fine-third/fine-hibernate/src/main/java/com/fr/third/org/hibernate/jpa/criteria/expression/LiteralExpression.java

/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
 * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
 */
package com.fr.third.org.hibernate.jpa.criteria.expression;

import java.io.Serializable;

import com.fr.third.org.hibernate.jpa.criteria.CriteriaBuilderImpl;
import com.fr.third.org.hibernate.jpa.criteria.ParameterRegistry;
import com.fr.third.org.hibernate.jpa.criteria.ValueHandlerFactory;
import com.fr.third.org.hibernate.jpa.criteria.compile.RenderingContext;

/**
 * Represents a literal expression.
 *
 * @author Steve Ebersole
 */
public class LiteralExpression<T> extends ExpressionImpl<T> implements Serializable {
	private Object literal;

	@SuppressWarnings({ "unchecked" })
	public LiteralExpression(CriteriaBuilderImpl criteriaBuilder, T literal) {
		this( criteriaBuilder, (Class<T>) determineClass( literal ), literal );
	}

	private static Class determineClass(Object literal) {
		return literal == null ? null : literal.getClass();
	}

	public LiteralExpression(CriteriaBuilderImpl criteriaBuilder, Class<T> type, T literal) {
		super( criteriaBuilder, type );
		this.literal = literal;
	}

	@SuppressWarnings({ "unchecked" })
	public T getLiteral() {
		return (T) literal;
	}

	public void registerParameters(ParameterRegistry registry) {
		// nothing to do
	}

	@SuppressWarnings({ "unchecked" })
	public String render(RenderingContext renderingContext) {
		if ( ValueHandlerFactory.isNumeric( literal ) ) {
			return ValueHandlerFactory.determineAppropriateHandler( (Class) literal.getClass() ).render( literal );
		}
		else if ( ValueHandlerFactory.isBoolean( literal ) ) {
			return ValueHandlerFactory.determineAppropriateHandler( (Class) literal.getClass() ).render( literal );
		}

		// else...
		final String parameterName = renderingContext.registerLiteralParameterBinding( getLiteral(), getJavaType() );
		return ':' + parameterName;
	}

	/**
	 * Inline String literal.
	 *
	 * @return escaped String
	 */
	private String inlineLiteral(String literal) {
		return String.format("\'%s\'", escapeLiteral(literal));
	}

	/**
	 * Escape String literal.
	 *
	 * @return escaped String
	 */
	private String escapeLiteral(String literal) {
		return literal.replace("'", "''");
	}

	@SuppressWarnings({"unchecked"})
	public String renderProjection(RenderingContext renderingContext) {
		if (ValueHandlerFactory.isCharacter(literal)) {
			// In case literal is a Character, pass literal.toString() as the argument.
			return inlineLiteral(literal.toString());
		}
		// some drivers/servers do not like parameters in the select clause
		final ValueHandlerFactory.ValueHandler handler =
				ValueHandlerFactory.determineAppropriateHandler(literal.getClass());
		return handler.render(literal);
	}

	@Override
	@SuppressWarnings({ "unchecked" })
	protected void resetJavaType(Class targetType) {
		super.resetJavaType( targetType );
		ValueHandlerFactory.ValueHandler valueHandler = getValueHandler();
		if ( valueHandler == null ) {
			valueHandler = ValueHandlerFactory.determineAppropriateHandler( targetType );
			forceConversion( valueHandler );
		}

		if ( valueHandler != null ) {
			literal = valueHandler.convert( literal );
		}
	}
}