org.eclipse.osbp.jpa.services/src/org/eclipse/osbp/jpa/services/metadata/EntityClassMetadata.java

/**
 * Copyright 2009-2013 Oy Vaadin Ltd
 *
 * 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.eclipse.osbp.jpa.services.metadata;


/**
 * An extended version of {@link ClassMetadata} that provides additional
 * information about classes annotated with the <code>Entity</code> annotation.
 * 
 * @author Petter Holmström (Vaadin Ltd)
 * @since 1.0
 */
public class EntityClassMetadata<T> extends ClassMetadata<T> {

    private static final long serialVersionUID = -4870942071257502328L;
    private final String entityName;
    private String versionProperty;
    private String identifierProperty;

    /**
     * Creates a new instance of <code>EntityClassMetadata</code>.
     * 
     * @param mappedClass
     *            the entity class (must not be null).
     * @param entityName
     *            the entity name (must not be null).
     */
    EntityClassMetadata(Class<T> mappedClass, String entityName) {
        super(mappedClass);
        assert entityName != null : "entityName must not be null";
        this.entityName = entityName;
    }

    /**
     * Sets the name of the property that contains the version, if any.
     * 
     * @param propertyName
     *            the property name, may be null.
     */
    void setVersionPropertyName(String propertyName) {
        if (propertyName != null) {
            PropertyMetadata pm = getProperty(propertyName);
            if (pm == null || !(pm instanceof PersistentPropertyMetadata)) {
                throw new IllegalArgumentException("Invalid property");
            }
        }
        this.versionProperty = propertyName;
    }

    /**
     * Sets the name of the property that contains the identifier, if any.
     * 
     * @param propertyName
     *            the property name, may be null.
     * @throws IllegalArgumentException
     *             if <code>propertyName</code> is invalid (i.e. the property
     *             does not exist or is transient).
     */
    void setIdentifierPropertyName(String propertyName)
            throws IllegalArgumentException {
        if (propertyName != null) {
            PropertyMetadata pm = getProperty(propertyName);
            if (pm == null || !(pm instanceof PersistentPropertyMetadata)) {
                throw new IllegalArgumentException("Invalid property");
            }
        }
        this.identifierProperty = propertyName;
    }

    /**
     * The name of the entity. If no explicit entity name has been given, this
     * is the simple class name.
     */
    public String getEntityName() {
        return entityName;
    }

    /**
     * If the entity has a version property or not.
     * 
     * @see #getVersionProperty()
     */
    public boolean hasVersionProperty() {
        return versionProperty != null;
    }

    /**
     * Gets the version property, if it exists.
     * 
     * @see #hasVersionProperty()
     * @return the version property metadata, or null if not available.
     */
    public PersistentPropertyMetadata getVersionProperty() {
        return versionProperty == null ? null
                : (PersistentPropertyMetadata) getProperty(versionProperty);
    }

    /**
     * If the entity has an identifier property or not.
     * 
     * @see #getIdentifierProperty()
     * @see #hasEmbeddedIdentifier()
     */
    public boolean hasIdentifierProperty() {
        return identifierProperty != null;
    }

    /**
     * Gets the identifier property, if it exists. If
     * {@link #hasEmbeddedIdentifier() } returns true, this property is the
     * embedded identifier.
     * 
     * @see #hasIdentifierProperty()
     * @see #hasEmbeddedIdentifier()
     * @return the identifier property metadata, or null if not available.
     */
    public PersistentPropertyMetadata getIdentifierProperty() {
        return identifierProperty == null ? null
                : (PersistentPropertyMetadata) getProperty(identifierProperty);
    }

    /**
     * If the entity has an embedded identifier. This property cannot be true
     * unless {@link #hasIdentifierProperty() } also returns true.
     */
    public boolean hasEmbeddedIdentifier() {
        return hasIdentifierProperty()
                && getIdentifierProperty().getPropertyKind() == PropertyKind.EMBEDDED;
    }

    @Override
    public boolean equals(Object obj) {
        if (super.equals(obj)) { // Includes a check of the parameter class
            EntityClassMetadata<?> other = (EntityClassMetadata<?>) obj;
            return ( other == null ? false : entityName.equals(other.entityName) )
                    && (versionProperty == null ? other.versionProperty == null
                            : versionProperty.equals(other.versionProperty))
                    && (identifierProperty == null ? other.identifierProperty == null
                            : identifierProperty
                                    .equals(other.identifierProperty));
        }
        return false;
    }

    @Override
    public int hashCode() {
        int hash = super.hashCode();
        hash = hash * 31 + entityName.hashCode();
        if (versionProperty != null) {
            hash = hash * 31 + versionProperty.hashCode();
        }
        if (identifierProperty != null) {
            hash = hash * 31 + identifierProperty.hashCode();
        }
        return hash;
    }
}