RequestPredicate (Helidon 1.0.1 API)

java.lang.Object
- io.helidon.webserver.RequestPredicate

```
public final class RequestPredicate
extends Object
```
Fluent API that allows to create chains of request conditions for composing logical expressions to match requests.
A new expression can be created using the create() method. This method will initialize an expression with an empty condition that will match any request.
Conditions are added to the expression by chaining method invocations and form a logical AND expression. Each method invocation will return a different instance representing the last condition in the expression. Each instance can represent only one condition, invoking a method representing a condition more than once per instance will throw an IllegalStateException.
The expression can be evaluated against a request using the test(ServerRequest) method, or a RequestPredicate.ConditionalHandler can be used to evaluate the expression and delegate to other handlers based on the result of the evaluation.
The thenApply(Handler) method can be invoked on an expression to create a RequestPredicate.ConditionalHandler.
The handler to be used for matching requests is passed as parameter to thenApply(Handler) and the handler to be used for requests that do not match can be specified using RequestPredicate.ConditionalHandler.otherwise(Handler).
Examples

Invoke a Handler only when the request contains a header name foo and accepts text/plain, otherwise return a response with 404 code.
```
 RequestPredicate.create()
                 .containsHeader("foo")
                 .accepts(MediaType.TEXT_PLAIN)
                 .thenApply((req, resp) -> {
                     // handler logic
                 });
 
```
Invoke a Handler only when the request contains a header named foo otherwise invoke another handler that throws an exception.
```
 RequestPredicate.create()
                 .containsHeader("foo")
                 .thenApply((req, resp) -> {
                     // handler logic
                 })
                 .otherwise(req, resp) -> {
                     throw new RuntimeException("Missing 'foo' header!");
                 });
 
```

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`RequestPredicate.ConditionalHandler` A `Handler` that conditionally delegates to other `Handler` instances based on a `RequestPredicate`.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`RequestPredicate`	`accepts(MediaType... contentType)` Only accept request that accepts any of the given content types.
`RequestPredicate`	`accepts(String... contentType)` Accept requests only when it accepts any of the given content types.
`RequestPredicate`	`and(Predicate<ServerRequest> predicate)` Returns a composed predicate that represents a logical AND expression between this predicate and another predicate.
`RequestPredicate`	`containsCookie(String name)` Accept request only when the specified cookie exists.
`RequestPredicate`	`containsCookie(String name, Predicate<String> predicate)` Accept requests only when the specified cookie is valid.
`RequestPredicate`	`containsCookie(String name, String value)` Accept requests only when the specified cookie contains a given value.
`RequestPredicate`	`containsHeader(String name)` Accept requests only when the specified header name exists.
`RequestPredicate`	`containsHeader(String name, Predicate<String> predicate)` Accept requests only when the specified header is valid.
`RequestPredicate`	`containsHeader(String name, String value)` Accept requests only when the specified header contains a given value.
`RequestPredicate`	`containsQueryParameter(String name)` Accept requests only when the specified query parameter exists.
`RequestPredicate`	`containsQueryParameter(String name, Predicate<String> predicate)` Accept requests only when the specified query parameter is valid.
`RequestPredicate`	`containsQueryParameter(String name, String value)` Accept requests only when the specified query parameter contains a given value.
`static RequestPredicate`	`create()` Creates new empty `RequestPredicate` instance.
`RequestPredicate`	`hasContentType(MediaType... contentType)` Only accept requests with any of the given content types.
`RequestPredicate`	`hasContentType(String... contentType)` Only accept requests with any of the given content types.
`RequestPredicate`	`isOfMethod(Http.Method... methods)` Accepts only requests with one of specified HTTP methods.
`RequestPredicate`	`isOfMethod(String... methods)` Accepts only requests with one of specified HTTP methods.
`RequestPredicate`	`negate()` Return a predicate that represents the logical negation of this predicate.
`RequestPredicate`	`or(Predicate<ServerRequest> predicate)` Returns a composed predicate that represents a logical OR expression between this predicate and another predicate.
`boolean`	`test(ServerRequest request)` Evaluate this predicate.
`RequestPredicate.ConditionalHandler`	`thenApply(Handler handler)` Set the `Handler` to use when this predicate matches the request.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - thenApply
```
public RequestPredicate.ConditionalHandler thenApply(Handler handler)
```
    Set the Handler to use when this predicate matches the request.
    
    Parameters:
    
    handler - handler to use this predicate instance matches
    
    Returns:
    
    instance of RequestPredicate.ConditionalHandler that can be used to specify another Handler to use when this predicates does not match the request
    
    See Also:
    
    RequestPredicate.ConditionalHandler.otherwise(Handler)
  - test
```
public boolean test(ServerRequest request)
```
    Evaluate this predicate.
    
    Parameters:
    
    request - the server request
    
    Returns:
    
    the computed value
  - and
```
public RequestPredicate and(Predicate<ServerRequest> predicate)
```
    Returns a composed predicate that represents a logical AND expression between this predicate and another predicate.
    
    Parameters:
    
    predicate - predicate to compose with
    
    Returns:
    
    composed predicate representing the logical expression between this predicate AND the provided predicate
  - or
```
public RequestPredicate or(Predicate<ServerRequest> predicate)
```
    Returns a composed predicate that represents a logical OR expression between this predicate and another predicate.
    
    Parameters:
    
    predicate - predicate that compute the new value
    
    Returns:
    
    composed predicate representing the logical expression between this predicate OR the provided predicate
  - negate
```
public RequestPredicate negate()
```
    Return a predicate that represents the logical negation of this predicate.
    
    Returns:
    
    new predicate that represents the logical negation of this predicate.
  - isOfMethod
```
public RequestPredicate isOfMethod(String... methods)
```
    Accepts only requests with one of specified HTTP methods.
    
    Parameters:
    
    methods - Acceptable method names
    
    Returns:
    
    composed predicate representing the logical expression between this predicate AND the provided predicate
    
    Throws:
    
    NullPointerException - if the specified methods array is null
  - isOfMethod
```
public RequestPredicate isOfMethod(Http.Method... methods)
```
    Accepts only requests with one of specified HTTP methods.
    
    Parameters:
    
    methods - Acceptable method names
    
    Returns:
    
    composed predicate representing the logical expression between this predicate AND the provided predicate
    
    Throws:
    
    NullPointerException - if the methods type array is null
  - containsHeader
```
public RequestPredicate containsHeader(String name)
```
    Accept requests only when the specified header name exists.
    
    Parameters:
    
    name - header name
    
    Returns:
    
    composed predicate representing the logical expression between this predicate AND the provided predicate
    
    Throws:
    
    NullPointerException - if the specified name is null
  - containsHeader
```
public RequestPredicate containsHeader(String name,
                                       String value)
```
    Accept requests only when the specified header contains a given value. If the request contains more then one header, it will be accepted if any of the values is equal to the provided value.
    
    Parameters:
    
    name - header name
    
    value - the expected header value
    
    Returns:
    
    composed predicate representing the logical expression between this predicate AND the provided predicate
    
    Throws:
    
    NullPointerException - if the specified name or value is null
  - containsHeader
```
public RequestPredicate containsHeader(String name,
                                       Predicate<String> predicate)
```
    Accept requests only when the specified header is valid. A header is valid when the supplied predicate matches the header value. If the request contains more than one header, it will be accepted if the predicate matches any of the values.
    
    Parameters:
    
    name - header name
    
    predicate - predicate to match the header value
    
    Returns:
    
    composed predicate representing the logical expression between this predicate AND the provided predicate
    
    Throws:
    
    NullPointerException - if the specified name or predicate is null
  - containsQueryParameter
```
public RequestPredicate containsQueryParameter(String name)
```
    Accept requests only when the specified query parameter exists.
    
    Parameters:
    
    name - query parameter name
    
    Returns:
    
    composed predicate representing the logical expression between this predicate AND the provided predicate
    
    Throws:
    
    NullPointerException - if the specified name is null
  - containsQueryParameter
```
public RequestPredicate containsQueryParameter(String name,
                                               String value)
```
    Accept requests only when the specified query parameter contains a given value.
    
    Parameters:
    
    name - query parameter name
    
    value - expected query parameter value
    
    Returns:
    
    composed predicate representing the logical expression between this predicate AND the provided predicate
    
    Throws:
    
    NullPointerException - if the specified name or value is null
  - containsQueryParameter
```
public RequestPredicate containsQueryParameter(String name,
                                               Predicate<String> predicate)
```
    Accept requests only when the specified query parameter is valid.
    
    Parameters:
    
    name - query parameter name
    
    predicate - to match the query parameter value
    
    Returns:
    
    composed predicate representing the logical expression between this predicate AND the provided predicate
    
    Throws:
    
    NullPointerException - if the specified name or predicate is null
  - containsCookie
```
public RequestPredicate containsCookie(String name)
```
    Accept request only when the specified cookie exists.
    
    Parameters:
    
    name - cookie name
    
    Returns:
    
    composed predicate representing the logical expression between this predicate AND the provided predicate
    
    Throws:
    
    NullPointerException - if the specified name is null
  - containsCookie
```
public RequestPredicate containsCookie(String name,
                                       String value)
```
    Accept requests only when the specified cookie contains a given value.
    
    Parameters:
    
    name - cookie name
    
    value - expected cookie value
    
    Returns:
    
    composed predicate representing the logical expression between this predicate AND the provided predicate
    
    Throws:
    
    NullPointerException - if the specified name or value is null
  - containsCookie
```
public RequestPredicate containsCookie(String name,
                                       Predicate<String> predicate)
```
    Accept requests only when the specified cookie is valid.
    
    Parameters:
    
    name - cookie name
    
    predicate - predicate to match the cookie value
    
    Returns:
    
    composed predicate representing the logical expression between this predicate AND the provided predicate
    
    Throws:
    
    NullPointerException - if the specified name or predicate is null
  - accepts
```
public RequestPredicate accepts(String... contentType)
```
    Accept requests only when it accepts any of the given content types.
    
    Parameters:
    
    contentType - the content types to test
    
    Returns:
    
    composed predicate representing the logical expression between this predicate AND the provided predicate
    
    Throws:
    
    NullPointerException - if the specified content type array is null
  - accepts
```
public RequestPredicate accepts(MediaType... contentType)
```
    Only accept request that accepts any of the given content types.
    
    Parameters:
    
    contentType - the content types to test
    
    Returns:
    
    composed predicate representing the logical expression between this predicate AND the provided predicate
    
    Throws:
    
    NullPointerException - if the specified content type array is null
  - hasContentType
```
public RequestPredicate hasContentType(String... contentType)
```
    Only accept requests with any of the given content types.
    
    Parameters:
    
    contentType - Content type
    
    Returns:
    
    composed predicate representing the logical expression between this predicate AND the provided predicate
    
    Throws:
    
    NullPointerException - if the specified content type array is null
  - hasContentType
```
public RequestPredicate hasContentType(MediaType... contentType)
```
    Only accept requests with any of the given content types.
    
    Parameters:
    
    contentType - Content type
    
    Returns:
    
    composed predicate representing the logical expression between this predicate AND the provided predicate
    
    Throws:
    
    NullPointerException - if the specified content type array is null
  - create
```
public static RequestPredicate create()
```
    Creates new empty RequestPredicate instance.
    
    Returns:
    
    new empty predicate (accepts all requests).

Class RequestPredicate

Examples

Nested Class Summary

Method Summary

Methods inherited from class java.lang.Object

Method Detail

thenApply

test

and

or

negate

isOfMethod

isOfMethod

containsHeader

containsHeader

containsHeader

containsQueryParameter

containsQueryParameter

containsQueryParameter

containsCookie

containsCookie

containsCookie

accepts

accepts

hasContentType

hasContentType

create