Package org.apache.sis.io.wkt

Class StoredTree.Deflater

java.lang.Object

org.apache.sis.io.wkt.StoredTree.Deflater

Enclosing class:

StoredTree

private static final class StoredTree.Deflater
extends Object

A helper class for compressing a tree of Elements as a tree of StoredTree.Nodes. Contrarily to Element instances, Nodes instances can be shared between many trees. Each instances shall be used for constructing only one StoredTree.Node. After node construction, this instance lives longer in the sharedValues map for sharing offsets arrays.

See Also:

• StoredTree(List, Map)

Field Summary

Fields

Modifier and Type	Field	Description
private int	count	Number of valid elements in offsets.
private short[]	offsets	The Element.offset value of StoredTree.root together with offsets of all Element.children in iteration order.
private Map<Object,Object>	sharedValues	Pool to use for sharing unique instances of values.

Constructor Summary

Constructors

Constructor	Description
Deflater(Map<Object,Object> sharedValues)	Pool of previously constructed values used for replacing equal instances by unique instances.

Method Summary

Modifier and Type	Method	Description
(package private) final void	addOffset(Element element)	Adds the given Element.offset value.
boolean	equals(Object other)	Compares the offsets arrays for equality.
int	hashCode()	Computes a hash code value based only on the offsets array.
(package private) final short[]	offsets()	Returns all Element.offset values in iteration order.
(package private) final Object	unique(Object value)	Returns a unique instance of given object.

Methods inherited from class java.lang.Object

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

Field Details

sharedValues

private Map<Object,Object> sharedValues

Pool to use for sharing unique instances of values. This is a copy of WKTFormat.sharedValues map. This is reset to null when not needed anymore.

offsets

private short[] offsets

The Element.offset value of StoredTree.root together with offsets of all Element.children in iteration order. Order is defined by StoredTree.Node constructor. This array is expanded as needed. Shall not be modified after call to offsets().

count

private int count

Number of valid elements in offsets.

Constructor Details

Deflater

Deflater(Map<Object,Object> sharedValues)

Pool of previously constructed values used for replacing equal instances by unique instances. May contain String, Long, Double and StoredTree.Node instances among others.

Parameters:

sharedValues - pool of previously created objects.

Method Details

unique

final Object unique(Object value)

Returns a unique instance of given object. The given value can be a StoredTree.Node instance provided that it is not an anonymous node (i.e. StoredTree.keyword() shall be non-null).

Parameters:

value - the value for which to get a unique instance.

Returns:

a previous instance from the pool, or value if none.

See Also:

• StoredTree.Node.hashCode()
• StoredTree.Node.equals(Object)

addOffset

final void addOffset(Element element)

Adds the given Element.offset value.

See Also:

• StoredTree.Inflater.nextOffset()

offsets

final short[] offsets()

Returns all Element.offset values in iteration order. This method may return an array shared by different StoredTree.Node instances; do not modify.

equals

public boolean equals(Object other)

Compares the offsets arrays for equality. This is used by offsets() (indirectly, through Map) as a workaround for Java arrays not overriding equals(Object) method.

Overrides:

equals in class Object

hashCode

public int hashCode()

Computes a hash code value based only on the offsets array. See equals(Object) for rational.

Overrides:

hashCode in class Object