Package org.aspectj.org.eclipse.jdt.internal.compiler.apt.util

Class ManyToMany<T1,T2>

java.lang.Object

org.aspectj.org.eclipse.jdt.internal.compiler.apt.util.ManyToMany<T1,T2>

public class ManyToMany<T1,T2>
extends Object

Manage a Map<T1, Set<T2>>, with reverse links so that it is possible to efficiently find all T1s that have a particular T2 associated with them. Access to the map is synchronized, so that it is possible to read and write simultaneously from multiple threads.

The map permits the null value for keys nor for value elements.

Design invariants preserved by all operations on this map are as follows:

• If a key exists, it has at least one value associated with it; that is, for all k such that null != containsKey(k), getValues(k) returns a non-empty set.
• If a value exists, it has at least one key associated with it; that is, for all v such that null != containsValue(v), getKeys(v) returns a non-empty set.

Constructor Summary

Constructors

Constructor	Description
ManyToMany()

Method Summary

Modifier and Type	Method	Description
boolean	clear()	Empty all maps.
void	clearDirtyBit()	Sets the dirty bit to false.
boolean	containsKey(T1 key)	Equivalent to keySet().contains(key).
boolean	containsKeyValuePair(T1 key, T2 value)	Is there a key that is mapped to the specified value? Search within the forward map.
boolean	containsValue(T2 value)	Equivalent to values().contains(value).
Set<T1>	getKeys(T2 value)	Search the reverse map for all keys that have been associated with a particular value.
Set<T1>	getKeySet()
Set<T2>	getValues(T1 key)	Search the forward map for all values associated with a particular key.
Set<T2>	getValueSet()
boolean	isDirty()	Return the state of the dirty bit.
boolean	keyHasOtherValues(T1 key, T2 value)	Check whether key has an association to any values other than value - that is, whether the same key has been added with multiple values.
boolean	put(T1 key, T2 value)	Associate the specified value with the key.
boolean	remove(T1 key, T2 value)	Remove a particular key-value association.
boolean	removeKey(T1 key)	Remove the key and its associated key/value entries.
boolean	removeValue(T2 value)	Remove the value and its associated key/value entries.
boolean	valueHasOtherKeys(T2 value, T1 key)	Check whether value has an association from any keys other than key - that is, whether the same value has been added with multiple keys.

Methods inherited from class java.lang.Object

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

Constructor Details

ManyToMany

public ManyToMany()

Method Details

clear

public boolean clear()

Empty all maps. If the maps previously contained entries, this will set the dirty bit.

Returns:

true if the maps contained any entries prior to being cleared

clearDirtyBit

public void clearDirtyBit()

Sets the dirty bit to false. Internal operations do not use the dirty bit; clearing it will not affect behavior of the map. It's just there for the convenience of callers who don't want to keep track of every put() and remove().

containsKey

public boolean containsKey(T1 key)

Equivalent to keySet().contains(key).

Returns:

true if the map contains the specified key.

containsKeyValuePair

public boolean containsKeyValuePair(T1 key,
 T2 value)

Is there a key that is mapped to the specified value? Search within the forward map.

Returns:

true if such a key exists

containsValue

public boolean containsValue(T2 value)

Equivalent to values().contains(value).

Returns:

true if the map contains the specified value (regardless of what key it might be associated with).

getKeys

public Set<T1> getKeys(T2 value)

Search the reverse map for all keys that have been associated with a particular value.

Returns:

the set of keys that are associated with the specified value, or an empty set if the value does not exist in the map.

getValues

public Set<T2> getValues(T1 key)

Search the forward map for all values associated with a particular key. Returns a copy of the set of values.

Returns:

a copy of the set of values that are associated with the specified key, or an empty set if the key does not exist in the map.

getKeySet

public Set<T1> getKeySet()

Returns:

a copy of the set of all keys (that is, all items of type T1). If the maps are empty, the returned set will be empty, not null. The returned set can be modified by the caller without affecting the map.

See Also:

• getValueSet()

getValueSet

public Set<T2> getValueSet()

Returns:

a copy of the set of all values (that is, all items of type T2). If the maps are empty, the returned set will be empty, not null. The returned set can be modified by the caller without affecting the map.

See Also:

• getKeySet()

isDirty

public boolean isDirty()

Return the state of the dirty bit. All operations that change the state of the maps, including @see #clear(), set the dirty bit if any content actually changed. The only way to clear the dirty bit is to call @see #clearDirtyBit().

Returns:

true if the map content has changed since it was created or since the last call to clearDirtyBit().

See Also:

• clearDirtyBit()

keyHasOtherValues

public boolean keyHasOtherValues(T1 key,
 T2 value)

Check whether key has an association to any values other than value - that is, whether the same key has been added with multiple values. Equivalent to asking whether the intersection of getValues(key) and the set containing value is non-empty.

Returns:

true iff key is in the map and is associated with values other than value.

See Also:

• valueHasOtherKeys(Object, Object)

put

public boolean put(T1 key,
 T2 value)

Associate the specified value with the key. Adds the entry to both the forward and reverse maps. Adding the same value twice to a particular key has no effect. Because this is a many-to-many map, adding a new value for an existing key does not change the existing association, it adds a new one.

Parameters:

key - can be null

value - can be null

Returns:

true if the key/value pair did not exist prior to being added

remove

public boolean remove(T1 key,
 T2 value)

Remove a particular key-value association. This is the inverse of put(key, value). If the key does not exist, or the value does not exist, or the association does not exist, this call has no effect.

Returns:

true if the key/value pair existed in the map prior to removal

removeKey

public boolean removeKey(T1 key)

Remove the key and its associated key/value entries. Calling removeKey(k) is equivalent to calling remove(k,v) for every v in getValues(k).

Returns:

true if the key existed in the map prior to removal

removeValue

public boolean removeValue(T2 value)

Remove the value and its associated key/value entries. Calling removeValue(v) is equivalent to calling remove(k,v) for every k in getKeys(v).

Returns:

true if the value existed in the map prior to removal.

valueHasOtherKeys

public boolean valueHasOtherKeys(T2 value,
 T1 key)

Check whether value has an association from any keys other than key - that is, whether the same value has been added with multiple keys. Equivalent to asking whether the intersection of getKeys(value) and the set containing key is non-empty.

Returns:

true iff value is in the map and is associated with keys other than key.

See Also:

• keyHasOtherValues(Object, Object)