That old Spring magic
has me in its SpEL
Craig Walls
About me




           SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
About me

• Java, Spring, and OSGi fanatic




              SpringOne 2GX 2009. All rights reserved. Do not distribute wi...
About me

• Java, Spring, and OSGi fanatic


• Principal consultant with
  Improving Enterprises




               Spring...
About me

• Java, Spring, and OSGi fanatic


• Principal consultant with
  Improving Enterprises

• Author




           ...
About me

• Java, Spring, and OSGi fanatic


• Principal consultant with
  Improving Enterprises

• Author




           ...
Agenda




                                                                                          3
         SpringOne ...
Agenda

• Introducing SpEL




                                                                                           ...
Agenda

• Introducing SpEL


• Using SpEL




                                                                            ...
Agenda

• Introducing SpEL


• Using SpEL


• SpEL Essentials




                                                        ...
Agenda

• Introducing SpEL


• Using SpEL


• SpEL Essentials


• A few SpEL incantations




                            ...
Agenda

• Introducing SpEL


• Using SpEL


• SpEL Essentials


• A few SpEL incantations


• Q&A


                      ...
Download the examples




          Approximately the same code...

http://spring.habuma.com/examples/SpEL-examples.zip


...
Introducing SpEL




          SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
What is SpEL




                                                                                           6
          Sp...
What is SpEL

• New in Spring 3.0




                                                                                    ...
What is SpEL

• New in Spring 3.0
  – Originally conceived in Spring.NET




                                             ...
What is SpEL

• New in Spring 3.0
  – Originally conceived in Spring.NET

• The Spring Expression Language




           ...
What is SpEL

• New in Spring 3.0
  – Originally conceived in Spring.NET

• The Spring Expression Language
• Much like Uni...
What is SpEL

• New in Spring 3.0
   – Originally conceived in Spring.NET

• The Spring Expression Language
• Much like Un...
What is SpEL

• New in Spring 3.0
   – Originally conceived in Spring.NET

• The Spring Expression Language
• Much like Un...
What is SpEL

• New in Spring 3.0
   – Originally conceived in Spring.NET

• The Spring Expression Language
• Much like Un...
What is SpEL

• New in Spring 3.0
   – Originally conceived in Spring.NET

• The Spring Expression Language
• Much like Un...
Using SpEL




       SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
Configuring beans with SpEL (XML)




          SpringOne 2GX 2009. All rights reserved. Do not distribute without permiss...
Configuring beans with SpEL (XML)




<bean id="appConfigurer"
  class="com.habuma.spel.tests.Witch">
 <property name="name...
Configuring beans with SpEL (@Value)




          SpringOne 2GX 2009. All rights reserved. Do not distribute without perm...
Configuring beans with SpEL (@Value)



@Component
public class Wizard {
  @Value("#{systemEnvironment['WIZARD_NAME']}")
 ...
Programming with SpEL




          SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
Programming with SpEL


ExpressionParser parser = new SpelAntlrExpressionParser();

StandardEvaluationContext context =
  ...
Essential SpEL




         SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
Literal expressions




           SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
Literal expressions


                         #{'abracadabra'}




           SpringOne 2GX 2009. All rights reserved. Do...
Literal expressions


                          #{'abracadabra'}



        #{42}




            SpringOne 2GX 2009. All ...
Literal expressions


                          #{'abracadabra'}



        #{42}                                         ...
Literal expressions


                          #{'abracadabra'}



        #{42}                                         ...
Literal expressions


                           #{'abracadabra'}



        #{42}                                        ...
Literal expressions


                           #{'abracadabra'}



        #{42}                                        ...
Literal expressions


                           #{'abracadabra'}



        #{42}                                        ...
Ready-to-use variables




           SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
Ready-to-use variables

    #{systemProperties['WIZARD_NAME']}




             SpringOne 2GX 2009. All rights reserved. D...
Ready-to-use variables

    #{systemProperties['WIZARD_NAME']}
          #{systemProperties.WIZARD_NAME}




             ...
Ready-to-use variables

    #{systemProperties['WIZARD_NAME']}
          #{systemProperties.WIZARD_NAME}


   #{systemEnvi...
Ready-to-use variables

    #{systemProperties['WIZARD_NAME']}
          #{systemProperties.WIZARD_NAME}


   #{systemEnvi...
Ready-to-use variables

    #{systemProperties['WIZARD_NAME']}
          #{systemProperties.WIZARD_NAME}


   #{systemEnvi...
Ready-to-use variables

     #{systemProperties['WIZARD_NAME']}
             #{systemProperties.WIZARD_NAME}


    #{syste...
Ready-to-use variables




           SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
Ready-to-use variables



        #{request.getParameter('wizardId')}




            SpringOne 2GX 2009. All rights reser...
Ready-to-use variables



        #{request.getParameter('wizardId')}



         #{session.getAttribute('wizard')}




  ...
Ready-to-use variables



           #{request.getParameter('wizardId')}



             #{session.getAttribute('wizard')}...
Constructors




          SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
Constructors



   #{new com.habuma.spel.tests.Wizard('Gandalf')}




              SpringOne 2GX 2009. All rights reserve...
Constructors



   #{new com.habuma.spel.tests.Wizard('Gandalf')}




            #{new String('hokus pokus')}




       ...
Accessing object members




          SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
Accessing object members


                               #{elf.name}




          SpringOne 2GX 2009. All rights reserve...
Accessing object members


                               #{elf.name}


                               #{elf.Name}




   ...
Accessing object members


                               #{elf.name}


                               #{elf.Name}


     ...
Accessing object members


                               #{elf.name}


                               #{elf.Name}


     ...
Mixing expressions and text




           SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
Mixing expressions and text



                Embeds the wizard’s
                 name in some text
       The wizard’s ...
Arithmetic operators




           SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
Arithmetic operators

               #{'Harry' + ' ' + 'Potter'}




           SpringOne 2GX 2009. All rights reserved. D...
Arithmetic operators

                #{'Harry' + ' ' + 'Potter'}


        #{25 + 52}




            SpringOne 2GX 2009....
Arithmetic operators

                #{'Harry' + ' ' + 'Potter'}


        #{25 + 52}                                    ...
Arithmetic operators

                #{'Harry' + ' ' + 'Potter'}


        #{25 + 52}                                    ...
Arithmetic operators

                #{'Harry' + ' ' + 'Potter'}


        #{25 + 52}                                    ...
Arithmetic operators

                #{'Harry' + ' ' + 'Potter'}


        #{25 + 52}                                    ...
Arithmetic operators

                #{'Harry' + ' ' + 'Potter'}


        #{25 + 52}                                    ...
Arithmetic operators

                #{'Harry' + ' ' + 'Potter'}


        #{25 + 52}                                    ...
Relational operators




           SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
Relational operators


     #{42 > 7}




             SpringOne 2GX 2009. All rights reserved. Do not distribute without ...
Relational operators


     #{42 > 7}                                                                           #{7 > 42}
...
Relational operators


     #{42 > 7}                                                                           #{7 > 42}
...
Relational operators


     #{42 > 7}                                                                           #{7 > 42}
...
Relational operators


      #{42 > 7}                                                                            #{7 > 42...
Relational operators


      #{42 > 7}                                                                            #{7 > 42...
Logical operators




           SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
Logical operators


    #{witch.isWicked() and witch.name == 'Elphaba'}




              SpringOne 2GX 2009. All rights r...
Logical operators


    #{witch.isWicked() and witch.name == 'Elphaba'}


    #{witch.isWicked() or witch.name == 'Tattypo...
Logical operators


    #{witch.isWicked() and witch.name == 'Elphaba'}


    #{witch.isWicked() or witch.name == 'Tattypo...
Ternary and Elvis operator




           SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
Ternary and Elvis operator



      #{wizard.isGood() ? 'Gandalf' : 'Saruman'}




             SpringOne 2GX 2009. All ri...
Ternary and Elvis operator



      #{wizard.isGood() ? 'Gandalf' : 'Saruman'}




            #{wizard.name ?: 'unknown'}...
The type operator : T()




           SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
The type operator : T()


     #{T(String)}




              SpringOne 2GX 2009. All rights reserved. Do not distribute w...
The type operator : T()


     #{T(String)}


                    #{T(Math)}




              SpringOne 2GX 2009. All rig...
The type operator : T()


     #{T(String)}


                    #{T(Math)}


                                           ...
The type operator : T()


     #{T(String)}


                    #{T(Math)}


                                           ...
Accessing class members




          SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
Accessing class members



              #{T(Math).floor(42.56)}




          SpringOne 2GX 2009. All rights reserved. Do...
Accessing class members



              #{T(Math).floor(42.56)}



                            #{T(Math).PI}




        ...
instanceof




             SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
instanceof

         #{‘Sabrina’ instanceof T(String)}




             SpringOne 2GX 2009. All rights reserved. Do not di...
instanceof

         #{‘Sabrina’ instanceof T(String)}

             #{123 instanceof T(Integer)}




              Spring...
instanceof

         #{‘Sabrina’ instanceof T(String)}

             #{123 instanceof T(Integer)}

             #{123L ins...
instanceof

         #{‘Sabrina’ instanceof T(String)}

             #{123 instanceof T(Integer)}

             #{123L ins...
instanceof

         #{‘Sabrina’ instanceof T(String)}

             #{123 instanceof T(Integer)}

              #{123L in...
Regular expressions




          SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
Regular expressions


    #{phoneNumber matches 'd{3}-d{3}-d{4}'}




             SpringOne 2GX 2009. All rights reserved...
Regular expressions


     #{phoneNumber matches 'd{3}-d{3}-d{4}'}



   #{websiteUrl matches
           'http://www.[a-zA...
Regular expressions


      #{phoneNumber matches 'd{3}-d{3}-d{4}'}



    #{websiteUrl matches
            'http://www.[a...
Setting variables




           SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
Setting variables




Assuming that the root object has a name property...




               SpringOne 2GX 2009. All righ...
Setting variables




Assuming that the root object has a name property...

                       name = 'Broomhilda'



...
Accessing collection members




          SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
Accessing collection members


                                       Arrays
                             #{wizards[0]}


...
Accessing collection members


                                       Arrays
                             #{wizards[0]}


...
Collection selection




            SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
Collection selection


      Select all witches that aren’t wicked
                 #{witches.?[!isWicked()]}




        ...
Collection selection


      Select all witches that aren’t wicked
                 #{witches.?[!isWicked()]}

          S...
Collection selection


      Select all witches that aren’t wicked
                 #{witches.?[!isWicked()]}

          S...
Collection projection




           SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
Collection projection




         Get the names of all wizards

                      #{wizards.![name]}




           S...
The #this variable




           SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
The #this variable



      Get the names of all wizards whose
       name is lexically ordered after ‘G’
         #{wizar...
Adding a custom function

      Only available with programmatic SpEL




                                                ...
Adding a custom function

         Only available with programmatic SpEL
context = new StandardEvaluationContext();
parser...
Adding a custom function

          Only available with programmatic SpEL
context = new StandardEvaluationContext();
parse...
Demo




   SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
A few SpEL incantations




    SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
Wiring in a system property
(with a default)




               SpringOne 2GX 2009. All rights reserved. Do not distribute...
Wiring in a system property
(with a default)




<bean class="Wizard">
 <property name="name"
           value=
     "#{sy...
Wiring bean references




           SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
Wiring bean references



@Value("#{pricingService}")
private PricingService pricingService;




                 SpringOn...
Wiring bean references



@Value("#{pricingService}")
private PricingService pricingService;
                             ...
Wiring bean references



@Value("#{pricingService}")
private PricingService pricingService;
                             ...
Wiring bean references



@Value("#{pricingService}")
private PricingService pricingService;
                             ...
Selective bean wiring




           SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
Selective bean wiring




@Value("#{systemProperties['PRICING'] == 'aggressive'"
       + "? aggressivePricing : regularPr...
Selective collection wiring




            SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
Selective collection wiring

public interface TaxRule {
  boolean appliesToState(String state);
  double calculateTax(doub...
Selective collection wiring

                                                                            <util:list id="ta...
Selective collection wiring

                                                                             <util:list id="t...
Parting thoughts




                                                                                            38
      ...
Parting thoughts

• SpEL expressions are great for doing Spring
  configuration magic




                                ...
Parting thoughts

• SpEL expressions are great for doing Spring
  configuration magic
• SpEL expressions are just Strings....
Parting thoughts

• SpEL expressions are great for doing Spring
  configuration magic
• SpEL expressions are just Strings....
Parting thoughts

• SpEL expressions are great for doing Spring
  configuration magic
• SpEL expressions are just Strings....
Parting thoughts

• SpEL expressions are great for doing Spring
  configuration magic
• SpEL expressions are just Strings....
Parting thoughts

• SpEL expressions are great for doing Spring
  configuration magic
• SpEL expressions are just Strings....
Q&A
Thank you!
Don’t forget to turn in your evaluations!!!




             SpringOne 2GX 2009. All rights reserved. Do no...
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That old Spring magic has me in its SpEL

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Presentation on the Spring Expression Language that I gave at SpringOne/2GX 2009 in New Orleans, LA.

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That old Spring magic has me in its SpEL

  1. 1. That old Spring magic has me in its SpEL Craig Walls
  2. 2. About me SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  3. 3. About me • Java, Spring, and OSGi fanatic SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  4. 4. About me • Java, Spring, and OSGi fanatic • Principal consultant with Improving Enterprises SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  5. 5. About me • Java, Spring, and OSGi fanatic • Principal consultant with Improving Enterprises • Author SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  6. 6. About me • Java, Spring, and OSGi fanatic • Principal consultant with Improving Enterprises • Author SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  7. 7. Agenda 3 SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  8. 8. Agenda • Introducing SpEL 3 SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  9. 9. Agenda • Introducing SpEL • Using SpEL 3 SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  10. 10. Agenda • Introducing SpEL • Using SpEL • SpEL Essentials 3 SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  11. 11. Agenda • Introducing SpEL • Using SpEL • SpEL Essentials • A few SpEL incantations 3 SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  12. 12. Agenda • Introducing SpEL • Using SpEL • SpEL Essentials • A few SpEL incantations • Q&A 3 SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  13. 13. Download the examples Approximately the same code... http://spring.habuma.com/examples/SpEL-examples.zip 4 SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  14. 14. Introducing SpEL SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  15. 15. What is SpEL 6 SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  16. 16. What is SpEL • New in Spring 3.0 6 SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  17. 17. What is SpEL • New in Spring 3.0 – Originally conceived in Spring.NET 6 SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  18. 18. What is SpEL • New in Spring 3.0 – Originally conceived in Spring.NET • The Spring Expression Language 6 SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  19. 19. What is SpEL • New in Spring 3.0 – Originally conceived in Spring.NET • The Spring Expression Language • Much like Unified EL, OGNL, JBoss EL, and others 6 SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  20. 20. What is SpEL • New in Spring 3.0 – Originally conceived in Spring.NET • The Spring Expression Language • Much like Unified EL, OGNL, JBoss EL, and others • Will be used across entire Spring portfolio 6 SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  21. 21. What is SpEL • New in Spring 3.0 – Originally conceived in Spring.NET • The Spring Expression Language • Much like Unified EL, OGNL, JBoss EL, and others • Will be used across entire Spring portfolio • Succinctly express complex concepts 6 SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  22. 22. What is SpEL • New in Spring 3.0 – Originally conceived in Spring.NET • The Spring Expression Language • Much like Unified EL, OGNL, JBoss EL, and others • Will be used across entire Spring portfolio • Succinctly express complex concepts • Can be used to wire bean properties 6 SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  23. 23. What is SpEL • New in Spring 3.0 – Originally conceived in Spring.NET • The Spring Expression Language • Much like Unified EL, OGNL, JBoss EL, and others • Will be used across entire Spring portfolio • Succinctly express complex concepts • Can be used to wire bean properties • Can be used outside of Spring 6 SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  24. 24. Using SpEL SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  25. 25. Configuring beans with SpEL (XML) SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  26. 26. Configuring beans with SpEL (XML) <bean id="appConfigurer" class="com.habuma.spel.tests.Witch"> <property name="name" value="#{systemProperties['WITCH_NAME']}" /> </bean> SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  27. 27. Configuring beans with SpEL (@Value) SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  28. 28. Configuring beans with SpEL (@Value) @Component public class Wizard { @Value("#{systemEnvironment['WIZARD_NAME']}") private String name; // ... } SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  29. 29. Programming with SpEL SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  30. 30. Programming with SpEL ExpressionParser parser = new SpelAntlrExpressionParser(); StandardEvaluationContext context = new StandardEvaluationContext(rootObject); Expression ex = parser.parseExpression("witches.^[isWicked()]"); Witch wickedWitch = (Witch) ex.getValue(context); SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  31. 31. Essential SpEL SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  32. 32. Literal expressions SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  33. 33. Literal expressions #{'abracadabra'} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  34. 34. Literal expressions #{'abracadabra'} #{42} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  35. 35. Literal expressions #{'abracadabra'} #{42} #{3.1415926} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  36. 36. Literal expressions #{'abracadabra'} #{42} #{3.1415926} #{1e4} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  37. 37. Literal expressions #{'abracadabra'} #{42} #{3.1415926} #{1e4} #{true} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  38. 38. Literal expressions #{'abracadabra'} #{42} #{3.1415926} #{1e4} #{true} #{false} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  39. 39. Literal expressions #{'abracadabra'} #{42} #{3.1415926} #{1e4} #{true} #{false} #{null} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  40. 40. Ready-to-use variables SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  41. 41. Ready-to-use variables #{systemProperties['WIZARD_NAME']} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  42. 42. Ready-to-use variables #{systemProperties['WIZARD_NAME']} #{systemProperties.WIZARD_NAME} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  43. 43. Ready-to-use variables #{systemProperties['WIZARD_NAME']} #{systemProperties.WIZARD_NAME} #{systemEnvironment['WIZARD_NAME']} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  44. 44. Ready-to-use variables #{systemProperties['WIZARD_NAME']} #{systemProperties.WIZARD_NAME} #{systemEnvironment['WIZARD_NAME']} #{systemEnvironment.WIZARD_NAME} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  45. 45. Ready-to-use variables #{systemProperties['WIZARD_NAME']} #{systemProperties.WIZARD_NAME} #{systemEnvironment['WIZARD_NAME']} #{systemEnvironment.WIZARD_NAME} #{wizardBean.name} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  46. 46. Ready-to-use variables #{systemProperties['WIZARD_NAME']} #{systemProperties.WIZARD_NAME} #{systemEnvironment['WIZARD_NAME']} #{systemEnvironment.WIZARD_NAME} #{wizardBean.name} Only available when using SpEL in Spring configuration SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  47. 47. Ready-to-use variables SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  48. 48. Ready-to-use variables #{request.getParameter('wizardId')} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  49. 49. Ready-to-use variables #{request.getParameter('wizardId')} #{session.getAttribute('wizard')} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  50. 50. Ready-to-use variables #{request.getParameter('wizardId')} #{session.getAttribute('wizard')} Can only be used to configure appropriately-scoped beans SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  51. 51. Constructors SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  52. 52. Constructors #{new com.habuma.spel.tests.Wizard('Gandalf')} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  53. 53. Constructors #{new com.habuma.spel.tests.Wizard('Gandalf')} #{new String('hokus pokus')} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  54. 54. Accessing object members SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  55. 55. Accessing object members #{elf.name} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  56. 56. Accessing object members #{elf.name} #{elf.Name} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  57. 57. Accessing object members #{elf.name} #{elf.Name} #{elf.getName()} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  58. 58. Accessing object members #{elf.name} #{elf.Name} #{elf.getName()} #{elf.name?.length()} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  59. 59. Mixing expressions and text SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  60. 60. Mixing expressions and text Embeds the wizard’s name in some text The wizard’s name is #{wizard.name} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  61. 61. Arithmetic operators SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  62. 62. Arithmetic operators #{'Harry' + ' ' + 'Potter'} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  63. 63. Arithmetic operators #{'Harry' + ' ' + 'Potter'} #{25 + 52} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  64. 64. Arithmetic operators #{'Harry' + ' ' + 'Potter'} #{25 + 52} #{2.19 + 2.02} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  65. 65. Arithmetic operators #{'Harry' + ' ' + 'Potter'} #{25 + 52} #{2.19 + 2.02} #{77 - 25} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  66. 66. Arithmetic operators #{'Harry' + ' ' + 'Potter'} #{25 + 52} #{2.19 + 2.02} #{77 - 25} #{52 - -25} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  67. 67. Arithmetic operators #{'Harry' + ' ' + 'Potter'} #{25 + 52} #{2.19 + 2.02} #{77 - 25} #{52 - -25} #{6 * 7} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  68. 68. Arithmetic operators #{'Harry' + ' ' + 'Potter'} #{25 + 52} #{2.19 + 2.02} #{77 - 25} #{52 - -25} #{6 * 7} #{42 / 6} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  69. 69. Arithmetic operators #{'Harry' + ' ' + 'Potter'} #{25 + 52} #{2.19 + 2.02} #{77 - 25} #{52 - -25} #{6 * 7} #{42 / 6} #{44 % 7} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  70. 70. Relational operators SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  71. 71. Relational operators #{42 > 7} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  72. 72. Relational operators #{42 > 7} #{7 > 42} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  73. 73. Relational operators #{42 > 7} #{7 > 42} #{10000 == 1e4} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  74. 74. Relational operators #{42 > 7} #{7 > 42} #{10000 == 1e4} #{‘Apple’ == ‘Apple’} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  75. 75. Relational operators #{42 > 7} #{7 > 42} #{10000 == 1e4} #{‘Apple’ == ‘Apple’} #{‘Apple’ < ‘Orange’} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  76. 76. Relational operators #{42 > 7} #{7 > 42} #{10000 == 1e4} #{‘Apple’ == ‘Apple’} #{‘Apple’ < ‘Orange’} #{‘Orange’ > ‘Apple’} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  77. 77. Logical operators SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  78. 78. Logical operators #{witch.isWicked() and witch.name == 'Elphaba'} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  79. 79. Logical operators #{witch.isWicked() and witch.name == 'Elphaba'} #{witch.isWicked() or witch.name == 'Tattypoo'} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  80. 80. Logical operators #{witch.isWicked() and witch.name == 'Elphaba'} #{witch.isWicked() or witch.name == 'Tattypoo'} #{!witch.isWicked()} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  81. 81. Ternary and Elvis operator SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  82. 82. Ternary and Elvis operator #{wizard.isGood() ? 'Gandalf' : 'Saruman'} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  83. 83. Ternary and Elvis operator #{wizard.isGood() ? 'Gandalf' : 'Saruman'} #{wizard.name ?: 'unknown'} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  84. 84. The type operator : T() SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  85. 85. The type operator : T() #{T(String)} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  86. 86. The type operator : T() #{T(String)} #{T(Math)} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  87. 87. The type operator : T() #{T(String)} #{T(Math)} #{T(int)} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  88. 88. The type operator : T() #{T(String)} #{T(Math)} #{T(int)} #{T(java.util.Date)} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  89. 89. Accessing class members SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  90. 90. Accessing class members #{T(Math).floor(42.56)} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  91. 91. Accessing class members #{T(Math).floor(42.56)} #{T(Math).PI} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  92. 92. instanceof SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  93. 93. instanceof #{‘Sabrina’ instanceof T(String)} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  94. 94. instanceof #{‘Sabrina’ instanceof T(String)} #{123 instanceof T(Integer)} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  95. 95. instanceof #{‘Sabrina’ instanceof T(String)} #{123 instanceof T(Integer)} #{123L instanceof T(Long)} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  96. 96. instanceof #{‘Sabrina’ instanceof T(String)} #{123 instanceof T(Integer)} #{123L instanceof T(Long)} #{1.23 instanceof T(Double)} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  97. 97. instanceof #{‘Sabrina’ instanceof T(String)} #{123 instanceof T(Integer)} #{123L instanceof T(Long)} #{1.23 instanceof T(Double)} #{true instanceof T(Boolean)} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  98. 98. Regular expressions SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  99. 99. Regular expressions #{phoneNumber matches 'd{3}-d{3}-d{4}'} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  100. 100. Regular expressions #{phoneNumber matches 'd{3}-d{3}-d{4}'} #{websiteUrl matches 'http://www.[a-zA-Z0-9]*.(com|edu|net)'} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  101. 101. Regular expressions #{phoneNumber matches 'd{3}-d{3}-d{4}'} #{websiteUrl matches 'http://www.[a-zA-Z0-9]*.(com|edu|net)'} #{customerEmail matches '[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+.[a-zA-Z]{2,4}'} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  102. 102. Setting variables SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  103. 103. Setting variables Assuming that the root object has a name property... SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  104. 104. Setting variables Assuming that the root object has a name property... name = 'Broomhilda' SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  105. 105. Accessing collection members SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  106. 106. Accessing collection members Arrays #{wizards[0]} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  107. 107. Accessing collection members Arrays #{wizards[0]} Maps and Properties #{magicWords['abracadabra']} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  108. 108. Collection selection SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  109. 109. Collection selection Select all witches that aren’t wicked #{witches.?[!isWicked()]} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  110. 110. Collection selection Select all witches that aren’t wicked #{witches.?[!isWicked()]} Select the first wicked witch #{witches.^[isWicked()]} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  111. 111. Collection selection Select all witches that aren’t wicked #{witches.?[!isWicked()]} Select the first wicked witch #{witches.^[isWicked()]} Select the last wicked witch #{witches.$[isWicked()]} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  112. 112. Collection projection SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  113. 113. Collection projection Get the names of all wizards #{wizards.![name]} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  114. 114. The #this variable SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  115. 115. The #this variable Get the names of all wizards whose name is lexically ordered after ‘G’ #{wizards.![name].?[#this > 'G']} SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  116. 116. Adding a custom function Only available with programmatic SpEL 31 SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  117. 117. Adding a custom function Only available with programmatic SpEL context = new StandardEvaluationContext(); parser = new SpelAntlrExpressionParser(); context.registerFunction("inEnglish", EnglishNumberInator.class.getDeclaredMethod( "translate", new Class[] {int.class})); 31 SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  118. 118. Adding a custom function Only available with programmatic SpEL context = new StandardEvaluationContext(); parser = new SpelAntlrExpressionParser(); context.registerFunction("inEnglish", EnglishNumberInator.class.getDeclaredMethod( "translate", new Class[] {int.class})); Expression ex = parser.parseExpression("#inEnglish(123)"); String englishNumber = ex.getValue(context); 31 SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  119. 119. Demo SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  120. 120. A few SpEL incantations SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  121. 121. Wiring in a system property (with a default) SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  122. 122. Wiring in a system property (with a default) <bean class="Wizard"> <property name="name" value= "#{systemProperties['WIZARD_NAME'] ?: 'Gandalf'}" /> </bean> SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  123. 123. Wiring bean references SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  124. 124. Wiring bean references @Value("#{pricingService}") private PricingService pricingService; SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  125. 125. Wiring bean references @Value("#{pricingService}") private PricingService pricingService; ...or... <property name="pricingService" value="#{pricingService}" /> SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  126. 126. Wiring bean references @Value("#{pricingService}") private PricingService pricingService; ...or... <property name="pricingService" value="#{pricingService}" /> Don’t do this! SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  127. 127. Wiring bean references @Value("#{pricingService}") private PricingService pricingService; ...or... <property name="pricingService" value="#{pricingService}" /> Don’t do this! However... SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  128. 128. Selective bean wiring SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  129. 129. Selective bean wiring @Value("#{systemProperties['PRICING'] == 'aggressive'" + "? aggressivePricing : regularPricing}") private PricingService pricingService; SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  130. 130. Selective collection wiring SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  131. 131. Selective collection wiring public interface TaxRule { boolean appliesToState(String state); double calculateTax(double base); } SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  132. 132. Selective collection wiring <util:list id="taxRules"> public interface TaxRule { <ref id="revenueTax" /> boolean appliesToState(String state); <ref id="carpetTax" /> double calculateTax(double base); <ref id="existenceTax" /> } <ref id="justBecauseTax" /> </util:list> SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  133. 133. Selective collection wiring <util:list id="taxRules"> public interface TaxRule { <ref id="revenueTax" /> boolean appliesToState(String state); <ref id="carpetTax" /> double calculateTax(double base); <ref id="existenceTax" /> } <ref id="justBecauseTax" /> </util:list> <bean id="taxProcessor" class="TaxProcessor" scope="session"> <aop:scoped-proxy /> <property name="taxRules" value= "#{taxRules.?[appliesToState(session.getAttribute('user').state)]}" /> </bean> SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  134. 134. Parting thoughts 38 SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  135. 135. Parting thoughts • SpEL expressions are great for doing Spring configuration magic 38 SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  136. 136. Parting thoughts • SpEL expressions are great for doing Spring configuration magic • SpEL expressions are just Strings...no compile- time help to ensure type-safety, syntax, etc. 38 SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  137. 137. Parting thoughts • SpEL expressions are great for doing Spring configuration magic • SpEL expressions are just Strings...no compile- time help to ensure type-safety, syntax, etc. • Don’t abuse SpEL 38 SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  138. 138. Parting thoughts • SpEL expressions are great for doing Spring configuration magic • SpEL expressions are just Strings...no compile- time help to ensure type-safety, syntax, etc. • Don’t abuse SpEL – Remember Goethe’s Sorcerer’s Apprentice 38 SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  139. 139. Parting thoughts • SpEL expressions are great for doing Spring configuration magic • SpEL expressions are just Strings...no compile- time help to ensure type-safety, syntax, etc. • Don’t abuse SpEL – Remember Goethe’s Sorcerer’s Apprentice – A little bit of magic in the wrong hands can be dangerous 38 SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  140. 140. Parting thoughts • SpEL expressions are great for doing Spring configuration magic • SpEL expressions are just Strings...no compile- time help to ensure type-safety, syntax, etc. • Don’t abuse SpEL – Remember Goethe’s Sorcerer’s Apprentice – A little bit of magic in the wrong hands can be dangerous • Write tests!!! 38 SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
  141. 141. Q&A Thank you! Don’t forget to turn in your evaluations!!! SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.
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