com.beasys.commerce.util
Class ExpressionHelper

java.lang.Object
  com.beasys.commerce.util.ExpressionHelper

Deprecated Use ExpressionHelper instead.

public class ExpressionHelper
extends Object

Helper class to handle dealing with Expression, Criteria, and Logical objects.

See Also

Expression, Criteria, Logical

Nested Class Summary

static class

ExpressionHelper.ParseException Deprecated Exception to report an error while parsing a query expression.

Constructor Summary

ExpressionHelper()
Deprecated

Method Summary

static ExpressionHelper.ParseException	convertException(Exception excep) Deprecated Convert a generic exception into a ParseException.
static String	fromStringLiteral(String in) Deprecated Convert a String literal (which may contain quoted characters) into a corresponding String value.
static int	getOrdinalValue(char ch) Deprecated Get the ordinal (Unicode) value of a character.
static boolean	isHexString(String str) Deprecated Determine is a string contains only ASCII hexidecimal characters ([0-9a-fA-F]).
static Logical	join(Expression expr1, Expression expr2) Deprecated Join together two expression via an AND expression.
static Expression	normalize(Expression expr) Deprecated Normalize an Expression.
static Expression	parse(String queryStr) Deprecated Convert a query expression string into an Expression object.
static void	printTree(int depth, PrintWriter out, Expression expr) Deprecated For debug purposes, print the given expression as a tree at the given depth.
static void	printTree(PrintWriter out, Expression expr) Deprecated For debug purposes, print the given expression as a tree.
static String	toString(Criteria c) Deprecated Return a string representation of the given criteria.
static String	toString(Expression expr) Deprecated Get a string representation of the given expression.
static String	toString(Logical l) Deprecated Return a string representation of the given Logical.
static String	toStringLiteral(String in) Deprecated Get an ASCII String literal from a Java string.
static String	toTree(Expression expr) Deprecated For debug purposes, return a tree representation of the given expression.

Methods inherited from class java.lang.Object

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

Constructor Detail

ExpressionHelper

public ExpressionHelper()

Deprecated

Method Detail

parse

public static Expression parse(String queryStr)
                        throws ExpressionHelper.ParseException,
                               IllegalArgumentException

Deprecated

Convert a query expression string into an Expression object.

The string should follow the query syntax specified in the Personalization Server documentation. The expression syntax is tree-based, with each leaf in the tree beinging of the form "property comparator value" (e.g. "identifier == '1234'").

Property (LHS)

This specifies the object property to match against. To specify a property name which contains non-identifier characters (e.g. whitespace, double quotes, dashes), you can use the "toProperty('property name')" form in the left-hand-side. To specify scopenames as part of the property name, either use the "scope.name" form or the "toProperty('scope', 'property')" form in the left-hand-side.

Comparators

The valid comparision operators are = (or ==), !=, <, >, <=, >=, "like", and "contains". The "like" operator expects the pattern (which is the value of the leaf) to use * (match all) and ? (match any); "like" also is only expected to work against String values, although it might work with other datatypes depending upon the search implementation. The "contains" operator is only expected to work against multi-valued properties, although it might work with other datatypes depending upon the search implementation.

Value (RHS)

• String literal values are enclosed in single quotes (back-slash is the quoting character, unicode characters not supported). Additionally, unicode (e.g. "\u6565"), octal (e.g. "\7", "\65", "\377"), and standard Java escape sequences (e.g. "\n", "\r", "\b") are allowed in the string literals.
• Boolean literal are either the "true" or "false" keyword (without quotes).
• Number literals are Java form (scientific notation is supported).
• Time literals are presented in "toDate(['formatStr'], 'dateStr')" format. formatStr must be a valid SimpleDateFormat format string; if omitted, 'MM/dd/yyyy HH:mm:ss z' is used. Also, the "now" keyword specifies the current time/date.
• Collections cannot be represented in the expression syntax.

Each branch in the tree is comprised of 1 or more leafs or branches separated by either "&&" (boolean AND) or "||" (boolean OR). They can be enclosed in parenthesis for clearity and ordering (AND has precendance over OR). Additionally, "!" marks a branch as using negative logical (boolean NOT). The "!" operator can only be used preceding an open parenthesis.

Examples of valid expression strings:

• identifier == '00099abv48932ds'
• ((UserAge <= 35 && colors contains 'red') || (UserAge > 35 && !(colors contains 'black')) && mimeType == 'text/html'
• toProperty('MyApp', 'Launch Date') < now && !(MyApp.expireDate > toDate('HH:mm:ss MM-dd-yyyy', '12:12:12 12/12/2002'))

Parameters

queryStr - the query expression string

Returns

an Expression object representing (null if queryStr is a null expression).

Throws

ExpressionHelper.ParseException - thrown on a an invalid expression query or a parser error.

IllegalArgumentException - thrown on a general error.

See Also

convertException(java.lang.Exception), normalize(com.beasys.commerce.foundation.expression.Expression)

join

public static Logical join(Expression expr1,
                           Expression expr2)

Deprecated

Join together two expression via an AND expression.

Parameters

expr1 - the first expression.

expr2 - the second expression.

Returns

a Logical of the two expressions.

normalize

public static Expression normalize(Expression expr)

Deprecated

Normalize an Expression.

This will remove:

• Non-root Logicals which contain only one Expression
• Logicals which contain only one Criteria.

Parameters

expr - the incoming expression.

Returns

the normalized expression, null if normalized to nothing.

toString

public static String toString(Expression expr)

Deprecated

Get a string representation of the given expression.

Pretty much, a string generated from this method can be parse()'ed into the equivalent (not neccessarily identical) expression tree.

Parameters

expr - the expression.

Returns

the query syntax representation of the expression.

toString

public static String toString(Criteria c)

Deprecated

Return a string representation of the given criteria.

toString

public static String toString(Logical l)

Deprecated

Return a string representation of the given Logical.

toTree

public static String toTree(Expression expr)

Deprecated

For debug purposes, return a tree representation of the given expression.

printTree

public static void printTree(PrintWriter out,
                             Expression expr)

Deprecated

For debug purposes, print the given expression as a tree.

Parameters

out - the output stream to print on.

expr - the expression.

printTree

public static void printTree(int depth,
                             PrintWriter out,
                             Expression expr)

Deprecated

For debug purposes, print the given expression as a tree at the given depth.

Parameters

depth - the depth of this expression in the tree.

out - the output stream to print on.

expr - the expression.

fromStringLiteral

public static String fromStringLiteral(String in)

Deprecated

Convert a String literal (which may contain quoted characters) into a corresponding String value.

This supports the standard Java Language Specification escape sequences.

Parameters

in - the input string literal.

Returns

the string value.

isHexString

public static boolean isHexString(String str)

Deprecated

Determine is a string contains only ASCII hexidecimal characters ([0-9a-fA-F]).

toStringLiteral

public static String toStringLiteral(String in)

Deprecated

Get an ASCII String literal from a Java string.

This will quote some special characters with back-slashes.

The output of this can be sent through fromStringLiteral(java.lang.String) to result in the original String.

getOrdinalValue

public static int getOrdinalValue(char ch)

Deprecated

Get the ordinal (Unicode) value of a character.

convertException

public static ExpressionHelper.ParseException convertException(Exception excep)

Deprecated

Convert a generic exception into a ParseException.