org.apache.accumulo.core.security

Class ColumnVisibility

java.lang.Object

org.apache.accumulo.core.security.ColumnVisibility

public class ColumnVisibility
extends Object

Validate the column visibility is a valid expression and set the visibility for a Mutation. See ColumnVisibility(byte[]) for the definition of an expression.

The expression is a sequence of characters from the set [A-Za-z0-9_-.] along with the binary operators "&" and "|" indicating that both operands are necessary, or the either is necessary. The following are valid expressions for visibility:

 A
 A|B
 (A|B)&(C|D)
 orange|(red&yellow)
 

The following are not valid expressions for visibility:

 A|B&C
 A=B
 A|B|
 A&|B
 ()
 )
 dog|!cat
 

In addition to the base set of visibilities, any character can be used in the expression if it is quoted. If the quoted term contains '"' or '\', then escape the character with '\'. The quote(String) method can be used to properly quote and escape terms automatically. The following is an example of a quoted term:

 "A#C"&B
 

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ColumnVisibility.Node
static class	ColumnVisibility.NodeComparator
static class	ColumnVisibility.NodeType

Constructor Summary

Constructors

Constructor and Description
ColumnVisibility() Empty visibility.
ColumnVisibility(byte[] expression) A convenience method for constructing from a string already encoded in UTF-8 bytes.
ColumnVisibility(String expression) Set the column visibility for a Mutation.
ColumnVisibility(org.apache.hadoop.io.Text expression) A convenience method for constructing from a string already encoded in UTF-8 bytes and contained in a Text object.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	equals(ColumnVisibility otherLe) Compares two ColumnVisibilities for string equivalence, not as a meaningful comparison of terms and conditions.
boolean	equals(Object obj) See equals(ColumnVisibility)
byte[]	flatten() Generates a byte[] that represents a normalized, but logically equivalent, form of the supplied expression.
byte[]	getExpression() Accessor for the underlying byte string.
ColumnVisibility.Node	getParseTree()
int	hashCode()
static byte[]	quote(byte[] term) A convenience method to quote terms which are already encoded as UTF-8 bytes.
static String	quote(String term) Use to properly quote terms in a column visibility expression.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

ColumnVisibility

public ColumnVisibility()

Empty visibility. Normally, elements with empty visibility can be seen by everyone. Though, one could change this behavior with filters.

See Also:

ColumnVisibility(String)

ColumnVisibility

public ColumnVisibility(String expression)

Set the column visibility for a Mutation.

Parameters:

expression - An expression of the rights needed to see this mutation. The expression syntax is defined at the class-level documentation

ColumnVisibility

public ColumnVisibility(org.apache.hadoop.io.Text expression)

A convenience method for constructing from a string already encoded in UTF-8 bytes and contained in a Text object.

See Also:

ColumnVisibility(String)

ColumnVisibility

public ColumnVisibility(byte[] expression)

A convenience method for constructing from a string already encoded in UTF-8 bytes.

See Also:

ColumnVisibility(String)

Method Detail

getExpression

public byte[] getExpression()

Accessor for the underlying byte string.

Returns:

byte array representation of a visibility expression

flatten

public byte[] flatten()

Generates a byte[] that represents a normalized, but logically equivalent, form of the supplied expression.

Returns:

normalized expression in byte[] form

toString

public String toString()

Overrides:

toString in class Object

equals

public boolean equals(Object obj)

See equals(ColumnVisibility)

Overrides:

equals in class Object

equals

public boolean equals(ColumnVisibility otherLe)

Compares two ColumnVisibilities for string equivalence, not as a meaningful comparison of terms and conditions.

hashCode

public int hashCode()

Overrides:

hashCode in class Object

getParseTree

public ColumnVisibility.Node getParseTree()

quote

public static String quote(String term)

Use to properly quote terms in a column visibility expression. If no quoting is needed, then nothing is done.

Examples of using quote :

 import static org.apache.accumulo.core.security.ColumnVisibility.quote;
   .
   .
   .
 ColumnVisibility cv = new ColumnVisibility(quote("A#C") + "&" + quote("FOO"));
 

quote

public static byte[] quote(byte[] term)

A convenience method to quote terms which are already encoded as UTF-8 bytes.

See Also:

quote(String)