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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.cayenne.map;

import java.io.Serializable;
import java.util.Collection;
import java.util.Collections;
import java.util.SortedMap;
import java.util.TreeMap;

import org.apache.cayenne.CayenneRuntimeException;
import org.apache.cayenne.configuration.ConfigurationNode;
import org.apache.cayenne.configuration.ConfigurationNodeVisitor;
import org.apache.cayenne.di.AdhocObjectFactory;
import org.apache.cayenne.util.Util;
import org.apache.cayenne.util.XMLEncoder;
import org.apache.cayenne.util.XMLSerializable;

/**
 * A mapping descriptor of an embeddable class. Embeddable is a persistent class
 * that doesn't have its own identity and is embedded in other persistent
 * classes. It can be viewed as a custom type mapped to one or more database
 * columns. Embeddable mapping can include optional default column names that
 * can be overriden by the owning entity.
 * 
 * @since 3.0
 */
public class Embeddable implements ConfigurationNode, XMLSerializable, Serializable {

	private static final long serialVersionUID = -7163768090567642099L;
	
	protected String className;
	protected SortedMap<String, EmbeddableAttribute> attributes;
	protected DataMap dataMap;

	public Embeddable() {
		this(null);
	}

	public Embeddable(String className) {
		this.attributes = new TreeMap<String, EmbeddableAttribute>();
		this.className = className;
	}

	/**
	 * @since 3.1
	 */
	public <T> T acceptVisitor(ConfigurationNodeVisitor<T> visitor) {
		return visitor.visitEmbeddable(this);
	}

	public DataMap getDataMap() {
		return dataMap;
	}

	public void setDataMap(DataMap dataMap) {
		this.dataMap = dataMap;
	}

	/**
	 * Returns Java class of the embeddable.
	 * 
	 * @deprecated since 4.0 this method based on statically defined class
	 *             loading algorithm is not going to work in environments like
	 *             OSGi. {@link AdhocObjectFactory} should be used as it can
	 *             provide the environment-specific class loading policy.
	 */
	@Deprecated
	public Class<?> getJavaClass() {
		String name = getClassName();

		try {
			return Util.getJavaClass(name);
		} catch (ClassNotFoundException e) {
			throw new CayenneRuntimeException("Failed to load class " + name + ": " + e.getMessage(), e);
		}
	}

	/**
	 * Returns EmbeddableAttribute of this Embeddable that maps to
	 * <code>dbAttribute</code> parameter. Returns null if no such attribute is
	 * found.
	 */
	public EmbeddableAttribute getAttributeForDbPath(String dbPath) {
		for (EmbeddableAttribute attribute : attributes.values()) {
			if (dbPath.equals(attribute.getDbAttributeName())) {
				return attribute;
			}
		}

		return null;
	}

	/**
	 * Returns an unmodifiable sorted map of embeddable attributes.
	 */
	public SortedMap<String, EmbeddableAttribute> getAttributeMap() {
		// create a new instance ... Caching unmodifiable map causes
		// serialization issues (esp. with Hessian).
		return Collections.unmodifiableSortedMap(attributes);
	}

	/**
	 * Returns an unmodifiable collection of embeddable attributes.
	 */
	public Collection<EmbeddableAttribute> getAttributes() {
		// create a new instance. Caching unmodifiable collection causes
		// serialization issues (esp. with Hessian).
		return Collections.unmodifiableCollection(attributes.values());
	}

	/**
	 * Adds new embeddable attribute to the entity, setting its parent
	 * embeddable to be this object. If attribute has no name,
	 * IllegalArgumentException is thrown.
	 */
	public void addAttribute(EmbeddableAttribute attribute) {
		if (attribute.getName() == null) {
			throw new IllegalArgumentException("Attempt to insert unnamed attribute.");
		}

		Object existingAttribute = attributes.get(attribute.getName());
		if (existingAttribute != null) {
			if (existingAttribute == attribute) {
				return;
			} else {
				throw new IllegalArgumentException("An attempt to override embeddable attribute '"
						+ attribute.getName() + "'");
			}
		}

		attributes.put(attribute.getName(), attribute);
		attribute.setEmbeddable(this);
	}

	public EmbeddableAttribute getAttribute(String name) {
		return attributes.get(name);
	}

	public void removeAttribute(String name) {
		attributes.remove(name);
	}

	public String getClassName() {
		return className;
	}

	public void setClassName(String className) {
		this.className = className;
	}

	/**
	 * {@link XMLSerializable} implementation that generates XML for embeddable.
	 */
	public void encodeAsXML(XMLEncoder encoder) {
		encoder.print("<embeddable");
		if (getClassName() != null) {
			encoder.print(" className=\"");
			encoder.print(getClassName());
			encoder.print("\"");
		}
		encoder.println(">");

		encoder.indent(1);
		encoder.print(attributes);
		encoder.indent(-1);
		encoder.println("</embeddable>");
	}
}