io.grpc:grpc-api 1.60.1 · io.grpc.LoadBalancerProvider

Provider of LoadBalancers. Each provider is bounded to a load-balancing policy name.

Implementations can be automatically discovered by gRPC via Java's SPI mechanism. For automatic discovery, the implementation must have a zero-argument constructor and include a resource named META-INF/services/io.grpc.LoadBalancerProvider in their JAR. The file's contents should be the implementation's class name. Implementations that need arguments in their constructor can be manually registered by LoadBalancerRegistry#register.

Implementations should not throw. If they do, it may interrupt class loading. If exceptions may reasonably occur for implementation-specific reasons, implementations should generally handle the exception gracefully and return false from isAvailable().

Modifier and Type	Class and Description
private static class	LoadBalancerProvider.UnknownConfig

Modifier and Type	Field and Description
private static final NameResolver.ConfigOrError	UNKNOWN_CONFIG A sentinel value indicating that service config is not supported.

Constructor Summary

Access	Constructor and Description
public	LoadBalancerProvider()

Method Summary

Modifier and Type	Method and Description
public final boolean	equals(Object the reference object with which to compare. other) Overrides java.lang.Object.equals. Uses identity equality.
public abstract String	getPolicyName() Returns the load-balancing policy name associated with this provider, which makes it selectable via `LoadBalancerRegistry#getProvider`.
public abstract int	getPriority() A priority, from 0 to 10 that this provider should be used, taking the current environment into consideration.
public final int	hashCode() Overrides java.lang.Object.hashCode. Returns a hash code value for the object.
public abstract boolean	isAvailable() Whether this provider is available for use, taking the current environment into consideration.
public NameResolver.ConfigOrError	Returns: a tuple of the fully parsed and validated balancer configuration, else the Status. parseLoadBalancingPolicyConfig(Map<String, ?> The `Map` representation of the load balancing policy choice. rawLoadBalancingPolicyConfig) Parses the config for the Load Balancing policy unpacked from the service config.
public final String	toString() Overrides java.lang.Object.toString. Returns a string representation of the object.

Inherited from io.grpc.LoadBalancer.Factory:: newLoadBalancer

Field Detail

UNKNOWN_CONFIG	back to summary
private static final NameResolver.ConfigOrError UNKNOWN_CONFIG A sentinel value indicating that service config is not supported. This can be used to indicate that parsing of the service config is neither right nor wrong, but doesn't have any meaning.

Constructor Detail

LoadBalancerProvider	back to summary
public LoadBalancerProvider()

Method Detail

equals back to summary

equals	back to summary
public final boolean equals(Object other) Overrides java.lang.Object.equals. Uses identity equality. Parameters other:Object Doc from java.lang.Object.equals. the reference object with which to compare. Returns:boolean Doc from java.lang.Object.equals. `true` if this object is the same as the obj argument; `false` otherwise. Annotations @Override

public final boolean equals(Object other)

Overrides java.lang.Object.equals.

Uses identity equality.

Parameters

other:Object

Doc from java.lang.Object.equals.

the reference object with which to compare.

Returns:boolean

Doc from java.lang.Object.equals.

true if this object is the same as the obj argument; false otherwise.

Annotations

@Override

getPolicyName back to summary

getPolicyName	back to summary
public abstract String getPolicyName() Returns the load-balancing policy name associated with this provider, which makes it selectable via `LoadBalancerRegistry#getProvider`. This is called only when the class is loaded. It shouldn't change, and there is no point doing so. The policy name should consist of only lower case letters letters, underscore and digits, and can only start with letters.

public abstract String getPolicyName()

Returns the load-balancing policy name associated with this provider, which makes it selectable via LoadBalancerRegistry#getProvider. This is called only when the class is loaded. It shouldn't change, and there is no point doing so.

The policy name should consist of only lower case letters letters, underscore and digits, and can only start with letters.

getPriority	back to summary
public abstract int getPriority() A priority, from 0 to 10 that this provider should be used, taking the current environment into consideration. 5 should be considered the default, and then tweaked based on environment detection. A priority of 0 does not imply that the provider wouldn't work; just that it should be last in line.

hashCode back to summary

hashCode	back to summary
public final int hashCode() Overrides java.lang.Object.hashCode. Doc from java.lang.Object.hashCode. Returns a hash code value for the object. This method is supported for the benefit of hash tables such as those provided by `java.util.HashMap`. The general contract of `hashCode` is: Whenever it is invoked on the same object more than once during an execution of a Java application, the `hashCode` method must consistently return the same integer, provided no information used in `equals` comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application. If two objects are equal according to the `equals` method, then calling the `hashCode` method on each of the two objects must produce the same integer result. It is not required that if two objects are unequal according to the `equals` method, then calling the `hashCode` method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables. Returns:int a hash code value for this object. Annotations @Override

public final int hashCode()

Overrides java.lang.Object.hashCode.

Doc from java.lang.Object.hashCode.

Returns a hash code value for the object. This method is supported for the benefit of hash tables such as those provided by java.util.HashMap.

The general contract of hashCode is:

Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
If two objects are equal according to the equals method, then calling the hashCode method on each of the two objects must produce the same integer result.
It is not required that if two objects are unequal according to the equals method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.

Returns:int

a hash code value for this object.

Annotations

@Override

isAvailable	back to summary
public abstract boolean isAvailable() Whether this provider is available for use, taking the current environment into consideration. If `false`, `newLoadBalancer` is not safe to be called.

parseLoadBalancingPolicyConfig back to summary

parseLoadBalancingPolicyConfig	back to summary
public NameResolver.ConfigOrError parseLoadBalancingPolicyConfig(Map<String, ?> rawLoadBalancingPolicyConfig) Parses the config for the Load Balancing policy unpacked from the service config. This will return a `ConfigOrError` which contains either the successfully parsed config, or the `Status` representing the failure to parse. Implementations are expected to not throw exceptions but return a Status representing the failure. If successful, the load balancing policy config should be immutable. Parameters rawLoadBalancingPolicyConfig:Map<String, ?> The `Map` representation of the load balancing policy choice. Returns:NameResolver.ConfigOrError a tuple of the fully parsed and validated balancer configuration, else the Status. Since 1.20.0 See Also A24-lb-policy-config.md

public NameResolver.ConfigOrError parseLoadBalancingPolicyConfig(Map<String, ?> rawLoadBalancingPolicyConfig)

Parses the config for the Load Balancing policy unpacked from the service config. This will return a ConfigOrError which contains either the successfully parsed config, or the Status representing the failure to parse. Implementations are expected to not throw exceptions but return a Status representing the failure. If successful, the load balancing policy config should be immutable.

Parameters

rawLoadBalancingPolicyConfig:Map<String, ?>: The Map representation of the load balancing policy choice.

Returns:NameResolver.ConfigOrError

a tuple of the fully parsed and validated balancer configuration, else the Status.

Since

1.20.0

See Also

A24-lb-policy-config.md

toString	back to summary
public final String toString() Overrides java.lang.Object.toString. Doc from java.lang.Object.toString. Returns a string representation of the object. Returns:String a string representation of the object. Annotations @Override

toString

back to summary

public final String toString()

Overrides java.lang.Object.toString.

Doc from java.lang.Object.toString.

Returns a string representation of the object.

Returns:String

a string representation of the object.

Annotations