Class ExprLookup
- java.lang.Object
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- org.apache.commons.configuration2.interpol.ExprLookup
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- All Implemented Interfaces:
Lookup
public class ExprLookup extends java.lang.Object implements Lookup
Lookup that allows expressions to be evaluated.ExprLookup.Variables vars = new ExprLookup.Variables(); vars.add(new ExprLookup.Variable("String", org.apache.commons.lang.StringUtils.class)); vars.add(new ExprLookup.Variable("Util", new Utility("Hello"))); vars.add(new ExprLookup.Variable("System", "Class:java.lang.System")); XMLConfiguration config = new XMLConfiguration(TEST_FILE); config.setLogger(log); ExprLookup lookup = new ExprLookup(vars); lookup.setConfiguration(config); String str = lookup.lookup("'$[element] ' + String.trimToEmpty('$[space.description]')");
In the example above TEST_FILE contains xml that looks like:<configuration> <element>value</element> <space xml:space="preserve"> <description xml:space="default"> Some text </description> </space> </configuration>
The result will be "value Some text". This lookup uses Apache Commons Jexl and requires that the dependency be added to any projects which use this.- Since:
- 1.7
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Nested Class Summary
Nested Classes Modifier and Type Class Description static class
ExprLookup.Variable
The key and corresponding object that will be made available to the JexlContext for use in expressions.static class
ExprLookup.Variables
List wrapper used to allow the Variables list to be created as beans in DefaultConfigurationBuilder.
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Constructor Summary
Constructors Constructor Description ExprLookup()
The default constructor.ExprLookup(ExprLookup.Variables list)
Constructor for use by applications.ExprLookup(ExprLookup.Variables list, java.lang.String prefix, java.lang.String suffix)
Constructor for use by applications.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description ConfigurationInterpolator
getInterpolator()
Gets theConfigurationInterpolator
used by this object.ConfigurationLogger
getLogger()
Gets the logger used by this object.ExprLookup.Variables
getVariables()
Gets the list of Variables that are accessible within expressions.java.lang.String
lookup(java.lang.String var)
Evaluates the expression.void
setInterpolator(ConfigurationInterpolator interpolator)
Sets theConfigurationInterpolator
to be used by this object.void
setLogger(ConfigurationLogger logger)
Sets the logger to be used by this object.void
setVariablePrefixMatcher(java.lang.String prefix)
Sets the prefix to use to identify subordinate expressions.void
setVariables(ExprLookup.Variables list)
Add the Variables that will be accessible within expressions.void
setVariableSuffixMatcher(java.lang.String suffix)
Sets the suffix to use to identify subordinate expressions.
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Constructor Detail
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ExprLookup
public ExprLookup()
The default constructor. Will get used when the Lookup is constructed via configuration.
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ExprLookup
public ExprLookup(ExprLookup.Variables list)
Constructor for use by applications.- Parameters:
list
- The list of objects to be accessible in expressions.
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ExprLookup
public ExprLookup(ExprLookup.Variables list, java.lang.String prefix, java.lang.String suffix)
Constructor for use by applications.- Parameters:
list
- The list of objects to be accessible in expressions.prefix
- The prefix to use for subordinate lookups.suffix
- The suffix to use for subordinate lookups.
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Method Detail
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setVariablePrefixMatcher
public void setVariablePrefixMatcher(java.lang.String prefix)
Sets the prefix to use to identify subordinate expressions. This cannot be the same as the prefix used for the primary expression.- Parameters:
prefix
- The String identifying the beginning of the expression.
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setVariableSuffixMatcher
public void setVariableSuffixMatcher(java.lang.String suffix)
Sets the suffix to use to identify subordinate expressions. This cannot be the same as the suffix used for the primary expression.- Parameters:
suffix
- The String identifying the end of the expression.
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setVariables
public void setVariables(ExprLookup.Variables list)
Add the Variables that will be accessible within expressions.- Parameters:
list
- The list of Variables.
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getVariables
public ExprLookup.Variables getVariables()
Gets the list of Variables that are accessible within expressions. This method returns a copy of the variables managed by this lookup; so modifying this object has no impact on this lookup.- Returns:
- the List of Variables that are accessible within expressions.
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getLogger
public ConfigurationLogger getLogger()
Gets the logger used by this object.- Returns:
- the
Log
- Since:
- 2.0
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setLogger
public void setLogger(ConfigurationLogger logger)
Sets the logger to be used by this object. If no logger is passed in, no log output is generated.- Parameters:
logger
- theLog
- Since:
- 2.0
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getInterpolator
public ConfigurationInterpolator getInterpolator()
Gets theConfigurationInterpolator
used by this object.- Returns:
- the
ConfigurationInterpolator
- Since:
- 2.0
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setInterpolator
public void setInterpolator(ConfigurationInterpolator interpolator)
Sets theConfigurationInterpolator
to be used by this object.- Parameters:
interpolator
- theConfigurationInterpolator
(may be null)- Since:
- 2.0
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