jpa/org.eclipse.persistence.jpa.jpql/src/main/java/org/eclipse/persistence/jpa/jpql/parser/EmptyCollectionComparisonExpression.java - eclipselink - Git at Google

 /*
  * Copyright (c) 2006, 2021 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0 which is available at
  * http://www.eclipse.org/legal/epl-2.0,
  * or the Eclipse Distribution License v. 1.0 which is available at
  * http://www.eclipse.org/org/documents/edl-v10.php.
  *
  * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
  */

 // Contributors:
 //     Oracle - initial API and implementation
 //
 package org.eclipse.persistence.jpa.jpql.parser;

 import java.util.Collection;
 import java.util.List;
 import org.eclipse.persistence.jpa.jpql.ExpressionTools;
 import org.eclipse.persistence.jpa.jpql.WordParser;

 /**
  * This expression tests whether or not the collection designated by the collection-valued path
  * expression is empty (i.e, has no elements).
  *
  * <div><b>BNF:</b> <code>empty_collection_comparison_expression ::= collection_valued_path_expression IS [NOT] EMPTY</code><p></p></div>
  *
  * @version 2.5
  * @since 2.3
  * @author Pascal Filion
  */
 @SuppressWarnings("nls")
 public final class EmptyCollectionComparisonExpression extends AbstractExpression {

     /**
      * The actual <b>EMPTY</b> identifier found in the string representation of the JPQL query.
      */
     private String emptyIdentifier;

     /**
      * The {@link Expression} that represents the collection-valued path expression.
      */
     private AbstractExpression expression;

     /**
      * Determines whether a whitespace was parsed after <b>IS</b>.
      */
     private boolean hasSpaceAfterIs;

     /**
      * The actual <b>IS</b> identifier found in the string representation of the JPQL query.
      */
     private String isIdentifier;

     /**
      * The actual <b>IS</b> identifier found in the string representation of the JPQL query.
      */
     private String notIdentifier;

     /**
      * Creates a new <code>NullComparisonExpression</code>.
      *
      * @param parent The parent of this expression
      * @param expression The {@link Expression} that represents the collection-valued path expression
      */
     public EmptyCollectionComparisonExpression(AbstractExpression parent, AbstractExpression expression) {
         super(parent);
         updateExpression(expression);
     }

     /**
      * Creates a new <code>NullComparisonExpression</code>.
      *
      * @param parent The parent of this expression
      * @param identifier The actual identifier, which is either {@link Expression#IS_EMPTY IS_EMPTY}
      * or {@link Expression#IS_NOT_EMPTY IS_NOT_EMPTY}
      * @param expression The {@link Expression} that represents the collection-valued path expression
      */
     EmptyCollectionComparisonExpression(AbstractExpression parent,
                                         String identifier,
                                         AbstractExpression expression) {

         super(parent, identifier);
         updateExpression(expression);
     }

     @Override
     public void accept(ExpressionVisitor visitor) {
         visitor.visit(this);
     }

     @Override
     public void acceptChildren(ExpressionVisitor visitor) {
         getExpression().accept(visitor);
     }

     @Override
     protected void addChildrenTo(Collection<Expression> children) {
         children.add(getExpression());
     }

     @Override
     protected void addOrderedChildrenTo(List<Expression> children) {

         // Expression
         if (expression != null) {
             children.add(expression);
         }

         if (hasExpression()) {
             children.add(buildStringExpression(SPACE));
         }

         // 'IS'
         children.add(buildStringExpression(IS));

         if (hasSpaceAfterIs) {
             children.add(buildStringExpression(SPACE));
         }

         // 'NOT'
         if (notIdentifier != null) {
             children.add(buildStringExpression(NOT));
         }

         children.add(buildStringExpression(SPACE));

         // 'EMPTY'
         children.add(buildStringExpression(EMPTY));
     }

     private StateFieldPathToCollectionValuedPathConverter buildConverter(AbstractExpression expression) {
         return new StateFieldPathToCollectionValuedPathConverter(this, expression);
     }

     @Override
     public JPQLQueryBNF findQueryBNF(Expression expression) {

         if ((this.expression != null) && this.expression.isAncestor(expression)) {
             return getQueryBNF(CollectionValuedPathExpressionBNF.ID);
         }

         return super.findQueryBNF(expression);
     }

     /**
      * Returns the actual <b>EMPTY</b> found in the string representation of the JPQL query, which
      * has the actual case that was used.
      *
      * @return The <b>EMPTY</b> identifier that was actually parsed
      */
     public String getActualEmptyIdentifier() {
         return emptyIdentifier;
     }

     /**
      * Returns the actual <b>IS</b> found in the string representation of the JPQL query, which has
      * the actual case that was used.
      *
      * @return The <b>IS</b> identifier that was actually parsed, or an empty string if it was not
      * parsed
      */
     public String getActualIsIdentifier() {
         return (isIdentifier != null) ? isIdentifier : ExpressionTools.EMPTY_STRING;
     }

     /**
      * Returns the actual <b>NOT</b> found in the string representation of the JPQL query, which has
      * the actual case that was used.
      *
      * @return The <b>NOT</b> identifier that was actually parsed, or an empty string if it was not
      * parsed
      */
     public String getActualNotIdentifier() {
         return (notIdentifier != null) ? notIdentifier : ExpressionTools.EMPTY_STRING;
     }

     /**
      * Returns the {@link Expression} that represents the collection-valued path expression if it was
      * parsed.
      *
      * @return The expression that was parsed representing the collection valued path expression
      */
     public Expression getExpression() {
         if (expression == null) {
             expression = buildNullExpression();
         }
         return expression;
     }

     /**
      * Returns the identifier for this expression that may include <b>NOT</b> if it was parsed. The
      * identifier <b>IS</b> should always be part of the identifier but it is possible it is not
      * present when this expression is invalid.
      *
      * @return Either <b>IS NOT EMPTY</b>, <b>NOT EMPTY</b>, <b>IS EMPTY</b> or <b>EMPTY</b>
      */
     public String getIdentifier() {

         if ((isIdentifier != null) && (notIdentifier != null)) {
             return IS_NOT_EMPTY;
         }

         if ((isIdentifier == null) && (notIdentifier != null)) {
             return "NOT_EMPTY";
         }

         if (isIdentifier != null) {
             return IS_EMPTY;
         }

         return EMPTY;
     }

     @Override
     public JPQLQueryBNF getQueryBNF() {
         return getQueryBNF(EmptyCollectionComparisonExpressionBNF.ID);
     }

     /**
      * Determines whether the expression was parsed.
      *
      * @return <code>true</code> if the expression was parsed; <code>false</code> otherwise
      */
     public boolean hasExpression() {
         return expression != null &&
               !expression.isNull();
     }

     /**
      * Determines whether the identifier <b>NOT</b> was part of the query.
      *
      * @return <code>true</code> if the identifier <b>NOT</b> was parsed; <code>false</code> otherwise
      */
     public boolean hasNot() {
         return notIdentifier != null;
     }

     /**
      * Determines whether a whitespace was found after <b>IS</b>.
      *
      * @return <code>true</code> if there was a whitespace after <b>IS</b>; <code>false</code> otherwise
      */
     public boolean hasSpaceAfterIs() {
         return hasSpaceAfterIs;
     }

     @Override
     protected void parse(WordParser wordParser, boolean tolerant) {

         String identifier = getText();

         if (identifier != null) {

             // 'IS'
             isIdentifier = wordParser.moveForward(IS);
             hasSpaceAfterIs = true;

             wordParser.moveForward(1);

             // 'NOT'
             if (identifier == IS_NOT_EMPTY) {
                 notIdentifier = wordParser.moveForward(NOT);
                 wordParser.moveForward(1);
             }

             // 'EMPTY'
             emptyIdentifier = wordParser.moveForward(EMPTY);
         }
         else {

             // Parse 'IS'
             if (wordParser.startsWithIdentifier(IS)) {
                 isIdentifier = wordParser.moveForward(IS);
                 hasSpaceAfterIs = wordParser.skipLeadingWhitespace() > 0;
             }

             // Parse 'NOT'
             if (wordParser.startsWithIdentifier(NOT)) {
                 notIdentifier = wordParser.moveForward(NOT);
                 wordParser.skipLeadingWhitespace();
             }

             // Parse 'EMPTY'
             emptyIdentifier = wordParser.moveForward(EMPTY);
         }
     }

     @Override
     protected void toParsedText(StringBuilder writer, boolean actual) {

         // Expression
         if (expression != null) {
             expression.toParsedText(writer, actual);
             writer.append(SPACE);
         }

         // 'IS'
         if (isIdentifier != null) {
             writer.append(actual ? isIdentifier : IS);
         }

         if (hasSpaceAfterIs) {
             writer.append(SPACE);
         }

         // 'NOT'
         if (notIdentifier != null) {
             writer.append(actual ? notIdentifier : NOT);
             writer.append(SPACE);
         }

         // 'EMPTY'
         writer.append(actual ? emptyIdentifier : EMPTY);
     }

     private void updateExpression(AbstractExpression expression) {

         // Make sure a StateFieldPathExpression is converted into a
         // CollectionValuedPathExpression
         if (expression != null) {

             StateFieldPathToCollectionValuedPathConverter converter = buildConverter(expression);
             expression.accept(converter);

             this.expression = converter.expression;
             this.expression.setParent(this);

             // The old expression needs to be parented in order to be removed from
             // the parsing system
             expression.setParent(this);
         }
     }

     /**
      * This visitor converts a {@link StateFieldPathExpression} into a {@link CollectionValuedPathExpression}.
      * The parser only creates state field path expressions but this expression only supports a
      * collection valued path expression.
      */
     private static class StateFieldPathToCollectionValuedPathConverter extends AbstractExpressionVisitor {

         private AbstractExpression expression;
         private AbstractExpression parent;

         /**
          * Creates a new <code>StateFieldPathToCollectionValuedPathConverter</code>.
          *
          * @param parent The parent of the expression
          * @param expression The expression that might need to be converted
          */
         StateFieldPathToCollectionValuedPathConverter(AbstractExpression parent,
                                                       AbstractExpression expression) {
             super();

             this.parent     = parent;
             this.expression = expression;
         }

         @Override
         public void visit(StateFieldPathExpression expression) {
             this.expression = new CollectionValuedPathExpression(parent, expression.getText());
         }
     }
 }
	/*
	* Copyright (c) 2006, 2021 Oracle and/or its affiliates. All rights reserved.
	*
	* This program and the accompanying materials are made available under the
	* terms of the Eclipse Public License v. 2.0 which is available at
	* http://www.eclipse.org/legal/epl-2.0,
	* or the Eclipse Distribution License v. 1.0 which is available at
	* http://www.eclipse.org/org/documents/edl-v10.php.
	*
	* SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
	*/

	// Contributors:
	// Oracle - initial API and implementation
	//
	package org.eclipse.persistence.jpa.jpql.parser;

	import java.util.Collection;
	import java.util.List;
	import org.eclipse.persistence.jpa.jpql.ExpressionTools;
	import org.eclipse.persistence.jpa.jpql.WordParser;

	/**
	* This expression tests whether or not the collection designated by the collection-valued path
	* expression is empty (i.e, has no elements).
	*
	* <div><b>BNF:</b> <code>empty_collection_comparison_expression ::= collection_valued_path_expression IS [NOT] EMPTY</code><p></p></div>
	*
	* @version 2.5
	* @since 2.3
	* @author Pascal Filion
	*/
	@SuppressWarnings("nls")
	public final class EmptyCollectionComparisonExpression extends AbstractExpression {

	/**
	* The actual <b>EMPTY</b> identifier found in the string representation of the JPQL query.
	*/
	private String emptyIdentifier;

	/**
	* The {@link Expression} that represents the collection-valued path expression.
	*/
	private AbstractExpression expression;

	/**
	* Determines whether a whitespace was parsed after <b>IS</b>.
	*/
	private boolean hasSpaceAfterIs;

	/**
	* The actual <b>IS</b> identifier found in the string representation of the JPQL query.
	*/
	private String isIdentifier;

	/**
	* The actual <b>IS</b> identifier found in the string representation of the JPQL query.
	*/
	private String notIdentifier;

	/**
	* Creates a new <code>NullComparisonExpression</code>.
	*
	* @param parent The parent of this expression
	* @param expression The {@link Expression} that represents the collection-valued path expression
	*/
	public EmptyCollectionComparisonExpression(AbstractExpression parent, AbstractExpression expression) {
	super(parent);
	updateExpression(expression);
	}

	/**
	* Creates a new <code>NullComparisonExpression</code>.
	*
	* @param parent The parent of this expression
	* @param identifier The actual identifier, which is either {@link Expression#IS_EMPTY IS_EMPTY}
	* or {@link Expression#IS_NOT_EMPTY IS_NOT_EMPTY}
	* @param expression The {@link Expression} that represents the collection-valued path expression
	*/
	EmptyCollectionComparisonExpression(AbstractExpression parent,
	String identifier,
	AbstractExpression expression) {

	super(parent, identifier);
	updateExpression(expression);
	}

	@Override
	public void accept(ExpressionVisitor visitor) {
	visitor.visit(this);
	}

	@Override
	public void acceptChildren(ExpressionVisitor visitor) {
	getExpression().accept(visitor);
	}

	@Override
	protected void addChildrenTo(Collection<Expression> children) {
	children.add(getExpression());
	}

	@Override
	protected void addOrderedChildrenTo(List<Expression> children) {

	// Expression
	if (expression != null) {
	children.add(expression);
	}

	if (hasExpression()) {
	children.add(buildStringExpression(SPACE));
	}

	// 'IS'
	children.add(buildStringExpression(IS));

	if (hasSpaceAfterIs) {
	children.add(buildStringExpression(SPACE));
	}

	// 'NOT'
	if (notIdentifier != null) {
	children.add(buildStringExpression(NOT));
	}

	children.add(buildStringExpression(SPACE));

	// 'EMPTY'
	children.add(buildStringExpression(EMPTY));
	}

	private StateFieldPathToCollectionValuedPathConverter buildConverter(AbstractExpression expression) {
	return new StateFieldPathToCollectionValuedPathConverter(this, expression);
	}

	@Override
	public JPQLQueryBNF findQueryBNF(Expression expression) {

	if ((this.expression != null) && this.expression.isAncestor(expression)) {
	return getQueryBNF(CollectionValuedPathExpressionBNF.ID);
	}

	return super.findQueryBNF(expression);
	}

	/**
	* Returns the actual <b>EMPTY</b> found in the string representation of the JPQL query, which
	* has the actual case that was used.
	*
	* @return The <b>EMPTY</b> identifier that was actually parsed
	*/
	public String getActualEmptyIdentifier() {
	return emptyIdentifier;
	}

	/**
	* Returns the actual <b>IS</b> found in the string representation of the JPQL query, which has
	* the actual case that was used.
	*
	* @return The <b>IS</b> identifier that was actually parsed, or an empty string if it was not
	* parsed
	*/
	public String getActualIsIdentifier() {
	return (isIdentifier != null) ? isIdentifier : ExpressionTools.EMPTY_STRING;
	}

	/**
	* Returns the actual <b>NOT</b> found in the string representation of the JPQL query, which has
	* the actual case that was used.
	*
	* @return The <b>NOT</b> identifier that was actually parsed, or an empty string if it was not
	* parsed
	*/
	public String getActualNotIdentifier() {
	return (notIdentifier != null) ? notIdentifier : ExpressionTools.EMPTY_STRING;
	}

	/**
	* Returns the {@link Expression} that represents the collection-valued path expression if it was
	* parsed.
	*
	* @return The expression that was parsed representing the collection valued path expression
	*/
	public Expression getExpression() {
	if (expression == null) {
	expression = buildNullExpression();
	}
	return expression;
	}

	/**
	* Returns the identifier for this expression that may include <b>NOT</b> if it was parsed. The
	* identifier <b>IS</b> should always be part of the identifier but it is possible it is not
	* present when this expression is invalid.
	*
	* @return Either <b>IS NOT EMPTY</b>, <b>NOT EMPTY</b>, <b>IS EMPTY</b> or <b>EMPTY</b>
	*/
	public String getIdentifier() {

	if ((isIdentifier != null) && (notIdentifier != null)) {
	return IS_NOT_EMPTY;
	}

	if ((isIdentifier == null) && (notIdentifier != null)) {
	return "NOT_EMPTY";
	}

	if (isIdentifier != null) {
	return IS_EMPTY;
	}

	return EMPTY;
	}

	@Override
	public JPQLQueryBNF getQueryBNF() {
	return getQueryBNF(EmptyCollectionComparisonExpressionBNF.ID);
	}

	/**
	* Determines whether the expression was parsed.
	*
	* @return <code>true</code> if the expression was parsed; <code>false</code> otherwise
	*/
	public boolean hasExpression() {
	return expression != null &&
	!expression.isNull();
	}

	/**
	* Determines whether the identifier <b>NOT</b> was part of the query.
	*
	* @return <code>true</code> if the identifier <b>NOT</b> was parsed; <code>false</code> otherwise
	*/
	public boolean hasNot() {
	return notIdentifier != null;
	}

	/**
	* Determines whether a whitespace was found after <b>IS</b>.
	*
	* @return <code>true</code> if there was a whitespace after <b>IS</b>; <code>false</code> otherwise
	*/
	public boolean hasSpaceAfterIs() {
	return hasSpaceAfterIs;
	}

	@Override
	protected void parse(WordParser wordParser, boolean tolerant) {

	String identifier = getText();

	if (identifier != null) {

	// 'IS'
	isIdentifier = wordParser.moveForward(IS);
	hasSpaceAfterIs = true;

	wordParser.moveForward(1);

	// 'NOT'
	if (identifier == IS_NOT_EMPTY) {
	notIdentifier = wordParser.moveForward(NOT);
	wordParser.moveForward(1);
	}

	// 'EMPTY'
	emptyIdentifier = wordParser.moveForward(EMPTY);
	}
	else {

	// Parse 'IS'
	if (wordParser.startsWithIdentifier(IS)) {
	isIdentifier = wordParser.moveForward(IS);
	hasSpaceAfterIs = wordParser.skipLeadingWhitespace() > 0;
	}

	// Parse 'NOT'
	if (wordParser.startsWithIdentifier(NOT)) {
	notIdentifier = wordParser.moveForward(NOT);
	wordParser.skipLeadingWhitespace();
	}

	// Parse 'EMPTY'
	emptyIdentifier = wordParser.moveForward(EMPTY);
	}
	}

	@Override
	protected void toParsedText(StringBuilder writer, boolean actual) {

	// Expression
	if (expression != null) {
	expression.toParsedText(writer, actual);
	writer.append(SPACE);
	}

	// 'IS'
	if (isIdentifier != null) {
	writer.append(actual ? isIdentifier : IS);
	}

	if (hasSpaceAfterIs) {
	writer.append(SPACE);
	}

	// 'NOT'
	if (notIdentifier != null) {
	writer.append(actual ? notIdentifier : NOT);
	writer.append(SPACE);
	}

	// 'EMPTY'
	writer.append(actual ? emptyIdentifier : EMPTY);
	}

	private void updateExpression(AbstractExpression expression) {

	// Make sure a StateFieldPathExpression is converted into a
	// CollectionValuedPathExpression
	if (expression != null) {

	StateFieldPathToCollectionValuedPathConverter converter = buildConverter(expression);
	expression.accept(converter);

	this.expression = converter.expression;
	this.expression.setParent(this);

	// The old expression needs to be parented in order to be removed from
	// the parsing system
	expression.setParent(this);
	}
	}

	/**
	* This visitor converts a {@link StateFieldPathExpression} into a {@link CollectionValuedPathExpression}.
	* The parser only creates state field path expressions but this expression only supports a
	* collection valued path expression.
	*/
	private static class StateFieldPathToCollectionValuedPathConverter extends AbstractExpressionVisitor {

	private AbstractExpression expression;
	private AbstractExpression parent;

	/**
	* Creates a new <code>StateFieldPathToCollectionValuedPathConverter</code>.
	*
	* @param parent The parent of the expression
	* @param expression The expression that might need to be converted
	*/
	StateFieldPathToCollectionValuedPathConverter(AbstractExpression parent,
	AbstractExpression expression) {
	super();

	this.parent = parent;
	this.expression = expression;
	}

	@Override
	public void visit(StateFieldPathExpression expression) {
	this.expression = new CollectionValuedPathExpression(parent, expression.getText());
	}
	}
	}