package org.w3c.ddr.simple;
/**
* An interface representing evidence that is to be supplied to getPropertyValue
* or getPropertyValues methods of {@link Service}.
* The purpose of Evidence is to represent available information with which to identify the delivery context.
* In accordance with the minimum requirements of the DDR Simple API, this interface can support the
* representation of evidence as HTTP headers.
* Consumers of HTTP evidence must support case-insensitive field names as per RFC 2616 section 4.2.
*
* @author Jo Rabin (dotMobi)
* @author
Jose Manuel Cantera Fonseca (Telefonica I+D)
* @author
Rotan Hanrahan (MobileAware)
* @author
Ignacio Marin (Fundacion CTIC)
* Copyright
* © 2008 W3C®
* (MIT,
* ERCIM,
* Keio), All Rights Reserved.
* W3C liability,
* trademark
* and document use rules apply.
*
* @see Service#newHTTPEvidence()
*/
public interface Evidence {
/**
* Add a key / value pair to the collection of evidence.
* Any value put into evidence via this method can be retrieved via a corresponding call to get(key).
*
* @param key The key that identifies an element of the evidence.
* @param value The value of the identified element.
*/
public void put(String key, String value);
/**
* True if a value for the specified key exists.
*
* @param key The unique key that identifies an element of the evidence.
* @return The value 'true' if the identified element has a value that can be retrieved, and 'false' otherwise.
*/
public boolean exists(String key);
/**
* Get the value corresponding to the key.
* For a particular key K, if there was a previous call to put(K,value) then
* the value returned by get(K) will be the most recent value used in put(K,value).
*
* @param key The key that identifies an element of the evidence.
* @return The value of the element identified by the key.
*/
public String get(String key);
}