CollectionPropertyName.java

/*
 * Copyright 2005 The Apache Software Foundation.
 *
 * 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 net.sf.beanlib;

import java.util.HashSet;
import java.util.Set;

import org.apache.commons.lang.builder.EqualsBuilder;

/**
 * Used to uniquely identify a Collection or Map property of a JavaBean object.
 *
 * @author Joe D. Velopar
 */
public class CollectionPropertyName<T> {

    public static final CollectionPropertyName<?>[] EMPTY_ARRAY = {};
    private final Class<T> declaringClass;
    private final String collectionProperty;
    private final int hashCode;
    private final BeanGetter beanGetter = new BeanGetter();

    /** Convenient factory method. */
    public static <T> CollectionPropertyName<T>[] createCollectionPropertyNames(Class<T> declaringClass, String[] collectionProperties) {
        Set<CollectionPropertyName<T>> set = new HashSet<CollectionPropertyName<T>>();

        for (String s : collectionProperties) {
            set.add(new CollectionPropertyName<T>(declaringClass, s));
        }

        @SuppressWarnings("unchecked")
        CollectionPropertyName<T>[] ret = (CollectionPropertyName<T>[]) set.toArray(EMPTY_ARRAY);
        return ret;
    }

    /**
     * @param declaringClass declaring class of the Collection or Map property.
     * @param collectionProperty Collection or Map property name.
     */
    public CollectionPropertyName(Class<T> declaringClass, String collectionProperty) {
        this.declaringClass = declaringClass;
        this.collectionProperty = collectionProperty;
        this.hashCode = beanGetter.getBeanHashCode(this);
    }

    public Class<T> getDeclaringClass() {
        return declaringClass;
    }

    public String getCollectionProperty() {
        return collectionProperty;
    }

    @Override
    public boolean equals(Object obj) {
        if (!(obj instanceof CollectionPropertyName)) {
            return false;
        }
        CollectionPropertyName<?> that = (CollectionPropertyName<?>) obj;
        return new EqualsBuilder().append(this.declaringClass, that.declaringClass).append(this.collectionProperty, that.collectionProperty)
                .isEquals();
    }

    @Override
    public int hashCode() {
        return this.hashCode;
    }
}