org.openimaj.util.data

Class Context

java.lang.Object

java.util.AbstractMap<K,V>

java.util.HashMap<String,Object>

org.openimaj.util.data.Context

All Implemented Interfaces:

Serializable, Cloneable, Map<String,Object>

public class Context
extends HashMap<String,Object>
implements Cloneable

A Context is a Map which can give typed elements and can fail gracefully when elements don't exist.

Author:

Sina Samangooei (ss@ecs.soton.ac.uk)

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class java.util.AbstractMap

AbstractMap.SimpleEntry<K,V>, AbstractMap.SimpleImmutableEntry<K,V>

Constructor Summary

Constructors

Constructor and Description
Context() Default constructor to make an empty Context.
Context(boolean failfast) Construct an empty Context.
Context(Object... nameval) A conveniance function where nameval.length % 2 is assumed to == 0 and nameval contains pairs of "key" : value instances

Method Summary

Methods

Modifier and Type	Method and Description
Context	clone()
Context	combine(Context that, String thisprefix, String thatprefix) Combine this Context with another context by modifying any shared keys of both contexts to be prefixed with the given prefixes and then copying all the data from the given Context into this one.
<T> T	getTyped(String key) Get the object from the context with the given key and coerce the type.

Methods inherited from class java.util.HashMap

clear, containsKey, containsValue, entrySet, get, isEmpty, keySet, put, putAll, remove, size, values

Methods inherited from class java.util.AbstractMap

equals, hashCode, toString

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Map

equals, hashCode

Constructor Detail

Context

public Context()

Default constructor to make an empty Context. The Context is configured to return null from getTyped(String) if there is a casting issue or the object doesn't exist.

Context

public Context(Object... nameval)

A conveniance function where nameval.length % 2 is assumed to == 0 and nameval contains pairs of "key" : value instances

Parameters:

nameval -

Context

public Context(boolean failfast)

Construct an empty Context. The Context can optionally be configured to either return null from getTyped(String) or throw a RuntimeException if there is a casting issue or the object doesn't exist.

Parameters:

failfast - forces the getTyped to throw a runtime exception if set and the object does not exist or is not the correct type

Method Detail

getTyped

public <T> T getTyped(String key)

Get the object from the context with the given key and coerce the type.

Parameters:

key - the key

Returns:

the object with the given key coerced to the specific return type

clone

public Context clone()

Overrides:

clone in class HashMap<String,Object>

combine

public Context combine(Context that,
              String thisprefix,
              String thatprefix)

Combine this Context with another context by modifying any shared keys of both contexts to be prefixed with the given prefixes and then copying all the data from the given Context into this one.

If both prefixes are the same then the data being copied from the other context will have precedence. The prefixes can be null.

Parameters:

that - the context to combine with this

thisprefix - the prefix for keys in this context

thatprefix - the prefix for keys in the other context

Returns:

combined context