net.yetamine.osgi.jdbc.tweak.BundleControl Maven / Gradle / Ivy
/*
* Copyright 2016 Yetamine
*
* 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.
*/
package net.yetamine.osgi.jdbc.tweak;
import java.util.Set;
import java.util.function.Predicate;
import org.osgi.framework.Bundle;
/**
* Adjusts the options for handling a driver bundle.
*
*
* The JDBC support should consult all available OSGi services registering this
* interface when a driver bundle gets resolved. The services must be consulted
* in their ranking order, so that the most preferred ones have the last word
* and may override the options set by less preferred services.
*/
@FunctionalInterface
public interface BundleControl {
/**
* Represents a condition related to a state of a bundle which allows an
* action to occur.
*/
enum Condition implements Predicate {
/**
* This condition is never satisfied.
*/
NEVER {
/**
* @see java.util.function.Predicate#test(java.lang.Object)
*/
@Override
public boolean test(Bundle t) {
return false;
}
},
/**
* This conditions is satisfied if the bundle is not INSTALLED or
* UNINSTALLED, i.e., the bundle can be linked and its code might
* be run.
*/
WHEN_LINKABLE {
/**
* @see java.util.function.Predicate#test(java.lang.Object)
*/
@Override
public boolean test(Bundle t) {
return ((t.getState() & ~(Bundle.INSTALLED | Bundle.UNINSTALLED)) != 0);
}
},
/**
* This condition is satisfied when the bundle becomes ACTIVE and
* as long as it stays in this state. This should be the usual option to
* use if there is no special reason to prefer other options.
*/
WHEN_RUNNING {
/**
* @see java.util.function.Predicate#test(java.lang.Object)
*/
@Override
public boolean test(Bundle t) {
return ((t.getState() & Bundle.ACTIVE) != 0);
}
};
/**
* Tests if the given bundle satisfies the condition.
*
* @param t
* the bundle to test. It must not be {@code null}.
*
* @return {@code true} if the bundle satisfies this condition
*
* @see java.util.function.Predicate#test(java.lang.Object)
*/
@Override
public abstract boolean test(Bundle t);
}
/**
* Represents the options that the control may adjust.
*/
interface Options {
/**
* Returns the bundle that this instance is related to.
*
* @return the bundle
*/
Bundle bundle();
/**
* Returns the set of driver names declared by the {@link #bundle()},
* which is unmodifiable (i.e., it is always possible to learn all
* declared drivers).
*
* @return the set of driver names declared by the {@link #bundle()}
*/
Set declaredDrivers();
/**
* Returns the set of drivers chosen for loading.
*
*
* The set is a modifiable set, i.e., adding and removing values is
* possible, but it must be a subset of {@link #declaredDrivers()};
* implementations may prevent adding illegal values by throwing an
* exception on any such attempt, or be lenient and just ignore any
* illegal values when dealing with the actual content of the set.
*
*
* The returned set should contain all {@link #declaredDrivers()}
* initially, so that all declared drivers shall be registered by
* default.
*
* @return the set of driver chosen for loading
*/
Set loadableDrivers();
/**
* Returns the condition for the drivers registered by the
* {@link #bundle()} to be visible as OSGi services.
*
* @return the condition for the drivers to be visible as services
*/
Condition driversAvailable();
/**
* Sets the condition for the drivers registerd by the {@link #bundle()}
* to be visible as OSGi services.
*
* @param value
* the value to set. It must not be {@code null}.
*/
void driversAvailable(Condition value);
}
/**
* Adjusts possibly the control options for a bundle.
*
*
* This method may throw no exception. The JDBC support should disable any
* instance that throws any exception.
*
* @param options
* the options to be adjusted. It must not be {@code null}.
*/
void adjust(Options options);
}