org.apache.solr.common.util
Class NamedList<T>

java.lang.Object
  org.apache.solr.common.util.NamedList<T>

All Implemented Interfaces:

Serializable, Cloneable, Iterable<Map.Entry<String,T>>

Direct Known Subclasses:

SimpleOrderedMap

public class NamedList<T>
extends Object
implements Cloneable, Serializable, Iterable<Map.Entry<String,T>>

A simple container class for modeling an ordered list of name/value pairs.

Unlike Maps:

• Names may be repeated
• Order of elements is maintained
• Elements may be accessed by numeric index
• Names and Values can both be null

A NamedList provides fast access by element number, but not by name.

When a NamedList is serialized, order is considered more important than access by key, so ResponseWriters that output to a format such as JSON will normally choose a data structure that allows order to be easily preserved in various clients (i.e. not a straight map). If access by key is more important, see SimpleOrderedMap, or simply use a regular Map

Version:

$Id: NamedList.java 687489 2008-08-20 22:14:09Z ehatcher $

See Also:

Serialized Form

Field Summary

protected List

nvPairs

Constructor Summary

NamedList()
Creates an empty instance

NamedList(List nameValuePairs)
Creates an instance backed by an explicitly specified list of pairwise names/values.

Method Summary

void	add(String name, T val) Adds a name/value pair to the end of the list.
boolean	addAll(Map<String,T> args) Iterates over the Map and sequentially adds it's key/value pairs
boolean	addAll(NamedList<T> nl) Appends the elements of the given NamedList to this one.
NamedList<T>	clone() Makes a shallow copy of the named list.
T	get(String name) Gets the value for the first instance of the specified name found.
T	get(String name, int start) Gets the value for the first instance of the specified name found starting at the specified index.
List<T>	getAll(String name) Gets the values for the the specified name
String	getName(int idx) The name of the pair at the specified List index
T	getVal(int idx) The value of the pair at the specified List index
int	indexOf(String name, int start) Scans the list sequentially beginning at the specified index and returns the index of the first pair with the specified name.
Iterator<Map.Entry<String,T>>	iterator() Support the Iterable interface
T	remove(int idx) Removes the name/value pair at the specified index.
void	setName(int idx, String name) Modifies the name of the pair at the specified index.
T	setVal(int idx, T val) Modifies the value of the pair at the specified index.
int	size() The total number of name/value pairs
String	toString()

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

nvPairs

protected final List nvPairs

Constructor Detail

NamedList

public NamedList()

Creates an empty instance

NamedList

public NamedList(List nameValuePairs)

Creates an instance backed by an explicitly specified list of pairwise names/values.

Parameters:

nameValuePairs - underlying List which should be used to implement a NamedList; modifying this List will affect the NamedList.

Method Detail

size

public int size()

The total number of name/value pairs

getName

public String getName(int idx)

The name of the pair at the specified List index

Returns:

null if no name exists

getVal

public T getVal(int idx)

The value of the pair at the specified List index

Returns:

may be null

add

public void add(String name,
                T val)

Adds a name/value pair to the end of the list.

setName

public void setName(int idx,
                    String name)

Modifies the name of the pair at the specified index.

setVal

public T setVal(int idx,
                T val)

Modifies the value of the pair at the specified index.

Returns:

the value that used to be at index

remove

public T remove(int idx)

Removes the name/value pair at the specified index.

Returns:

the value at the index removed

indexOf

public int indexOf(String name,
                   int start)

Scans the list sequentially beginning at the specified index and returns the index of the first pair with the specified name.

Parameters:

name - name to look for, may be null

start - index to begin searching from

Returns:

The index of the first matching pair, -1 if no match

get

public T get(String name)

Gets the value for the first instance of the specified name found.

Returns:

null if not found or if the value stored was null.

See Also:

indexOf(java.lang.String, int), get(String,int)

get

public T get(String name,
             int start)

Gets the value for the first instance of the specified name found starting at the specified index.

Returns:

null if not found or if the value stored was null.

See Also:

indexOf(java.lang.String, int)

getAll

public List<T> getAll(String name)

Gets the values for the the specified name

Parameters:

name - Name

Returns:

List of values

toString

public String toString()

Overrides:

toString in class Object

addAll

public boolean addAll(Map<String,T> args)

Iterates over the Map and sequentially adds it's key/value pairs

addAll

public boolean addAll(NamedList<T> nl)

Appends the elements of the given NamedList to this one.

clone

public NamedList<T> clone()

Makes a shallow copy of the named list.

Overrides:

clone in class Object

iterator

public Iterator<Map.Entry<String,T>> iterator()

Support the Iterable interface

Specified by:

iterator in interface Iterable<Map.Entry<String,T>>