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Cayenne Object Persistence Framework
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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.
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package org.apache.cayenne.map;

import java.util.Iterator;

import org.apache.commons.collections.IteratorUtils;
import org.apache.commons.lang.StringUtils;
import org.apache.cayenne.CayenneException;
import org.apache.cayenne.CayenneRuntimeException;
import org.apache.cayenne.util.Util;
import org.apache.cayenne.util.XMLEncoder;

/**
 * An ObjAttribute is a mapping descriptor of a Java class property.
 * 
 * @author Misha Shengaout
 * @author Andrei Adamchik
 */
public class ObjAttribute extends Attribute {

    protected String type;
    protected boolean usedForLocking;
    protected String dbAttributePath;

    public ObjAttribute() {
    }

    public ObjAttribute(String name) {
        super(name);
    }

    public ObjAttribute(String name, String type, ObjEntity entity) {
        setName(name);
        setType(type);
        setEntity(entity);
    }

    /**
     * Returns Java class of an object property described by this attribute. Wraps any
     * thrown exceptions into CayenneRuntimeException.
     */
    public Class getJavaClass() {
        if (this.getType() == null) {
            return null;
        }

        try {
            // tolerate null class loader
            return Util.getJavaClass(getType());
        }
        catch (ClassNotFoundException e) {
            throw new CayenneRuntimeException("Failed to load class for name '"
                    + this.getType()
                    + "': "
                    + e.getMessage(), e);
        }
    }

    /**
     * Prints itself as XML to the provided XMLEncoder.
     * 
     * @since 1.1
     */
    public void encodeAsXML(XMLEncoder encoder) {
        encoder.print("");
    }

    /**
     * Returns fully qualified Java class name of the object property represented by this
     * attribute.
     */
    public String getType() {
        return type;
    }

    /**
     * Sets the type of the data object property. Type is expected to be a fully qualified
     * Java class name.
     */
    public void setType(String type) {
        this.type = type;
    }

    /**
     * Returns whether this attribute should be used for locking.
     * 
     * @since 1.1
     */
    public boolean isUsedForLocking() {
        return usedForLocking;
    }

    /**
     * Sets whether this attribute should be used for locking.
     * 
     * @since 1.1
     */
    public void setUsedForLocking(boolean usedForLocking) {
        this.usedForLocking = usedForLocking;
    }

    /**
     * Returns a DbAttribute mapped by this ObjAttribute.
     */
    public DbAttribute getDbAttribute() {
        Iterator pathIterator = getDbPathIterator();
        Object o = null;
        while (pathIterator.hasNext()) {
            o = pathIterator.next();
        }
        return (DbAttribute) o;
    }

    public Iterator getDbPathIterator() {
        if (dbAttributePath == null) {
            return IteratorUtils.EMPTY_ITERATOR;
        }

        ObjEntity ent = (ObjEntity) getEntity();
        if (ent == null) {
            return IteratorUtils.EMPTY_ITERATOR;
        }

        DbEntity dbEnt = ent.getDbEntity();
        if (dbEnt == null) {
            return IteratorUtils.EMPTY_ITERATOR;
        }

        int lastPartStart = dbAttributePath.lastIndexOf('.');
        if (lastPartStart < 0) {
            Attribute attribute = dbEnt.getAttribute(dbAttributePath);
            if (attribute == null) {
                return IteratorUtils.EMPTY_ITERATOR;
            }
            return IteratorUtils.singletonIterator(attribute);
        }

        return dbEnt.resolvePathComponents(dbAttributePath);
    }

    /**
     * Set mapped DbAttribute.
     */
    public void setDbAttribute(DbAttribute dbAttribute) {
        if (dbAttribute == null) {
            this.setDbAttributePath(null);
        }
        else {
            this.setDbAttributePath(dbAttribute.getName());
        }
    }

    /**
     * Returns the dbAttributeName.
     * 
     * @return String
     */
    public String getDbAttributeName() {
        if (dbAttributePath == null)
            return null;
        int lastPartStart = dbAttributePath.lastIndexOf('.');
        String lastPart = StringUtils.substring(
                dbAttributePath,
                lastPartStart + 1,
                dbAttributePath.length());
        return lastPart;
    }

    /**
     * Sets the dbAttributeName.
     * 
     * @param dbAttributeName The dbAttributeName to set
     */
    public void setDbAttributeName(String dbAttributeName) {
        if (dbAttributePath == null || dbAttributeName == null) {
            dbAttributePath = dbAttributeName;
            return;
        }
        int lastPartStart = dbAttributePath.lastIndexOf('.');
        String newPath = (lastPartStart > 0
                ? StringUtils.chomp(dbAttributePath, ".")
                : "");
        newPath += (newPath.length() > 0 ? "." : "") + dbAttributeName;
        this.dbAttributePath = newPath;
    }

    public void setDbAttributePath(String dbAttributePath) {
        this.dbAttributePath = dbAttributePath;
    }

    public String getDbAttributePath() {
        return dbAttributePath;
    }

    public boolean isCompound() {
        return (dbAttributePath != null && dbAttributePath.indexOf('.') >= 0);
    }

    /**
     * @deprecated Since 1.2 unused.
     */
    public boolean mapsToDependentDbEntity() {
        Iterator i = getDbPathIterator();
        if (!i.hasNext()) {
            return false;
        }

        Object o = i.next();
        if (!i.hasNext()) {
            return false;
        }

        Object o1 = i.next();
        if (!(o1 instanceof DbAttribute)) {
            return false;
        }

        DbRelationship toDependent = (DbRelationship) o;
        return toDependent.isToDependentPK();
    }

    /**
     * @deprecated Since 1.2 unused.
     */
    public void validate() throws CayenneException {
        String head = "ObjAttribute: " + getName() + " ";
        ObjEntity ent = (ObjEntity) getEntity();
        if (ent == null) {
            throw new CayenneException(head + "Parent ObjEntity not defined.");
        }
        head += "ObjEntity: " + ent.getName() + " ";

        if (getName() == null)
            throw new CayenneException(head + "ObjAttribute's name not defined.");

        if (getDbAttributePath() == null)
            throw new CayenneException(head + "dbAttributePath not defined.");

        try {
            Iterator i = getDbPathIterator();
            boolean dbAttributeFound = false;
            while (i.hasNext()) {
                Object pathPart = i.next();
                if (pathPart instanceof DbRelationship) {
                    DbRelationship r = (DbRelationship) pathPart;
                    if (r.isToMany())
                        throw new CayenneException(head
                                + "DbRelationship: "
                                + r.getName()
                                + " is to-many.");
                }
                else if (pathPart instanceof DbAttribute) {
                    dbAttributeFound = true;
                }
            }
            if (!dbAttributeFound)
                throw new CayenneException(head + "DbAttribute not found.");
        }
        catch (CayenneException ex) {
            throw ex;
        }
        catch (Exception ex) {
            throw new CayenneException(head + ex.getMessage(), ex);
        }
    }

    /**
     * Returns an ObjAttribute stripped of any server-side information, such as
     * DbAttribute mapping.
     * 
     * @since 1.2
     */
    public ObjAttribute getClientAttribute() {
        ObjAttribute attribute = new ObjAttribute(getName());
        attribute.setType(getType());

        // TODO: will likely need "userForLocking" property as well.

        return attribute;
    }
}