org.openeos.services.ui.form.abstractform.UIBeanSelectorProvider.java Source code

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Here is the source code for org.openeos.services.ui.form.abstractform.UIBeanSelectorProvider.java

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/**
 * Copyright 2014 Fernando Rincon Martin <frm.rincon@gmail.com>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.openeos.services.ui.form.abstractform;

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.SortedSet;
import java.util.TreeSet;

import org.abstractform.binding.BFormInstance;
import org.abstractform.core.FormInstance;
import org.abstractform.core.fluent.selector.AbstractSelectorProvider;
import org.hibernate.Criteria;
import org.hibernate.SessionFactory;
import org.hibernate.criterion.Criterion;
import org.hibernate.criterion.Restrictions;
import org.hibernate.type.BooleanType;
import org.hibernate.type.StringType;
import org.hibernate.type.Type;
import org.mvel2.CompileException;
import org.mvel2.MVEL;
import org.openeos.services.dictionary.IIdentificationCapable;
import org.openeos.services.ui.internal.UIBeanImpl;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.transaction.annotation.Transactional;

public class UIBeanSelectorProvider<T> extends AbstractSelectorProvider<T> {

    private static final Logger LOG = LoggerFactory.getLogger(UIBeanSelectorProvider.class);

    private SessionFactory sessionFactory;
    private Class<T> beanClass;
    private FormInstance formInstance;
    private String sqlRestriction;

    public UIBeanSelectorProvider(SessionFactory sessionFactory, Class<T> beanClass, FormInstance formInstance,
            String sqlRestriction) {
        this.sessionFactory = sessionFactory;
        this.beanClass = beanClass;
        this.formInstance = formInstance;
        this.sqlRestriction = sqlRestriction;
        if (sqlRestriction != null && formInstance instanceof BFormInstance<?, ?>) {

            this.formInstance.addFieldChangeListener(new PropertyChangeListener() {

                @Override
                public void propertyChange(PropertyChangeEvent evt) {
                    // TODO This is not good idea, maybe cached query, check if query changed and fire if it changed. 
                    fireElementsChanged();
                }
            });
        }
    }

    @Override
    @Transactional(readOnly = true)
    public SortedSet<T> getElements() {
        Criteria crit = sessionFactory.getCurrentSession().createCriteria(beanClass);
        if (sqlRestriction != null && formInstance instanceof BFormInstance<?, ?>) {
            Object value = ((BFormInstance<?, ?>) formInstance).getValue();
            if (value instanceof UIBeanImpl) {
                value = ((UIBeanImpl) value).getBeanWrapped();
            }
            crit.add(buildSqlRestriction(sqlRestriction, value));
        }
        final List<T> listElements = crit.list();
        TreeSet<T> result = new TreeSet<T>(new Comparator<T>() {

            @Override
            public int compare(T o1, T o2) {
                return Integer.compare(listElements.indexOf(o1), listElements.indexOf(o2));
            }
        });
        result.addAll(listElements);
        return result;
    }

    private Criterion buildSqlRestriction(String sqlRestriction, Object value) {
        try {
            String result = sqlRestriction;
            int first = result.indexOf("@");
            List<Object> values = new ArrayList<Object>();
            List<Type> types = new ArrayList<Type>();
            while (first != -1) {
                String parameter = result.substring(first);
                int second = parameter.indexOf("@", 1);
                if (second == -1) {
                    LOG.warn(
                            "There are a sql restrictoion not well formed, the sql restriction is: '{}' for bean class {} ",
                            sqlRestriction, beanClass.getName());
                    break;
                }
                parameter = parameter.substring(0, second + 1);
                String parameterWithoutRim = parameter.substring(1, parameter.length() - 1);
                Map<String, Object> mvelContext = new HashMap<String, Object>();
                mvelContext.put("source", value);
                Object parameterValue = MVEL.eval(parameterWithoutRim, mvelContext);
                // TODO Make more types
                if (String.class.isAssignableFrom(parameterValue.getClass())) {
                    values.add(parameterValue);
                    types.add(StringType.INSTANCE);
                } else if (Boolean.class.isAssignableFrom(parameterValue.getClass())) {
                    values.add(parameterValue);
                    types.add(BooleanType.INSTANCE);
                } else {
                    throw new UnsupportedOperationException();
                }
                result = result.substring(0, first) + "? " + result.substring(second + first + 1);
                first = result.indexOf("@");
            }
            Type[] t = new Type[types.size()];
            return Restrictions.sqlRestriction(result, values.toArray(), types.toArray(t));
        } catch (CompileException ex) {
            LOG.warn(String.format("Compiling validation expression '%s' of class '%s' has thrown an error: %s",
                    sqlRestriction, beanClass.toString(), ex.getMessage()), ex);
            return Restrictions.sqlRestriction("0=1");
        }
    }

    @Override
    public String getText(T element) {
        if (element instanceof IIdentificationCapable) {
            IIdentificationCapable identif = (IIdentificationCapable) element;
            return identif.getIdentifier();
        }
        return element.toString();
    }

}