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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.
/*
* Copyright (C) 2012-2015 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 com.google.common.base.Objects;
import com.google.common.base.Predicate;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Iterables;
import java.util.Iterator;
import java.util.Map;
/**
* An immutable representation of secondary index metadata.
*/
public class IndexMetadata {
public enum Kind {
KEYS,
CUSTOM,
COMPOSITES
}
static final String NAME = "index_name";
static final String KIND = "kind";
static final String OPTIONS = "options";
/**
* The name of the option used to specify the index target (Cassandra 3.0 onwards).
*/
public static final String TARGET_OPTION_NAME = "target";
/**
* The name of the option used to specify a custom index class name.
*/
public static final String CUSTOM_INDEX_OPTION_NAME = "class_name";
/**
* The name of the option used to specify that the index is on the collection (map) keys.
*/
public static final String INDEX_KEYS_OPTION_NAME = "index_keys";
/**
* The name of the option used to specify that the index is on the collection (map) entries.
*/
public static final String INDEX_ENTRIES_OPTION_NAME = "index_keys_and_values";
private final TableMetadata table;
private final String name;
private final Kind kind;
private final String target;
private final Map options;
private IndexMetadata(TableMetadata table, String name, Kind kind, String target, Map options) {
this.table = table;
this.name = name;
this.kind = kind;
this.target = target;
this.options = options;
}
/**
* Build an IndexMetadata from a system_schema.indexes row.
*/
static IndexMetadata fromRow(TableMetadata table, Row indexRow) {
String name = indexRow.getString(NAME);
Kind kind = Kind.valueOf(indexRow.getString(KIND));
Map options = indexRow.getMap(OPTIONS, String.class, String.class);
String target = options.get(TARGET_OPTION_NAME);
return new IndexMetadata(table, name, kind, target, options);
}
/**
* Build an IndexMetadata from a legacy layout (index information is stored
* along with indexed column).
*/
static IndexMetadata fromLegacy(ColumnMetadata column, ColumnMetadata.Raw raw) {
Map indexColumns = raw.indexColumns;
if (indexColumns.isEmpty())
return null;
String type = indexColumns.get(ColumnMetadata.INDEX_TYPE);
if (type == null)
return null;
String indexName = indexColumns.get(ColumnMetadata.INDEX_NAME);
String kindStr = indexColumns.get(ColumnMetadata.INDEX_TYPE);
Kind kind = kindStr == null ? null : Kind.valueOf(kindStr);
// Special case check for the value of the index_options column being a string with value 'null' as this
// column appears to be set this way (JAVA-834).
String indexOptionsCol = indexColumns.get(ColumnMetadata.INDEX_OPTIONS);
Map options;
if (indexOptionsCol == null || indexOptionsCol.isEmpty() || indexOptionsCol.equals("null")) {
options = ImmutableMap.of();
} else {
options = SimpleJSONParser.parseStringMap(indexOptionsCol);
}
String target = targetFromLegacyOptions(column, options);
return new IndexMetadata((TableMetadata) column.getParent(), indexName, kind, target, options);
}
private static String targetFromLegacyOptions(ColumnMetadata column, Map options) {
String columnName = Metadata.escapeId(column.getName());
if (options.containsKey(INDEX_KEYS_OPTION_NAME))
return String.format("keys(%s)", columnName);
if (options.containsKey(INDEX_ENTRIES_OPTION_NAME))
return String.format("entries(%s)", columnName);
if (column.getType() instanceof DataType.CollectionType && column.getType().isFrozen())
return String.format("full(%s)", columnName);
// Note: the keyword 'values' is not accepted as a valid index target function until 3.0
return columnName;
}
/**
* Returns the metadata of the table this index is part of.
*
* @return the table this index is part of.
*/
public TableMetadata getTable() {
return table;
}
/**
* Returns the index name.
*
* @return the index name.
*/
public String getName() {
return name;
}
/**
* Returns the index kind.
*
* @return the index kind.
*/
public Kind getKind() {
return kind;
}
/**
* Returns the index target.
*
* @return the index target.
*/
public String getTarget() {
return target;
}
/**
* Returns whether this index is a custom one.
*
* If it is indeed a custom index, {@link #getIndexClassName} will
* return the name of the class used in Cassandra to implement that
* index.
*
* @return {@code true} if this metadata represents a custom index.
*/
public boolean isCustomIndex() {
return getIndexClassName() != null;
}
/**
* The name of the class used to implement the custom index, if it is one.
*
* @return the name of the class used Cassandra side to implement this
* custom index if {@code isCustomIndex() == true}, {@code null} otherwise.
*/
public String getIndexClassName() {
return getOption(CUSTOM_INDEX_OPTION_NAME);
}
/**
* Return the value for the given option name.
*
* @param name Option name
* @return Option value
*/
public String getOption(String name) {
return options != null ? options.get(name) : null;
}
/**
* Returns a CQL query representing this index.
*
* This method returns a single 'CREATE INDEX' query corresponding to
* this index definition.
*
* @return the 'CREATE INDEX' query corresponding to this index.
*/
public String asCQLQuery() {
String keyspaceName = Metadata.escapeId(table.getKeyspace().getName());
String tableName = Metadata.escapeId(table.getName());
String indexName = Metadata.escapeId(this.name);
return isCustomIndex()
? String.format("CREATE CUSTOM INDEX %s ON %s.%s (%s) USING '%s' %s;", indexName, keyspaceName, tableName, getTarget(), getIndexClassName(), getOptionsAsCql())
: String.format("CREATE INDEX %s ON %s.%s (%s);", indexName, keyspaceName, tableName, getTarget());
}
/**
* Builds a string representation of the custom index options.
*
* @return String representation of the custom index options, similar to what Cassandra stores in
* the 'index_options' column of the 'schema_columns' table in the 'system' keyspace.
*/
private String getOptionsAsCql() {
Iterable> filtered = Iterables.filter(options.entrySet(), new Predicate>() {
@Override
public boolean apply(Map.Entry input) {
return
!input.getKey().equals(TARGET_OPTION_NAME) &&
!input.getKey().equals(CUSTOM_INDEX_OPTION_NAME);
}
});
if (Iterables.isEmpty(filtered)) return "";
StringBuilder builder = new StringBuilder();
builder.append("WITH OPTIONS = {");
Iterator> it = filtered.iterator();
while (it.hasNext()) {
Map.Entry option = it.next();
builder.append(String.format("'%s' : '%s'", option.getKey(), option.getValue()));
if (it.hasNext())
builder.append(", ");
}
builder.append("}");
return builder.toString();
}
public int hashCode() {
return Objects.hashCode(name, kind, target, options);
}
public boolean equals(Object obj) {
if (obj == this)
return true;
if (!(obj instanceof IndexMetadata))
return false;
IndexMetadata other = (IndexMetadata) obj;
return Objects.equal(name, other.name)
&& Objects.equal(kind, other.kind)
&& Objects.equal(target, other.target)
&& Objects.equal(options, other.options);
}
}