Class DistributedProxySelector
java.lang.Object
java.net.ProxySelector
org.apache.hc.client5.http.impl.routing.DistributedProxySelector
A DistributedProxySelector is a custom
ProxySelector
implementation that
delegates proxy selection to a list of underlying ProxySelectors in a
distributed manner. It ensures that proxy selection is load-balanced
across the available ProxySelectors, and provides thread safety by
maintaining separate states for each thread.
The DistributedProxySelector class maintains a list of ProxySelectors,
a ThreadLocal
variable for the current ProxySelector
, and an AtomicInteger
to keep track of the shared index across all threads. When the select()
method is called, it delegates the proxy selection to the current
ProxySelector or the next available one in the list if the current one
returns an empty proxy list. Any exceptions that occur during proxy
selection are caught and ignored, and the next ProxySelector is tried.
The connectFailed() method notifies the active ProxySelector
of a
connection failure, allowing the underlying ProxySelector to handle
connection failures according to its own logic.
- Since:
- 5.3
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate final ThreadLocal
<ProxySelector> AThreadLocal
variable holding the currentProxySelector
for each thread, ensuring thread safety when accessing the currentProxySelector
.private static final org.slf4j.Logger
private final List
<ProxySelector> A list ofProxySelector
instances to be used by the DistributedProxySelector for selecting proxies.private final AtomicInteger
AnAtomicInteger
representing the shared index across all threads for maintaining the current position in the list of ProxySelectors, ensuring proper distribution ofProxySelector
usage. -
Constructor Summary
ConstructorsConstructorDescriptionDistributedProxySelector
(List<ProxySelector> selectors) Constructs a DistributedProxySelector with the given list ofProxySelector
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Method Summary
Modifier and TypeMethodDescriptionvoid
connectFailed
(URI uri, SocketAddress sa, IOException ioe) Notifies the activeProxySelector
of a connection failure.private ProxySelector
Retrieves the next availableProxySelector
in the list of selectors, incrementing the shared index atomically to ensure proper distribution across different threads.Selects a list of proxies for the givenURI
by delegating to the currentProxySelector
or the next availableProxySelector
in the list if the current one returns an empty proxy list.Methods inherited from class java.net.ProxySelector
getDefault, setDefault
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Field Details
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LOG
private static final org.slf4j.Logger LOG -
selectors
A list ofProxySelector
instances to be used by the DistributedProxySelector for selecting proxies. -
currentSelector
AThreadLocal
variable holding the currentProxySelector
for each thread, ensuring thread safety when accessing the currentProxySelector
.
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Constructor Details
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DistributedProxySelector
Constructs a DistributedProxySelector with the given list ofProxySelector
. The constructor initializes the currentSelector as aThreadLocal
, and the sharedIndex as anAtomicInteger
.- Parameters:
selectors
- the list of ProxySelectors to use.- Throws:
IllegalArgumentException
- if the list is null or empty.
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Method Details
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select
Selects a list of proxies for the givenURI
by delegating to the currentProxySelector
or the next availableProxySelector
in the list if the current one returns an empty proxy list. If anException
occurs, it will be caught and ignored, and the nextProxySelector
will be tried.- Specified by:
select
in classProxySelector
- Parameters:
uri
- theURI
to select a proxy for.- Returns:
- a list of proxies for the given
URI
.
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connectFailed
Notifies the activeProxySelector
of a connection failure. This method retrieves the currentProxySelector
from theThreadLocal
variable and delegates the handling of the connection failure to the underlying ProxySelector's connectFailed() method. After handling the connection failure, the current ProxySelector is removed from theThreadLocal
variable.- Specified by:
connectFailed
in classProxySelector
- Parameters:
uri
- theURI
that failed to connect.sa
- theSocketAddress
of the proxy that failed to connect.ioe
- theIOException
that resulted from the failed connection.
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nextSelector
Retrieves the next availableProxySelector
in the list of selectors, incrementing the shared index atomically to ensure proper distribution across different threads.- Returns:
- the next
ProxySelector
in the list.
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