/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 WARRANTIESOR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.aries.application.modelling.internal;
import static org.apache.aries.application.utils.AppConstants.LOG_ENTRY;
import static org.apache.aries.application.utils.AppConstants.LOG_EXIT;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import org.apache.aries.application.modelling.ImportedPackage;
import org.apache.aries.application.modelling.utils.impl.ModellingHelperImpl;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A class to merge collections of package requirements, such that multiple requirements
* for the same package are consolidated to a single requirement with a version constraint
* that is the intersection of the original version requirements.
*/
public final class PackageRequirementMerger
{
private final Logger logger = LoggerFactory.getLogger(PackageRequirementMerger.class);
/** The merged requirements, or null if the merge failed. */
private final Collection<ImportedPackage> mergedRequirements;
/** Names of packages for which requirements were incompatible. */
private final Set<String> invalidRequirements = new HashSet<String>();
/**
* Constructor.
* @param requirements the package requirements to be merged.
* @throws NullPointerException if the parameter is {@code null}.
*/
public PackageRequirementMerger(Collection<ImportedPackage> requirements)
{
logger.debug(LOG_ENTRY, "PackageRequirementMerger", requirements);
if (requirements == null)
{
NullPointerException npe = new NullPointerException();
logger.debug(LOG_EXIT, "PackageRequirementMerger", npe);
throw npe;
}
// Do the merge.
Map<String, ImportedPackage> reqMap = new HashMap<String, ImportedPackage>();
for (ImportedPackage req : requirements)
{
String pkgName = req.getPackageName();
ImportedPackage existingReq = reqMap.get(pkgName);
if (existingReq == null)
{
reqMap.put(pkgName, req);
continue;
}
ImportedPackage intersectReq = ModellingHelperImpl.intersectPackage_(req, existingReq);
if (intersectReq != null)
{
reqMap.put(pkgName, intersectReq);
continue;
}
invalidRequirements.add(pkgName);
}
mergedRequirements = (invalidRequirements.isEmpty() ? reqMap.values() : null);
logger.debug(LOG_EXIT,"PackageRequirementMerger");
}
/**
* Check if the requirements could be successfully merged.
* @return true if the merge was successful; false if the requirements were not compatible.
*/
public boolean isMergeSuccessful()
{
logger.debug(LOG_ENTRY, "isMergeSuccessful");
boolean result = mergedRequirements != null;
logger.debug(LOG_EXIT, "isMergeSuccessful", result);
return result;
}
/**
* Get the merged package requirements. The result will mirror the input collection,
* except that multiple requirements for the same package will be replaced by a single
* requirement that is the intersection of all the input requirements.
* <p>
* The {@code isMergeSuccessful} method should be checked for success prior to calling this method.
* @param inputRequirements
* @return A collection of package requirements, or {@code null} if the input contained incompatible requirements.
* @throws IllegalStateException if the merge was not successful.
*/
public Collection<ImportedPackage> getMergedRequirements()
{
logger.debug(LOG_ENTRY, "getMergedRequirements");
if (mergedRequirements == null)
{
IllegalStateException ise = new IllegalStateException();
logger.debug(LOG_EXIT, "getMergedRequirements", ise);
throw ise;
}
logger.debug(LOG_EXIT, "getMergedRequirements", mergedRequirements);
return Collections.unmodifiableCollection(mergedRequirements);
}
/**
* Get the names of packages that caused the merge to fail due to their constraints
* being mutually exclusive.
* @return an unmodifiable set of package names.
*/
public Set<String> getInvalidRequirements()
{
logger.debug(LOG_ENTRY, "getInvalidRequirements");
logger.debug(LOG_EXIT, "getInvalidRequirements", invalidRequirements);
return Collections.unmodifiableSet(invalidRequirements);
}
}