// $Id: FromClause.java 10173 2006-07-26 18:04:07Z steve.ebersole@jboss.com $
package org.hibernate.hql.ast.tree;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.hibernate.hql.antlr.HqlSqlTokenTypes;
import org.hibernate.hql.ast.util.ASTIterator;
import org.hibernate.hql.ast.util.ASTUtil;
import antlr.SemanticException;
import antlr.collections.AST;
/**
* Represents the 'FROM' part of a query or subquery, containing all mapped class references.
*
* @author josh
*/
public class FromClause extends HqlSqlWalkerNode implements HqlSqlTokenTypes, DisplayableNode {
private static Log log = LogFactory.getLog( FromClause.class );
public static final int ROOT_LEVEL = 1;
private int level = ROOT_LEVEL;
private Set fromElements = new HashSet();
private Map fromElementByClassAlias = new HashMap();
private Map fromElementByTableAlias = new HashMap();
private Map fromElementsByPath = new HashMap();
/**
* All of the implicit FROM xxx JOIN yyy elements that are the destination of a collection. These are created from
* index operators on collection property references.
*/
private Map collectionJoinFromElementsByPath = new HashMap();
/**
* Pointer to the parent FROM clause, if there is one.
*/
private FromClause parentFromClause;
/**
* Collection of FROM clauses of which this is the parent.
*/
private Set childFromClauses;
/**
* Counts the from elements as they are added.
*/
private int fromElementCounter = 0;
/**
* Implied FROM elements to add onto the end of the FROM clause.
*/
private List impliedElements = new LinkedList();
/**
* Adds a new from element to the from node.
*
* @param path The reference to the class.
* @param alias The alias AST.
* @return FromElement - The new FROM element.
*/
public FromElement addFromElement(String path, AST alias) throws SemanticException {
// The path may be a reference to an alias defined in the parent query.
String classAlias = ( alias == null ) ? null : alias.getText();
checkForDuplicateClassAlias( classAlias );
FromElementFactory factory = new FromElementFactory( this, null, path, classAlias, null, false );
return factory.addFromElement();
}
void registerFromElement(FromElement element) {
fromElements.add( element );
String classAlias = element.getClassAlias();
if ( classAlias != null ) {
// The HQL class alias refers to the class name.
fromElementByClassAlias.put( classAlias, element );
}
// Associate the table alias with the element.
String tableAlias = element.getTableAlias();
if ( tableAlias != null ) {
fromElementByTableAlias.put( tableAlias, element );
}
}
void addDuplicateAlias(String alias, FromElement element) {
fromElementByClassAlias.put( alias, element );
}
private void checkForDuplicateClassAlias(String classAlias) throws SemanticException {
if ( classAlias != null && fromElementByClassAlias.containsKey( classAlias ) ) {
throw new SemanticException( "Duplicate definition of alias '"
+ classAlias + "'" );
}
}
/**
* Retreives the from-element represented by the given alias.
*
* @param aliasOrClassName The alias by which to locate the from-element.
* @return The from-element assigned the given alias, or null if none.
*/
public FromElement getFromElement(String aliasOrClassName) {
FromElement fromElement = ( FromElement ) fromElementByClassAlias.get( aliasOrClassName );
if ( fromElement == null && getSessionFactoryHelper().isStrictJPAQLComplianceEnabled() ) {
fromElement = findIntendedAliasedFromElementBasedOnCrazyJPARequirements( aliasOrClassName );
}
if ( fromElement == null && parentFromClause != null ) {
fromElement = parentFromClause.getFromElement( aliasOrClassName );
}
return fromElement;
}
private FromElement findIntendedAliasedFromElementBasedOnCrazyJPARequirements(String specifiedAlias) {
Iterator itr = fromElementByClassAlias.entrySet().iterator();
while ( itr.hasNext() ) {
Map.Entry entry = ( Map.Entry ) itr.next();
String alias = ( String ) entry.getKey();
if ( alias.equalsIgnoreCase( specifiedAlias ) ) {
return ( FromElement ) entry.getValue();
}
}
return null;
}
/**
* Convenience method to check whether a given token represents a from-element alias.
*
* @param possibleAlias The potential from-element alias to check.
* @return True if the possibleAlias is an alias to a from-element visible
* from this point in the query graph.
*/
public boolean isFromElementAlias(String possibleAlias) {
boolean isAlias = containsClassAlias( possibleAlias );
if ( !isAlias && parentFromClause != null ) {
// try the parent FromClause...
isAlias = parentFromClause.isFromElementAlias( possibleAlias );
}
return isAlias;
}
/**
* Returns the list of from elements in order.
*
* @return the list of from elements (instances of FromElement).
*/
public List getFromElements() {
return ASTUtil.collectChildren( this, fromElementPredicate );
}
public FromElement getFromElement() {
// TODO: not sure about this one
// List fromElements = getFromElements();
// if ( fromElements == null || fromElements.isEmpty() ) {
// throw new QueryException( "Unable to locate from element" );
// }
return (FromElement) getFromElements().get(0);
}
/**
* Returns the list of from elements that will be part of the result set.
*
* @return the list of from elements that will be part of the result set.
*/
public List getProjectionList() {
return ASTUtil.collectChildren( this, projectionListPredicate );
}
public List getCollectionFetches() {
return ASTUtil.collectChildren( this, collectionFetchPredicate );
}
public boolean hasCollectionFecthes() {
return getCollectionFetches().size() > 0;
}
public List getExplicitFromElements() {
return ASTUtil.collectChildren( this, explicitFromPredicate );
}
private static ASTUtil.FilterPredicate fromElementPredicate = new ASTUtil.IncludePredicate() {
public boolean include(AST node) {
FromElement fromElement = ( FromElement ) node;
return fromElement.isFromOrJoinFragment();
}
};
private static ASTUtil.FilterPredicate projectionListPredicate = new ASTUtil.IncludePredicate() {
public boolean include(AST node) {
FromElement fromElement = ( FromElement ) node;
return fromElement.inProjectionList();
}
};
private static ASTUtil.FilterPredicate collectionFetchPredicate = new ASTUtil.IncludePredicate() {
public boolean include(AST node) {
FromElement fromElement = ( FromElement ) node;
return fromElement.isFetch() && fromElement.getQueryableCollection() != null;
}
};
private static ASTUtil.FilterPredicate explicitFromPredicate = new ASTUtil.IncludePredicate() {
public boolean include(AST node) {
final FromElement fromElement = ( FromElement ) node;
return !fromElement.isImplied();
}
};
FromElement findCollectionJoin(String path) {
return ( FromElement ) collectionJoinFromElementsByPath.get( path );
}
/**
* Look for an existing implicit or explicit join by the
* given path.
*/
FromElement findJoinByPath(String path) {
FromElement elem = findJoinByPathLocal( path );
if ( elem == null && parentFromClause != null ) {
elem = parentFromClause.findJoinByPath( path );
}
return elem;
}
FromElement findJoinByPathLocal(String path) {
Map joinsByPath = fromElementsByPath;
return ( FromElement ) joinsByPath.get( path );
}
void addJoinByPathMap(String path, FromElement destination) {
if ( log.isDebugEnabled() ) {
log.debug( "addJoinByPathMap() : " + path + " -> " + destination );
}
fromElementsByPath.put( path, destination );
}
/**
* Returns true if the from node contains the class alias name.
*
* @param alias The HQL class alias name.
* @return true if the from node contains the class alias name.
*/
public boolean containsClassAlias(String alias) {
boolean isAlias = fromElementByClassAlias.containsKey( alias );
if ( !isAlias && getSessionFactoryHelper().isStrictJPAQLComplianceEnabled() ) {
isAlias = findIntendedAliasedFromElementBasedOnCrazyJPARequirements( alias ) != null;
}
return isAlias;
}
/**
* Returns true if the from node contains the table alias name.
*
* @param alias The SQL table alias name.
* @return true if the from node contains the table alias name.
*/
public boolean containsTableAlias(String alias) {
return fromElementByTableAlias.keySet().contains( alias );
}
public String getDisplayText() {
return "FromClause{" +
"level=" + level +
", fromElementCounter=" + fromElementCounter +
", fromElements=" + fromElements.size() +
", fromElementByClassAlias=" + fromElementByClassAlias.keySet() +
", fromElementByTableAlias=" + fromElementByTableAlias.keySet() +
", fromElementsByPath=" + fromElementsByPath.keySet() +
", collectionJoinFromElementsByPath=" + collectionJoinFromElementsByPath.keySet() +
", impliedElements=" + impliedElements +
"}";
}
public void setParentFromClause(FromClause parentFromClause) {
this.parentFromClause = parentFromClause;
if ( parentFromClause != null ) {
level = parentFromClause.getLevel() + 1;
parentFromClause.addChild( this );
}
}
private void addChild(FromClause fromClause) {
if ( childFromClauses == null ) {
childFromClauses = new HashSet();
}
childFromClauses.add( fromClause );
}
public FromClause locateChildFromClauseWithJoinByPath(String path) {
if ( childFromClauses != null && !childFromClauses.isEmpty() ) {
Iterator children = childFromClauses.iterator();
while ( children.hasNext() ) {
FromClause child = ( FromClause ) children.next();
if ( child.findJoinByPathLocal( path ) != null ) {
return child;
}
}
}
return null;
}
public void promoteJoin(FromElement elem) {
if ( log.isDebugEnabled() ) {
log.debug( "Promoting [" + elem + "] to [" + this + "]" );
}
//TODO: implement functionality
// this might be painful to do here, as the "join post processing" for
// the subquery has already been performed (meaning that for
// theta-join dialects, the join conditions have already been moved
// over to the where clause). A "simple" solution here might to
// perform "join post processing" once for the entire query (including
// any subqueries) at one fell swoop
}
public boolean isSubQuery() {
// TODO : this is broke for subqueries in statements other than selects...
return parentFromClause != null;
}
void addCollectionJoinFromElementByPath(String path, FromElement destination) {
if ( log.isDebugEnabled() ) {
log.debug( "addCollectionJoinFromElementByPath() : " + path + " -> " + destination );
}
collectionJoinFromElementsByPath.put( path, destination ); // Add the new node to the map so that we don't create it twice.
}
public FromClause getParentFromClause() {
return parentFromClause;
}
public int getLevel() {
return level;
}
public int nextFromElementCounter() {
return fromElementCounter++;
}
public void resolve() {
// Make sure that all from elements registered with this FROM clause are actually in the AST.
ASTIterator iter = new ASTIterator( this.getFirstChild() );
Set childrenInTree = new HashSet();
while ( iter.hasNext() ) {
childrenInTree.add( iter.next() );
}
for ( Iterator iterator = fromElements.iterator(); iterator.hasNext(); ) {
FromElement fromElement = ( FromElement ) iterator.next();
if ( !childrenInTree.contains( fromElement ) ) {
throw new IllegalStateException( "Element not in AST: " + fromElement );
}
}
}
public void addImpliedFromElement(FromElement element) {
impliedElements.add( element );
}
public String toString() {
return "FromClause{" +
"level=" + level +
"}";
}
}
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