CrossParameterScriptAssertParameterValidator.java

package com.sishuok.spring4.validator;

import org.hibernate.validator.internal.util.Contracts;
import org.hibernate.validator.internal.util.logging.Log;
import org.hibernate.validator.internal.util.logging.LoggerFactory;
import org.hibernate.validator.internal.util.scriptengine.ScriptEvaluator;
import org.hibernate.validator.internal.util.scriptengine.ScriptEvaluatorFactory;

import javax.script.ScriptException;
import javax.validation.ConstraintDeclarationException;
import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
import javax.validation.constraintvalidation.SupportedValidationTarget;
import javax.validation.constraintvalidation.ValidationTarget;

import static org.hibernate.validator.internal.util.logging.Messages.MESSAGES;

/**
 * <p>User: Zhang Kaitao
 * <p>Date: 13-12-15
 * <p>Version: 1.0
 */
@SupportedValidationTarget(ValidationTarget.PARAMETERS)
public class CrossParameterScriptAssertParameterValidator implements ConstraintValidator<CrossParameterScriptAssert, Object[]> {

    private static final Log log = LoggerFactory.make();

    private String script;
    private String languageName;
    private String alias;

    public void initialize(CrossParameterScriptAssert constraintAnnotation) {
        validateParameters( constraintAnnotation );

        this.script = constraintAnnotation.script();
        this.languageName = constraintAnnotation.lang();
        this.alias = constraintAnnotation.alias();
    }

    public boolean isValid(Object[] value, ConstraintValidatorContext constraintValidatorContext) {

        Object evaluationResult;
        ScriptEvaluator scriptEvaluator;

        try {
            ScriptEvaluatorFactory evaluatorFactory = ScriptEvaluatorFactory.getInstance();
            scriptEvaluator = evaluatorFactory.getScriptEvaluatorByLanguageName( languageName );
        }
        catch ( ScriptException e ) {
            throw new ConstraintDeclarationException( e );
        }

        try {
            evaluationResult = scriptEvaluator.evaluate( script, value, alias );
        }
        catch ( ScriptException e ) {
            throw log.getErrorDuringScriptExecutionException( script, e );
        }

        if ( evaluationResult == null ) {
            throw log.getScriptMustReturnTrueOrFalseException( script );
        }
        if ( !( evaluationResult instanceof Boolean ) ) {
            throw log.getScriptMustReturnTrueOrFalseException(
                    script,
                    evaluationResult,
                    evaluationResult.getClass().getCanonicalName()
            );
        }
        return Boolean.TRUE.equals( evaluationResult );
    }

    private void validateParameters(CrossParameterScriptAssert constraintAnnotation) {
        Contracts.assertNotEmpty(constraintAnnotation.script(), MESSAGES.parameterMustNotBeEmpty("script"));
        Contracts.assertNotEmpty( constraintAnnotation.lang(), MESSAGES.parameterMustNotBeEmpty( "lang" ) );
        Contracts.assertNotEmpty( constraintAnnotation.alias(), MESSAGES.parameterMustNotBeEmpty( "alias" ) );
    }
}