[翻译]Drools6.2帮助文档-9. Drools命令



9.1. API
Drools提供的XML序列化/反序列化命令需要使用特殊的类，这将会在下面的章节详细介绍。
下面示例脚本的网址，包括JAXB, Xstream, JSON的序列化：

http://fisheye.jboss.org/browse/JBossRules/trunk/drools-camel/src/test/resources/org/drools/camel/component/jaxb.mvt?r=HEAD

http://fisheye.jboss.org/browse/JBossRules/trunk/drools-camel/src/test/resources/org/drools/camel/component/jaxb.mvt?r=HEAD

http://fisheye.jboss.org/browse/JBossRules/trunk/drools-camel/src/test/resources/org/drools/camel/component/xstream.mvt?r=HEAD

9.1.1.
XStream
在使用Xstream序列化命令之前，需要从DroolsHelperProvider中获取一个XStream实例。这个方法可以将转换器注册到实例中。
序列化
BatchExecutionHelperProviderImpl.newXStreamMarshaller().toXML(command);
反序列化
BatchExecutionHelperProviderImpl.newXStreamMarshaller().fromXML(xml)

9.1.2. JSON
使用JSON API序列化/反序列化的方法与XStream类似

序列化

BatchExecutionHelper.newJSonMarshaller().toXML(command);

反序列化

BatchExecutionHelper.newJSonMarshaller().fromXML(xml)

9.1.3. JAXB
有两个方法使用JAXB，你可以定论模型的XSD文件，也可以使用POJO模型。这两种情况下，你必须先在JAXBContext中声明你的类型。为了做到这一点，你需要
使用Drools Helper类。一旦你有了JAXBContext，你就可以根据需要创建序列化器/反序列化器。
9.1.3.1
使用XSD文件定义模型
为了使用在XSD文件中定义的模型，你需要有一个KnowledgeBase（知识库），这样你可以把XSD模型以资源的形式加载到KnowledgeBase中。
首先，XSD文件必须以XSD资源类型加载到KnowledgeBuilder中，再使用KnowledgeBuilder创建KnowledgeBase，最后通过KnowledgeBase创建JAXBContext。
代码段如下：
Options xjcOpts =
new Options();

xjcOpts.setSchemaLanguage(Language.XMLSCHEMA);

JaxbConfiguration jaxbConfiguration = KnowledgeBuilderFactory.newJaxbConfiguration( xjcOpts,
"xsd" );

kbuilder.add(ResourceFactory.newClassPathResource("person.xsd", getClass()), ResourceType.XSD, jaxbConfiguration);

KnowledgeBase kbase = kbuilder.newKnowledgeBase();
List<String> classesName =
new ArrayList<String>();

classesName.add("org.drools.compiler.test.Person");

JAXBContext jaxbContext = KnowledgeBuilderHelper.newJAXBContext(classesName.toArray(new
String[classesName.size()]), kbase);
9.1.3.2.使用POJO模型
使用DroolsJaxbHelperProviderImpl创建JAXBContext，有两个参数：
1.classNames:
一个包含规范类名的数组，将在序列化/反序列化过程中使用的类。
2.properties: JAXB自定义的属性
代码段
List<String> classNames =
new ArrayList<String>(); classNames.add("org.drools.compiler.test.Person");
JAXBContext jaxbContext = DroolsJaxbHelperProviderImpl.createDroolsJaxbContext(classNames,
null); Marshaller marshaller = jaxbContext.createMarshaller();

9.2.支持的命令
目前，支持以下命令：

BatchExecutionCommand

InsertObjectCommand

RetractCommand

ModifyCommand

GetObjectCommand

InsertElementsCommand

FireAllRulesCommand

StartProcessCommand

SignalEventCommand

CompleteWorkItemCommand

AbortWorkItemCommand

QueryCommand

SetGlobalCommand

GetGlobalCommand

GetObjectsCommand

注意：对于下面这样的代码片段，我们将使用一个POJO对象

org.drools.compiler.test.Person that has two fields

name: String

age: Integer

注意：后面的例子中，为了序列化我们需要先使用下面的代码片段：

XStream

String xml = BatchExecutionHelper.newXStreamMarshaller().toXML(command);

JSON

String xml = BatchExecutionHelper.newJSonMarshaller().toXML(command);

JAXB

Marshaller marshaller = jaxbContext.createMarshaller();

StringWriter xml = new StringWriter();

marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);

marshaller.marshal(command, xml);

9.2.1. BatchExecutionCommand

描述：包含一组将要被发送并执行的命令的Command

属性：表9.1 BatchExecutionCommand属性

名称	描述	是否必需
lookup	设置将要被执行的命令的knowledge session id	是
commands	将要被执行的命令的数组	否

创建命令代码段：

BatchExecutionCommand command =
new BatchExecutionCommand(); command.setLookup("ksession1");
InsertObjectCommand insertObjectCommand = new InsertObjectCommand(new
Person("john",
25)); FireAllRulesCommand fireAllRulesCommand =
new FireAllRulesCommand(); command.getCommands().add(insertObjectCommand); command.getCommands().add(fireAllRulesCommand);

XML 输出

XStream

<batch-execution
lookup="ksession1">

<insert>

<org.drools.compiler.test.Person>

<name>john</name>

<age>25</age>

</org.drools.compiler.test.Person>

</insert>

<fire-all-rules/>

</batch-execution>

JSON

{"batch-execution":{"lookup":"ksession1","commands":[{"insert":{"object":{"org.drools.compiler.test.Person":{"name":"john","age":25}}}},{"fire-all-rules":""}]}}

JAXB

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>

<batch-execution
lookup="ksession1">

<insert>

<object
xsi:type="person"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

<age>25</age>

<name>john</name>

</object>

</insert>

<fire-all-rules
max="-1"/>

</batch-execution>

9.2.2. InsertObjectCommand
描述：向Knowledge session中插入一个Object
属性：表9.2.InsertObjectCommand属性

名称	描述	是否必需
object	需要插入的对象	true
outIdentifier	FactHandle的ID，在对象被插入并添加到执行队列中时创建	false
returnObject	Boolean值，当对象必须在执行结果中返回时创建。默认值：true	false
entryPoint	插入的入口	false

创建代码
List<Command> cmds = ArrayList<Command>(); Command insertObjectCommand = CommandFactory.newInsert(new
Person("john",
25),
"john",
false,
null); cmds.add( insertObjectCommand ); BatchExecutionCommand command = CommandFactory.createBatchExecution(cmds,
"ksession1" );
XML输出

XStream

<batch-execution
lookup="ksession1">

<insert
out-identifier="john"
entry-point="my
stream"
return-object="false">

<org.drools.compiler.test.Person>

<name>john</name>

<age>25</age>

</org.drools.compiler.test.Person>

</insert>

</batch-execution>

JSON

{"batch-execution":{"lookup":"ksession1","commands":{"insert":{"entry-point":"my stream", "out-identifier":"john","return-object":false,"object":{"org.drools.compiler.test.Person":{"name":"john","age":25}}}}}}

JAXB

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>

<batch-execution
lookup="ksession1">

<insert
out-identifier="john"
entry-point="my
stream" >

<object
xsi:type="person"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

<age>25</age>

<name>john</name>

</object>

</insert>

</batch-execution>

9.2.3. RetractCommand
描述：从knowledge session中回收一个对象
属性：表9.3 RetractCommand属性

名称	描述	是否必需
handle	与将被回收的对象关联的FactHandle	true

创建代码：我们有两个方案，并得到同样的输出

从一个String对象创建FactHandle

BatchExecutionCommand command =
new
BatchExecutionCommand();

command.setLookup("ksession1");

RetractCommand retractCommand = new
RetractCommand();

retractCommand.setFactHandleFromString("123:234:345:456:567");

command.getCommands().add(retractCommand);

当对象插入时获取FactHandle，并设置给RetractCommand

BatchExecutionCommand command =
new BatchExecutionCommand();

command.setLookup("ksession1");

RetractCommand retractCommand = new
RetractCommand(factHandle);

command.getCommands().add(retractCommand);

XML输出

XStream

<batch-execution
lookup="ksession1">

<retract
fact-handle="0:234:345:456:567"/>

</batch-execution>

JSON

{"batch-execution":{"lookup":"ksession1","commands":{"retract":{"fact-handle":"0:234:345:456:567"}}}}

JAXB

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>

<batch-execution
lookup="ksession1">

<retract
fact-handle="0:234:345:456:567"/>

</batch-execution>

9.2.4. ModifyCommand
描述：允许你修改之前插入到knowledge session的对象的值
属性：表9.4.ModifyCommand属性

名称	描述	是否必需
handle	与待修改对象关联的FactHandle	true
setters	修改对象的Setter数组	true

创建代码

BatchExecutionCommand command =
new BatchExecutionCommand();

command.setLookup("ksession1");

ModifyCommand modifyCommand = new
ModifyCommand();

modifyCommand.setFactHandleFromString("123:234:345:456:567");

List<Setter> setters = new ArrayList<Setter>();

setters.add(new SetterImpl("age",
"30"));

modifyCommand.setSetters(setters);

command.getCommands().add(modifyCommand);

XML输出

XStream

<batch-execution
lookup="ksession1">

<modify
fact-handle="0:234:345:456:567">

<set
accessor="age"
value="30"/>

</modify>

</batch-execution>

JSON

{"batch-execution":{"lookup":"ksession1","commands":{"modify":{"fact-handle":"0:234:345:456:567","setters":{"accessor":"age","value":30}}}}}

JAXB

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>

<batch-execution
lookup="ksession1">

<modify
fact-handle="0:234:345:456:567">

<set
value="30"
accessor="age"/>

</modify>

</batch-execution>

9.2.5. GetObjectCommand
描述：从knowledge session中获取一个对象
属性：表9.5.GetObjectCommand属性

Name	Description	required
factHandle	与将获取的对象关联的FactHandle	true
outIdentifier	FactHandle的ID，在对象被插入并添加到执行队列中时创建	false

创建代码：

BatchExecutionCommand command =
new BatchExecutionCommand();

command.setLookup("ksession1");

GetObjectCommand getObjectCommand = new
GetObjectCommand();

getObjectCommand.setFactHandleFromString("123:234:345:456:567");

getObjectCommand.setOutIdentifier("john");

command.getCommands().add(getObjectCommand);

XML 输出

XStream

<batch-execution
lookup="ksession1">

<get-object
fact-handle="0:234:345:456:567"
out-identifier="john"/>

</batch-execution>

JSON

{"batch-execution":{"lookup":"ksession1","commands":{"get-object":{"fact-handle":"0:234:345:456:567","out-identifier":"john"}}}}

JAXB

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>

<batch-execution
lookup="ksession1">

<get-object
out-identifier="john"
fact-handle="0:234:345:456:567"/>

</batch-execution>

9.2.6. InsertElementsCommand
描述：插入一个对象数组
属性：表9.6.InsertElementsCommand

Name	Description	required
objects	将要插入的对象数组	true
outIdentifier	FactHandle的ID，在对象被插入并添加到执行队列中时创建	false
returnObject	Boolean值，当对象必须在执行结果中返回时创建。默认值：true	false
entryPoint	插入的入口	False

创建代码：

List<Command> cmds = ArrayList<Command>();

List<Object> objects = new ArrayList<Object>();

objects.add(new Person("john",
25));

objects.add(new Person("sarah",
35));

Command insertElementsCommand = CommandFactory.newInsertElements( objects );

cmds.add( insertElementsCommand );

BatchExecutionCommand command = CommandFactory.createBatchExecution(cmds,
"ksession1" );

XML output

XStream

<batch-execution
lookup="ksession1">

<insert-elements>

<org.drools.compiler.test.Person>

<name>john</name>

<age>25</age>

</org.drools.compiler.test.Person>

<org.drools.compiler.test.Person>

<name>sarah</name>

<age>35</age>

</org.drools.compiler.test.Person>

</insert-elements>

</batch-execution>

JSON

{"batch-execution":{"lookup":"ksession1","commands":{"insert-elements":{"objects":[{"containedObject":{"@class":"org.drools.compiler.test.Person","name":"john","age":25}},{"containedObject":{"@class":"Person","name":"sarah","age":35}}]}}}}

JAXB

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>

<batch-execution
lookup="ksession1">

<insert-elements
return-objects="true">

<list>

<element
xsi:type="person"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

<age>25</age>

<name>john</name>

</element>

<element
xsi:type="person"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

<age>35</age>

<name>sarah</name>

</element>

<list>

</insert-elements>

</batch-execution>

以下略：参见原文第9章

http://docs.jboss.org/drools/release/6.2.0.Final/drools-docs/html/index.html

9.2.7. FireAllRulesCommand
9.2.8. StartProcessCommand
9.2.9. SignalEventCommand
9.2.10. CompleteWorkItemCommand
9.2.11. AbortWorkItemCommand
9.2.12. QueryCommand
9.2.13. SetGlobalCommand
9.2.14. GetGlobalCommand
9.2.15. GetObjectsCommand