net.databinder.valid.hib.DatabinderValidator.java Source code

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Here is the source code for net.databinder.valid.hib.DatabinderValidator.java

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/*
 * Databinder: a simple bridge from Wicket to Hibernate
 * Copyright (C) 2008  Nathan Hamblen nathan@technically.us
    
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
package net.databinder.valid.hib;

import org.apache.wicket.Component;
import org.apache.wicket.markup.html.form.FormComponent;
import org.apache.wicket.model.IModel;
import org.apache.wicket.model.IWrapModel;
import org.apache.wicket.model.PropertyModel;
import org.apache.wicket.validation.IValidatable;
import org.apache.wicket.validation.IValidatorAddListener;
import org.apache.wicket.validation.ValidationError;
import org.apache.wicket.validation.validator.AbstractValidator;
import org.hibernate.Hibernate;
import org.hibernate.validator.ClassValidator;
import org.hibernate.validator.InvalidValue;

/**
 * Checks a base model and property name against Hibernate Validator.
 * @author Nathan Hamblen
 */
public class DatabinderValidator extends AbstractValidator implements IValidatorAddListener {
    /** base model, may be null until first call to onValidate. */
    private IModel base;
    /** property of base to validate, may be null until first call to onValidate. */
    private String property;
    /** component added to */
    private Component component;

    /**
     * Validator for a property of an entity.
     * @param base entity to validate
     * @param property property of base to validate
     */
    public DatabinderValidator(IModel base, String property) {
        this.base = base;
        this.property = property;
    }

    /**
     * Construct instance that attempts to determine the base object and property
     * to validate form the component it is added to. This is only possible for
     * components that depend on a parent CompoundPropertyModel or their own 
     * PropertyModels. The attempt is not made until the first validation check 
     * in {@link #onValidate(IValidatable)} (to allow the full component 
     * hierarchy to be constructed). Do not use an instance for more than 
     * one component.
     */
    public DatabinderValidator() {
    }

    /**
     * Checks the component against Hibernate Validator. If the base model
     * and property were not supplied in the constructor, they will be determined
     * from the component this validator was added to.
     */
    @SuppressWarnings("unchecked")
    @Override
    protected void onValidate(IValidatable comp) {
        if (base == null || property == null) {
            ModelProp mp = getModelProp(component);
            base = mp.model;
            property = mp.prop;
        }
        Object o = base.getObject();
        Class c = Hibernate.getClass(o);
        ClassValidator validator = new ClassValidator(c);
        for (InvalidValue iv : validator.getPotentialInvalidValues(property, comp.getValue()))
            comp.error(new ValidationError().setMessage(iv.getPropertyName() + " " + iv.getMessage()));
    }

    /** Retains component for possible use in onValidate. */
    public void onAdded(Component component) {
        this.component = component;
    }

    /** @return always true */
    @Override
    public boolean validateOnNullValue() {
        return true;
    }

    private static class ModelProp {
        IModel model;
        String prop;
    }

    /** @return base object and property derived from this component */
    private static ModelProp getModelProp(Component formComponent) {
        IModel model = formComponent.getModel();
        ModelProp mp = new ModelProp();
        if (model instanceof PropertyModel) {
            PropertyModel propModel = (PropertyModel) model;
            mp.model = propModel.getChainedModel();
            mp.prop = propModel.getPropertyExpression();
        } else if (model instanceof IWrapModel) {
            mp.model = ((IWrapModel) model).getWrappedModel();
            mp.prop = formComponent.getId();
        } else
            throw new UnrecognizedModelException(formComponent, model);
        return mp;
    }

    /**
     * Add immediately to a form component. Note that the component's model
     * object must be available for inspection at this point or an exception will
     * be thrown. (For a CompoundPropertyModel, this means the hierarchy must
     * be established.) This is only possible for components that depend on a 
     * parent CompoundPropertyModel or their own PropertyModels.
     * @param formComponent component to add validator to
     * @throws UnrecognizedModelException if no usable model is present
     */
    public static void addTo(FormComponent formComponent) {
        ModelProp mp = getModelProp(formComponent);
        formComponent.add(new DatabinderValidator(mp.model, mp.prop));
    }

    public static class UnrecognizedModelException extends RuntimeException {
        public UnrecognizedModelException(Component formComponent, IModel model) {
            super("DatabinderValidator doesn't recognize the model " + model + " of component "
                    + formComponent.toString());
        }
    }
}