How to check dynamically generated fields on the server side

Question

I developed a web application using Spring 3.1

In one of the modules I need to save one Operation object that has many OperationParameter objects. Thus, in the view, I provided an add button for the user to create OperationParameters for a specific operation.

Both models have a sleep mode display and there is one relationship between the operation and the operation parameter. And in the Operation model, I have a List of OperationParameters that will be inserted into the database when a new Operation is created with dynamically added Operation Parameters by the user.

When I do not use validation, it works fine. When I insert an operation for the operation model, the list of OperationParameters will also be inserted into the OperationParameter table.

My question is, how can I do server side validation for OperationParameter fields? And if the check fails, then how can I show the error of a specific field OperationParameter?

Operation.java

package com.abcprocure.servicerepo.model; // Generated Feb 9, 2012 11:30:06 AM by Hibernate Tools 3.2.1.GA import java.util.ArrayList; import java.util.List; import javax.persistence.CascadeType; import javax.persistence.Column; import javax.persistence.Embedded; import javax.persistence.Entity; import javax.persistence.FetchType; import javax.persistence.GeneratedValue; import javax.persistence.Id; import javax.persistence.JoinColumn; import javax.persistence.ManyToOne; import javax.persistence.OneToMany; import javax.persistence.Table; import org.apache.commons.collections.FactoryUtils; import org.apache.commons.collections.list.LazyList; @Entity @Table(name="Operations" ,schema="dbo" ) public class Operations implements java.io.Serializable { private int operationId; @Embedded private Services services; private String operationName; private String isHqlsql; private String isMultipleTables; private String listOfTablesAffected; private String hqlQuery; private String typeOfOperation; private String operationDetail; private String inputVariables; private String outputparamdatatype; private String isCountQuery; private String isDynamicWhereQry; private String isPaginationRequired; private String biInputParameters; private List<OperationParameters> operationParameterses = LazyList .decorate(new ArrayList<OperationParameters>(), FactoryUtils.instantiateFactory(OperationParameters.class)); public Operations() { } public Operations(int operationId, Services services, String operationName) { this.operationId = operationId; this.services = services; this.operationName = operationName; } public Operations(int operationId, Services services, String operationName, String isHqlsql, String isMultipleTables, String listOfTablesAffected, String hqlQuery, String typeOfOperation, String operationDetail, String inputVariables, String outputparamdatatype, String isCountQuery, List operationParameterses) { this.operationId = operationId; this.services = services; this.operationName = operationName; this.isHqlsql = isHqlsql; this.isMultipleTables = isMultipleTables; this.listOfTablesAffected = listOfTablesAffected; this.hqlQuery = hqlQuery; this.typeOfOperation = typeOfOperation; this.operationDetail = operationDetail; this.inputVariables = inputVariables; this.outputparamdatatype = outputparamdatatype; this.isCountQuery = isCountQuery; this.operationParameterses = operationParameterses; } @Id @GeneratedValue @Column(name="operationId", unique=true, nullable=false) public int getOperationId() { return this.operationId; } public void setOperationId(int operationId) { this.operationId = operationId; } @ManyToOne(fetch=FetchType.LAZY) @JoinColumn(name="serviceId", nullable=false) public Services getServices() { return this.services; } public void setServices(Services services) { this.services = services; } @Column(name="operationName", nullable=false, length=250) public String getOperationName() { return this.operationName; } public void setOperationName(String operationName) { this.operationName = operationName; } @Column(name="isHQLSQL", length=50) public String getIsHqlsql() { return this.isHqlsql; } public void setIsHqlsql(String isHqlsql) { this.isHqlsql = isHqlsql; } @Column(name="isMultipleTables", length=50) public String getIsMultipleTables() { return this.isMultipleTables; } public void setIsMultipleTables(String isMultipleTables) { this.isMultipleTables = isMultipleTables; } @Column(name="listOfTablesAffected", length=500) public String getListOfTablesAffected() { return this.listOfTablesAffected; } public void setListOfTablesAffected(String listOfTablesAffected) { this.listOfTablesAffected = listOfTablesAffected; } @Column(name="hqlQuery") public String getHqlQuery() { return this.hqlQuery; } public void setHqlQuery(String hqlQuery) { this.hqlQuery = hqlQuery; } @Column(name="typeOfOperation", length=50) public String getTypeOfOperation() { return this.typeOfOperation; } public void setTypeOfOperation(String typeOfOperation) { this.typeOfOperation = typeOfOperation; } @Column(name="operationDetail") public String getOperationDetail() { return this.operationDetail; } public void setOperationDetail(String operationDetail) { this.operationDetail = operationDetail; } @Column(name="inputVariables", length=5000) public String getInputVariables() { return this.inputVariables; } public void setInputVariables(String inputVariables) { this.inputVariables = inputVariables; } @Column(name="outputparamdatatype", length=50) public String getOutputparamdatatype() { return this.outputparamdatatype; } public void setOutputparamdatatype(String outputparamdatatype) { this.outputparamdatatype = outputparamdatatype; } @Column(name="isCountQuery", length=10) public String getIsCountQuery() { return this.isCountQuery; } public void setIsCountQuery(String isCountQuery) { this.isCountQuery = isCountQuery; } public String getIsDynamicWhereQry() { return isDynamicWhereQry; } public void setIsDynamicWhereQry(String isDynamicWhereQry) { this.isDynamicWhereQry = isDynamicWhereQry; } public String getIsPaginationRequired() { return isPaginationRequired; } public void setIsPaginationRequired(String isPaginationRequired) { this.isPaginationRequired = isPaginationRequired; } public String getBiInputParameters() { return biInputParameters; } public void setBiInputParameters(String biInputParameters) { this.biInputParameters = biInputParameters; } @OneToMany(cascade=CascadeType.ALL, fetch=FetchType.LAZY, mappedBy="operations") public List<OperationParameters> getOperationParameterses() { return this.operationParameterses; } public void setOperationParameterses(List<OperationParameters> operationParameterses) { this.operationParameterses = operationParameterses; } } 

OperationParameters.java

 package com.abcprocure.servicerepo.model; // Generated Feb 9, 2012 11:30:06 AM by Hibernate Tools 3.2.1.GA import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.FetchType; import javax.persistence.GeneratedValue; import javax.persistence.Id; import javax.persistence.JoinColumn; import javax.persistence.ManyToOne; import javax.persistence.Table; @Entity @Table(name="OperationParameters" ,schema="dbo" ) public class OperationParameters implements java.io.Serializable { private int parameterId; private Operations operations; private String inputOutputParamName; private String inputOutputParamType; private String inputOutputParamDataType; public OperationParameters() { } public OperationParameters(int parameterId, Operations operations, String inputOutputParamName, String inputOutputParamType, String inputOutputParamDataType) { this.parameterId = parameterId; this.operations = operations; this.inputOutputParamName = inputOutputParamName; this.inputOutputParamType = inputOutputParamType; this.inputOutputParamDataType = inputOutputParamDataType; } @Id @GeneratedValue @Column(name="parameterId", unique=true, nullable=false) public int getParameterId() { return this.parameterId; } public void setParameterId(int parameterId) { this.parameterId = parameterId; } @ManyToOne(fetch=FetchType.LAZY) @JoinColumn(name="operationId", nullable=false) public Operations getOperations() { return this.operations; } public void setOperations(Operations operations) { this.operations = operations; } @Column(name="inputOutputParamName", nullable=false, length=250) public String getInputOutputParamName() { return this.inputOutputParamName; } public void setInputOutputParamName(String inputOutputParamName) { this.inputOutputParamName = inputOutputParamName; } @Column(name="inputOutputParamType", nullable=false, length=250) public String getInputOutputParamType() { return this.inputOutputParamType; } public void setInputOutputParamType(String inputOutputParamType) { this.inputOutputParamType = inputOutputParamType; } @Column(name="inputOutputParamDataType", nullable=false, length=250) public String getInputOutputParamDataType() { return this.inputOutputParamDataType; } public void setInputOutputParamDataType(String inputOutputParamDataType) { this.inputOutputParamDataType = inputOutputParamDataType; } } 

The Conroller method to send a mail request to add a new operation.

 /** * Method that will serve the post request to add the operation and operation parameters submitted by the user. * @param operations * @param map * @return {@link String} The view name that will redirect to the get request to display the previous page with newly entered operation in the list. */ @RequestMapping(value="/add", method=RequestMethod.POST) public String addOperations(@ModelAttribute Operations operations, ModelMap map) { operations.getOperationParameterses().removeAll(Collections.singleton(null)); for(int i=0; i<operations.getOperationParameterses().size(); i++) { System.out.println("parameterName :: " + ((OperationParameters)operations.getOperationParameterses().get(i)).getInputOutputParamName()); if(((OperationParameters)operations.getOperationParameterses().get(i)).getInputOutputParamName() == null || "".equalsIgnoreCase((((OperationParameters)operations.getOperationParameterses().get(i))).getInputOutputParamName())) { operations.getOperationParameterses().remove(i); System.out.println("empty parameter removed...."); } } return "redirect:/operations/" + operations.getServices().getServiceId(); } 

Any good suggestion or example in this regard would be of great help to me. :)

**

Update

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I would also like to know if it is possible to check an array of fields and show an error in the jsp file?

Please help me.

Answer 1

After a week of brainstorming, I found a solution on my own. I am very glad that I finally achieved this. :)

To check dynamically generated fields, you need to depend on custom checks on the server side. Because, if we use annotation-based validation for dynamically generated fields, then after validation it will not go into the controller function.

That way, whenever you do custom checks, validation is called from a controller function. And there you can generate an error for dynamically generated fields in the list.

If the verification fails, you need to return to the jsp page and display the errors in the form. You need to display the dynamically generated field values ​​along with their errors using .

I hope this helps others who also want the same to work.

Answer 2

You can create a helper class that checks your OperationParameters based on its data type. For strings, check for null or empty strings, and so on. The validation class may also have some context validation, such as a valid email address.

Before saving the Operation object, before saving the Operation object, you iterate through the list of operations "Operation parameters", checking the data type and / or the field containing the information context (for example, email, workdays) , and call the correct check on your helper class.

If you catch inconsistency, just throw a custom exception that describes it. The part of your code that processes it can return json to your page using the violation field, which, in turn, will give feedback to the user (i.e. the red text below the field with your error message).