org.xins.server

Class JSONCallingConvention

java.lang.Object

org.xins.common.manageable.Manageable

org.xins.server.JSONCallingConvention

public class JSONCallingConvention
extends Manageable

The JSON calling convention. This version support Yahoo style JSON calls. For the definition of the calling convention, look at http://developer.yahoo.com/common/json.html This calling convention could be used for example with Google Web Toolkit. For an example, look at http://code.google.com/webtoolkit/documentation/examples/jsonrpc/

Since:

XINS 2.0.

Version:

$Revision: 1.14 $ $Date: 2013/01/04 10:11:41 $

Author:

Anthony Goubard

Nested Class Summary

Nested classes/interfaces inherited from class org.xins.common.manageable.Manageable

Manageable.State

Field Summary

Fields

Modifier and Type	Field and Description
protected static String	RESPONSE_CONTENT_TYPE The content type of the HTTP response.
protected static String	RESPONSE_ENCODING The response encoding format.

Fields inherited from class org.xins.common.manageable.Manageable

BOOTSTRAPPED, BOOTSTRAPPING, DEINITIALIZING, INITIALIZING, UNUSABLE, USABLE

Constructor Summary

Constructors

Constructor and Description
JSONCallingConvention()

Method Summary

Methods

Modifier and Type	Method and Description
protected FunctionRequest	convertRequestImpl(HttpServletRequest httpRequest) Converts an HTTP request to a XINS request (implementation method).
protected void	convertResultImpl(FunctionResult xinsResult, HttpServletResponse httpResponse, Map<String,Object> backpack) Converts a XINS result to an HTTP response (implementation method).
protected API	getAPI() Determines the current API.
protected String[]	getSupportedMethods() Determines which HTTP methods are supported for function invocations.
protected String[]	getSupportedMethods(HttpServletRequest request) Determines which HTTP methods are supported for function invocations, for the specified request.
protected boolean	matches(HttpServletRequest httpRequest) Checks if the specified request can possibly be handled by this calling convention as a function invocation.
protected Element	parseXMLRequest(HttpServletRequest httpRequest) Parses XML from the specified HTTP request and checks that the content type is correct.
protected Element	parseXMLRequest(HttpServletRequest httpRequest, boolean checkType) Parses XML from the specified HTTP request and optionally checks that the content type is correct.

Methods inherited from class org.xins.common.manageable.Manageable

assertUsable, bootstrap, bootstrapImpl, deinit, deinitImpl, getState, init, initImpl, isBootstrapped, isUsable

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

RESPONSE_ENCODING

protected static final String RESPONSE_ENCODING

The response encoding format.

See Also:

Constant Field Values

RESPONSE_CONTENT_TYPE

protected static final String RESPONSE_CONTENT_TYPE

The content type of the HTTP response.

See Also:

Constant Field Values

Constructor Detail

JSONCallingConvention

public JSONCallingConvention()

Method Detail

getSupportedMethods

protected String[] getSupportedMethods()

Determines which HTTP methods are supported for function invocations.

Each String in the returned array must be one supported method.

The returned array must not be null, it must only contain valid HTTP method names, so they may not contain whitespace, for example. Duplicates will be ignored. HTTP method names must be in uppercase.

There must be at least one HTTP method supported for function invocations.

Note that OPTIONS must not be returned by this method, as it is not an HTTP method that can ever be used to invoke a XINS function.

HTTP OPTIONS requests are treated differently. For the path * the capabilities of the whole server are returned. For other paths, the appropriate calling convention is determined, after which the set of supported HTTP methods is returned to the called.

Returns:

the HTTP methods supported, in a String array, must not be null.

matches

protected boolean matches(HttpServletRequest httpRequest)

Checks if the specified request can possibly be handled by this calling convention as a function invocation.

Implementations of this method should be optimized for performance, as this method may be called for each incoming request. Also, this method should not have any side-effects except possibly some caching in case there is a match.

If this method throws any exception, the exception is logged as an ignorable exception and false is assumed.

This method should only be called by the XINS/Java Server Framework.

Parameters:

httpRequest - the HTTP request to investigate, never null.

Returns:

true if this calling convention is possibly able to handle this request, or false if it is definitely not able to handle this request.

convertRequestImpl

protected FunctionRequest convertRequestImpl(HttpServletRequest httpRequest)
                                      throws InvalidRequestException,
                                             FunctionNotSpecifiedException

Converts an HTTP request to a XINS request (implementation method). This method should only be called from the XINS/Java Server Framework self. Then it is guaranteed that:

• the state is usable;
• the httpRequest argument is not null;
• the HTTP method is in the set of supported methods, as indicated by getSupportedMethods().

Note that getSupportedMethods(HttpServletRequest) will not have been called prior to this method call.

Parameters:

httpRequest - the HTTP request.

Returns:

the XINS request object, should not be null.

Throws:

InvalidRequestException - if the request is considerd to be invalid.

FunctionNotSpecifiedException - if the request does not indicate the name of the function to execute.

convertResultImpl

protected void convertResultImpl(FunctionResult xinsResult,
                     HttpServletResponse httpResponse,
                     Map<String,Object> backpack)
                          throws IOException

Converts a XINS result to an HTTP response (implementation method). This method should only be called from the XINS/Java Server Framework self. Then it is guaranteed that none of the arguments is null.

Parameters:

xinsResult - the XINS result object that should be converted to an HTTP response, will not be null.

httpResponse - the HTTP response object to configure.

backpack - the backpack.

Throws:

IOException - if the invocation of any of the methods in either httpResponse or httpRequest caused an I/O error.

getAPI

protected final API getAPI()

Determines the current API.

Returns:

the current API, never null.

Since:

XINS 1.5.0

getSupportedMethods

protected String[] getSupportedMethods(HttpServletRequest request)

Determines which HTTP methods are supported for function invocations, for the specified request.

Each String in the returned array must be one supported method.

The returned array may be null. If it is not, then the returned array must only contain valid HTTP method names, so they may not contain whitespace, for example. HTTP method names must be in uppercase.

There must be at least one HTTP method supported for function invocations.

Note that OPTIONS must not be returned by this method, as it is not an HTTP method that can ever be used to invoke a XINS function.

The set of supported methods must be a subset of the set returned by getSupportedMethods().

The default implementation of this method returns the set returned by getSupportedMethods().

Parameters:

request - the request to determine the supported methods for.

Returns:

the HTTP methods supported for the specified request, in a String array, can be null.

Since:

XINS 1.5.0

parseXMLRequest

protected Element parseXMLRequest(HttpServletRequest httpRequest)
                           throws IllegalArgumentException,
                                  InvalidRequestException

Parses XML from the specified HTTP request and checks that the content type is correct.

This method uses a cache to optimize performance if either of the parseXMLRequest methods is called multiple times for the same request.

Calling this method is equivalent with calling parseXMLRequest(HttpServletRequest,boolean) with the checkType argument set to true.

Parameters:

httpRequest - the HTTP request, cannot be null.

Returns:

the parsed element, never null.

Throws:

IllegalArgumentException - if httpRequest == null.

InvalidRequestException - if the HTTP request cannot be read or cannot be parsed correctly.

Since:

XINS 1.4.0

parseXMLRequest

protected Element parseXMLRequest(HttpServletRequest httpRequest,
                      boolean checkType)
                           throws IllegalArgumentException,
                                  InvalidRequestException

Parses XML from the specified HTTP request and optionally checks that the content type is correct.

Since XINS 1.4.0, this method uses a cache to optimize performance if either of the parseXMLRequest methods is called multiple times for the same request.

Parameters:

httpRequest - the HTTP request, cannot be null.

checkType - flag indicating whether this method should check that the content type of the request is text/xml.

Returns:

the parsed element, never null.

Throws:

IllegalArgumentException - if httpRequest == null.

InvalidRequestException - if the HTTP request cannot be read or cannot be parsed correctly.

Since:

XINS 1.3.0