Package org.springframework.core.env

Class AbstractPropertyResolver

java.lang.Object

org.springframework.core.env.AbstractPropertyResolver

All Implemented Interfaces:

ConfigurablePropertyResolver, PropertyResolver

Direct Known Subclasses:

PropertySourcesPropertyResolver

public abstract class AbstractPropertyResolver
extends Object
implements ConfigurablePropertyResolver

Abstract base class for resolving properties against any underlying source.

Since:

3.1

Author:

Chris Beams, Juergen Hoeller, Sam Brannen

Field Summary

Fields

Modifier and Type	Field	Description
static final String	DEFAULT_PLACEHOLDER_ESCAPE_CHARACTER_PROPERTY_NAME	JVM system property used to change the default escape character for property placeholder support: "spring.placeholder.escapeCharacter.default".
protected final Log	logger

Constructor Summary

Constructors

Constructor	Description
AbstractPropertyResolver()

Method Summary

Modifier and Type	Method	Description
boolean	containsProperty(String key)	Determine whether the given property key is available for resolution — for example, if the value for the given key is not null.
protected <T> T	convertValueIfNecessary(Object value, Class<T> targetType)	Convert the given value to the specified target type, if necessary.
ConfigurableConversionService	getConversionService()	Return the ConfigurableConversionService used when performing type conversions on properties.
static Character	getDefaultEscapeCharacter()	Get the default escape character to use when parsing strings for property placeholder resolution.
String	getProperty(String key)	Resolve the property value associated with the given key, or null if the key cannot be resolved.
<T> T	getProperty(String key, Class<T> targetType, T defaultValue)	Resolve the property value associated with the given key, or defaultValue if the key cannot be resolved.
String	getProperty(String key, String defaultValue)	Resolve the property value associated with the given key, or defaultValue if the key cannot be resolved.
protected abstract String	getPropertyAsRawString(String key)	Retrieve the specified property as a raw String, i.e.
String	getRequiredProperty(String key)	Resolve the property value associated with the given key (never null).
<T> T	getRequiredProperty(String key, Class<T> valueType)	Resolve the property value associated with the given key, converted to the given targetType (never null).
protected String	resolveNestedPlaceholders(String value)	Resolve placeholders within the given string, deferring to the value of setIgnoreUnresolvableNestedPlaceholders(boolean) to determine whether any unresolvable placeholders should raise an exception or be ignored.
String	resolvePlaceholders(String text)	Resolve ${...} placeholders in the given text, replacing them with corresponding property values as resolved by PropertyResolver.getProperty(java.lang.String).
String	resolveRequiredPlaceholders(String text)	Resolve ${...} placeholders in the given text, replacing them with corresponding property values as resolved by PropertyResolver.getProperty(java.lang.String).
void	setConversionService(ConfigurableConversionService conversionService)	Set the ConfigurableConversionService to be used when performing type conversions on properties.
void	setEscapeCharacter(Character escapeCharacter)	Set the escape character to use to ignore the placeholder prefix and the value separator, or null if no escaping should take place.
void	setIgnoreUnresolvableNestedPlaceholders(boolean ignoreUnresolvableNestedPlaceholders)	Set whether to throw an exception when encountering an unresolvable placeholder nested within the value of a given property.
void	setPlaceholderPrefix(String placeholderPrefix)	Set the prefix that placeholders replaced by this resolver must begin with.
void	setPlaceholderSuffix(String placeholderSuffix)	Set the suffix that placeholders replaced by this resolver must end with.
void	setRequiredProperties(String... requiredProperties)	Specify which properties must be present, to be verified by ConfigurablePropertyResolver.validateRequiredProperties().
void	setValueSeparator(String valueSeparator)	Set the separating character to be honored between placeholders replaced by this resolver and their associated default values, or null if no such special character should be processed as a value separator.
void	validateRequiredProperties()	Validate that each of the properties specified by ConfigurablePropertyResolver.setRequiredProperties(java.lang.String...) is present and resolves to a non-null value.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.springframework.core.env.PropertyResolver

getProperty

Field Details

DEFAULT_PLACEHOLDER_ESCAPE_CHARACTER_PROPERTY_NAME

public static final String DEFAULT_PLACEHOLDER_ESCAPE_CHARACTER_PROPERTY_NAME

JVM system property used to change the default escape character for property placeholder support: "spring.placeholder.escapeCharacter.default".

To configure a custom escape character, supply a string containing a single character (other than Character.MIN_VALUE). For example, supplying the following JVM system property via the command line sets the default escape character to '@'.

-Dspring.placeholder.escapeCharacter.default=@

To disable escape character support, set the value to an empty string — for example, by supplying the following JVM system property via the command line.

-Dspring.placeholder.escapeCharacter.default=

If the property is not set, '\' will be used as the default escape character.

May alternatively be configured via a spring.properties file in the root of the classpath.

Since:

6.2.7

See Also:

• getDefaultEscapeCharacter()
• Constant Field Values

logger

protected final Log logger

Constructor Details

AbstractPropertyResolver

public AbstractPropertyResolver()

Method Details

getConversionService

public ConfigurableConversionService getConversionService()

Description copied from interface: ConfigurablePropertyResolver

Return the ConfigurableConversionService used when performing type conversions on properties.

The configurable nature of the returned conversion service allows for the convenient addition and removal of individual Converter instances:

 ConfigurableConversionService cs = env.getConversionService();
 cs.addConverter(new FooConverter());
 

Specified by:

getConversionService in interface ConfigurablePropertyResolver

See Also:

• PropertyResolver.getProperty(String, Class)
• ConverterRegistry.addConverter(org.springframework.core.convert.converter.Converter<?, ?>)

setConversionService

public void setConversionService(ConfigurableConversionService conversionService)

Description copied from interface: ConfigurablePropertyResolver

Set the ConfigurableConversionService to be used when performing type conversions on properties.

Note: as an alternative to fully replacing the ConversionService, consider adding or removing individual Converter instances by drilling into ConfigurablePropertyResolver.getConversionService() and calling methods such as #addConverter.

Specified by:

setConversionService in interface ConfigurablePropertyResolver

See Also:

• PropertyResolver.getProperty(String, Class)
• ConfigurablePropertyResolver.getConversionService()
• ConverterRegistry.addConverter(org.springframework.core.convert.converter.Converter<?, ?>)

setPlaceholderPrefix

public void setPlaceholderPrefix(String placeholderPrefix)

Set the prefix that placeholders replaced by this resolver must begin with.

The default is "${".

Specified by:

setPlaceholderPrefix in interface ConfigurablePropertyResolver

See Also:

• SystemPropertyUtils.PLACEHOLDER_PREFIX

setPlaceholderSuffix

public void setPlaceholderSuffix(String placeholderSuffix)

Set the suffix that placeholders replaced by this resolver must end with.

The default is "}".

Specified by:

setPlaceholderSuffix in interface ConfigurablePropertyResolver

See Also:

• SystemPropertyUtils.PLACEHOLDER_SUFFIX

setValueSeparator

public void setValueSeparator(@Nullable
 String valueSeparator)

Set the separating character to be honored between placeholders replaced by this resolver and their associated default values, or null if no such special character should be processed as a value separator.

The default is ":".

Specified by:

setValueSeparator in interface ConfigurablePropertyResolver

See Also:

• SystemPropertyUtils.VALUE_SEPARATOR

setEscapeCharacter

public void setEscapeCharacter(@Nullable
 Character escapeCharacter)

Set the escape character to use to ignore the placeholder prefix and the value separator, or null if no escaping should take place.

The default is determined by getDefaultEscapeCharacter().

Specified by:

setEscapeCharacter in interface ConfigurablePropertyResolver

Since:

6.2

setIgnoreUnresolvableNestedPlaceholders

public void setIgnoreUnresolvableNestedPlaceholders(boolean ignoreUnresolvableNestedPlaceholders)

Set whether to throw an exception when encountering an unresolvable placeholder nested within the value of a given property. A false value indicates strict resolution, i.e. that an exception will be thrown. A true value indicates that unresolvable nested placeholders should be passed through in their unresolved ${...} form.

The default is false.

Specified by:

setIgnoreUnresolvableNestedPlaceholders in interface ConfigurablePropertyResolver

Since:

3.2

setRequiredProperties

public void setRequiredProperties(String... requiredProperties)

Description copied from interface: ConfigurablePropertyResolver

Specify which properties must be present, to be verified by ConfigurablePropertyResolver.validateRequiredProperties().

Specified by:

setRequiredProperties in interface ConfigurablePropertyResolver

validateRequiredProperties

public void validateRequiredProperties()

Description copied from interface: ConfigurablePropertyResolver

Validate that each of the properties specified by ConfigurablePropertyResolver.setRequiredProperties(java.lang.String...) is present and resolves to a non-null value.

Specified by:

validateRequiredProperties in interface ConfigurablePropertyResolver

containsProperty

public boolean containsProperty(String key)

Description copied from interface: PropertyResolver

Determine whether the given property key is available for resolution — for example, if the value for the given key is not null.

Specified by:

containsProperty in interface PropertyResolver

getProperty

@Nullable
public String getProperty(String key)

Description copied from interface: PropertyResolver

Resolve the property value associated with the given key, or null if the key cannot be resolved.

Specified by:

getProperty in interface PropertyResolver

Parameters:

key - the property name to resolve

See Also:

• PropertyResolver.getProperty(String, String)
• PropertyResolver.getProperty(String, Class)
• PropertyResolver.getRequiredProperty(String)

getProperty

public String getProperty(String key,
 String defaultValue)

Description copied from interface: PropertyResolver

Resolve the property value associated with the given key, or defaultValue if the key cannot be resolved.

Specified by:

getProperty in interface PropertyResolver

Parameters:

key - the property name to resolve

defaultValue - the default value to return if no value is found

See Also:

• PropertyResolver.getRequiredProperty(String)
• PropertyResolver.getProperty(String, Class)

getProperty

public <T> T getProperty(String key,
 Class<T> targetType,
 T defaultValue)

Description copied from interface: PropertyResolver

Resolve the property value associated with the given key, or defaultValue if the key cannot be resolved.

Specified by:

getProperty in interface PropertyResolver

Parameters:

key - the property name to resolve

targetType - the expected type of the property value

defaultValue - the default value to return if no value is found

See Also:

• PropertyResolver.getRequiredProperty(String, Class)

getRequiredProperty

public String getRequiredProperty(String key)
                           throws IllegalStateException

Description copied from interface: PropertyResolver

Resolve the property value associated with the given key (never null).

Specified by:

getRequiredProperty in interface PropertyResolver

Throws:

IllegalStateException - if the key cannot be resolved

See Also:

• PropertyResolver.getRequiredProperty(String, Class)

getRequiredProperty

public <T> T getRequiredProperty(String key,
 Class<T> valueType)
                          throws IllegalStateException

Description copied from interface: PropertyResolver

Resolve the property value associated with the given key, converted to the given targetType (never null).

Specified by:

getRequiredProperty in interface PropertyResolver

Throws:

IllegalStateException - if the given key cannot be resolved

resolvePlaceholders

public String resolvePlaceholders(String text)

Description copied from interface: PropertyResolver

Resolve ${...} placeholders in the given text, replacing them with corresponding property values as resolved by PropertyResolver.getProperty(java.lang.String). Unresolvable placeholders with no default value are ignored and passed through unchanged.

Specified by:

resolvePlaceholders in interface PropertyResolver

Parameters:

text - the String to resolve

Returns:

the resolved String (never null)

See Also:

• PropertyResolver.resolveRequiredPlaceholders(java.lang.String)

resolveRequiredPlaceholders

public String resolveRequiredPlaceholders(String text)
                                   throws IllegalArgumentException

Description copied from interface: PropertyResolver

Resolve ${...} placeholders in the given text, replacing them with corresponding property values as resolved by PropertyResolver.getProperty(java.lang.String). Unresolvable placeholders with no default value will cause an IllegalArgumentException to be thrown.

Specified by:

resolveRequiredPlaceholders in interface PropertyResolver

Returns:

the resolved String (never null)

Throws:

IllegalArgumentException - if given text is null or if any placeholders are unresolvable

resolveNestedPlaceholders

protected String resolveNestedPlaceholders(String value)

Resolve placeholders within the given string, deferring to the value of setIgnoreUnresolvableNestedPlaceholders(boolean) to determine whether any unresolvable placeholders should raise an exception or be ignored.

Invoked from getProperty(java.lang.String) and its variants, implicitly resolving nested placeholders. In contrast, resolvePlaceholders(java.lang.String) and resolveRequiredPlaceholders(java.lang.String) do not delegate to this method but rather perform their own handling of unresolvable placeholders, as specified by each of those methods.

Since:

3.2

See Also:

• setIgnoreUnresolvableNestedPlaceholders(boolean)

convertValueIfNecessary

@Nullable
protected <T> T convertValueIfNecessary(Object value,
 @Nullable
 Class<T> targetType)

Convert the given value to the specified target type, if necessary.

Parameters:

value - the original property value

targetType - the specified target type for property retrieval

Returns:

the converted value, or the original value if no conversion is necessary

Since:

4.3.5

getPropertyAsRawString

@Nullable
protected abstract String getPropertyAsRawString(String key)

Retrieve the specified property as a raw String, i.e. without resolution of nested placeholders.

Parameters:

key - the property name to resolve

Returns:

the property value or null if none found

getDefaultEscapeCharacter

@Nullable
public static Character getDefaultEscapeCharacter()
                                           throws IllegalArgumentException

Get the default escape character to use when parsing strings for property placeholder resolution.

This method attempts to retrieve the default escape character configured via the "spring.placeholder.escapeCharacter.default" JVM system property or Spring property.

Falls back to '\' if the property has not been set.

Returns:

the configured default escape character, null if escape character support has been disabled, or '\' if the property has not been set

Throws:

IllegalArgumentException - if the property is configured with an invalid value, such as Character.MIN_VALUE or a string containing more than one character

Since:

6.2.7

See Also:

• DEFAULT_PLACEHOLDER_ESCAPE_CHARACTER_PROPERTY_NAME
• SystemPropertyUtils.ESCAPE_CHARACTER
• SpringProperties