import org.apache.cassandra.db.index.composites.CompositesIndex; //导入依赖的package包/类
private static CFMetaData compositeIndexCFMD(String ksName, String cfName, final Boolean withIdxType, boolean withOldCfIds) throws ConfigurationException
{
    final Map<String, String> idxOpts = Collections.singletonMap(CompositesIndex.PREFIX_SIZE_OPTION, "1");
    final CompositeType composite = CompositeType.getInstance(Arrays.asList(new AbstractType<?>[]{UTF8Type.instance, UTF8Type.instance})); 
    return new CFMetaData(ksName,
            cfName,
            ColumnFamilyType.Standard,
            composite,
            null)
           .columnMetadata(new HashMap<ByteBuffer, ColumnDefinition>()
            {{
               ByteBuffer cName = ByteBuffer.wrap("col1".getBytes(Charsets.UTF_8));
               IndexType idxType = withIdxType ? IndexType.COMPOSITES : null;
               put(cName, new ColumnDefinition(cName, UTF8Type.instance, idxType, idxOpts, withIdxType ? "col1_idx" : null, 1));
            }});
}
 

import org.apache.cassandra.db.index.composites.CompositesIndex; //导入依赖的package包/类
/**
 * Returns the index comparator for index backed by CFS, or null.
 *
 * Note: it would be cleaner to have this be a member method. However we need this when opening indexes
 * sstables, but by then the CFS won't be fully initiated, so the SecondaryIndex object won't be accessible.
 */
public static CellNameType getIndexComparator(CFMetaData baseMetadata, ColumnDefinition cdef)
{
    switch (cdef.getIndexType())
    {
        case KEYS:
            return new SimpleDenseCellNameType(keyComparator);
        case COMPOSITES:
            return CompositesIndex.getIndexComparator(baseMetadata, cdef);
        case CUSTOM:
            return null;
    }
    throw new AssertionError();
}
 

import org.apache.cassandra.db.index.composites.CompositesIndex; //导入依赖的package包/类
/**
 * Returns the index comparator for index backed by CFS, or null.
 *
 * Note: it would be cleaner to have this be a member method. However we need this when opening indexes
 * sstables, but by then the CFS won't be fully initiated, so the SecondaryIndex object won't be accessible.
 */
public static AbstractType<?> getIndexComparator(CFMetaData baseMetadata, ColumnDefinition cdef)
{
    switch (cdef.getIndexType())
    {
        case KEYS:
            return keyComparator;
        case COMPOSITES:
            return CompositesIndex.getIndexComparator(baseMetadata, cdef);
        case CUSTOM:
            return null;
    }
    throw new AssertionError();
}
 

import org.apache.cassandra.db.index.composites.CompositesIndex; //导入依赖的package包/类
public void announceMigration() throws InvalidRequestException, ConfigurationException
{
    logger.debug("Updating column {} definition for index {}", columnName, indexName);
    CFMetaData cfm = Schema.instance.getCFMetaData(keyspace(), columnFamily()).clone();
    CFDefinition cfDef = cfm.getCfDef();
    ColumnDefinition cd = cfm.getColumnDefinition(columnName.key);

    if (isCustom)
    {
        cd.setIndexType(IndexType.CUSTOM, Collections.singletonMap(SecondaryIndex.CUSTOM_INDEX_OPTION_NAME, indexClass));
    }
    else if (cfDef.isComposite)
    {
        CompositeType composite = (CompositeType)cfm.comparator;
        Map<String, String> opts = new HashMap<String, String>();
        opts.put(CompositesIndex.PREFIX_SIZE_OPTION, String.valueOf(composite.types.size() - (cfDef.hasCollections ? 2 : 1)));
        cd.setIndexType(IndexType.COMPOSITES, opts);
    }
    else
    {
        cd.setIndexType(IndexType.KEYS, Collections.<String, String>emptyMap());
    }

    cd.setIndexName(indexName);
    cfm.addDefaultIndexNames();
    MigrationManager.announceColumnFamilyUpdate(cfm);
}