DEPRECATED

# com.bea.p13n.content.expression
ExpressionHelper Class

public class ExpressionHelper
extends `Object`

Helper class to handle dealing with content Expressions.

For details on what content expression should look like, see `ExpressionHelper.parse(String)```.

Hierarchy
  `Object`
  `ExpressionHelper`

## Nested Class Summary

`public static class` | `com.bea.p13n.content.expression.ExpressionHelper.ParseException` Exception to report an error while parsing a query expression.

## Field Summary

`public static final `String`` | `AND` Syntax textual and logical operator.
`public static final `String`` | `CONTAINS` Syntax textual contains operator.
`public static final `String`` | `CONTAINS_ALL` Syntax textual contains all operator.
`public static final `DateFormat`` | `defDateFormat` The default date formatter.
`public static final `String`` | `defDateFormatStr` The default datetime format string in the content expression syntax ("MM/dd/yyyy HH:mm:ss z").
`public static final `String`` | `EQUALS` Syntax textual equals operator.
`public static final `String`` | `GREATER_THAN` Syntax textual greater than operator.
`public static final `String`` | `GREATER_THAN_EQUALS` Syntax textual greater than or equals operator.
`public static final `String`` | `LESS_THAN` Syntax textual less than operator.
`public static final `String`` | `LESS_THAN_EQUALS` Syntax textual less than or equals operator.
`public static final `String`` | `LIKE` Syntax textual like operator.
`public static final `String`` | `LIKE_IGNORECASE` Syntax textual case-insensitive like operator.
`public static final `String`` | `NOT_EQUALS` Syntax textual not equals operator.
`public static final `String`` | `OR` Syntax textual or logical operator.

## Constructor Summary

ExpressionHelper()

## Method Summary

`public static `ExpressionHelper.ParseException`` | `convertException`(`Exception` excep) Convert a generic exception into a ParseException.
`public static `String`` | `fromStringLiteral`(`String` in) Convert a String literal (which may contain quoted characters) into a corresponding String value.
`public static `String`` | `getComparator`(`Expression` expr) Get the syntax comparator textual operator for the given leaf node.
`public static `String`` | `getContentId`(`Expression` expr) Return the content id from the expression, if it's an expression for a single content object based upon identifier.
`public static `Search`` | `getContentIdSearch`(`String` contentId) Get a search object for a single content based upon the supplied id.
`public static `Search`` | `getContentNameSearch`(`String` name) Get a search object for a single content based upon the name/path.
`public static `PropertyRef`` | `getLeftHandSide`(`Expression` expr) Get the left-hand-side of a valid leaf node, which should be a PropertyRef
`public static `String`` | `getLogicalComparator`(`Expression` expr) Get the syntax logical comparator textual operator for the given branch node.
`public static int` | `getOrdinalValue`(char ch) Get the ordinal (Unicode) value of a character.
`public static `Object`` | `getRightHandSide`(`Expression` expr) Get the right-hand-side of a valid leaf node.
`public static `Expression`` | `getSubExpression`(`Expression` expr, int count)
`public static boolean` | `isHexString`(`String` str) Determine if a string contains only ASCII hexidecimal characters ([0-9a-fA-F]).
`public static `Expression`` | `isLogicalNot`(`Expression` expr) Tell if an expression is really a logical not and, if so, returned the contained expression.
`public static boolean` | `isValidBranchNode`(`Expression` expr) Tell if an expression is a valid content branch node type.
`public static boolean` | `isValidLeafNode`(`Expression` expr) Tell if an expression is a valid content leaf node type.
`public static `LogicalAnd`` | `join`(`Expression` expr1, `Expression` expr2) Join together two expression via an AND expression.
`public static `Expression`` | `normalize`(`Expression` expr) Normalize an Expression.
`public static `Expression`` | `parse`(`String` queryStr) Convert a query expression string into an Expression object.
`public static void` | `print`(`PrintWriter` out, `Expression` expr) Print a string representation of the given expression.
`public static void` | `printBranchNode`(`PrintWriter` out, `Expression` expr) Return a string representation of the given expression branch.
`public static void` | `printLeafNode`(`PrintWriter` out, `Expression` expr) Return a string representation of the given leaf expression node.
`public static void` | `printTree`(`PrintWriter` out, `Expression` expr) For debug purposes, print the given expression as a tree.
`public static void` | `printTree`(int depth, `PrintWriter` out, `Expression` expr) For debug purposes, print the given expression as a tree at the given depth.
`public static `Expression`` | `realize`(`Expression` expr, `PropertyProvider` props) Realize an expression, which can contain property references, into an an expression which contains only literal values and can be sent to a ContentManager.
`public static `String`` | `toString`(`Expression` expr) Get a string representation of the given expression.
`public static `String`` | `toStringLiteral`(`String` in) Get an ASCII String literal from a Java string.
`public static `String`` | `toTree`(`Expression` expr) For debug purposes, return a tree representation of the given expression.

Methods from class `java.lang.`Object``
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

## Field Detail

### AND

    public static final String AND

  Syntax textual and logical operator.

### CONTAINS

    public static final String CONTAINS

  Syntax textual contains operator.

### CONTAINS_ALL

    public static final String CONTAINS_ALL

  Syntax textual contains all operator.

### defDateFormat

    public static final DateFormat defDateFormat

  The default date formatter.

### defDateFormatStr

    public static final String defDateFormatStr

  The default datetime format string in the content expression syntax ("MM/dd/yyyy HH:mm:ss z").

### EQUALS

    public static final String EQUALS

  Syntax textual equals operator.

### GREATER_THAN

    public static final String GREATER_THAN

  Syntax textual greater than operator.

### GREATER_THAN_EQUALS

    public static final String GREATER_THAN_EQUALS

  Syntax textual greater than or equals operator.

### LESS_THAN

    public static final String LESS_THAN

  Syntax textual less than operator.

### LESS_THAN_EQUALS

    public static final String LESS_THAN_EQUALS

  Syntax textual less than or equals operator.

### LIKE

    public static final String LIKE

  Syntax textual like operator.

### LIKE_IGNORECASE

    public static final String LIKE_IGNORECASE

  Syntax textual case-insensitive like operator.

### NOT_EQUALS

    public static final String NOT_EQUALS

  Syntax textual not equals operator.

### OR

    public static final String OR

  Syntax textual or logical operator.

## Constructor Detail

### ExpressionHelper

    public ExpressionHelper()

## Method Detail

### convertException(Exception) Method

    public static ExpressionHelper.ParseException convertException(Exception excep)

Convert a generic exception into a ParseException.

### fromStringLiteral(String) Method

    public static String fromStringLiteral(String in)

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.

### getComparator(Expression) Method

    public static String getComparator(Expression expr)
         throws IllegalArgumentException

Get the syntax comparator textual operator for the given leaf node.

#### Exceptions

``IllegalArgumentException``

### getContentId(Expression) Method

    public static String getContentId(Expression expr)

Return the content id from the expression, if it's an expression for a single content object based upon identifier.

#### Returns

the content id, or null if it's not a identifier equality expression.

### getContentIdSearch(String) Method

    public static Search getContentIdSearch(String contentId)

Get a search object for a single content based upon the supplied id.

### getContentNameSearch(String) Method

    public static Search getContentNameSearch(String name)

Get a search object for a single content based upon the name/path.

### getLeftHandSide(Expression) Method

    public static PropertyRef getLeftHandSide(Expression expr)
         throws IllegalArgumentException

Get the left-hand-side of a valid leaf node, which should be a PropertyRef

#### Exceptions

``IllegalArgumentException``

### getLogicalComparator(Expression) Method

    public static String getLogicalComparator(Expression expr)
         throws IllegalArgumentException

Get the syntax logical comparator textual operator for the given branch node.

#### Exceptions

``IllegalArgumentException``

### getOrdinalValue(char) Method

    public static int getOrdinalValue(char ch)

Get the ordinal (Unicode) value of a character.

### getRightHandSide(Expression) Method

    public static Object getRightHandSide(Expression expr)
         throws IllegalArgumentException

Get the right-hand-side of a valid leaf node.

#### Exceptions

``IllegalArgumentException``

### getSubExpression(Expression, int) Method

    public static Expression getSubExpression(Expression expr,
                                              int count)
         throws IllegalArgumentException

#### Exceptions

``IllegalArgumentException``

### isHexString(String) Method

    public static boolean isHexString(String str)

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

### isLogicalNot(Expression) Method

    public static Expression isLogicalNot(Expression expr)

Tell if an expression is really a logical not and, if so, returned the contained expression.

#### Parameters

expr
  the expression.

#### Returns

the contained expressions if expr is a logical not, null otherwise.

### isValidBranchNode(Expression) Method

    public static boolean isValidBranchNode(Expression expr)

Tell if an expression is a valid content branch node type.

### isValidLeafNode(Expression) Method

    public static boolean isValidLeafNode(Expression expr)

Tell if an expression is a valid content leaf node type.

### join(Expression, Expression) Method

    public static LogicalAnd join(Expression expr1,
                                  Expression expr2)

Join together two expression via an AND expression.

#### Parameters

expr1
  the first expression.

expr2
  the second expression.

#### Returns

a LogicalAnd of the two expressions.

### normalize(Expression) Method

    public static Expression normalize(Expression expr)
         throws IllegalArgumentException

Normalize an Expression.

This will recursively remove branches that contain only one Expression (which are boolean equivelant to the one child expression) or that contain no children (which are considered empty).

#### Parameters

expr
  the incoming expression.

#### Returns

the normalized expression, null if normalized to nothing.

#### Exceptions

``IllegalArgumentException``
  thrown if the expression is not a valid content expression.

### parse(String) Method

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

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 property set names as part of the property name, either use the "`properyset.name`" form or the "`toProperty('propertyset', 'property')`" form in the left-hand-side.

Comparators

The valid comparision operators are `=` (or `==`), `!=`, `<`, `>`, `<=`, `>=`, "`like`", "`likeignorecase`" and "`contains`". The "`like`" and "`likeignorecase`" operator expects the pattern (which is the value of the leaf) to use `*` (match all) and `?` (match any); "`like`" and "`likeignorecase`" also is only expected to work against String values, although it might work with other datatypes depending upon the search implementation. "`like`" operator does case-sensitive pattern match, while "`likeignorecase`" operator does case- insensitive pattern match. 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 literals 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 time at which the expression was created.
  - Collections cannot be represented in the expression syntax.
  - References to user, request, or session properties are represented as such:

         <type>Property(<propertyset>, <propertyname>)

         where <type> is one of 'user', 'request',
         or 'session', <propertyset> is the property set name
         and follows the rules for string literals.
         <propertyname> is the property name and follows the
         rules for string literals.

         References to properties should not be passed into a
         DocumentManager class. Expression which contain references to
         properties should be realized into a searchable expression via the
         realize() method.

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 logic (boolean NOT). The "`!`" operator can only be used preceding an open parenthesis.

Examples of valid expression strings: ``

- identifier == '00099abv48932ds'
- language == userProp('MyProperties', 'userPreferredLang')
- ((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'))

In the resulting expression tree, the following caveats apply for it to be valid for the ContentManager:

- Each branch node can only be a LogicalAnd, LogicalOr, LogicalMulitAnd, or LogicalMultiOr. Any other branch node type is invalid.
- Each leaf node can only be an Equals, GreaterOrEquals, GreaterThan, LessOrEquals, LessThan, NotEquals, StringLike, CollectionContains, or CollectionsContainsAll. Any other branch node type is invalid.
- Any valid branch or leaf node may be contained in a LogicalNot node.
- In each leaf node, the left-hand-side will always be a PropertyRef node, which must contain Strings for getPropertySet() and getPropertyName(). In non-realized expression, a leaf node can be a UserPropertyRef, RequestPropertyRef, or SessionPropertyRef to represent a reference to an external property. ContentManagers should not receive non-realized expression, and, therefore, should not receive these objects; they are free to raise an exception if one is found.
- The right-hand-side of Equals, NotEquals, GreaterOrEquals, GreaterThan, LessOrEquals, LessThan, or CollectionContains leaf nodes can be a Collection, Long, Double, String, or Timestamp.
- The right-hand-side of StringLike leaf nodes can be a String. Anything else is invalid.
- The right-hand-side of CollectionsContainsAll leaf nodes can be a Collection. Anything else is invalid.

#### Parameters

queryStr
  the query expression string

#### Returns

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

#### Exceptions

``ExpressionHelper.ParseException``
``IllegalArgumentException``
  thrown on a general error.

Related Topics

``ExpressionHelper.convertException(Exception)``
``ExpressionHelper.normalize(Expression)``

### print(PrintWriter, Expression) Method

    public static void print(PrintWriter out,
                             Expression expr)
         throws IllegalArgumentException

Print 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

out
  the output writer.

expr
  the expression.

#### Exceptions

``IllegalArgumentException``
  thrown if the given expression is not a valid content expression.

### printBranchNode(PrintWriter, Expression) Method

    public static void printBranchNode(PrintWriter out,
                                       Expression expr)

Return a string representation of the given expression branch.

### printLeafNode(PrintWriter, Expression) Method

    public static void printLeafNode(PrintWriter out,
                                     Expression expr)
         throws IllegalArgumentException

Return a string representation of the given leaf expression node.

#### Exceptions

``IllegalArgumentException``

### printTree(PrintWriter, Expression) Method

    public static void printTree(PrintWriter out,
                                 Expression expr)

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

#### Parameters

out
  the output stream to print on.

expr
  the expression.

### printTree(int, PrintWriter, Expression) Method

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

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.

### realize(Expression, PropertyProvider) Method

    public static Expression realize(Expression expr,
                                     PropertyProvider props)
         throws IllegalArgumentException

Realize an expression, which can contain property references, into an an expression which contains only literal values and can be sent to a ContentManager.

This will modify the passed in expression.

#### Parameters

expr
  the expression to realize.

props
  the object which provides values for property references.

#### Returns

the modified expression

#### Exceptions

``IllegalArgumentException``
  thrown if the expr is not a valid content expression or contain a reference to an unknown property type.

### toString(Expression) Method

    public static String toString(Expression expr)
         throws IllegalArgumentException

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.

#### Exceptions

``IllegalArgumentException``
  thrown if the given expression is not a valid content expression.

### toStringLiteral(String) Method

    public static String toStringLiteral(String in)

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 `ExpressionHelper.fromStringLiteral(String)``` to result in the original String.

### toTree(Expression) Method

    public static String toTree(Expression expr)

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