org.apache.shindig.gadgets.http

Class CacheKeyBuilder

java.lang.Object

org.apache.shindig.gadgets.http.CacheKeyBuilder

public class CacheKeyBuilder
extends Object

Builds the cache key object.

Takes extra care to build the cache keys that don't thrash persistent caches.

Constructor Summary

Constructors

Constructor and Description
CacheKeyBuilder()

Method Summary

Methods

Modifier and Type	Method and Description
String	build() Inserting the keys from the parameter map only if the keys are defined, prevents thrashing the existing persistent caches at rolling restart of high-traffic servers.
CacheKeyBuilder	setLegacyParam(int index, Object value) Sets a legacy cache key parameter.
CacheKeyBuilder	setParam(String name, Object value) Sets a cache key parameter.

Methods inherited from class java.lang.Object

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

Constructor Detail

CacheKeyBuilder

public CacheKeyBuilder()

Method Detail

setLegacyParam

public CacheKeyBuilder setLegacyParam(int index,
                             Object value)

Sets a legacy cache key parameter.

The legacy cache key parameters have a fixed order. Since the cache key is not required to have all of the legacy parameters filled in, the index of the parameter must be given.

Parameters:

index - the index to place this parameter at; valid values are 0 to - 1

value - the object that determines the legacy parameter

setParam

public CacheKeyBuilder setParam(String name,
                       Object value)

Sets a cache key parameter.

Each parameter needs to be inserted in the cache key builder manually, so that the user has an option to select the parameters that need to become part of the key.

Parameters:

name - the parameter name; if null, the param will not be inserted

value - the object that determines the value of the parameter

build

public String build()

Inserting the keys from the parameter map only if the keys are defined, prevents thrashing the existing persistent caches at rolling restart of high-traffic servers. The cache keys of all URIs that don't set these parameters must not change. TODO: String parameters that have KEY_SEPARATOR appearing as a part of a string param need to be escaped (e.g. with a backslash like so: ":" -> "\:") to prevent weird cache key collisions. Moreover the active character (backslash) needs to be escaped itself for similar reasons.