org.apache.wicket.model.ChainingModel.java Source code

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Here is the source code for org.apache.wicket.model.ChainingModel.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.wicket.model;

import java.io.Serializable;

import org.apache.wicket.Session;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Default implementation of IChainingModel
 *
 * @param <T>
 *            The Model object type
 *
 * @see CompoundPropertyModel
 * @see AbstractPropertyModel
 *
 * @since 6.0.0
 */
public class ChainingModel<T> implements IChainingModel<T> {
    private static final Logger LOG = LoggerFactory.getLogger(ChainingModel.class);

    /** Any model object (which may or may not implement IModel) */
    private Object target;

    public ChainingModel(final Object modelObject) {
        if (modelObject instanceof Session) {
            LOG.warn("It is not a good idea to reference the Session instance "
                    + "in models directly as it may lead to serialization problems. "
                    + "If you need to access a property of the session via the model use the "
                    + "page instance as the model object and 'session.attribute' as the path.");
        } else if (modelObject != null && (modelObject instanceof Serializable == false)) {
            LOG.warn(
                    "It is not a good idea to reference non-serializable {} "
                            + "in a model directly as it may lead to serialization problems.",
                    modelObject.getClass());
        }

        target = modelObject;
    }

    /**
     * Unsets this property model's instance variables and detaches the model.
     *
     * @see org.apache.wicket.model.IDetachable#detach()
     */
    @Override
    public void detach() {
        // Detach nested object if it's a detachable
        if (target instanceof IDetachable) {
            ((IDetachable) target).detach();
        }
    }

    @Override
    @SuppressWarnings("unchecked")
    public void setObject(T object) {
        if (target instanceof IModel) {
            ((IModel<T>) target).setObject(object);
        } else {
            target = object;
        }
    }

    @Override
    @SuppressWarnings("unchecked")
    public T getObject() {
        if (target instanceof IModel) {
            return ((IModel<T>) target).getObject();
        }
        return (T) target;
    }

    @Override
    public IModel<?> getChainedModel() {
        if (target instanceof IModel) {
            return (IModel<?>) target;
        }
        return null;
    }

    @Override
    public void setChainedModel(IModel<?> model) {
        target = model;
    }

    /**
     * @return The target - object or model
     */
    protected final Object getTarget() {
        return target;
    }

    /**
     * Sets a new target - object or model
     * @return this object
     */
    protected final ChainingModel<T> setTarget(final Object modelObject) {
        this.target = modelObject;
        return this;
    }

    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder("Model:classname=[");
        sb.append(getClass().getName()).append(']');
        sb.append(":nestedModel=[").append(target).append(']');
        return sb.toString();
    }
}