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/*
* ============LICENSE_START=======================================================
* feature-server-pool
* ================================================================================
* Copyright (C) 2020 AT&T Intellectual Property. 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.
* ============LICENSE_END=========================================================
*/
package org.onap.policy.drools.serverpool;
import java.io.Serializable;
import org.onap.policy.drools.core.lock.Lock;
import org.onap.policy.drools.core.lock.LockCallback;
import org.onap.policy.drools.serverpooltest.TargetLockWrapper;
/**
* This class implements the 'TargetLockWrapper' interface. There is one
* 'TargetLockWrapperImpl' class for each simulated host.
*/
public class TargetLockWrapperImpl implements TargetLockWrapper {
private static final long serialVersionUID = 1L;
// this is the 'TargetLock' instance associated with the wrapper
private TargetLock targetLock;
/**
* {@inheritDoc}
*/
@Override
public boolean free() {
return targetLock.free();
}
/**
* {@inheritDoc}
*/
@Override
public boolean isActive() {
return targetLock.isActive();
}
/**
* {@inheritDoc}
*/
@Override
public State getState() {
return TargetLockWrapper.State.valueOf(targetLock.getState().toString());
}
/**
* {@inheritDoc}
*/
@Override
public String getOwnerKey() {
return targetLock.getOwnerKey();
}
/**
* {@inheritDoc}
*/
@Override
public String toString() {
return "TLW-"
+ String.valueOf(AdapterImpl.getAdapter(TargetLockWrapperImpl.class.getClassLoader()))
+ "[" + targetLock.toString() + "]";
}
/**
* This method creates a new 'TargetLock'. Internally, an 'OwnerAdapter'
* instance is built as well, which translates the 'LockCallback'
* callbacks to 'TargetLockWrapper.Owner' callbacks. As with the call to
* 'new TargetLock(...)', it is possible for the callback occur before
* this method returns -- this can happen if the 'key' hashes to a bucket
* owned by the current host.
*
* @param key string key identifying the lock
* @param ownerKey string key identifying the owner, which must hash to
* a bucket owned by the current host (it is typically a 'RequestID')
* @param owner owner of the lock (will be notified when going from
* WAITING to ACTIVE)
* @param waitForLock this controls the behavior when 'key' is already
* locked - 'true' means wait for it to be freed, 'false' means fail
* @return a 'TargetLockWrapper' instance associated with the new
* 'TargetLock.
*/
static TargetLockWrapper newTargetLock(
String key, String ownerKey, TargetLockWrapper.Owner owner, boolean waitForLock) {
TargetLockWrapperImpl rval = new TargetLockWrapperImpl();
rval.targetLock =
new TargetLock(key, ownerKey,
TargetLockWrapperImpl.getOwnerAdapter(rval, owner),
waitForLock);
return rval;
}
/**
* This method creates a new 'TargetLock'. Internally, an 'OwnerAdapter'
* instance is built as well, which translates the 'LockCallback'
* callbacks to 'TargetLockWrapper.Owner' callbacks. As with the call to
* 'new TargetLock(...)', it is possible for the callback occur before
* this method returns -- this can happen if the 'key' hashes to a bucket
* owned by the current host.
*
* @param key string key identifying the lock
* @param ownerKey string key identifying the owner, which must hash to
* a bucket owned by the current host (it is typically a 'RequestID')
* @param owner owner of the lock (will be notified when going from
* WAITING to ACTIVE)
* @return a 'TargetLockWrapper' instance associated with the new
* 'TargetLock.
*/
static TargetLockWrapper newTargetLock(
String key, String ownerKey, TargetLockWrapper.Owner owner) {
TargetLockWrapperImpl rval = new TargetLockWrapperImpl();
rval.targetLock =
new TargetLock(key, ownerKey,
TargetLockWrapperImpl.getOwnerAdapter(rval, owner));
return rval;
}
/* ============================================================ */
/**
* This method builds an adapter that implements the 'LockCallback'
* callback interface, translating it to 'TargetLockWrapper.Owner'.
*
* @param targetLock the TargetLockWrapper that is using this adapter
* @param owner the 'TargetLockWrapper.Owner' callback
* @return an adapter implementing the 'LockCallback' interface
* ('null' is returned if 'owner' is null -- this is an error condition,
* but is used to verify the error handling of the 'TargetLock'
* constructor.
*/
public static LockCallback getOwnerAdapter(
TargetLockWrapper targetLock, TargetLockWrapper.Owner owner) {
return owner == null ? null : new OwnerAdapter(targetLock, owner);
}
/**
* This class is an adapter that implements the 'LockCallback' callback
* interface, translating it to a 'TargetLockWrapper.Owner' callback.
*/
public static class OwnerAdapter implements LockCallback, Serializable {
private static final long serialVersionUID = 1L;
// the 'TargetLockWrapper' instance to pass as an argument in the callback
TargetLockWrapper targetLock;
// the 'TargetLockWrapper.Owner' callback
TargetLockWrapper.Owner owner;
/**
* Constructor - initialize the adapter.
*
* @param targetLock this will be passed as an argument in the callback
* @param owner the object implementing the 'TargetLockWrapper.Owner'
* interface
*/
private OwnerAdapter(TargetLockWrapper targetLock, TargetLockWrapper.Owner owner) {
this.targetLock = targetLock;
this.owner = owner;
}
/**
* {@inheritDoc}
*/
@Override
public void lockAvailable(Lock lock) {
// forward 'lockAvailable' callback
owner.lockAvailable(targetLock);
}
/**
* {@inheritDoc}
*/
@Override
public void lockUnavailable(Lock lock) {
// forward 'lockUnavailable' callback
owner.lockUnavailable(targetLock);
}
}
}
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