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package oracle.toplink.essentials.internal.expressions;

import java.util.*;
import oracle.toplink.essentials.exceptions.*;
import oracle.toplink.essentials.querykeys.*;
import oracle.toplink.essentials.expressions.*;
import oracle.toplink.essentials.internal.helper.*;
import oracle.toplink.essentials.descriptors.ClassDescriptor;

/**
 * Superclass for any object type expressions.
 */
public abstract class ObjectExpression extends DataExpression {
    transient public ClassDescriptor descriptor;
    public Vector derivedExpressions;

    /** indicates whether subclasses should be joined */
    protected boolean shouldUseOuterJoinForMultitableInheritance;

    /** Is this query key to be resolved using an outer join or not. Does not apply to attributes. */
    protected boolean shouldUseOuterJoin;

    public ObjectExpression() {
        this.shouldUseOuterJoin = false;
    }

    public void addDerivedExpression(Expression addThis) {
        if (derivedExpressions == null) {
            derivedExpressions = oracle.toplink.essentials.internal.helper.NonSynchronizedVector.newInstance();
        }
        derivedExpressions.addElement(addThis);
    }

    /**
     * INTERNAL:
     * Return the expression to join the main table of this node to any auxiliary tables.
     */
    public Expression additionalExpressionCriteria() {
        if (getDescriptor() == null) {
            return null;
        }

        Expression criteria = getDescriptor().getQueryManager().getAdditionalJoinExpression();
        if(getSession().getPlatform().shouldPrintOuterJoinInWhereClause()) {
            if(isUsingOuterJoinForMultitableInheritance()) {
                Expression childrenCriteria = getDescriptor().getInheritancePolicy().getChildrenJoinExpression();
                childrenCriteria = getBaseExpression().twist(childrenCriteria, this);
                childrenCriteria.convertToUseOuterJoin();
                if(criteria == null) {
                    criteria = childrenCriteria;
                } else {
                    criteria = criteria.and(childrenCriteria);
                }
            }
        }

        return criteria;
    }

    /**
     * INTERNAL:
     * Used in case outer joins should be printed in FROM clause.
     * Each of the additional tables mapped to expressions that joins it.
     */
    public Map additionalExpressionCriteriaMap() {
        if (getDescriptor() == null) {
            return null;
        }

        HashMap tablesJoinExpressions = null;
        if(isUsingOuterJoinForMultitableInheritance()) {
            Vector tables = getDescriptor().getTables();
            tablesJoinExpressions = new HashMap();
            List childrenTables = getDescriptor().getInheritancePolicy().getChildrenTables();
            for( int i=0; i < childrenTables.size(); i++) {
                DatabaseTable table = (DatabaseTable)childrenTables.get(i);
                Expression joinExpression = (Expression)getDescriptor().getInheritancePolicy().getChildrenTablesJoinExpressions().get(table);
                if (getBaseExpression() != null){
                    joinExpression = getBaseExpression().twist(joinExpression, this);
                } else {
                    joinExpression = twist(joinExpression, this);
                }
                tablesJoinExpressions.put(table, joinExpression);
            }
        }
        
        return tablesJoinExpressions;
    }

    /**
     * PUBLIC:
     * Return an expression representing traversal of a 1:many or many:many relationship.
     * This allows you to query whether any of the "many" side of the relationship satisfies the remaining criteria.
     * 

Example: *

* TopLink: employee.anyOf("managedEmployees").get("firstName").equal("Bob") * Java: no direct equivalent * SQL: SELECT DISTINCT ... WHERE (t2.MGR_ID = t1.ID) AND (t2.F_NAME = 'Bob') *
*/ public Expression anyOf(String attributeName) { QueryKeyExpression queryKey = (QueryKeyExpression)newDerivedExpressionNamed(attributeName); queryKey.doQueryToManyRelationship(); return queryKey; } /** * ADVANCED: * Return an expression representing traversal of a 1:many or many:many relationship. * This allows you to query whether any of the "many" side of the relationship satisfies the remaining criteria. *

Example: *

* TopLink: employee.anyOf("managedEmployees").get("firstName").equal("Bob") * Java: no direct equivalent * SQL: SELECT DISTINCT ... WHERE (t2.MGR_ID (+) = t1.ID) AND (t2.F_NAME = 'Bob') *
*/ public Expression anyOfAllowingNone(String attributeName) { QueryKeyExpression queryKey = (QueryKeyExpression)newDerivedExpressionNamed(attributeName); queryKey.doUseOuterJoin(); queryKey.doQueryToManyRelationship(); return queryKey; } public QueryKeyExpression derivedExpressionNamed(String attributeName) { QueryKeyExpression existing = existingDerivedExpressionNamed(attributeName); if (existing != null) { return existing; } return newDerivedExpressionNamed(attributeName); } public Expression derivedManualExpressionNamed(String attributeName, ClassDescriptor aDescriptor) { Expression existing = existingDerivedExpressionNamed(attributeName); if (existing != null) { return existing; } return newManualDerivedExpressionNamed(attributeName, aDescriptor); } protected void doNotUseOuterJoin() { shouldUseOuterJoin = false; } protected void doUseOuterJoin() { shouldUseOuterJoin = true; } public QueryKeyExpression existingDerivedExpressionNamed(String attributeName) { if (derivedExpressions == null) { return null; } for (Enumeration e = derivedExpressions.elements(); e.hasMoreElements();) { QueryKeyExpression exp = (QueryKeyExpression)e.nextElement(); if (exp.getName().equals(attributeName)) { return exp; } } return null; } public Expression get(String attributeName, Vector arguments) { Expression operatorExpression = super.get(attributeName, arguments); if (operatorExpression != null) { return operatorExpression; } QueryKeyExpression result = derivedExpressionNamed(attributeName); result.doNotUseOuterJoin(); return result; } public Expression getAllowingNull(String attributeName, Vector arguments) { ObjectExpression exp = (ObjectExpression)existingDerivedExpressionNamed(attributeName); // The same (aliased) table cannot participate in a normal join and an outer join. // To help enforce this, if the node already exists if (exp != null) { return exp; } exp = (ObjectExpression)derivedExpressionNamed(attributeName); exp.doUseOuterJoin(); return exp; } public ClassDescriptor getDescriptor() { if (isAttribute()) { return null; } if (descriptor == null) { // Look first for query keys, then mappings. Ultimately we should have query keys // for everything and can dispense with the mapping part. ForeignReferenceQueryKey queryKey = (ForeignReferenceQueryKey)getQueryKeyOrNull(); if (queryKey != null) { descriptor = getSession().getDescriptor(queryKey.getReferenceClass()); return descriptor; } if (getMapping() == null) { throw QueryException.invalidQueryKeyInExpression(this); } // We assume this is either a foreign reference or an aggregate mapping descriptor = getMapping().getReferenceDescriptor(); if (getMapping().isVariableOneToOneMapping()) { throw QueryException.cannotQueryAcrossAVariableOneToOneMapping(getMapping(), descriptor); } } return descriptor; } /** * INTERNAL: Not to be confused with the public getField(String) * This returns a collection of all fields associated with this object. Really * only applies to query keys representing an object or to expression builders. */ public Vector getFields() { if (getDescriptor() == null) { return new Vector(1); } if ((descriptor.hasInheritance() && ! descriptor.getInheritancePolicy().hasMultipleTableChild()) || (shouldUseOuterJoinForMultitableInheritance())){ // return all fields because we can. return descriptor.getAllFields(); }else{ return descriptor.getFields(); } } /** * INTERNAL: * Returns the first field from each of the owned tables, used for * fine-grained pessimistic locking. */ protected Vector getForUpdateOfFields() { Vector allFields = getFields(); int expected = getTableAliases().size(); Vector firstFields = new Vector(expected); DatabaseTable lastTable = null; DatabaseField field = null; int i = 0; // The following loop takes O(n*m) time. n=# of fields. m=#tables. // However, in the m=1 case this will take one pass only. // Also assuming that fields are generally sorted by table, this will // take O(n) time. // An even faster way may be to go getDescriptor().getAdditionalPrimaryKeyFields. while ((i < allFields.size()) && (firstFields.size() < expected)) { field = (DatabaseField)allFields.elementAt(i++); if ((lastTable == null) || !field.getTable().equals(lastTable)) { lastTable = field.getTable(); int j = 0; while (j < firstFields.size()) { if (lastTable.equals(((DatabaseField)firstFields.elementAt(j)).getTable())) { break; } j++; } if (j == firstFields.size()) { firstFields.addElement(field); } } } return firstFields; } public Expression getManualQueryKey(String attributeName, ClassDescriptor aDescriptor) { return derivedManualExpressionNamed(attributeName, aDescriptor); } /** * INTERNAL: */ public Vector getOwnedTables() { if(isUsingOuterJoinForMultitableInheritance()) { return getDescriptor().getInheritancePolicy().getAllTables(); } else { return super.getOwnedTables(); } } protected boolean hasDerivedExpressions() { return derivedExpressions != null; } public boolean isObjectExpression() { return true; } /** * INTERNAL: * indicates whether additional expressions for multitable inheritance should be used and are available */ public boolean isUsingOuterJoinForMultitableInheritance() { return shouldUseOuterJoinForMultitableInheritance() && getDescriptor() != null && getDescriptor().hasInheritance() && getDescriptor().getInheritancePolicy().hasMultipleTableChild() && getDescriptor().getInheritancePolicy().shouldReadSubclasses(); } public QueryKeyExpression newDerivedExpressionNamed(String attributeName) { QueryKeyExpression result = new QueryKeyExpression(attributeName, this); addDerivedExpression(result); return result; } public Expression newManualDerivedExpressionNamed(String attributeName, ClassDescriptor aDescriptor) { QueryKeyExpression result = new ManualQueryKeyExpression(attributeName, this, aDescriptor); addDerivedExpression(result); return result; } /** * INTERNAL: * Used for cloning. */ protected void postCopyIn(Dictionary alreadyDone) { super.postCopyIn(alreadyDone); derivedExpressions = copyCollection(derivedExpressions, alreadyDone); } /** * INTERNAL: * The method was added to circumvent derivedFields and derivedTables being * protected. * @see oracle.toplink.essentials.expressions.ExpressionBuilder#registerIn(Dictionary alreadyDone) * @bug 2637484 INVALID QUERY KEY EXCEPTION THROWN USING BATCH READS AND PARALLEL EXPRESSIONS */ public void postCopyIn(Dictionary alreadyDone, Vector oldDerivedFields, Vector oldDerivedTables) { if (oldDerivedFields != null) { if (derivedFields == null) { derivedFields = copyCollection(oldDerivedFields, alreadyDone); } else { derivedFields.addAll(copyCollection(oldDerivedFields, alreadyDone)); } } if (oldDerivedTables != null) { if (derivedTables == null) { derivedTables = copyCollection(oldDerivedTables, alreadyDone); } else { derivedTables.addAll(copyCollection(oldDerivedTables, alreadyDone)); } } } /** * INTERNAL: * set the flag indicating whether subclasses should be joined */ public void setShouldUseOuterJoinForMultitableInheritance(boolean shouldUseOuterJoinForMultitableInheritance) { this.shouldUseOuterJoinForMultitableInheritance = shouldUseOuterJoinForMultitableInheritance; } public boolean shouldUseOuterJoin() { return shouldUseOuterJoin; } public boolean shouldUseOuterJoinForMultitableInheritance() { return shouldUseOuterJoinForMultitableInheritance; } /** * INTERNAL: * writes the first field from each of the owned tables, used for * fine-grained pessimistic locking. */ protected void writeForUpdateOfFields(ExpressionSQLPrinter printer, SQLSelectStatement statement) { for (Enumeration fieldsEnum = getForUpdateOfFields().elements(); fieldsEnum.hasMoreElements();) { DatabaseField field = (DatabaseField)fieldsEnum.nextElement(); writeField(printer, field, statement); } } }




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