viper.filters
Class Rules

java.lang.Object
  viper.filters.Rules

public class Rules

extends java.lang.Object

This class is simply a bunch of factory classes for standard rule types.

Constructor Summary

Rules()

Method Summary

static Filterable.Rule	getComparisonRelation(java.lang.Object o, java.lang.String relation) Gets a relation operation.
static Filterable.Rule	getComplexRule(Filterable f, java.lang.String complexRule, ErrorWriter err) Parses a rule of the form rule "value" (|| / &&) ...
static Filterable.Rule	getEquality(java.lang.Object o) Gets a rule that tests for equality with the target object.
static Filterable.Rule	getFalse() Gets a rule that always returns false.
static Filterable.Rule	getInequality(java.lang.Object o) Tests to see if two objects are not equal.
static Filterable.Rule	getTrue() Gets a rule that always returns true.

Methods inherited from class java.lang.Object

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

Constructor Detail

Rules

public Rules()

Method Detail

getFalse

public static Filterable.Rule getFalse()

Gets a rule that always returns false.

Returns:

the rule that always fails

getTrue

public static Filterable.Rule getTrue()

Gets a rule that always returns true.

Returns:

the rule that always passes

getEquality

public static Filterable.Rule getEquality(java.lang.Object o)

Gets a rule that tests for equality with the target object.

Parameters:

o - The object to test against.

Returns:

rule that tests for equality

getInequality

public static Filterable.Rule getInequality(java.lang.Object o)

Tests to see if two objects are not equal.

Parameters:

o - the object to test against.

Returns:

true iff o != the tested object.

getComparisonRelation

public static Filterable.Rule getComparisonRelation(java.lang.Object o,
                                                    java.lang.String relation)
                                             throws BadDataException

Gets a relation operation. If relation is == or !=, it uses the equals method of the object; otherwise, it casts the object to java.lang.Comparable.

Parameters:

o - The object to compare.

relation - String representing the relation, eg "<" or ">="

Returns:

the given comparison rule

Throws:

BadDataException

getComplexRule

public static Filterable.Rule getComplexRule(Filterable f,
                                             java.lang.String complexRule,
                                             ErrorWriter err)
                                      throws java.lang.IllegalArgumentException

Parses a rule of the form rule "value" (|| / &&) ...
The conjunctions and disjunctions have same precedence; to specify precedence, use parentheses

Parameters:

f - the rule type

complexRule - the string describing the rule

err - the error stream

Returns:

the complex rule

Throws:

java.lang.IllegalArgumentException - if the first rule was not valid. If a later rule is in error, it prints an error to the error writer and returns the valid rule so far. To get an exception on all errors, set err to null. Note that in this case, warnings (lack of quotes) will be ignored.