What is exchange class in java

Exchange class in Java

An "Exchange" class typically refers to a plain Java class used to encapsulate a message or a data exchange between components (commonly seen in messaging frameworks like Apache Camel). It is not a built-in Java SE class but a design pattern/POJO used to carry payload, metadata, and processing state.

Common responsibilities

• Payload: holds the main message/data (object or byte[]).
• Headers/Properties: stores metadata (key-value pairs).
• Exchange ID: unique identifier for the exchange instance.
• Pattern/Type: indicates message exchange pattern (e.g., InOnly, InOut).
• Attachments: optional binary or additional parts.
• Exception/Status: holds processing exceptions or status flags.
• Routing/Endpoint info: source/destination identifiers.

Typical structure (example)

public class Exchange {
    private final String id;
    private Object body;
    private Map<String, Object> headers = new HashMap<>();
    private Exception exception;

    public Exchange(String id, Object body) {
        this.id = id;
        this.body = body;
    }

    public String getId() { return id; }
    public Object getBody() { return body; }
    public void setBody(Object body) { this.body = body; }

    public Map<String, Object> getHeaders() { return headers; }
    public void setHeader(String name, Object value) { headers.put(name, value); }
    public Object getHeader(String name) { return headers.get(name); }

    public Exception getException() { return exception; }
    public void setException(Exception exception) { this.exception = exception; }
}