The base resource to use JCA CCI is the ConnectionFactory interface. The connector used must provide an implementation of this interface.

To use your connector, you can deploy it on your application server and fetch the ConnectionFactory from the server's JNDI environment (managed mode). The connector must be packaged as a RAR file (resource adapter archive) and contain a ra.xml file to describe its deployment characteristics. The actual name of the resource is specified when you deploy it. To access it within Spring, simply use Spring's JndiObjectFactoryBean / <jee:jndi-lookup> fetch the factory by its JNDI name.

Another way to use a connector is to embed it in your application (non-managed mode), not using an application server to deploy and configure it. Spring offers the possibility to configure a connector as a bean, through a provided FactoryBean (LocalConnectionFactoryBean). In this manner, you only need the connector library in the classpath (no RAR file and no ra.xml descriptor needed). The library must be extracted from the connector's RAR file, if necessary.

Once you have got access to your ConnectionFactory instance, you can inject it into your components. These components can either be coded against the plain CCI API or leverage Spring's support classes for CCI access (e.g. CciTemplate).

	Note
	When you use a connector in non-managed mode, you can't use global transactions because the resource is never enlisted / delisted in the current global transaction of the current thread. The resource is simply not aware of any global Java EE transactions that might be running.

In order to make connections to the EIS, you need to obtain a ConnectionFactory from the application server if you are in a managed mode, or directly from Spring if you are in a non-managed mode.

In a managed mode, you access a ConnectionFactory from JNDI; its properties will be configured in the application server.

<jee:jndi-lookup id="eciConnectionFactory" jndi-name="eis/cicseci"/>

In non-managed mode, you must configure the ConnectionFactory you want to use in the configuration of Spring as a JavaBean. The LocalConnectionFactoryBean class offers this setup style, passing in the ManagedConnectionFactory implementation of your connector, exposing the application-level CCI ConnectionFactory.

<bean id="eciManagedConnectionFactory" class="com.ibm.connector2.cics.ECIManagedConnectionFactory">
  <property name="serverName" value="TXSERIES"/>
  <property name="connectionURL" value="tcp://localhost/"/>
  <property name="portNumber" value="2006"/>
</bean>

<bean id="eciConnectionFactory" class="org.springframework.jca.support.LocalConnectionFactoryBean">
  <property name="managedConnectionFactory" ref="eciManagedConnectionFactory"/>
</bean>

	Note
	You can't directly instantiate a specific ConnectionFactory. You need to go through the corresponding implementation of the ManagedConnectionFactory interface for your connector. This interface is part of the JCA SPI specification.

JCA CCI allow the developer to configure the connections to the EIS using the ConnectionSpec implementation of your connector. In order to configure its properties, you need to wrap the target connection factory with a dedicated adapter, ConnectionSpecConnectionFactoryAdapter. So, the dedicated ConnectionSpec can be configured with the property connectionSpec (as an inner bean).

This property is not mandatory because the CCI ConnectionFactory interface defines two different methods to obtain a CCI connection. Some of the ConnectionSpec properties can often be configured in the application server (in managed mode) or on the corresponding local ManagedConnectionFactory implementation.

public interface ConnectionFactory implements Serializable, Referenceable {
  ...
  Connection getConnection() throws ResourceException;
  Connection getConnection(ConnectionSpec connectionSpec) throws ResourceException;
  ...
}

Spring provides a ConnectionSpecConnectionFactoryAdapter that allows for specifying a ConnectionSpec instance to use for all operations on a given factory. If the adapter's connectionSpec property is specified, the adapter uses the getConnection variant with the ConnectionSpec argument, otherwise the variant without argument.

<bean id="managedConnectionFactory"
    class="com.sun.connector.cciblackbox.CciLocalTxManagedConnectionFactory">
  <property name="connectionURL" value="jdbc:hsqldb:hsql://localhost:9001"/>
  <property name="driverName" value="org.hsqldb.jdbcDriver"/>
</bean>

<bean id="targetConnectionFactory"
    class="org.springframework.jca.support.LocalConnectionFactoryBean">
  <property name="managedConnectionFactory" ref="managedConnectionFactory"/>
</bean>

<bean id="connectionFactory"
    class="org.springframework.jca.cci.connection.ConnectionSpecConnectionFactoryAdapter">
  <property name="targetConnectionFactory" ref="targetConnectionFactory"/>
  <property name="connectionSpec">
    <bean class="com.sun.connector.cciblackbox.CciConnectionSpec">
      <property name="user" value="sa"/>
      <property name="password" value=""/>
    </bean>
  </property>
</bean>

If you want to use a single CCI connection, Spring provides a further ConnectionFactory adapter to manage this. The SingleConnectionFactory adapter class will open a single connection lazily and close it when this bean is destroyed at application shutdown. This class will expose special Connection proxies that behave accordingly, all sharing the same underlying physical connection.

<bean id="eciManagedConnectionFactory"
    class="com.ibm.connector2.cics.ECIManagedConnectionFactory">
  <property name="serverName" value="TEST"/>
  <property name="connectionURL" value="tcp://localhost/"/>
  <property name="portNumber" value="2006"/>
</bean>

<bean id="targetEciConnectionFactory"
    class="org.springframework.jca.support.LocalConnectionFactoryBean">
  <property name="managedConnectionFactory" ref="eciManagedConnectionFactory"/>
</bean>

<bean id="eciConnectionFactory"
    class="org.springframework.jca.cci.connection.SingleConnectionFactory">
  <property name="targetConnectionFactory" ref="targetEciConnectionFactory"/>
</bean>

	Note
	This ConnectionFactory adapter cannot directly be configured with a ConnectionSpec. Use an intermediary ConnectionSpecConnectionFactoryAdapter that the SingleConnectionFactory talks to if you require a single connection for a specific ConnectionSpec.

One of the aims of the JCA CCI support is to provide convenient facilities for manipulating CCI records. The developer can specify the strategy to create records and extract datas from records, for use with Spring's CciTemplate. The following interfaces will configure the strategy to use input and output records if you don't want to work with records directly in your application.

In order to create an input Record, the developer can use a dedicated implementation of the RecordCreator interface.

public interface RecordCreator {

  Record createRecord(RecordFactory recordFactory) throws ResourceException, DataAccessException;
}

As you can see, the createRecord(..) method receives a RecordFactory instance as parameter, which corresponds to the RecordFactory of the ConnectionFactory used. This reference can be used to create IndexedRecord or MappedRecord instances. The following sample shows how to use the RecordCreator interface and indexed/mapped records.

public class MyRecordCreator implements RecordCreator {

  public Record createRecord(RecordFactory recordFactory) throws ResourceException {
    IndexedRecord input = recordFactory.createIndexedRecord("input");
    input.add(new Integer(id));
    return input;
  }
}

An output Record can be used to receive data back from the EIS. Hence, a specific implementation of the RecordExtractor interface can be passed to Spring's CciTemplate for extracting data from the output Record.

public interface RecordExtractor {

  Object extractData(Record record) throws ResourceException, SQLException, DataAccessException;
}

The following sample shows how to use the RecordExtractor interface.

public class MyRecordExtractor implements RecordExtractor {

  public Object extractData(Record record) throws ResourceException {
    CommAreaRecord commAreaRecord = (CommAreaRecord) record;
    String str = new String(commAreaRecord.toByteArray());
    String field1 = string.substring(0,6);
    String field2 = string.substring(6,1);
    return new OutputObject(Long.parseLong(field1), field2);
  }
}

The CciTemplate is the central class of the core CCI support package (org.springframework.jca.cci.core). It simplifies the use of CCI since it handles the creation and release of resources. This helps to avoid common errors like forgetting to always close the connection. It cares for the lifecycle of connection and interaction objects, letting application code focus on generating input records from application data and extracting application data from output records.

The JCA CCI specification defines two distinct methods to call operations on an EIS. The CCI Interaction interface provides two execute method signatures:

public interface javax.resource.cci.Interaction {
  ...
  boolean execute(InteractionSpec spec, Record input, Record output) throws ResourceException;

  Record execute(InteractionSpec spec, Record input) throws ResourceException;
  ...
}

Depending on the template method called, CciTemplate will know which execute method to call on the interaction. In any case, a correctly initialized InteractionSpec instance is mandatory.

CciTemplate.execute(..) can be used in two ways:

With the first approach, the following methods of the template will be used. These methods directly correspond to those on the Interaction interface.

public class CciTemplate implements CciOperations {

  public Record execute(InteractionSpec spec, Record inputRecord)
      throws DataAccessException { ... }

  public void execute(InteractionSpec spec, Record inputRecord, Record outputRecord)
      throws DataAccessException { ... }

}

With the second approach, we need to specify the record creation and record extraction strategies as arguments. The interfaces used are those describe in the previous section on record conversion. The corresponding CciTemplate methods are the following:

public class CciTemplate implements CciOperations {

  public Record execute(InteractionSpec spec, RecordCreator inputCreator)
      throws DataAccessException { ... }

  public Object execute(InteractionSpec spec, Record inputRecord, RecordExtractor outputExtractor)
      throws DataAccessException { ... }

  public Object execute(InteractionSpec spec, RecordCreator creator, RecordExtractor extractor)
      throws DataAccessException { ... }

}

Unless the outputRecordCreator property is set on the template (see the following section), every method will call the corresponding execute method of the CCI Interaction with two parameters: InteractionSpec and input Record, receiving an output Record as return value.

CciTemplate also provides methods to create IndexRecord and MappedRecord outside a RecordCreator implementation, through its createIndexRecord(..) and createMappedRecord(..) methods. This can be used within DAO implementations to create Record instances to pass into corresponding CciTemplate.execute(..) methods.

public class CciTemplate implements CciOperations {

  public IndexedRecord createIndexedRecord(String name) throws DataAccessException { ... }

  public MappedRecord createMappedRecord(String name) throws DataAccessException { ... }

}

Spring's CCI support provides a abstract class for DAOs, supporting injection of a ConnectionFactory or a CciTemplate instances. The name of the class is CciDaoSupport: It provides simple setConnectionFactory and setCciTemplate methods. Internally, this class will create a CciTemplate instance for a passed-in ConnectionFactory, exposing it to concrete data access implementations in subclasses.

public abstract class CciDaoSupport {

  public void setConnectionFactory(ConnectionFactory connectionFactory) { ... }
  public ConnectionFactory getConnectionFactory() { ... }

  public void setCciTemplate(CciTemplate cciTemplate) { ... }
  public CciTemplate getCciTemplate() { ... }

}

If the connector used only supports the Interaction.execute(..) method with input and output records as parameters (that is, it requires the desired output record to be passed in instead of returning an appropriate output record), you can set the outputRecordCreator property of the CciTemplate to automatically generate an output record to be filled by the JCA connector when the response is received. This record will be then returned to the caller of the template.

This property simply holds an implementation of the RecordCreator interface, used for that purpose. The RecordCreator interface has already been discussed in Section 24.3.1, “Record conversion”. The outputRecordCreator property must be directly specified on the CciTemplate. This could be done in the application code like so:

cciTemplate.setOutputRecordCreator(new EciOutputRecordCreator());

Or (recommended) in the Spring configuration, if the CciTemplate is configured as a dedicated bean instance:

<bean id="eciOutputRecordCreator" class="eci.EciOutputRecordCreator"/>

<bean id="cciTemplate" class="org.springframework.jca.cci.core.CciTemplate">
  <property name="connectionFactory" ref="eciConnectionFactory"/>
  <property name="outputRecordCreator" ref="eciOutputRecordCreator"/>
</bean>

	Note
	As the CciTemplate class is thread-safe, it will usually be configured as a shared instance.

The following table summarizes the mechanisms of the CciTemplate class and the corresponding methods called on the CCI Interaction interface:

CciTemplate also offers the possibility to work directly with CCI connections and interactions, in the same manner as JdbcTemplate and JmsTemplate. This is useful when you want to perform multiple operations on a CCI connection or interaction, for example.

The interface ConnectionCallback provides a CCI Connection as argument, in order to perform custom operations on it, plus the CCI ConnectionFactory which the Connection was created with. The latter can be useful for example to get an associated RecordFactory instance and create indexed/mapped records, for example.

public interface ConnectionCallback {

  Object doInConnection(Connection connection, ConnectionFactory connectionFactory)
      throws ResourceException, SQLException, DataAccessException;
}

The interface InteractionCallback provides the CCI Interaction, in order to perform custom operations on it, plus the corresponding CCI ConnectionFactory.

public interface InteractionCallback {

  Object doInInteraction(Interaction interaction, ConnectionFactory connectionFactory)
      throws ResourceException, SQLException, DataAccessException;
}

	Note
	InteractionSpec objects can either be shared across multiple template calls or newly created inside every callback method. This is completely up to the DAO implementation.

In this section, the usage of the CciTemplate will be shown to acces to a CICS with ECI mode, with the IBM CICS ECI connector.

Firstly, some initializations on the CCI InteractionSpec must be done to specify which CICS program to access and how to interact with it.

ECIInteractionSpec interactionSpec = new ECIInteractionSpec();
interactionSpec.setFunctionName("MYPROG");
interactionSpec.setInteractionVerb(ECIInteractionSpec.SYNC_SEND_RECEIVE);

Then the program can use CCI via Spring's template and specify mappings between custom objects and CCI Records.

public class MyDaoImpl extends CciDaoSupport implements MyDao {

  public OutputObject getData(InputObject input) {
    ECIInteractionSpec interactionSpec = ...;

    OutputObject output = (ObjectOutput) getCciTemplate().execute(interactionSpec,
        new RecordCreator() {
          public Record createRecord(RecordFactory recordFactory) throws ResourceException {
            return new CommAreaRecord(input.toString().getBytes());
          }
        },
        new RecordExtractor() {
          public Object extractData(Record record) throws ResourceException {
            CommAreaRecord commAreaRecord = (CommAreaRecord)record;
            String str = new String(commAreaRecord.toByteArray());
            String field1 = string.substring(0,6);
            String field2 = string.substring(6,1);
            return new OutputObject(Long.parseLong(field1), field2);
          }
        });

    return output;
  }
}

As discussed previously, callbacks can be used to work directly on CCI connections or interactions.

public class MyDaoImpl extends CciDaoSupport implements MyDao {

  public OutputObject getData(InputObject input) {
    ObjectOutput output = (ObjectOutput) getCciTemplate().execute(
        new ConnectionCallback() {
          public Object doInConnection(Connection connection, ConnectionFactory factory)
              throws ResourceException {
              
            // do something...
          }
        });
    }
    return output;
  }
}

	Note
	With a ConnectionCallback, the Connection used will be managed and closed by the CciTemplate, but any interactions created on the connection must be managed by the callback implementation.

For a more specific callback, you can implement an InteractionCallback. The passed-in Interaction will be managed and closed by the CciTemplate in this case.

public class MyDaoImpl extends CciDaoSupport implements MyDao {

  public String getData(String input) {
    ECIInteractionSpec interactionSpec = ...;

    String output = (String) getCciTemplate().execute(interactionSpec,
        new InteractionCallback() {
          public Object doInInteraction(Interaction interaction, ConnectionFactory factory)
              throws ResourceException {
            Record input = new CommAreaRecord(inputString.getBytes());
            Record output = new CommAreaRecord();
            interaction.execute(holder.getInteractionSpec(), input, output);
            return new String(output.toByteArray());
          }
        });

    return output;
  }
}

For the examples above, the corresponding configuration of the involved Spring beans could look like this in non-managed mode:

<bean id="managedConnectionFactory" class="com.ibm.connector2.cics.ECIManagedConnectionFactory">
  <property name="serverName" value="TXSERIES"/>
  <property name="connectionURL" value="local:"/>
  <property name="userName" value="CICSUSER"/>
  <property name="password" value="CICS"/>
</bean>

<bean id="connectionFactory" class="org.springframework.jca.support.LocalConnectionFactoryBean">
  <property name="managedConnectionFactory" ref="managedConnectionFactory"/>
</bean>

<bean id="component" class="mypackage.MyDaoImpl">
  <property name="connectionFactory" ref="connectionFactory"/>
</bean>

In managed mode (that is, in a Java EE environment), the configuration could look as follows:

<jee:jndi-lookup id="connectionFactory" jndi-name="eis/cicseci"/>

<bean id="component" class="MyDaoImpl">
  <property name="connectionFactory" ref="connectionFactory"/>
</bean>

MappingRecordOperation essentially performs the same work as CciTemplate, but represents a specific, pre-configured operation as an object. It provides two template methods to specify how to convert an input object to a input record, and how to convert an output record to an output object (record mapping):

Here are the signatures of these methods:

public abstract class MappingRecordOperation extends EisOperation {
  ...
  protected abstract Record createInputRecord(RecordFactory recordFactory, Object inputObject)
      throws ResourceException, DataAccessException { ... }

  protected abstract Object extractOutputData(Record outputRecord)
      throws ResourceException, SQLException, DataAccessException { ... }
  ...
}

Thereafter, in order to execute an EIS operation, you need to use a single execute method, passing in an application-level input object and receiving an application-level output object as result:

public abstract class MappingRecordOperation extends EisOperation {
  ...
  public Object execute(Object inputObject) throws DataAccessException {
  ...
}

As you can see, contrary to the CciTemplate class, this execute(..) method does not have an InteractionSpec as argument. Instead, the InteractionSpec is global to the operation. The following constructor must be used to instantiate an operation object with a specific InteractionSpec:

InteractionSpec spec = ...;
MyMappingRecordOperation eisOperation = new MyMappingRecordOperation(getConnectionFactory(), spec);
...

Some connectors use records based on a COMMAREA which represents an array of bytes containing parameters to send to the EIS and data returned by it. Spring provides a special operation class for working directly on COMMAREA rather than on records. The MappingCommAreaOperation class extends the MappingRecordOperation class to provide such special COMMAREA support. It implicitly uses the CommAreaRecord class as input and output record type, and provides two new methods to convert an input object into an input COMMAREA and the output COMMAREA into an output object.

public abstract class MappingCommAreaOperation extends MappingRecordOperation {
  ...
  protected abstract byte[] objectToBytes(Object inObject)
      throws IOException, DataAccessException;

  protected abstract Object bytesToObject(byte[] bytes)
      throws IOException, DataAccessException;
  ...
}

As every MappingRecordOperation subclass is based on CciTemplate internally, the same way to automatically generate output records as with CciTemplate is available. Every operation object provides a corresponding setOutputRecordCreator(..) method. For further information, see Section 24.3.4, “Automatic output record generation”.

The operation object approach uses records in the same manner as the CciTemplate class.

In this section, the usage of the MappingRecordOperation will be shown to access a database with the Blackbox CCI connector.

	Note
	The original version of this connector is provided by the Java EE SDK (version 1.3), available from Sun.

Firstly, some initializations on the CCI InteractionSpec must be done to specify which SQL request to execute. In this sample, we directly define the way to convert the parameters of the request to a CCI record and the way to convert the CCI result record to an instance of the Person class.

public class PersonMappingOperation extends MappingRecordOperation {

  public PersonMappingOperation(ConnectionFactory connectionFactory) {
    setConnectionFactory(connectionFactory);
    CciInteractionSpec interactionSpec = new CciConnectionSpec();
    interactionSpec.setSql("select * from person where person_id=?");
    setInteractionSpec(interactionSpec);
  }

  protected Record createInputRecord(RecordFactory recordFactory, Object inputObject)
      throws ResourceException {
    Integer id = (Integer) inputObject;
    IndexedRecord input = recordFactory.createIndexedRecord("input");
    input.add(new Integer(id));
    return input;
  }

  protected Object extractOutputData(Record outputRecord)
      throws ResourceException, SQLException {
    ResultSet rs = (ResultSet) outputRecord;
    Person person = null;
    if (rs.next()) {
      Person person = new Person();
      person.setId(rs.getInt("person_id"));
      person.setLastName(rs.getString("person_last_name"));
      person.setFirstName(rs.getString("person_first_name"));
    }
    return person;
  }
}

Then the application can execute the operation object, with the person identifier as argument. Note that operation object could be set up as shared instance, as it is thread-safe.

public class MyDaoImpl extends CciDaoSupport implements MyDao {

  public Person getPerson(int id) {
    PersonMappingOperation query = new PersonMappingOperation(getConnectionFactory());
    Person person = (Person) query.execute(new Integer(id));
    return person;
  }
}

The corresponding configuration of Spring beans could look as follows in non-managed mode:

<bean id="managedConnectionFactory"
    class="com.sun.connector.cciblackbox.CciLocalTxManagedConnectionFactory">
  <property name="connectionURL" value="jdbc:hsqldb:hsql://localhost:9001"/>
  <property name="driverName" value="org.hsqldb.jdbcDriver"/>
</bean>

<bean id="targetConnectionFactory"
    class="org.springframework.jca.support.LocalConnectionFactoryBean">
  <property name="managedConnectionFactory" ref="managedConnectionFactory"/>
</bean>

<bean id="connectionFactory"
    class="org.springframework.jca.cci.connection.ConnectionSpecConnectionFactoryAdapter">
  <property name="targetConnectionFactory" ref="targetConnectionFactory"/>
  <property name="connectionSpec">
    <bean class="com.sun.connector.cciblackbox.CciConnectionSpec">
      <property name="user" value="sa"/>
      <property name="password" value=""/>
    </bean>
  </property>
</bean>

<bean id="component" class="MyDaoImpl">
  <property name="connectionFactory" ref="connectionFactory"/>
</bean>

In managed mode (that is, in a Java EE environment), the configuration could look as follows:

<jee:jndi-lookup id="targetConnectionFactory" jndi-name="eis/blackbox"/>

<bean id="connectionFactory"
    class="org.springframework.jca.cci.connection.ConnectionSpecConnectionFactoryAdapter">
  <property name="targetConnectionFactory" ref="targetConnectionFactory"/>
  <property name="connectionSpec">
    <bean class="com.sun.connector.cciblackbox.CciConnectionSpec">
      <property name="user" value="sa"/>
      <property name="password" value=""/>
    </bean>
  </property>
</bean>

<bean id="component" class="MyDaoImpl">
  <property name="connectionFactory" ref="connectionFactory"/>
</bean>

In this section, the usage of the MappingCommAreaOperation will be shown: accessing a CICS with ECI mode with the IBM CICS ECI connector.

Firstly, the CCI InteractionSpec needs to be initialized to specify which CICS program to access and how to interact with it.

public abstract class EciMappingOperation extends MappingCommAreaOperation {

  public EciMappingOperation(ConnectionFactory connectionFactory, String programName) {
    setConnectionFactory(connectionFactory);
    ECIInteractionSpec interactionSpec = new ECIInteractionSpec(),
    interactionSpec.setFunctionName(programName);
    interactionSpec.setInteractionVerb(ECIInteractionSpec.SYNC_SEND_RECEIVE);
    interactionSpec.setCommareaLength(30);
    setInteractionSpec(interactionSpec);
    setOutputRecordCreator(new EciOutputRecordCreator());
  }

  private static class EciOutputRecordCreator implements RecordCreator {
    public Record createRecord(RecordFactory recordFactory) throws ResourceException {
      return new CommAreaRecord();
    }
  }
}

The abstract EciMappingOperation class can then be subclassed to specify mappings between custom objects and Records.

public class MyDaoImpl extends CciDaoSupport implements MyDao {

  public OutputObject getData(Integer id) {
    EciMappingOperation query = new EciMappingOperation(getConnectionFactory(), "MYPROG") {
      protected abstract byte[] objectToBytes(Object inObject) throws IOException {
        Integer id = (Integer) inObject;
        return String.valueOf(id);
      }
      protected abstract Object bytesToObject(byte[] bytes) throws IOException;
        String str = new String(bytes);
        String field1 = str.substring(0,6);
        String field2 = str.substring(6,1);
        String field3 = str.substring(7,1);
        return new OutputObject(field1, field2, field3);
      }
    });

    return (OutputObject) query.execute(new Integer(id));
  }
}

The corresponding configuration of Spring beans could look as follows in non-managed mode:

<bean id="managedConnectionFactory" class="com.ibm.connector2.cics.ECIManagedConnectionFactory">
  <property name="serverName" value="TXSERIES"/>
  <property name="connectionURL" value="local:"/>
  <property name="userName" value="CICSUSER"/>
  <property name="password" value="CICS"/>
</bean>

<bean id="connectionFactory" class="org.springframework.jca.support.LocalConnectionFactoryBean">
  <property name="managedConnectionFactory" ref="managedConnectionFactory"/>
</bean>

<bean id="component" class="MyDaoImpl">
  <property name="connectionFactory" ref="connectionFactory"/>
</bean>

In managed mode (that is, in a Java EE environment), the configuration could look as follows:

<jee:jndi-lookup id="connectionFactory" jndi-name="eis/cicseci"/>

<bean id="component" class="MyDaoImpl">
  <property name="connectionFactory" ref="connectionFactory"/>
</bean>