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A driver for Apache Cassandra 1.2+ that works exclusively with the Cassandra Query Language version 3 (CQL3) and Cassandra's binary protocol.

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/*
 *      Copyright (C) 2012 DataStax Inc.
 *
 *   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 com.datastax.driver.core;

import java.util.*;

import com.google.common.base.Predicate;
import com.google.common.collect.Iterables;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Describes a Table.
 */
public class TableMetadata {

    private static final Logger logger = LoggerFactory.getLogger(TableMetadata.class);

    static final String CF_NAME                      = "columnfamily_name";

    private static final String KEY_VALIDATOR        = "key_validator";
    private static final String COMPARATOR           = "comparator";
    private static final String VALIDATOR            = "default_validator";

    private static final String KEY_ALIASES          = "key_aliases";
    private static final String COLUMN_ALIASES       = "column_aliases";
    private static final String VALUE_ALIAS          = "value_alias";

    private static final String DEFAULT_KEY_ALIAS    = "key";
    private static final String DEFAULT_COLUMN_ALIAS = "column";
    private static final String DEFAULT_VALUE_ALIAS  = "value";

    private static final Comparator columnMetadataComparator = new Comparator() {
        public int compare(ColumnMetadata c1, ColumnMetadata c2) {
            return c1.getName().compareTo(c2.getName());
        }
    };

    private final KeyspaceMetadata keyspace;
    private final String name;
    private final List partitionKey;
    private final List clusteringColumns;
    private final Map columns;
    private final Options options;
    private final List clusteringOrder;

    private final VersionNumber cassandraVersion;

    /**
     * Clustering orders.
     * 

* This is used by {@link #getClusteringOrder} to indicate the clustering * order of a table. */ public static enum Order { ASC, DESC; static final Predicate isAscending = new Predicate() { public boolean apply(Order o) { return o == ASC; } }; } private TableMetadata(KeyspaceMetadata keyspace, String name, List partitionKey, List clusteringColumns, LinkedHashMap columns, Options options, List clusteringOrder, VersionNumber cassandraVersion) { this.keyspace = keyspace; this.name = name; this.partitionKey = partitionKey; this.clusteringColumns = clusteringColumns; this.columns = columns; this.options = options; this.clusteringOrder = clusteringOrder; this.cassandraVersion = cassandraVersion; } static TableMetadata build(KeyspaceMetadata ksm, Row row, Map rawCols, VersionNumber cassandraVersion) { String name = row.getString(CF_NAME); CassandraTypeParser.ParseResult keyValidator = CassandraTypeParser.parseWithComposite(row.getString(KEY_VALIDATOR)); CassandraTypeParser.ParseResult comparator = CassandraTypeParser.parseWithComposite(row.getString(COMPARATOR)); List columnAliases = cassandraVersion.getMajor() >= 2 || row.getString(COLUMN_ALIASES) == null ? Collections.emptyList() : SimpleJSONParser.parseStringList(row.getString(COLUMN_ALIASES)); int clusteringSize = findClusteringSize(comparator, rawCols.values(), columnAliases, cassandraVersion); boolean isDense = clusteringSize != comparator.types.size() - 1; boolean isCompact = isDense || !comparator.isComposite; List partitionKey = nullInitializedList(keyValidator.types.size()); List clusteringColumns = nullInitializedList(clusteringSize); List clusteringOrder = nullInitializedList(clusteringSize); // We use a linked hashmap because we will keep this in the order of a 'SELECT * FROM ...'. LinkedHashMap columns = new LinkedHashMap(); Options options = null; try { options = new Options(row, isCompact, cassandraVersion); } catch (RuntimeException e) { // See ControlConnection#refreshSchema for why we'd rather not probably this further. Since table options is one thing // that tends to change often in Cassandra, it's worth special casing this. logger.error(String.format("Error parsing schema options for table %s.%s: " + "Cluster.getMetadata().getKeyspace(\"%s\").getTable(\"%s\").getOptions() will return null", ksm.getName(), name, ksm.getName(), name), e); } TableMetadata tm = new TableMetadata(ksm, name, partitionKey, clusteringColumns, columns, options, clusteringOrder, cassandraVersion); // We use this temporary set just so non PK columns are added in lexicographical order, which is the one of a // 'SELECT * FROM ...' Set otherColumns = new TreeSet(columnMetadataComparator); if (cassandraVersion.getMajor() < 2) { // In C* 1.2, only the REGULAR columns are in the columns schema table, so we need to add the names from // the aliases (and make sure we handle default aliases). List keyAliases = row.getString(KEY_ALIASES) == null ? Collections.emptyList() : SimpleJSONParser.parseStringList(row.getString(KEY_ALIASES)); for (int i = 0; i < partitionKey.size(); i++) { String alias = keyAliases.size() > i ? keyAliases.get(i) : (i == 0 ? DEFAULT_KEY_ALIAS : DEFAULT_KEY_ALIAS + (i + 1)); partitionKey.set(i, ColumnMetadata.forAlias(tm, alias, keyValidator.types.get(i))); } for (int i = 0; i < clusteringSize; i++) { String alias = columnAliases.size() > i ? columnAliases.get(i) : DEFAULT_COLUMN_ALIAS + (i + 1); clusteringColumns.set(i, ColumnMetadata.forAlias(tm, alias, comparator.types.get(i))); clusteringOrder.set(i, comparator.reversed.get(i) ? Order.DESC : Order.ASC); } // We have a value alias if we're dense if (isDense) { String alias = row.isNull(VALUE_ALIAS) ? DEFAULT_VALUE_ALIAS : row.getString(VALUE_ALIAS); DataType type = CassandraTypeParser.parseOne(row.getString(VALIDATOR)); otherColumns.add(ColumnMetadata.forAlias(tm, alias, type)); } } for (ColumnMetadata.Raw rawCol : rawCols.values()) { ColumnMetadata col = ColumnMetadata.fromRaw(tm, rawCol); switch (rawCol.kind) { case PARTITION_KEY: partitionKey.set(rawCol.componentIndex, col); break; case CLUSTERING_KEY: clusteringColumns.set(rawCol.componentIndex, col); clusteringOrder.set(rawCol.componentIndex, rawCol.isReversed ? Order.DESC : Order.ASC); break; default: otherColumns.add(col); break; } } for (ColumnMetadata c : partitionKey) columns.put(c.getName(), c); for (ColumnMetadata c : clusteringColumns) columns.put(c.getName(), c); for (ColumnMetadata c : otherColumns) columns.put(c.getName(), c); ksm.add(tm); return tm; } private static int findClusteringSize(CassandraTypeParser.ParseResult comparator, Collection cols, List columnAliases, VersionNumber cassandraVersion) { // In 2.0, this is relatively easy, we just find the biggest 'componentIndex' amongst the clustering columns. // For 1.2 however, this is slightly more subtle: we need to infer it based on whether the comparator is composite or not, and whether we have // regular columns or not. if (cassandraVersion.getMajor() >= 2) { int maxId = -1; for (ColumnMetadata.Raw col : cols) if (col.kind == ColumnMetadata.Raw.Kind.CLUSTERING_KEY) maxId = Math.max(maxId, col.componentIndex); return maxId + 1; } else { int size = comparator.types.size(); if (comparator.isComposite) return !comparator.collections.isEmpty() || (columnAliases.size() == size - 1 && comparator.types.get(size - 1).equals(DataType.text())) ? size - 1 : size; else // We know cols only has the REGULAR ones for 1.2 return !columnAliases.isEmpty() || cols.isEmpty() ? size : 0; } } private static List nullInitializedList(int size) { List l = new ArrayList(size); for (int i = 0; i < size; ++i) l.add(null); return l; } /** * Returns the name of this table. * * @return the name of this CQL table. */ public String getName() { return name; } /** * Returns the keyspace this table belong to. * * @return the keyspace metadata of the keyspace this table belong to. */ public KeyspaceMetadata getKeyspace() { return keyspace; } /** * Returns metadata on a column of this table. * * @param name the name of the column to retrieve ({@code name} will be * interpreted as a case-insensitive identifier unless enclosed in double-quotes, * see {@link Metadata#quote}). * @return the metadata for the {@code name} column if it exists, or * {@code null} otherwise. */ public ColumnMetadata getColumn(String name) { return columns.get(Metadata.handleId(name)); } /** * Returns a list containing all the columns of this table. * * The order of the columns in the list is consistent with * the order of the columns returned by a {@code SELECT * FROM thisTable}: * the first column is the partition key, next are the clustering * columns in their defined order, and then the rest of the * columns follow in alphabetic order. * * @return a list containing the metadata for the columns of this table. */ public List getColumns() { return new ArrayList(columns.values()); } /** * Returns the list of columns composing the primary key for this table. * * A table will always at least have a partition key (that * may itself be one or more columns), so the returned list at least * has one element. * * @return the list of columns composing the primary key for this table. */ public List getPrimaryKey() { List pk = new ArrayList(partitionKey.size() + clusteringColumns.size()); pk.addAll(partitionKey); pk.addAll(clusteringColumns); return pk; } /** * Returns the list of columns composing the partition key for this table. * * A table always has a partition key so the returned list has * at least one element. * * @return the list of columns composing the partition key for this table. */ public List getPartitionKey() { return Collections.unmodifiableList(partitionKey); } /** * Returns the list of clustering columns for this table. * * @return the list of clustering columns for this table. * If there is no clustering columns, an empty list is returned. */ public List getClusteringColumns() { return Collections.unmodifiableList(clusteringColumns); } /** * Returns the clustering order for this table. *

* The returned contains the clustering order of each clustering column. The * {@code i}th element of the result correspond to the order (ascending or * descending) of the {@code i}th clustering column (see * {@link #getClusteringColumns}). Note that a table defined without any * particular clustering order is equivalent to one for which all the * clustering key are in ascending order. * * @return a list with the clustering order for each clustering column. */ public List getClusteringOrder() { return clusteringOrder; } /** * Returns the options for this table. * * @return the options for this table. */ public Options getOptions() { return options; } void add(ColumnMetadata column) { columns.put(column.getName(), column); } /** * Returns a {@code String} containing CQL queries representing this * table and the index on it. * * In other words, this method returns the queries that would allow you to * recreate the schema of this table, along with the index defined on * columns of this table. * * Note that the returned String is formatted to be human readable (for * some definition of human readable at least). * * @return the CQL queries representing this table schema as a {code * String}. */ public String exportAsString() { StringBuilder sb = new StringBuilder(); sb.append(asCQLQuery(true)); for (ColumnMetadata column : columns.values()) { ColumnMetadata.IndexMetadata index = column.getIndex(); if (index == null) continue; sb.append('\n').append(index.asCQLQuery()); } return sb.toString(); } /** * Returns a CQL query representing this table. * * This method returns a single 'CREATE TABLE' query with the options * corresponding to this table definition. * * Note that the returned string is a single line; the returned query * is not formatted in any way. * * @return the 'CREATE TABLE' query corresponding to this table. * @see #exportAsString */ public String asCQLQuery() { return asCQLQuery(false); } private String asCQLQuery(boolean formatted) { StringBuilder sb = new StringBuilder(); sb.append("CREATE TABLE ").append(Metadata.escapeId(keyspace.getName())).append('.').append(Metadata.escapeId(name)).append(" ("); newLine(sb, formatted); for (ColumnMetadata cm : columns.values()) newLine(sb.append(spaces(4, formatted)).append(cm).append(','), formatted); // PK sb.append(spaces(4, formatted)).append("PRIMARY KEY ("); if (partitionKey.size() == 1) { sb.append(partitionKey.get(0).getName()); } else { sb.append('('); boolean first = true; for (ColumnMetadata cm : partitionKey) { if (first) first = false; else sb.append(", "); sb.append(Metadata.escapeId(cm.getName())); } sb.append(')'); } for (ColumnMetadata cm : clusteringColumns) sb.append(", ").append(Metadata.escapeId(cm.getName())); sb.append(')'); newLine(sb, formatted); // end PK // Options sb.append(") WITH "); if (options.isCompactStorage) and(sb.append("COMPACT STORAGE"), formatted); if (!Iterables.all(clusteringOrder, Order.isAscending)) and(appendClusteringOrder(sb), formatted); sb.append("read_repair_chance = ").append(options.readRepair); and(sb, formatted).append("dclocal_read_repair_chance = ").append(options.localReadRepair); if (cassandraVersion.getMajor() < 2 || (cassandraVersion.getMajor() == 2 && cassandraVersion.getMinor() == 0)) and(sb, formatted).append("replicate_on_write = ").append(options.replicateOnWrite); and(sb, formatted).append("gc_grace_seconds = ").append(options.gcGrace); and(sb, formatted).append("bloom_filter_fp_chance = ").append(options.bfFpChance); and(sb, formatted).append("caching = '").append(options.caching).append('\''); if (options.comment != null) and(sb, formatted).append("comment = '").append(options.comment).append('\''); and(sb, formatted).append("compaction = ").append(formatOptionMap(options.compaction)); and(sb, formatted).append("compression = ").append(formatOptionMap(options.compression)); if (cassandraVersion.getMajor() >= 2) { and(sb, formatted).append("default_time_to_live = ").append(options.defaultTTL); and(sb, formatted).append("speculative_retry = '").append(options.speculativeRetry).append('\''); and(sb, formatted).append("index_interval = ").append(options.indexInterval); } sb.append(';'); return sb.toString(); } private StringBuilder appendClusteringOrder(StringBuilder sb) { sb.append("CLUSTERING ORDER BY ("); for (int i = 0; i < clusteringColumns.size(); i++) { if (i > 0) sb.append(", "); sb.append(clusteringColumns.get(i).getName()).append(' ').append(clusteringOrder.get(i)); } return sb.append(')'); } private static String formatOptionMap(Map m) { StringBuilder sb = new StringBuilder(); sb.append("{ "); boolean first = true; for (Map.Entry entry : m.entrySet()) { if (first) first = false; else sb.append(", "); sb.append('\'').append(entry.getKey()).append('\''); sb.append(" : "); try { sb.append(Integer.parseInt(entry.getValue())); } catch (NumberFormatException e) { sb.append('\'').append(entry.getValue()).append('\''); } } sb.append(" }"); return sb.toString(); } private StringBuilder and(StringBuilder sb, boolean formatted) { return newLine(sb, formatted).append(spaces(2, formatted)).append(" AND "); } private String spaces(int n, boolean formatted) { if (!formatted) return ""; StringBuilder sb = new StringBuilder(); for (int i = 0; i < n; i++) sb.append(' '); return sb.toString(); } private StringBuilder newLine(StringBuilder sb, boolean formatted) { if (formatted) sb.append('\n'); return sb; } public static class Options { private static final String COMMENT = "comment"; private static final String READ_REPAIR = "read_repair_chance"; private static final String LOCAL_READ_REPAIR = "local_read_repair_chance"; private static final String REPLICATE_ON_WRITE = "replicate_on_write"; private static final String GC_GRACE = "gc_grace_seconds"; private static final String BF_FP_CHANCE = "bloom_filter_fp_chance"; private static final String CACHING = "caching"; private static final String COMPACTION_CLASS = "compaction_strategy_class"; private static final String COMPACTION_OPTIONS = "compaction_strategy_options"; private static final String MIN_COMPACTION_THRESHOLD = "min_compaction_threshold"; private static final String MAX_COMPACTION_THRESHOLD = "max_compaction_threshold"; private static final String POPULATE_CACHE_ON_FLUSH = "populate_io_cache_on_flush"; private static final String COMPRESSION_PARAMS = "compression_parameters"; private static final String MEMTABLE_FLUSH_PERIOD_MS = "memtable_flush_period_in_ms"; private static final String DEFAULT_TTL = "default_time_to_live"; private static final String SPECULATIVE_RETRY = "speculative_retry"; private static final String INDEX_INTERVAL = "index_interval"; private static final double DEFAULT_BF_FP_CHANCE = 0.01; private static final boolean DEFAULT_POPULATE_CACHE_ON_FLUSH = false; private static final int DEFAULT_MEMTABLE_FLUSH_PERIOD = 0; private static final int DEFAULT_DEFAULT_TTL = 0; private static final String DEFAULT_SPECULATIVE_RETRY = "NONE"; private static final int DEFAULT_INDEX_INTERVAL = 128; private final boolean isCompactStorage; private final String comment; private final double readRepair; private final double localReadRepair; private final boolean replicateOnWrite; private final int gcGrace; private final double bfFpChance; private final String caching; private final boolean populateCacheOnFlush; private final int memtableFlushPeriodMs; private final int defaultTTL; private final String speculativeRetry; private final int indexInterval; private final Map compaction = new HashMap(); private final Map compression = new HashMap(); Options(Row row, boolean isCompactStorage, VersionNumber version) { this.isCompactStorage = isCompactStorage; this.comment = row.isNull(COMMENT) ? "" : row.getString(COMMENT); this.readRepair = row.getDouble(READ_REPAIR); this.localReadRepair = row.getDouble(LOCAL_READ_REPAIR); this.replicateOnWrite = (version.getMajor() > 2 || (version.getMajor() == 2 && version.getMinor() >= 1)) || row.isNull(REPLICATE_ON_WRITE) ? true : row.getBool(REPLICATE_ON_WRITE); this.gcGrace = row.getInt(GC_GRACE); this.bfFpChance = row.isNull(BF_FP_CHANCE) ? DEFAULT_BF_FP_CHANCE : row.getDouble(BF_FP_CHANCE); this.caching = row.getString(CACHING); this.populateCacheOnFlush = row.isNull(POPULATE_CACHE_ON_FLUSH) ? DEFAULT_POPULATE_CACHE_ON_FLUSH : row.getBool(POPULATE_CACHE_ON_FLUSH); this.memtableFlushPeriodMs = version.getMajor() < 2 || row.isNull(MEMTABLE_FLUSH_PERIOD_MS) ? DEFAULT_MEMTABLE_FLUSH_PERIOD : row.getInt(MEMTABLE_FLUSH_PERIOD_MS); this.defaultTTL = version.getMajor() < 2 || row.isNull(DEFAULT_TTL) ? DEFAULT_DEFAULT_TTL : row.getInt(DEFAULT_TTL); this.speculativeRetry = version.getMajor() < 2 || row.isNull(SPECULATIVE_RETRY) ? DEFAULT_SPECULATIVE_RETRY : row.getString(SPECULATIVE_RETRY); this.indexInterval = version.getMajor() < 2 || row.isNull(INDEX_INTERVAL) ? DEFAULT_INDEX_INTERVAL : row.getInt(INDEX_INTERVAL); this.compaction.put("class", row.getString(COMPACTION_CLASS)); this.compaction.putAll(SimpleJSONParser.parseStringMap(row.getString(COMPACTION_OPTIONS))); this.compression.putAll(SimpleJSONParser.parseStringMap(row.getString(COMPRESSION_PARAMS))); } /** * Returns whether the table uses the {@code COMPACT STORAGE} option. * * @return whether the table uses the {@code COMPACT STORAGE} option. */ public boolean isCompactStorage() { return isCompactStorage; } /** * Returns the commentary set for this table. * * @return the commentary set for this table, or {@code null} if noe has been set. */ public String getComment() { return comment; } /** * Returns the chance with which a read repair is triggered for this table. * * @return the read repair change set for table (in [0.0, 1.0]). */ public double getReadRepairChance() { return readRepair; } /** * Returns the cluster local read repair chance set for this table. * * @return the local read repair change set for table (in [0.0, 1.0]). */ public double getLocalReadRepairChance() { return localReadRepair; } /** * Returns whether replicateOnWrite is set for this table. * * This is only meaningful for tables holding counters. * * @return whether replicateOnWrite is set for this table. */ public boolean getReplicateOnWrite() { return replicateOnWrite; } /** * Returns the tombstone garbage collection grace time in seconds for this table. * * @return the tombstone garbage collection grace time in seconds for this table. */ public int getGcGraceInSeconds() { return gcGrace; } /** * Returns the false positive chance for the Bloom filter of this table. * * @return the Bloom filter false positive chance for this table (in [0.0, 1.0]). */ public double getBloomFilterFalsePositiveChance() { return bfFpChance; } /** * Returns the caching option for this table. * * @return the caching option for this table. */ public String getCaching() { return caching; } /** * Whether the populate I/O cache on flush is set on this table. * * @return whether the populate I/O cache on flush is set on this table. */ public boolean getPopulateIOCacheOnFlush() { return populateCacheOnFlush; } /* * Returns the memtable flush period (in milliseconds) option for this table. *

* Note: this option is not available in Cassandra 1.2 and will return 0 (no periodic * flush) when connected to 1.2 nodes. * * @return the memtable flush period option for this table or 0 if no * periodic flush is configured. */ public int getMemtableFlushPeriodInMs() { return memtableFlushPeriodMs; } /** * Returns the default TTL for this table. *

* Note: this option is not available in Cassandra 1.2 and will return 0 (no default * TTL) when connected to 1.2 nodes. * * @return the default TTL for this table or 0 if no default TTL is * configured. */ public int getDefaultTimeToLive() { return defaultTTL; } /** * Returns the speculative retry option for this table. *

* Note: this option is not available in Cassandra 1.2 and will return "NONE" (no * speculative retry) when connected to 1.2 nodes. * * @return the speculative retry option this table. */ public String getSpeculativeRetry() { return speculativeRetry; } /** * Returns the index interval option for this table. *

* Note: this option is not available in Cassandra 1.2 (more precisely, it is not * configurable per-table) and will return 128 (the default index interval) when * connected to 1.2 nodes. * * @return the index interval option for this table. */ public int getIndexInterval() { return indexInterval; } /** * Returns the compaction options for this table. * * @return a map containing the compaction options for this table. */ public Map getCompaction() { return new HashMap(compaction); } /** * Returns the compression options for this table. * * @return a map containing the compression options for this table. */ public Map getCompression() { return new HashMap(compression); } } }





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