com.googlecode.genericdao.search

Class BaseSearchProcessor

java.lang.Object

com.googlecode.genericdao.search.BaseSearchProcessor

Direct Known Subclasses:

JPASearchProcessor

public abstract class BaseSearchProcessor
extends Object

This class provides two methods for generating query language to fulfill an ISearch.

1. generateQL() - is used for getting the actual search results.
2. generateRowCountQL() - is used for getting just the number of results.

Both methods return a query language sting and a list of values for filling named parameters. For example the following query and parameter list might be returned:

 select _it from com.example.Cat _it
   where _it.age > :p1 and _it.name != :p2
   
 parameter list: [3, 'Mittens']
 

This is an abstract class. A subclass must be used to implement individual query languages. Currently only HQL query language is supported ( com.googlecode.genericdao.dao.hibernate.HibernateSearchToQLProcessor). The that implementation could be used for EQL query language as well with no or minor modifications.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	BaseSearchProcessor.AliasNode
protected static class	BaseSearchProcessor.SearchContext

Field Summary

Fields

Modifier and Type	Field and Description
protected Pattern	INJECTION_CHECK Regex pattern for a valid property name/path.
protected MetadataUtil	metadataUtil
protected int	qlType
protected static int	QLTYPE_EQL
protected static int	QLTYPE_HQL
protected static String	ROOT_PATH
protected String	rootAlias

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	BaseSearchProcessor(int qlType, MetadataUtil metadataUtil)

Method Summary

Methods

Modifier and Type	Method and Description
protected Filter	addExplicitNullChecks(Filter filter) Used by negate(Filter).
protected void	appendCustomExpression(StringBuilder sb, BaseSearchProcessor.SearchContext ctx, String expression) append a custom expression to the string builder, replacing any property tokens (i.e "{prop}") with a reference to the property.
protected void	appendCustomExpression(StringBuilder sb, BaseSearchProcessor.SearchContext ctx, String expression, List<?> values) append a custom expression to the string builder, replacing any property tokens (i.e "{prop}") with a reference to the property and value tokens (i.e.
protected void	applyFetches(BaseSearchProcessor.SearchContext ctx, List<String> fetches, List<Field> fields) Apply the fetch list to the alias tree in the search context.
protected List<String>	checkAndCleanFetches(List<String> fetches) Check for injection attack in property strings.
protected List<Field>	checkAndCleanFields(List<Field> fields) Check for injection attack in property strings.
protected List<Filter>	checkAndCleanFilters(List<Filter> filters) Check for injection attack in property strings.
protected List<Sort>	checkAndCleanSorts(List<Sort> sorts) Check for injection attack in property strings.
protected String	filterToQL(BaseSearchProcessor.SearchContext ctx, Filter filter) Recursively generate the QL fragment for a given search filter option.
protected String	generateFromClause(BaseSearchProcessor.SearchContext ctx, boolean doEagerFetching) Internal method for generating from clause.
protected String	generateJoins(BaseSearchProcessor.SearchContext ctx, boolean doEagerFetching) Internal method for generating the join portion of the from clause.
protected String	generateOrderByClause(BaseSearchProcessor.SearchContext ctx, List<Sort> sorts) Internal method for generating order by clause.
String	generateQL(Class<?> entityClass, ISearch search, List<Object> paramList) Generate the QL string for a given search.
String	generateRowCountQL(Class<?> entityClass, ISearch search, List<Object> paramList) Generate the QL string that will query the total number of results from a given search (paging is ignored).
protected String	generateSelectClause(BaseSearchProcessor.SearchContext ctx, List<Field> fields, boolean distinct) Internal method for generating the select clause based on the fields of the given search.
protected String	generateSimpleAllOrSome(BaseSearchProcessor.SearchContext ctx, String property, Filter filter, String operation) In the case of simple ALL/SOME/NONE filters, a simpler hql syntax is used (which is also compatible with collections of values).
protected String	generateSubquery(BaseSearchProcessor.SearchContext ctx, String property, Filter filter) Generate a QL string for a subquery on the given property that uses the given filter.
protected String	generateWhereClause(BaseSearchProcessor.SearchContext ctx, List<Filter> filters, boolean isDisjunction) Internal method for generating where clause for given search.
protected BaseSearchProcessor.AliasNode	getAliasForPathIfItExists(BaseSearchProcessor.SearchContext ctx, String path) Given a full path to an entity (ex.
Filter	getFilterFromExample(Object example)
Filter	getFilterFromExample(Object example, ExampleOptions options)
MetadataUtil	getMetadataUtil() The MetadataUtil used by this search processor.
protected BaseSearchProcessor.AliasNode	getOrCreateAlias(BaseSearchProcessor.SearchContext ctx, String path, boolean setFetch) Given a full path to an entity (ex.
protected String	getPathRef(BaseSearchProcessor.SearchContext ctx, String path) Given a full path to a property (ex.
protected Filter	negate(Filter filter) Return a filter that negates the given filter.
protected String	param(BaseSearchProcessor.SearchContext ctx, Object value) Add value to paramList and return the named parameter string ":pX".
protected Object	prepareValue(Class<?> rootClass, String property, Object value, boolean isCollection) Convert a property value to the expected type for that property.
protected void	securityCheckProperty(String property) Used by securityCheck() to check a property string for injection attack.
protected void	setFetchOnAliasNodeAndAllAncestors(BaseSearchProcessor.AliasNode node)
void	setRootAlias(String alias) This is the string used to represent the root entity of the search within the query.
protected String[]	splitPath(BaseSearchProcessor.SearchContext ctx, String path) Split a path into two parts.

Methods inherited from class java.lang.Object

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

Field Detail

QLTYPE_HQL

protected static int QLTYPE_HQL

QLTYPE_EQL

protected static int QLTYPE_EQL

qlType

protected int qlType

metadataUtil

protected MetadataUtil metadataUtil

rootAlias

protected String rootAlias

ROOT_PATH

protected static final String ROOT_PATH

See Also:

Constant Field Values

INJECTION_CHECK

protected Pattern INJECTION_CHECK

Regex pattern for a valid property name/path.

Constructor Detail

BaseSearchProcessor

protected BaseSearchProcessor(int qlType,
                   MetadataUtil metadataUtil)

Method Detail

getMetadataUtil

public MetadataUtil getMetadataUtil()

The MetadataUtil used by this search processor. This can only be set in the constructor.

setRootAlias

public void setRootAlias(String alias)

This is the string used to represent the root entity of the search within the query. The default value is "_it". It may be necessary to use a different alias if there are entities in the data model with the name or property "_it".

generateQL

public String generateQL(Class<?> entityClass,
                ISearch search,
                List<Object> paramList)

Generate the QL string for a given search. Fill paramList with the values to be used for the query. All parameters within the query string are specified as named parameters ":pX", where X is the index of the parameter value in paramList.

generateRowCountQL

public String generateRowCountQL(Class<?> entityClass,
                        ISearch search,
                        List<Object> paramList)

Generate the QL string that will query the total number of results from a given search (paging is ignored). Fill paramList with the values to be used for the query. All parameters within the query string are specified as named parameters ":pX", where X is the index of the parameter value in paramList. NOTE: Returns null if column operators are used in the search. Such a search will always return 1 row.

generateSelectClause

protected String generateSelectClause(BaseSearchProcessor.SearchContext ctx,
                          List<Field> fields,
                          boolean distinct)

Internal method for generating the select clause based on the fields of the given search.

applyFetches

protected void applyFetches(BaseSearchProcessor.SearchContext ctx,
                List<String> fetches,
                List<Field> fields)

Apply the fetch list to the alias tree in the search context.

generateFromClause

protected String generateFromClause(BaseSearchProcessor.SearchContext ctx,
                        boolean doEagerFetching)

Internal method for generating from clause. This method should be called after generating other clauses because it relies on the aliases they create. This method takes every path that is called for in the other clauses and makes it available as an alias using left joins. It also adds join fetching for properties specified by fetches if doEagerFetching is true. NOTE: When using eager fetching, applyFetches() must be executed first.

generateJoins

protected String generateJoins(BaseSearchProcessor.SearchContext ctx,
                   boolean doEagerFetching)

Internal method for generating the join portion of the from clause. This method should be called after generating other clauses because it relies on the aliases they create. This method takes every path that is called for in the other clauses and makes it available as an alias using left joins. It also adds join fetching for properties specified by fetches if doEagerFetching is true . NOTE: When using eager fetching, applyFetches() must be executed first.

generateOrderByClause

protected String generateOrderByClause(BaseSearchProcessor.SearchContext ctx,
                           List<Sort> sorts)

Internal method for generating order by clause. Uses sort options from search.

generateWhereClause

protected String generateWhereClause(BaseSearchProcessor.SearchContext ctx,
                         List<Filter> filters,
                         boolean isDisjunction)

Internal method for generating where clause for given search. Uses filter options from search.

filterToQL

protected String filterToQL(BaseSearchProcessor.SearchContext ctx,
                Filter filter)

Recursively generate the QL fragment for a given search filter option.

generateSubquery

protected String generateSubquery(BaseSearchProcessor.SearchContext ctx,
                      String property,
                      Filter filter)

Generate a QL string for a subquery on the given property that uses the given filter. This is used by SOME, ALL and NONE filters.

Parameters:

ctx - - a new context just for this sub-query

property - - the property of the main query that points to the collection on which to query

filter - - the filter to use for the where clause of the sub-query

generateSimpleAllOrSome

protected String generateSimpleAllOrSome(BaseSearchProcessor.SearchContext ctx,
                             String property,
                             Filter filter,
                             String operation)

In the case of simple ALL/SOME/NONE filters, a simpler hql syntax is used (which is also compatible with collections of values). Simple filters include ALL/SOME/NONE filters with exactly one sub-filter where that filter applies to the elements of the collection directly (as opposed to their properties) and the operator is =, !=, <, <=, >, or >=.

For example:

 Filter.some("some_collection_of_strings", Filter.equal("", "Bob")
 Filter.all("some_collection_of_numbers", Filter.greaterThan(null, 23)
 

If the filter meets these criteria as a simple ALL/SOME/NONE filter, the QL string for the filter will be returned. If not, null is returned.

Parameters:

ctx - - the context of the SOME/ALL/NONE filter

property - - the property of the SOME/ALL/NONE filter

filter - - the sub-filter that is the value of the SOME/ALL/NONE filter

operation - - a string used to fill in the collection operation. The value should be either "some" or "all".

prepareValue

protected Object prepareValue(Class<?> rootClass,
                  String property,
                  Object value,
                  boolean isCollection)

Convert a property value to the expected type for that property. Ex. a Long to and Integer.

Parameters:

isCollection - true if the value is a collection of values, for example with IN and NOT_IN operators.

Returns:

the converted value.

negate

protected Filter negate(Filter filter)

Return a filter that negates the given filter.

addExplicitNullChecks

protected Filter addExplicitNullChecks(Filter filter)

Used by negate(Filter). There's a complication with null values in the database so that !(x == 1) is not the opposite of (x == 1). Rather !(x == 1 and x != null) is the same as (x == 1). This method applies the null check explicitly to all filters included in the given filter tree.

appendCustomExpression

protected void appendCustomExpression(StringBuilder sb,
                          BaseSearchProcessor.SearchContext ctx,
                          String expression)

append a custom expression to the string builder, replacing any property tokens (i.e "{prop}") with a reference to the property.

appendCustomExpression

protected void appendCustomExpression(StringBuilder sb,
                          BaseSearchProcessor.SearchContext ctx,
                          String expression,
                          List<?> values)

append a custom expression to the string builder, replacing any property tokens (i.e "{prop}") with a reference to the property and value tokens (i.e. "?n") with params.

param

protected String param(BaseSearchProcessor.SearchContext ctx,
           Object value)

Add value to paramList and return the named parameter string ":pX".

getPathRef

protected String getPathRef(BaseSearchProcessor.SearchContext ctx,
                String path)

Given a full path to a property (ex. department.manager.salary), return the reference to that property that uses the appropriate alias (ex. a4_manager.salary).

splitPath

protected String[] splitPath(BaseSearchProcessor.SearchContext ctx,
                 String path)

Split a path into two parts. The first part will need to be aliased. The second part will be a property of that alias. For example: (department.manager.salary) would return [department.manager, salary].

getOrCreateAlias

protected BaseSearchProcessor.AliasNode getOrCreateAlias(BaseSearchProcessor.SearchContext ctx,
                                             String path,
                                             boolean setFetch)

Given a full path to an entity (ex. department.manager), return the alias to reference that entity (ex. a4_manager). If there is no alias for the given path, one will be created.

getAliasForPathIfItExists

protected BaseSearchProcessor.AliasNode getAliasForPathIfItExists(BaseSearchProcessor.SearchContext ctx,
                                                      String path)

Given a full path to an entity (ex. department.manager), return the alias to reference that entity (ex. a4_manager). If there is no alias for the given path, one will be created.

Returns:

the associated AliasNode or null if none.

setFetchOnAliasNodeAndAllAncestors

protected void setFetchOnAliasNodeAndAllAncestors(BaseSearchProcessor.AliasNode node)

checkAndCleanFields

protected List<Field> checkAndCleanFields(List<Field> fields)

1. Check for injection attack in property strings.
2. The field list may not contain nulls.

checkAndCleanFetches

protected List<String> checkAndCleanFetches(List<String> fetches)

1. Check for injection attack in property strings.
2. Remove null fetches from the list.

checkAndCleanSorts

protected List<Sort> checkAndCleanSorts(List<Sort> sorts)

1. Check for injection attack in property strings.
2. Remove null sorts from the list.

checkAndCleanFilters

protected List<Filter> checkAndCleanFilters(List<Filter> filters)

1. Check for injection attack in property strings.
2. Check for values that are incongruent with the operator.
3. Remove null filters from the list.
4. Simplify out junctions (and/or) that have only one sub-filter.
5. Remove filters that require sub-filters but have none (and/or/not/some/all/none)

securityCheckProperty

protected void securityCheckProperty(String property)

Used by securityCheck() to check a property string for injection attack.

getFilterFromExample

public Filter getFilterFromExample(Object example)

getFilterFromExample

public Filter getFilterFromExample(Object example,
                          ExampleOptions options)