org.springframework.beans.factory.config
Class PropertyPlaceholderConfigurer

java.lang.Object
  org.springframework.beans.factory.config.PropertyResourceConfigurer
      org.springframework.beans.factory.config.PropertyPlaceholderConfigurer

All Implemented Interfaces:

BeanFactoryPostProcessor, Ordered

Direct Known Subclasses:

PreferencesPlaceholderConfigurer

public class PropertyPlaceholderConfigurer

extends PropertyResourceConfigurer

A property resource configurer that resolves placeholders in bean property values of context definitions. It pulls values from a properties file into bean definitions.

The default placeholder syntax follows the Ant / Log4J / JSP EL style:

${...}

Example XML context definition:

<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName"><value>${driver}</value></property>
<property name="url"><value>jdbc:${dbname}</value></property>
</bean>

Example properties file:

driver=com.mysql.jdbc.Driver
dbname=mysql:mydb

PropertyPlaceholderConfigurer checks simple property values, lists, maps, props, and bean names in bean references. Furthermore, placeholder values can also cross-reference other placeholders, like:

rootPath=myrootdir subPath=${rootPath}/subdir

In contrast to PropertyOverrideConfigurer, this configurer allows to fill in explicit placeholders in context definitions. Therefore, the original definition cannot specify any default values for such bean properties, and the placeholder properties file is supposed to contain an entry for each defined placeholder.

If a configurer cannot resolve a placeholder, a BeanDefinitionStoreException will be thrown. If you want to check against multiple properties files, specify multiple resources via the "locations" setting. You can also define multiple PropertyPlaceholderConfigurers, each with its own placeholder syntax.

Default property values can be defined via "properties", to make overriding definitions in properties files optional. A configurer will also check against system properties (e.g. "user.dir") if it cannot resolve a placeholder with any of the specified properties. This can be customized via "systemPropertiesMode".

Note that the context definition is aware of being incomplete; this is immediately obvious when looking at the XML definition file.

Since:

02.10.2003

Version:

$Id: PropertyPlaceholderConfigurer.java,v 1.10 2004/03/19 17:52:29 jhoeller Exp $

Author:

Juergen Hoeller

See Also:

PropertyOverrideConfigurer, PropertyResourceConfigurer.setLocations(org.springframework.core.io.Resource[]), PropertyResourceConfigurer.setProperties(java.util.Properties), setPlaceholderPrefix(java.lang.String), setPlaceholderSuffix(java.lang.String), setSystemPropertiesMode(int), System.getProperty(String)

Field Summary

static java.lang.String	DEFAULT_PLACEHOLDER_PREFIX
static java.lang.String	DEFAULT_PLACEHOLDER_SUFFIX
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.PropertyResourceConfigurer

logger

Constructor Summary

PropertyPlaceholderConfigurer()

Method Summary

protected void	parseBeanDefinition(java.util.Properties props, BeanDefinition beanDefinition)
protected void	parseGenericArgumentValues(java.util.Properties props, java.util.Set gas)
protected void	parseIndexedArgumentValues(java.util.Properties props, java.util.Map ias)
protected void	parseList(java.util.Properties props, java.util.List listVal) Parse the given List, exchanging its values if necessary.
protected void	parseMap(java.util.Properties props, java.util.Map mapVal) Parse the given Map, exchanging its values if necessary.
protected void	parsePropertyValues(java.util.Properties props, MutablePropertyValues pvs)
protected void	parseSet(java.util.Properties props, java.util.Set setVal) Parse the given Set, exchanging its values if necessary.
protected java.lang.String	parseString(java.util.Properties props, java.lang.String strVal, java.lang.String originalPlaceholder) Parse values recursively to be able to resolve cross-references between placeholder values.
protected java.lang.Object	parseValue(java.util.Properties props, java.lang.Object value)
protected void	processProperties(ConfigurableListableBeanFactory beanFactory, java.util.Properties props) Apply the given Properties to the bean factory.
protected java.lang.String	resolvePlaceholder(java.lang.String placeholder, java.util.Properties props) Resolve the given placeholder using the given properties.
void	setIgnoreUnresolvablePlaceholders(boolean ignoreUnresolvablePlaceholders) Set whether to ignore unresolvable placeholders.
void	setPlaceholderPrefix(java.lang.String placeholderPrefix) Set the prefix that a placeholder string starts with.
void	setPlaceholderSuffix(java.lang.String placeholderSuffix) Set the suffix that a placeholder string ends with.
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.PropertyResourceConfigurer

getOrder, postProcessBeanFactory, setIgnoreResourceNotFound, setLocation, setLocations, setOrder, setProperties

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DEFAULT_PLACEHOLDER_PREFIX

public static final java.lang.String DEFAULT_PLACEHOLDER_PREFIX

See Also:

Constant Field Values

DEFAULT_PLACEHOLDER_SUFFIX

public static final java.lang.String DEFAULT_PLACEHOLDER_SUFFIX

See Also:

Constant Field Values

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

setPlaceholderPrefix

public void setPlaceholderPrefix(java.lang.String placeholderPrefix)

Set the prefix that a placeholder string starts with. The default is "${".

See Also:

DEFAULT_PLACEHOLDER_PREFIX

setPlaceholderSuffix

public void setPlaceholderSuffix(java.lang.String placeholderSuffix)

Set the suffix that a placeholder string ends with. The default is "}".

See Also:

DEFAULT_PLACEHOLDER_SUFFIX

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

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)

setIgnoreUnresolvablePlaceholders

public void setIgnoreUnresolvablePlaceholders(boolean ignoreUnresolvablePlaceholders)

Set whether to ignore unresolvable placeholders. Default is false: An exception will be thrown if a placeholder cannot not be resolved.

processProperties

protected void processProperties(ConfigurableListableBeanFactory beanFactory,
                                 java.util.Properties props)
                          throws BeansException

Description copied from class: PropertyResourceConfigurer

Apply the given Properties to the bean factory.

Specified by:

processProperties in class PropertyResourceConfigurer

Parameters:

beanFactory - the bean factory used by the application context

props - the Properties to apply

Throws:

BeansException - in case of errors

parseBeanDefinition

protected void parseBeanDefinition(java.util.Properties props,
                                   BeanDefinition beanDefinition)

parsePropertyValues

protected void parsePropertyValues(java.util.Properties props,
                                   MutablePropertyValues pvs)

parseIndexedArgumentValues

protected void parseIndexedArgumentValues(java.util.Properties props,
                                          java.util.Map ias)

parseGenericArgumentValues

protected void parseGenericArgumentValues(java.util.Properties props,
                                          java.util.Set gas)

parseValue

protected java.lang.Object parseValue(java.util.Properties props,
                                      java.lang.Object value)

parseList

protected void parseList(java.util.Properties props,
                         java.util.List listVal)

Parse the given List, exchanging its values if necessary.

parseSet

protected void parseSet(java.util.Properties props,
                        java.util.Set setVal)

Parse the given Set, exchanging its values if necessary.

parseMap

protected void parseMap(java.util.Properties props,
                        java.util.Map mapVal)

Parse the given Map, exchanging its values if necessary.

parseString

protected java.lang.String parseString(java.util.Properties props,
                                       java.lang.String strVal,
                                       java.lang.String originalPlaceholder)
                                throws BeansException

Parse values recursively to be able to resolve cross-references between placeholder values.

Throws:

BeansException

resolvePlaceholder

protected java.lang.String resolvePlaceholder(java.lang.String placeholder,
                                              java.util.Properties props)

Resolve the given placeholder using the given properties. 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

See Also:

setSystemPropertiesMode(int)