import org.sonatype.aether.repository.RepositoryPolicy; //导入依赖的package包/类
public static RepositoryPolicy toRepositoryPolicy( org.apache.maven.model.RepositoryPolicy policy )
{
    boolean enabled = true;
    String checksums = RepositoryPolicy.CHECKSUM_POLICY_WARN;
    String updates = RepositoryPolicy.UPDATE_POLICY_DAILY;

    if ( policy != null )
    {
        enabled = policy.isEnabled();
        if ( policy.getUpdatePolicy() != null )
        {
            updates = policy.getUpdatePolicy();
        }
        if ( policy.getChecksumPolicy() != null )
        {
            checksums = policy.getChecksumPolicy();
        }
    }

    return new RepositoryPolicy( enabled, updates, checksums );
}
 

import org.sonatype.aether.repository.RepositoryPolicy; //导入依赖的package包/类
public void addRepo(String id, String url, boolean snapshot) {
  synchronized (repos) {
    delRepo(id);
    RemoteRepository rr = new RemoteRepository(id, "default", url);
    rr.setPolicy(snapshot, new RepositoryPolicy(
        true,
        RepositoryPolicy.UPDATE_POLICY_DAILY,
        RepositoryPolicy.CHECKSUM_POLICY_WARN));
    repos.add(rr);
  }
}
 

import org.sonatype.aether.repository.RepositoryPolicy; //导入依赖的package包/类
public static RepositorySystemSession repositorySystemSession(RepositorySystem system)
{
	MavenRepositorySystemSession session = new MavenRepositorySystemSession();
	session.setLocalRepositoryManager(system.newLocalRepositoryManager(LOCAL_REPO));
	
	session.setTransferListener(new LoggingTransferListener());
	session.setRepositoryListener(new LoggingRepositoryListener());
	
	session.setChecksumPolicy(RepositoryPolicy.CHECKSUM_POLICY_WARN);
	
	return session;
}
 

import org.sonatype.aether.repository.RepositoryPolicy; //导入依赖的package包/类
private void injectSession( MetadataResolutionRequest request )
{
    RepositorySystemSession session = legacySupport.getRepositorySession();

    if ( session != null )
    {
        request.setOffline( session.isOffline() );
        request.setForceUpdate( RepositoryPolicy.UPDATE_POLICY_ALWAYS.equals( session.getUpdatePolicy() ) );
    }
}
 

import org.sonatype.aether.repository.RepositoryPolicy; //导入依赖的package包/类
private static boolean policyEquals( RepositoryPolicy p1, RepositoryPolicy p2 )
{
    if ( p1 == p2 )
    {
        return true;
    }
    // update policy doesn't affect contents
    return p1.isEnabled() == p2.isEnabled() && eq( p1.getChecksumPolicy(), p2.getChecksumPolicy() );
}
 

import org.sonatype.aether.repository.RepositoryPolicy; //导入依赖的package包/类
private PluginPrefixResult resolveFromRepository( PluginPrefixRequest request )
{
    RequestTrace trace = DefaultRequestTrace.newChild( null, request );

    List<MetadataRequest> requests = new ArrayList<MetadataRequest>();

    for ( String pluginGroup : request.getPluginGroups() )
    {
        org.sonatype.aether.metadata.Metadata metadata =
            new DefaultMetadata( pluginGroup, "maven-metadata.xml", DefaultMetadata.Nature.RELEASE_OR_SNAPSHOT );

        requests.add( new MetadataRequest( metadata, null, REPOSITORY_CONTEXT ).setTrace( trace ) );

        for ( RemoteRepository repository : request.getRepositories() )
        {
            requests.add( new MetadataRequest( metadata, repository, REPOSITORY_CONTEXT ).setTrace( trace ) );
        }
    }

    // initial try, use locally cached metadata

    List<MetadataResult> results = repositorySystem.resolveMetadata( request.getRepositorySession(), requests );
    requests.clear();

    PluginPrefixResult result = processResults( request, trace, results, requests );

    if ( result != null )
    {
        return result;
    }

    // second try, refetch all (possibly outdated) metadata that wasn't updated in the first attempt

    if ( !request.getRepositorySession().isOffline() && !requests.isEmpty() )
    {
        DefaultRepositorySystemSession session =
            new DefaultRepositorySystemSession( request.getRepositorySession() );
        session.setUpdatePolicy( RepositoryPolicy.UPDATE_POLICY_ALWAYS );

        results = repositorySystem.resolveMetadata( session, requests );

        return processResults( request, trace, results, null );
    }

    return null;
}