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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 java.util.*;
/**
* Metadata describing the columns returned in a {@link ResultSet} or a
* {@link PreparedStatement}.
*
* A {@code columnDefinitions}} instance is mainly a list of
* {@code ColumnsDefinitions.Definition}. The definitions or metadata for a column
* can be accessed either by:
*
* - index (indexed from 0)
* - name
*
*
* When accessed by name, column selection is case insensitive. In case multiple
* columns only differ by the case of their name, then the column returned with
* be the first column that has been defined in CQL without forcing case sensitivity
* (that is, it has either been defined without quotes or is fully lowercase).
* If none of the columns have been defined in this manner, the first column matching
* (with case insensitivity) is returned. You can force the case of a selection
* by double quoting the name.
*
* For example:
*
* - If {@code cd} contains column {@code fOO}, then {@code cd.contains("foo")},
* {@code cd.contains("fOO")} and {@code cd.contains("Foo")} will return {@code true}.
* - If {@code cd} contains both {@code foo} and {@code FOO} then:
*
* - {@code cd.getType("foo")}, {@code cd.getType("fOO")} and {@code cd.getType("FOO")}
* will all match column {@code foo}.
* - {@code cd.getType("\"FOO\"")} will match column {@code FOO}
*
*
* Note that the preceding rules mean that if a {@code ColumnDefinitions} object
* contains multiple occurrences of the exact same name (be it the same column
* multiple times or columns from different tables with the same name), you
* will have to use selection by index to disambiguate.
*/
public class ColumnDefinitions implements Iterable {
static final ColumnDefinitions EMPTY = new ColumnDefinitions(new Definition[0], CodecRegistry.DEFAULT_INSTANCE);
private final Definition[] byIdx;
private final Map byName;
final CodecRegistry codecRegistry;
ColumnDefinitions(Definition[] defs, CodecRegistry codecRegistry) {
this.byIdx = defs;
this.codecRegistry = codecRegistry;
this.byName = new HashMap(defs.length);
for (int i = 0; i < defs.length; i++) {
// Be optimistic, 99% of the time, previous will be null.
int[] previous = this.byName.put(defs[i].name.toLowerCase(), new int[]{i});
if (previous != null) {
int[] indexes = new int[previous.length + 1];
System.arraycopy(previous, 0, indexes, 0, previous.length);
indexes[indexes.length - 1] = i;
this.byName.put(defs[i].name.toLowerCase(), indexes);
}
}
}
/**
* Returns the number of columns described by this {@code Columns}
* instance.
*
* @return the number of columns described by this metadata.
*/
public int size() {
return byIdx.length;
}
/**
* Returns whether this metadata contains a given name.
*
* @param name the name to check.
* @return {@code true} if this metadata contains the column named {@code name},
* {@code false} otherwise.
*/
public boolean contains(String name) {
return findAllIdx(name) != null;
}
/**
* The first index in this metadata of the provided name, if present.
*
* @param name the name of the column.
* @return the index of the first occurrence of {@code name} in this metadata if
* {@code contains(name)}, -1 otherwise.
*/
public int getIndexOf(String name) {
return findFirstIdx(name);
}
/**
* Returns an iterator over the {@link Definition} contained in this metadata.
*
* The order of the iterator will be the one of this metadata.
*
* @return an iterator over the {@link Definition} contained in this metadata.
*/
@Override
public Iterator iterator() {
return Arrays.asList(byIdx).iterator();
}
/**
* Returns a list containing all the definitions of this metadata in order.
*
* @return a list of the {@link Definition} contained in this metadata.
*/
public List asList() {
return Arrays.asList(byIdx);
}
/**
* Returns the name of the {@code i}th column in this metadata.
*
* @param i the index in this metadata.
* @return the name of the {@code i}th column in this metadata.
* @throws IndexOutOfBoundsException if {@code i < 0} or {@code i >= size()}
*/
public String getName(int i) {
return byIdx[i].name;
}
/**
* Returns the type of the {@code i}th column in this metadata.
*
* @param i the index in this metadata.
* @return the type of the {@code i}th column in this metadata.
* @throws IndexOutOfBoundsException if {@code i < 0} or {@code i >= size()}
*/
public DataType getType(int i) {
return byIdx[i].type;
}
/**
* Returns the type of the first occurrence of {@code name} in this metadata.
*
* @param name the name of the column.
* @return the type of (the first occurrence of) {@code name} in this metadata.
* @throws IllegalArgumentException if {@code name} is not in this metadata.
*/
public DataType getType(String name) {
return getType(getFirstIdx(name));
}
/**
* Returns the keyspace of the {@code i}th column in this metadata.
*
* @param i the index in this metadata.
* @return the keyspace of the {@code i}th column in this metadata.
* @throws IndexOutOfBoundsException if {@code i < 0} or {@code i >= size()}
*/
public String getKeyspace(int i) {
return byIdx[i].keyspace;
}
/**
* Returns the keyspace of the first occurrence of {@code name} in this metadata.
*
* @param name the name of the column.
* @return the keyspace of (the first occurrence of) column {@code name} in this metadata.
* @throws IllegalArgumentException if {@code name} is not in this metadata.
*/
public String getKeyspace(String name) {
return getKeyspace(getFirstIdx(name));
}
/**
* Returns the table of the {@code i}th column in this metadata.
*
* @param i the index in this metadata.
* @return the table of the {@code i}th column in this metadata.
* @throws IndexOutOfBoundsException if {@code i < 0} or {@code i >= size()}
*/
public String getTable(int i) {
return byIdx[i].table;
}
/**
* Returns the table of first occurrence of {@code name} in this metadata.
*
* @param name the name of the column.
* @return the table of (the first occurrence of) column {@code name} in this metadata.
* @throws IllegalArgumentException if {@code name} is not in this metadata.
*/
public String getTable(String name) {
return getTable(getFirstIdx(name));
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
sb.append("Columns[");
for (int i = 0; i < size(); i++) {
if (i != 0)
sb.append(", ");
Definition def = byIdx[i];
sb.append(def.name).append('(').append(def.type).append(')');
}
sb.append(']');
return sb.toString();
}
int findFirstIdx(String name) {
int[] indexes = findAllIdx(name);
return indexes == null ? -1 : indexes[0];
}
int[] findAllIdx(String name) {
boolean caseSensitive = false;
if (name.length() >= 2 && name.charAt(0) == '"' && name.charAt(name.length() - 1) == '"') {
name = name.substring(1, name.length() - 1);
caseSensitive = true;
}
int[] indexes = byName.get(name.toLowerCase());
if (!caseSensitive || indexes == null)
return indexes;
// First, optimistic and assume all are matching
int nbMatch = 0;
for (int i = 0; i < indexes.length; i++)
if (name.equals(byIdx[indexes[i]].name))
nbMatch++;
if (nbMatch == indexes.length)
return indexes;
int[] result = new int[nbMatch];
int j = 0;
for (int i = 0; i < indexes.length; i++) {
int idx = indexes[i];
if (name.equals(byIdx[idx].name))
result[j++] = idx;
}
return result;
}
int[] getAllIdx(String name) {
int[] indexes = findAllIdx(name);
if (indexes == null)
throw new IllegalArgumentException(name + " is not a column defined in this metadata");
return indexes;
}
int getFirstIdx(String name) {
return getAllIdx(name)[0];
}
/**
* A column definition.
*/
public static class Definition {
private final String keyspace;
private final String table;
private final String name;
private final DataType type;
Definition(String keyspace, String table, String name, DataType type) {
this.keyspace = keyspace;
this.table = table;
this.name = name;
this.type = type;
}
/**
* The name of the keyspace this column is part of.
*
* @return the name of the keyspace this column is part of.
*/
public String getKeyspace() {
return keyspace;
}
/**
* Returns the name of the table this column is part of.
*
* @return the name of the table this column is part of.
*/
public String getTable() {
return table;
}
/**
* Returns the name of the column.
*
* @return the name of the column.
*/
public String getName() {
return name;
}
/**
* Returns the type of the column.
*
* @return the type of the column.
*/
public DataType getType() {
return type;
}
@Override
public final int hashCode() {
return Arrays.hashCode(new Object[]{keyspace, table, name, type});
}
@Override
public final boolean equals(Object o) {
if (!(o instanceof Definition))
return false;
Definition other = (Definition) o;
return keyspace.equals(other.keyspace)
&& table.equals(other.table)
&& name.equals(other.name)
&& type.equals(other.type);
}
}
}