org.gridgain.grid.spi.deployment.GridDeploymentSpi Maven / Gradle / Ivy
/*
Copyright (C) GridGain Systems. All Rights Reserved.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
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*/
package org.gridgain.grid.spi.deployment;
import org.gridgain.grid.*;
import org.gridgain.grid.compute.*;
import org.gridgain.grid.spi.*;
import org.gridgain.grid.spi.deployment.local.*;
import org.gridgain.grid.spi.deployment.uri.*;
import org.jetbrains.annotations.*;
/**
* Grid deployment SPI is in charge of deploying tasks and classes from different
* sources.
*
* Class loaders that are in charge of loading task classes (and other classes)
* can be deployed directly by calling {@link #register(ClassLoader, Class)} method or
* by SPI itself, for example by asynchronously scanning some folder for new tasks.
* When method {@link #findResource(String)} is called by the system, SPI must return a
* class loader associated with given class. Every time a class loader
* gets (re)deployed or released, callbacks
* {@link GridDeploymentListener#onUnregistered(ClassLoader)}} must be called by SPI.
*
* If peer class loading is enabled (which is default behavior, see
* {@link GridConfiguration#isPeerClassLoadingEnabled()}), then it is usually
* enough to deploy class loader only on one grid node. Once a task starts executing
* on the grid, all other nodes will automatically load all task classes from
* the node that initiated the execution. Hot redeployment is also supported
* with peer class loading. Every time a task changes and gets redeployed on a
* node, all other nodes will detect it and will redeploy this task as well.
*
* Note that peer class loading comes into effect only if a task was
* not locally deployed, otherwise, preference will always be given to
* local deployment.
*
*
* Gridgain provides the following {@code GridDeploymentSpi} implementations:
*
* - {@link GridLocalDeploymentSpi}
* - {@link GridUriDeploymentSpi}
*
* NOTE: this SPI (i.e. methods in this interface) should never be used directly. SPIs provide
* internal view on the subsystem and is used internally by GridGain kernal. In rare use cases when
* access to a specific implementation of this SPI is required - an instance of this SPI can be obtained
* via {@link Grid#configuration()} method to check its configuration properties or call other non-SPI
* methods. Note again that calling methods from this interface on the obtained instance can lead
* to undefined behavior and explicitly not supported.
*/
public interface GridDeploymentSpi extends GridSpi, GridSpiJsonConfigurable {
/**
* Finds class loader for the given class.
*
* @param rsrcName Class name or class alias to find class loader for.
* @return Deployed class loader, or {@code null} if not deployed.
*/
public GridDeploymentResource findResource(String rsrcName);
/**
* Registers a class loader with this SPI. This method exists
* to be able to add external class loaders to deployment SPI.
* Deployment SPI may also have its own class loaders. For example,
* in case of GAR deployment, every GAR file is loaded and deployed
* with a separate class loader maintained internally by the SPI.
*
* The array of classes passed in should be checked for presence of
* {@link GridComputeTaskName} annotations. The classes that have this annotation
* should be accessible by this name from {@link #findResource(String)} method.
*
* @param ldr Class loader to register.
* @param rsrc Class that should be checked for aliases.
* Currently the only alias in the system is {@link GridComputeTaskName} for
* task classes; in future, there may be others.
* @return {@code True} if resource was registered.
* @throws GridSpiException If registration failed.
*/
public boolean register(ClassLoader ldr, Class rsrc) throws GridSpiException;
/**
* Unregisters all class loaders that have a class with given name or have
* a class with give {@link GridComputeTaskName} value.
*
* @param rsrcName Either class name or {@link GridComputeTaskName} value for a class
* whose class loader needs to be unregistered.
* @return {@code True} if resource was unregistered.
*/
public boolean unregister(String rsrcName);
/**
* Sets or unsets deployment event listener. Grid implementation will use this listener
* to properly add and remove various deployments.
*
* @param lsnr Listener for deployment events. {@code null} to unset the listener.
*/
public void setListener(@Nullable GridDeploymentListener lsnr);
}