Spring Framework

org.springframework.beans.factory.config
Class PropertyPlaceholderConfigurer

java.lang.Object
  extended by org.springframework.core.io.support.PropertiesLoaderSupport
      extended by org.springframework.beans.factory.config.PropertyResourceConfigurer
          extended by org.springframework.beans.factory.config.PlaceholderConfigurerSupport
              extended by org.springframework.beans.factory.config.PropertyPlaceholderConfigurer
All Implemented Interfaces:
Aware, BeanFactoryAware, BeanNameAware, BeanFactoryPostProcessor, Ordered, PriorityOrdered
Direct Known Subclasses:
PreferencesPlaceholderConfigurer, ServletContextPropertyPlaceholderConfigurer

public class PropertyPlaceholderConfigurer
extends PlaceholderConfigurerSupport

PlaceholderConfigurerSupport subclass that resolves ${...} placeholders against local properties and/or system properties and environment variables.

As of Spring 3.1, PropertySourcesPlaceholderConfigurer should be used preferentially over this implementation; it is more flexible through taking advantage of the Environment and PropertySource mechanisms also made available in Spring 3.1.

PropertyPlaceholderConfigurer is still appropriate for use when:

Prior to Spring 3.1, the <context:property-placeholder/> namespace element registered an instance of PropertyPlaceholderConfigurer. It will still do so if using the spring-context-3.0.xsd definition of the namespace. That is, you can preserve registration of PropertyPlaceholderConfigurer through the namespace, even if using Spring 3.1; simply do not update your xsi:schemaLocation and continue using the 3.0 XSD.

Since:
02.10.2003
Author:
Juergen Hoeller, Chris Beams
See Also:
setSystemPropertiesModeName(java.lang.String), PlaceholderConfigurerSupport, PropertyOverrideConfigurer, PropertySourcesPlaceholderConfigurer

Field Summary
static int SYSTEM_PROPERTIES_MODE_FALLBACK
          Check system properties if not resolvable in the specified properties.
static int SYSTEM_PROPERTIES_MODE_NEVER
          Never check system properties.
static int SYSTEM_PROPERTIES_MODE_OVERRIDE
          Check system properties first, before trying the specified properties.
 
Fields inherited from class org.springframework.beans.factory.config.PlaceholderConfigurerSupport
DEFAULT_PLACEHOLDER_PREFIX, DEFAULT_PLACEHOLDER_SUFFIX, DEFAULT_VALUE_SEPARATOR, ignoreUnresolvablePlaceholders, nullValue, placeholderPrefix, placeholderSuffix, valueSeparator
 
Fields inherited from class org.springframework.core.io.support.PropertiesLoaderSupport
localOverride, localProperties, logger, XML_FILE_EXTENSION
 
Fields inherited from interface org.springframework.core.Ordered
HIGHEST_PRECEDENCE, LOWEST_PRECEDENCE
 
Constructor Summary
PropertyPlaceholderConfigurer()
           
 
Method Summary
protected  java.lang.String parseStringValue(java.lang.String strVal, java.util.Properties props, java.util.Set<?> visitedPlaceholders)
          Deprecated. as of Spring 3.0, in favor of using resolvePlaceholder(java.lang.String, java.util.Properties, int) with PropertyPlaceholderHelper. Only retained for compatibility with Spring 2.5 extensions.
protected  void processProperties(ConfigurableListableBeanFactory beanFactoryToProcess, java.util.Properties props)
          Visit each bean definition in the given bean factory and attempt to replace ${...} property placeholders with values from the given properties.
protected  java.lang.String resolvePlaceholder(java.lang.String placeholder, java.util.Properties props)
          Resolve the given placeholder using the given properties.
protected  java.lang.String resolvePlaceholder(java.lang.String placeholder, java.util.Properties props, int systemPropertiesMode)
          Resolve the given placeholder using the given properties, performing a system properties check according to the given mode.
protected  java.lang.String resolveSystemProperty(java.lang.String key)
          Resolve the given key as JVM system property, and optionally also as system environment variable if no matching system property has been found.
 void setSearchSystemEnvironment(boolean searchSystemEnvironment)
          Set whether to search for a matching system environment variable if no matching system property has been found.
 void setSystemPropertiesMode(int systemPropertiesMode)
          Set how to check system properties: as fallback, as override, or never.
 void setSystemPropertiesModeName(java.lang.String constantName)
          Set the system property mode by the name of the corresponding constant, e.g.
 
Methods inherited from class org.springframework.beans.factory.config.PlaceholderConfigurerSupport
doProcessProperties, setBeanFactory, setBeanName, setIgnoreUnresolvablePlaceholders, setNullValue, setPlaceholderPrefix, setPlaceholderSuffix, setValueSeparator
 
Methods inherited from class org.springframework.beans.factory.config.PropertyResourceConfigurer
convertProperties, convertProperty, convertPropertyValue, getOrder, postProcessBeanFactory, setOrder
 
Methods inherited from class org.springframework.core.io.support.PropertiesLoaderSupport
loadProperties, mergeProperties, setFileEncoding, setIgnoreResourceNotFound, setLocalOverride, setLocation, setLocations, setProperties, setPropertiesArray, setPropertiesPersister
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

SYSTEM_PROPERTIES_MODE_NEVER

public static final int SYSTEM_PROPERTIES_MODE_NEVER
Never check system properties.

See Also:
Constant Field Values

SYSTEM_PROPERTIES_MODE_FALLBACK

public static final int SYSTEM_PROPERTIES_MODE_FALLBACK
Check system properties if not resolvable in the specified properties. This is the default.

See Also:
Constant Field Values

SYSTEM_PROPERTIES_MODE_OVERRIDE

public static final int SYSTEM_PROPERTIES_MODE_OVERRIDE
Check system properties first, before trying the specified properties. This allows system properties to override any other property source.

See Also:
Constant Field Values
Constructor Detail

PropertyPlaceholderConfigurer

public PropertyPlaceholderConfigurer()
Method Detail

setSystemPropertiesModeName

public void setSystemPropertiesModeName(java.lang.String constantName)
                                 throws java.lang.IllegalArgumentException
Set the system property mode by the name of the corresponding constant, e.g. "SYSTEM_PROPERTIES_MODE_OVERRIDE".

Parameters:
constantName - name of the constant
Throws:
java.lang.IllegalArgumentException - if an invalid constant was specified
See Also:
setSystemPropertiesMode(int)

setSystemPropertiesMode

public void setSystemPropertiesMode(int systemPropertiesMode)
Set how to check system properties: as fallback, as override, or never. For example, will resolve ${user.dir} to the "user.dir" system property.

The default is "fallback": If not being able to resolve a placeholder with the specified properties, a system property will be tried. "override" will check for a system property first, before trying the specified properties. "never" will not check system properties at all.

See Also:
SYSTEM_PROPERTIES_MODE_NEVER, SYSTEM_PROPERTIES_MODE_FALLBACK, SYSTEM_PROPERTIES_MODE_OVERRIDE, setSystemPropertiesModeName(java.lang.String)

setSearchSystemEnvironment

public void setSearchSystemEnvironment(boolean searchSystemEnvironment)
Set whether to search for a matching system environment variable if no matching system property has been found. Only applied when "systemPropertyMode" is active (i.e. "fallback" or "override"), right after checking JVM system properties.

Default is "true". Switch this setting off to never resolve placeholders against system environment variables. Note that it is generally recommended to pass external values in as JVM system properties: This can easily be achieved in a startup script, even for existing environment variables.

NOTE: Access to environment variables does not work on the Sun VM 1.4, where the corresponding System.getenv(java.lang.String) support was disabled - before it eventually got re-enabled for the Sun VM 1.5. Please upgrade to 1.5 (or higher) if you intend to rely on the environment variable support.

See Also:
setSystemPropertiesMode(int), System.getProperty(String), System.getenv(String)

resolvePlaceholder

protected java.lang.String resolvePlaceholder(java.lang.String placeholder,
                                              java.util.Properties props,
                                              int systemPropertiesMode)
Resolve the given placeholder using the given properties, performing a system properties check according to the given mode.

The default implementation delegates to resolvePlaceholder (placeholder, props) before/after the system properties check.

Subclasses can override this for custom resolution strategies, including customized points for the system properties check.

Parameters:
placeholder - the placeholder to resolve
props - the merged properties of this configurer
systemPropertiesMode - the system properties mode, according to the constants in this class
Returns:
the resolved value, of null if none
See Also:
setSystemPropertiesMode(int), System.getProperty(java.lang.String), resolvePlaceholder(String, java.util.Properties)

resolvePlaceholder

protected java.lang.String resolvePlaceholder(java.lang.String placeholder,
                                              java.util.Properties props)
Resolve the given placeholder using the given properties. The default implementation simply checks for a corresponding property key.

Subclasses can override this for customized placeholder-to-key mappings or custom resolution strategies, possibly just using the given properties as fallback.

Note that system properties will still be checked before respectively after this method is invoked, according to the system properties mode.

Parameters:
placeholder - the placeholder to resolve
props - the merged properties of this configurer
Returns:
the resolved value, of null if none
See Also:
setSystemPropertiesMode(int)

resolveSystemProperty

protected java.lang.String resolveSystemProperty(java.lang.String key)
Resolve the given key as JVM system property, and optionally also as system environment variable if no matching system property has been found.

Parameters:
key - the placeholder to resolve as system property key
Returns:
the system property value, or null if not found
See Also:
setSearchSystemEnvironment(boolean), System.getProperty(String), System.getenv(String)

processProperties

protected void processProperties(ConfigurableListableBeanFactory beanFactoryToProcess,
                                 java.util.Properties props)
                          throws BeansException
Visit each bean definition in the given bean factory and attempt to replace ${...} property placeholders with values from the given properties.

Specified by:
processProperties in class PropertyResourceConfigurer
Parameters:
beanFactoryToProcess - the BeanFactory used by the application context
props - the Properties to apply
Throws:
BeansException - in case of errors

parseStringValue

@Deprecated
protected java.lang.String parseStringValue(java.lang.String strVal,
                                                       java.util.Properties props,
                                                       java.util.Set<?> visitedPlaceholders)
Deprecated. as of Spring 3.0, in favor of using resolvePlaceholder(java.lang.String, java.util.Properties, int) with PropertyPlaceholderHelper. Only retained for compatibility with Spring 2.5 extensions.

Parse the given String value for placeholder resolution.

Parameters:
strVal - the String value to parse
props - the Properties to resolve placeholders against
visitedPlaceholders - the placeholders that have already been visited during the current resolution attempt (ignored in this version of the code)

Spring Framework