Add Conditional Content with If/Else Leave feedback

Overview

Conditional blocks allow you to display different content in your documents based on data values. GroupDocs.Assembly for Java supports if/elseif/else syntax similar to Java, enabling you to create dynamic documents that adapt their content based on conditions.

The main syntax elements are:

<<if [condition]>> - display content if condition is true
<<elseif [condition]>> - display content if previous conditions are false and this condition is true
<<else>> - display content if all conditions are false
<</if>> - closing tag

Here are the steps to use conditional content:

Create a template with conditional blocks
Define conditions using expressions that return boolean values
Provide content for each condition branch
Assemble the document with your data

Note
Conditional expressions must return boolean values. You can use comparison operators (==, !=, <, >, <=, >=), logical operators (&&, ||, !), and method calls that return boolean.

Simple If/Else Block

Display content based on a simple condition:

import com.groupdocs.assembly.*;

public class Customer
{
    private String name;
    private double balance;

    public String getName() { return name; }
    public void setName(String value) { name = value; }
    public double getBalance() { return balance; }
    public void setBalance(double value) { balance = value; }
}

public static void simpleConditional() throws Exception
{
    Customer customer = new Customer();
    customer.setName("John Doe");
    customer.setBalance(1500.00);

    DocumentAssembler assembler = new DocumentAssembler();
    assembler.assembleDocument("ConditionalTemplate.docx", "ConditionalOutput.docx",
        new DataSourceInfo(customer, "customer"));

    System.out.println("Conditional content generated successfully.");
}

Template Example for Simple If/Else

In your template (ConditionalTemplate.docx):

Customer: <<[customer.getName()]>>

<<if [customer.getBalance() > 1000]>>
Status: Premium Customer
You have a high balance and qualify for special benefits.
<<else>>
Status: Standard Customer
Thank you for your business.
<</if>>

If/Elseif/Else Block

Use multiple conditions with elseif:

import com.groupdocs.assembly.*;

public class Order
{
    private double amount;

    public double getAmount() { return amount; }
    public void setAmount(double value) { amount = value; }
}

public static void multipleConditions() throws Exception
{
    Order order = new Order();
    order.setAmount(750.00);

    DocumentAssembler assembler = new DocumentAssembler();
    assembler.assembleDocument("ConditionalTemplate.docx", "ConditionalOutput.docx",
        new DataSourceInfo(order, "order"));

    System.out.println("Multiple conditions processed successfully.");
}

Template with elseif:

Order Amount: <<[order.getAmount()]:"$#,##0.00">>

<<if [order.getAmount() > 1000]>>
Discount: 10% (Large order discount)
<<elseif [order.getAmount() > 500]>>
Discount: 5% (Medium order discount)
<<else>>
Discount: No discount available
<</if>>

Conditional Content with Collections

Check if collections have items:

import com.groupdocs.assembly.*;
import java.util.Arrays;
import java.util.List;

public class Report
{
    private List<String> items;

    public List<String> getItems() { return items; }
    public void setItems(List<String> value) { items = value; }
}

public static void conditionalWithCollections() throws Exception
{
    Report report = new Report();
    report.setItems(Arrays.asList("Item 1", "Item 2", "Item 3"));

    DocumentAssembler assembler = new DocumentAssembler();
    assembler.assembleDocument("ConditionalTemplate.docx", "ConditionalOutput.docx",
        new DataSourceInfo(report, "report"));

    System.out.println("Conditional content with collections generated successfully.");
}

Template:

<<if [report.getItems().any()]>>
Items:
<<foreach [item in report.getItems()]>>
- <<[item]>>
<</foreach>>
<<else>>
No items available.
<</if>>

Conditional Content in Data Bands

Use conditional blocks within foreach loops:

import com.groupdocs.assembly.*;

public class Product
{
    private String name;
    private double price;
    private boolean inStock;

    public Product(String name, double price, boolean inStock)
    {
        this.name = name;
        this.price = price;
        this.inStock = inStock;
    }

    public String getName() { return name; }
    public double getPrice() { return price; }
    public boolean isInStock() { return inStock; }
}

public static void conditionalInDataBand() throws Exception
{
    // Pass an array (or a POJO with a typed List<Product> getter) so that the engine
    // knows the item type; a raw java.util.List passed directly loses its element type
    Product[] products = new Product[]
    {
        new Product("Laptop", 999.99, true),
        new Product("Mouse", 29.99, false),
        new Product("Keyboard", 79.99, true)
    };

    DocumentAssembler assembler = new DocumentAssembler();
    assembler.assembleDocument("ConditionalTemplate.docx", "ConditionalOutput.docx",
        new DataSourceInfo(products, "products"));

    System.out.println("Conditional content in data band generated successfully.");
}

Template:

<<foreach [in products]>>
<<[getName()]>> - <<[getPrice()]:"$#,##0.00">>
<<if [isInStock()]>>
✓ In Stock
<<else>>
✗ Out of Stock
<</if>>

<</foreach>>

Complex Conditions

Use logical operators for complex conditions:

import com.groupdocs.assembly.*;

public class Employee
{
    private int yearsOfService;
    private double salary;
    private String department;

    public int getYearsOfService() { return yearsOfService; }
    public void setYearsOfService(int value) { yearsOfService = value; }
    public double getSalary() { return salary; }
    public void setSalary(double value) { salary = value; }
    public String getDepartment() { return department; }
    public void setDepartment(String value) { department = value; }
}

public static void complexConditions() throws Exception
{
    Employee employee = new Employee();
    employee.setYearsOfService(5);
    employee.setSalary(75000);
    employee.setDepartment("Engineering");

    DocumentAssembler assembler = new DocumentAssembler();
    assembler.assembleDocument("ConditionalTemplate.docx", "ConditionalOutput.docx",
        new DataSourceInfo(employee, "employee"));

    System.out.println("Complex conditions processed successfully.");
}

Template with complex conditions:

<<if [employee.getYearsOfService() >= 5 && employee.getSalary() > 70000]>>
Eligible for promotion
<<elseif [employee.getDepartment() == "Engineering"]>>
Consider for technical leadership
<<else>>
Standard review process
<</if>>

Note
In template expressions, the == operator compares strings by value, so you do not need to call equals().

Conditional Formatting

Apply different formatting based on conditions:

import com.groupdocs.assembly.*;

public class Invoice
{
    private double amount;
    private boolean paid;

    public double getAmount() { return amount; }
    public void setAmount(double value) { amount = value; }
    public boolean isPaid() { return paid; }
    public void setPaid(boolean value) { paid = value; }
}

public static void conditionalFormatting() throws Exception
{
    Invoice invoice = new Invoice();
    invoice.setAmount(1500.00);
    invoice.setPaid(false);

    DocumentAssembler assembler = new DocumentAssembler();
    assembler.assembleDocument("ConditionalTemplate.docx", "ConditionalOutput.docx",
        new DataSourceInfo(invoice, "invoice"));

    System.out.println("Conditional formatting applied successfully.");
}

Template:

Amount: <<[invoice.getAmount()]:"$#,##0.00">>

<<if [invoice.isPaid()]>>
Status: PAID
<<else>>
Status: UNPAID - Payment Required
<</if>>

Using Methods in Conditions

Call methods that return boolean values:

import com.groupdocs.assembly.*;
import java.util.Arrays;
import java.util.List;

public class OrderWithItems
{
    private List<OrderItem> items;

    public List<OrderItem> getItems() { return items; }
    public void setItems(List<OrderItem> value) { items = value; }

    public boolean hasItems()
    {
        return items != null && items.size() > 0;
    }
}

public class OrderItem
{
    private String name;

    public OrderItem(String name) { this.name = name; }

    public String getName() { return name; }
}

public static void conditionalWithMethods() throws Exception
{
    OrderWithItems order = new OrderWithItems();
    order.setItems(Arrays.asList(new OrderItem("Product")));

    DocumentAssembler assembler = new DocumentAssembler();
    assembler.assembleDocument("ConditionalTemplate.docx", "ConditionalOutput.docx",
        new DataSourceInfo(order, "order"));

    System.out.println("Conditional with methods processed successfully.");
}

Template:

<<if [order.hasItems()]>>
Order contains items.
<<else>>
Order is empty.
<</if>>

Warning
Conditional blocks must be properly closed with <</if>>. Nested conditional blocks are supported, but ensure proper nesting and closing of all blocks.

Advanced Usage Topics

To learn more about table-row conditional blocks, conditional formatting in different document types, and advanced conditional scenarios, please refer to the advanced usage section.

More resources

GitHub Examples

You may easily run the code above and see the feature in action in our GitHub examples:

Free Online Apps

Along with the full-featured Java library, we provide simple but powerful free online apps.

To assemble documents from templates and data sources, you can use the online apps from the GroupDocs.Assembly App Product Family.

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Add Conditional Content with If/Else Leave feedback

Overview

Simple If/Else Block

Template Example for Simple If/Else

If/Elseif/Else Block

Conditional Content with Collections

Conditional Content in Data Bands

Complex Conditions

Conditional Formatting

Using Methods in Conditions

Advanced Usage Topics

More resources

GitHub Examples

Free Online Apps

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