14.4. 以表单或流程形式进行文档附件

流程

1. 创建自定义 marshalling 策略 .java 文件，其中包含 org.kie.api.marshalling.ObjectMarshallingStrategy 接口的实施。这个接口可让您实施自定义文档总结策略所需的变量持久性。

   这个接口中的以下方法可帮助您创建策略：

   • 布尔值接受（Object 对象）: 确定策略是否可以被汇总指定对象
   • byte[] marshal(Context context, ObjectOutput os, Object object): Marshals the specified 对象并将 marshalled 对象返回为 byte[]
   • Object unmarshal（Context context, ObjectInputStream is, byte[] 对象, ClassLoader classloader）: 阅读作为 byte[] 接收的对象并返回 unmarshalled 对象
   • void write(ObjectOutputStream os, Object object): Same 作为 marshal 方法，提供向后兼容
   • 对象 read(ObjectInputStream os): Same 作为 unmarshal 方法，为向后兼容提供

   以下代码示例是 ObjectMarshallingStrategy 实施示例，用于从 Content Management Interoperability Services(CMIS)系统存储和检索数据：

   从 CMIS 系统存储和检索数据的实现示例

   package org.jbpm.integration.cmis.impl;
   
   import java.io.ByteArrayInputStream;
   import java.io.ByteArrayOutputStream;
   import java.io.IOException;
   import java.io.ObjectInputStream;
   import java.io.ObjectOutputStream;
   import java.util.HashMap;
   
   import org.apache.chemistry.opencmis.client.api.Folder;
   import org.apache.chemistry.opencmis.client.api.Session;
   import org.apache.chemistry.opencmis.commons.data.ContentStream;
   import org.apache.commons.io.IOUtils;
   import org.drools.core.common.DroolsObjectInputStream;
   import org.jbpm.document.Document;
   import org.jbpm.integration.cmis.UpdateMode;
   
   import org.kie.api.marshalling.ObjectMarshallingStrategy;
   
   public class OpenCMISPlaceholderResolverStrategy extends OpenCMISSupport implements ObjectMarshallingStrategy {
   
   	private String user;
   	private String password;
   	private String url;
   	private String repository;
   	private String contentUrl;
   	private UpdateMode mode = UpdateMode.OVERRIDE;
   
   	public OpenCMISPlaceholderResolverStrategy(String user, String password, String url, String repository) {
   		this.user = user;
   		this.password = password;
   		this.url = url;
   		this.repository = repository;
   	}
   
   	public OpenCMISPlaceholderResolverStrategy(String user, String password, String url, String repository, UpdateMode mode) {
   		this.user = user;
   		this.password = password;
   		this.url = url;
   		this.repository = repository;
   		this.mode = mode;
   	}
   
   	   public OpenCMISPlaceholderResolverStrategy(String user, String password, String url, String repository, String contentUrl) {
   	        this.user = user;
   	        this.password = password;
   	        this.url = url;
   	        this.repository = repository;
   	        this.contentUrl = contentUrl;
   	    }
   
   	    public OpenCMISPlaceholderResolverStrategy(String user, String password, String url, String repository, String contentUrl, UpdateMode mode) {
   	        this.user = user;
   	        this.password = password;
   	        this.url = url;
   	        this.repository = repository;
   	        this.contentUrl = contentUrl;
   	        this.mode = mode;
   	    }
   
   	public boolean accept(Object object) {
   		if (object instanceof Document) {
   			return true;
   		}
   		return false;
   	}
   
   	public byte[] marshal(Context context, ObjectOutputStream os, Object object) throws IOException {
   		Document document = (Document) object;
   		Session session = getRepositorySession(user, password, url, repository);
   		try {
   			if (document.getContent() != null) {
   				String type = getType(document);
   				if (document.getIdentifier() == null || document.getIdentifier().isEmpty()) {
   					String location = getLocation(document);
   
   					Folder parent = findFolderForPath(session, location);
   					if (parent == null) {
   						parent = createFolder(session, null, location);
   					}
   					org.apache.chemistry.opencmis.client.api.Document doc = createDocument(session, parent, document.getName(), type, document.getContent());
   					document.setIdentifier(doc.getId());
   					document.addAttribute("updated", "true");
   				} else {
   					if (document.getContent() != null && "true".equals(document.getAttribute("updated"))) {
   						org.apache.chemistry.opencmis.client.api.Document doc = updateDocument(session, document.getIdentifier(), type, document.getContent(), mode);
   
   						document.setIdentifier(doc.getId());
   						document.addAttribute("updated", "false");
   					}
   				}
   			}
   			ByteArrayOutputStream buff = new ByteArrayOutputStream();
   	        ObjectOutputStream oos = new ObjectOutputStream( buff );
   	        oos.writeUTF(document.getIdentifier());
   	        oos.writeUTF(object.getClass().getCanonicalName());
   	        oos.close();
   	        return buff.toByteArray();
   		} finally {
   			session.clear();
   		}
   	}
   
   	public Object unmarshal(Context context, ObjectInputStream ois, byte[] object, ClassLoader classloader) throws IOException, ClassNotFoundException {
   		DroolsObjectInputStream is = new DroolsObjectInputStream( new ByteArrayInputStream( object ), classloader );
   		String objectId = is.readUTF();
   		String canonicalName = is.readUTF();
   		Session session = getRepositorySession(user, password, url, repository);
   		try {
   			org.apache.chemistry.opencmis.client.api.Document doc = (org.apache.chemistry.opencmis.client.api.Document) findObjectForId(session, objectId);
   			Document document = (Document) Class.forName(canonicalName).newInstance();
   			document.setAttributes(new HashMap<String, String>());
   
   			document.setIdentifier(objectId);
   			document.setName(doc.getName());
   			document.setLastModified(doc.getLastModificationDate().getTime());
   			document.setSize(doc.getContentStreamLength());
   			document.addAttribute("location", getFolderName(doc.getParents()) + getPathAsString(doc.getPaths()));
   			if (doc.getContentStream() != null && contentUrl == null) {
   				ContentStream stream = doc.getContentStream();
   				document.setContent(IOUtils.toByteArray(stream.getStream()));
   				document.addAttribute("updated", "false");
   				document.addAttribute("type", stream.getMimeType());
   			} else {
   			    document.setLink(contentUrl + document.getIdentifier());
   			}
   			return document;
   		} catch(Exception e) {
   			throw new RuntimeException("Cannot read document from CMIS", e);
   		} finally {
   			is.close();
   			session.clear();
   		}
   	}
   
   	public Context createContext() {
   		return null;
   	}
   
   	// For backward compatibility with previous serialization mechanism
   	public void write(ObjectOutputStream os, Object object) throws IOException {
   		Document document = (Document) object;
   		Session session = getRepositorySession(user, password, url, repository);
   		try {
   			if (document.getContent() != null) {
   				String type = document.getAttribute("type");
   				if (document.getIdentifier() == null) {
   					String location = document.getAttribute("location");
   
   					Folder parent = findFolderForPath(session, location);
   					if (parent == null) {
   						parent = createFolder(session, null, location);
   					}
   					org.apache.chemistry.opencmis.client.api.Document doc = createDocument(session, parent, document.getName(), type, document.getContent());
   					document.setIdentifier(doc.getId());
   					document.addAttribute("updated", "false");
   				} else {
   					if (document.getContent() != null && "true".equals(document.getAttribute("updated"))) {
   						org.apache.chemistry.opencmis.client.api.Document doc = updateDocument(session, document.getIdentifier(), type, document.getContent(), mode);
   
   						document.setIdentifier(doc.getId());
   						document.addAttribute("updated", "false");
   					}
   				}
   			}
   			ByteArrayOutputStream buff = new ByteArrayOutputStream();
   	        ObjectOutputStream oos = new ObjectOutputStream( buff );
   	        oos.writeUTF(document.getIdentifier());
   	        oos.writeUTF(object.getClass().getCanonicalName());
   	        oos.close();
   		} finally {
   			session.clear();
   		}
   	}
   
   	public Object read(ObjectInputStream os) throws IOException, ClassNotFoundException {
   		String objectId = os.readUTF();
   		String canonicalName = os.readUTF();
   		Session session = getRepositorySession(user, password, url, repository);
   		try {
   			org.apache.chemistry.opencmis.client.api.Document doc = (org.apache.chemistry.opencmis.client.api.Document) findObjectForId(session, objectId);
   			Document document = (Document) Class.forName(canonicalName).newInstance();
   
   			document.setIdentifier(objectId);
   			document.setName(doc.getName());
   			document.addAttribute("location", getFolderName(doc.getParents()) + getPathAsString(doc.getPaths()));
   			if (doc.getContentStream() != null) {
   				ContentStream stream = doc.getContentStream();
   				document.setContent(IOUtils.toByteArray(stream.getStream()));
   				document.addAttribute("updated", "false");
   				document.addAttribute("type", stream.getMimeType());
   			}
   			return document;
   		} catch(Exception e) {
   			throw new RuntimeException("Cannot read document from CMIS", e);
   		} finally {
   			session.clear();
   		}
   	}
   
   }

2. 在 Business Central 中，转至 Menu Design Projects。

3. 单击项目名称，再单击 Settings。

   图 14.4. 设置标签页

   
4. 点 Deployments MarshallingStrategy Add Marshalling Strategy。
5. 在 Name 字段中输入自定义文档 marshalling 策略的标识符，如 org.jbpm.integration.cmis.impl.OpenCMISPlaceholderResolverStrategy。
6. 从 Resolver 下拉菜单中选择相关选项，如本例中的 Reflection。
7. 单击 Test 以验证您的部署描述符文件。

8. 单击 Deploy to build 并部署更新的项目。

   或者，如果您不使用 Business Central，您可以导航到 PROJECT_HOME/src/main/resources/META_INF/kie-deployment-descriptor.xml （如果适用）并使用所需的 < marshalling-strategies > 元素编辑部署描述符文件。

   具有自定义文档总结策略的部署描述符文件示例

   <deployment-descriptor
       xsi:schemaLocation="http://www.jboss.org/jbpm deployment-descriptor.xsd"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
     <persistence-unit>org.jbpm.domain</persistence-unit>
     <audit-persistence-unit>org.jbpm.domain</audit-persistence-unit>
     <audit-mode>JPA</audit-mode>
     <persistence-mode>JPA</persistence-mode>
     <runtime-strategy>SINGLETON</runtime-strategy>
     <marshalling-strategies>
       <marshalling-strategy>
         <resolver>reflection</resolver>
         <identifier>
           org.jbpm.integration.cmis.impl.OpenCMISPlaceholderResolverStrategy
         </identifier>
       </marshalling-strategy>
     </marshalling-strategies>

9. 要启用存储在自定义位置的文档要附加到表单和进程，在相关流程中创建文档变量，并将任务输入和输出映射到 Business Central 中的变量。