1. ptc\Windchill_12.0\Windchill\codebase\rest\custom\domain\DocMgmt\v5\import.js
function action_updatePrimaryConentOfDocument(data, params) {
    var doc = Java.type('ext.sconce.solution.ODataHelper');
    return doc.updatePrimaryConentOfDocument(data, params);
}


2. ptc\Windchill_12.0\Windchill\codebase\rest\custom\domain\DocMgmt\v5\import.json
"actions" : [
         {
            "name": "updatePrimaryConentOfDocument",
            "importName": "updatePrimaryConentOfDocument",
            "description": "API to update update Primary Content Of WTDocument & remove existing content",
            "includeInServiceDocument": true,
            "parameters": [
                {
                    "name": "Number",
                    "type": "String",
					"isNullable": false,
					"isCollection": false
				},
				{
                    "name": "fileLocation",
                    "type": "String",
					"isNullable": false,
					"isCollection": false
				},
				{
                    "name": "fileName",
                    "type": "String",
					"isNullable": false,
					"isCollection": false
				}
            ],
            "returnType": {
                "type": "Edm.String",
                "isCollection":false,
				"isNullable": true
            }
        }
	]	

Input:
fileLocation: D:\TestUploadFolder
Number      : 0000007608
fileName    : Sample.pdf


3. Java file:
package ext.sconce.solution;

import java.beans.PropertyVetoException;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

import org.apache.logging.log4j.Logger;
import org.apache.olingo.commons.api.data.Parameter;
import org.apache.olingo.commons.api.http.HttpStatusCode;
import org.apache.olingo.server.api.ODataApplicationException;
import org.json.JSONObject;

import com.flexnet.lm.binary.StringUtil;
import com.ptc.odata.core.entity.action.ActionProcessorData;
import com.ptc.odata.core.entity.property.EntityAttribute;
import com.ptc.odata.core.entity.property.PropertyValueType;

import wt.content.ApplicationData;
import wt.content.ContentHelper;
import wt.content.ContentHolder;
import wt.content.ContentItem;
import wt.content.ContentRoleType;
import wt.content.ContentServerHelper;
import wt.doc.WTDocument;
import wt.fc.QueryResult;
import wt.log4j.LogR;
import wt.pds.StatementSpec;
import wt.pom.Transaction;
import wt.util.WTException;
import wt.util.WTProperties;
import wt.util.WTPropertyVetoException;

public class ODataHelper {

	private static String CLASSNAME = ODataHelper.class.getName();
	private static Logger logger = LogR.getLoggerInternal(CLASSNAME);

	public static EntityAttribute updatePrimaryConentOfDocument(ActionProcessorData data,
			HashMap<String, Parameter> params) {
		if (logger.isDebugEnabled())
			logger.debug(CLASSNAME + " - updatePrimaryConentOfDocument Start");

		Map<String, Object> responseMap = new HashMap<String, Object>();
		String fileName = "";
		String Number = "";
		String fileLocation = "";
		try {
			Number = getStringParameter(data, params, "Number");
			fileLocation = getStringParameter(data, params, "fileLocation");
			fileName = getStringParameter(data, params, "fileName");
			logger.debug("Number:" + Number + "fileLocation" + fileLocation + "fileName " + fileName);
			updatePrimaryConentOfDocument(Number, fileLocation, fileName);
			responseMap.put("Message", "update Primary Conent Of Document successfully.");
		} catch (ODataApplicationException e) {
			e.printStackTrace();
			responseMap.put("Error", e.getMessage());
		}
		EntityAttribute result = new EntityAttribute(null, "values", PropertyValueType.PRIMITIVE,
				new JSONObject(responseMap));

		return result;
	}

	public static String getStringParameter(ActionProcessorData data, Map params, String stringName)
			throws ODataApplicationException {
		StringUtil.isEmpty("");
		Parameter param = (Parameter) params.get(stringName);
		if (org.springframework.util.StringUtils.isEmpty(param.getValue())) {
			String errorMsg = "Invalid Parameter - " + stringName + "not found in the request";
			throw new ODataApplicationException(errorMsg, HttpStatusCode.BAD_REQUEST.getStatusCode(), data.getLocale());
		} else {
			return (String) param.getValue();
		}
	}

	public static void updatePrimaryConentOfDocument(String Number, String fileLocation, String fileName) {
		logger.debug("updatePrimaryConentOfDocument - replaceContent - BEGIN");
		WTDocument wtdoc = getDocumentByNumber(Number);
		if (wtdoc != null) {
			Transaction trx = new Transaction();
			try {
				trx.start();
				ApplicationData wtdContent = ApplicationData.newApplicationData((ContentHolder) wtdoc);
				wtdContent.setFileName(fileName);
				wtdContent.setRole(ContentRoleType.PRIMARY);

				WTProperties wtproperties = wt.util.WTProperties.getLocalProperties();
				String dirSeparator = wtproperties.getProperty("dir.sep");
				logger.debug("Path : " + fileLocation + dirSeparator + fileName);
				File file = new File(fileLocation + dirSeparator + fileName);

				wtdoc = (WTDocument) wt.vc.VersionControlHelper.service.getLatestIteration(wtdoc, true);
				deletePrimaryContent(wtdoc);
				try (FileInputStream istream = new FileInputStream(file)) {
					ContentServerHelper.service.updatePrimary(wtdoc, wtdContent, istream);
					istream.close();
				}

				ContentServerHelper.service.updateHolderFormat(wtdoc);
				logger.debug("Replaced content - wtdoc: " + wtdoc.getIdentity());
				trx.commit();
				trx = null;
				logger.debug("Completed updatePrimaryConentOfDocument END");
			} catch (WTException | PropertyVetoException | IOException ex) {
				System.out.println(
						" Error while updating primary content = " + ex + "for WTDocument " + wtdoc.getIdentity());
				ex.printStackTrace();
			} finally {
				if (trx != null) {
					trx.rollback();
				}
			}
		}
	}

	public static WTDocument deletePrimaryContent(WTDocument wtdoc) {
		try {
			QueryResult qrCI = ContentHelper.service.getContentsByRole((ContentHolder) wtdoc, ContentRoleType.PRIMARY);
			if (qrCI.size() > 0) {
				ContentItem ci = (ContentItem) qrCI.nextElement();
				ContentServerHelper.service.deleteContent(wtdoc, ci);
			}
		} catch (WTException | WTPropertyVetoException ex) {
			ex.printStackTrace();
		}
		return wtdoc;
	}
	
	public static WTDocument getDocumentByNumber(String docNumber) {
	WTDocument doc = null;
		try {
			wt.fc.QueryResult result = null;
			wt.query.QuerySpec query = new wt.query.QuerySpec(WTDocument.class);
			wt.query.WhereExpression condition1 = new wt.query.SearchCondition(WTDocument.class, WTDocument.NUMBER,
					wt.query.SearchCondition.EQUAL, docNumber);
			int fromIndices[] = { 0, 1 };
			query.appendWhere(condition1, fromIndices);
			result = wt.fc.PersistenceHelper.manager.find((StatementSpec) query);
			while (result.hasMoreElements()) {
				doc = (WTDocument) result.nextElement();
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
		return doc;
	}
}