UniqueKey.java

/**
 * Copyright (C) 2011  JTalks.org Team
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */
package org.jtalks.poulpe.util.databasebackup.domain;

import java.util.Collections;
import java.util.Set;

import org.apache.commons.lang3.Validate;
import org.apache.commons.lang3.builder.EqualsBuilder;
import org.apache.commons.lang3.builder.HashCodeBuilder;
import org.apache.commons.lang3.builder.ToStringBuilder;

import com.google.common.collect.Sets;

/**
 * The class represent a Primary or Unique key description data object. The class is immutable.
 * 
 * @author Evgeny Surovtsev
 * 
 */
public final class UniqueKey implements TableKey {
    /**
     * Initiate an instance of the class with a given Primary Key value.
     * 
     * @param columnName
     *            A String that represents Primary Key value.
     */
    public UniqueKey(String indexName, String columnName) {
        Validate.notNull(indexName, "indexName must not be null");
        Validate.notNull(columnName, "columnName must not be null");
        this.indexName = indexName;
        this.columnNameSet = Sets.newHashSet(columnName);
    }

    /**
     * Initiate an instance of the class with a given Primary Key value.
     * 
     * @param columnName
     *            A String that represents Primary Key value.
     */
    public UniqueKey(String indexName, Set<String> columnNameSet) {
        Validate.notNull(indexName, "indexName must not be null");
        Validate.notNull(columnNameSet, "columnNameSet must not be null");
        Validate.notEmpty(columnNameSet, "columnNameSet must have at least 1 element");

        this.indexName = indexName;
        this.columnNameSet = Sets.newHashSet(columnNameSet);
    }

    /**
     * @return column name.
     */
    public Set<String> getColumnNameSet() {
        return Collections.unmodifiableSet(columnNameSet);
    }

    /**
     * @return index name.
     */
    public String getIndexName() {
        return indexName;
    }

    @Override
    public int hashCode() {
        final int initialOddNum = 31;
        final int multiplierOddNum = 17;
        return new HashCodeBuilder(initialOddNum, multiplierOddNum)
                .append(columnNameSet)
                .append(indexName)
                .toHashCode();
    }

    @Override
    public String toString() {
        return ToStringBuilder.reflectionToString(this);
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null || this.getClass() != obj.getClass()) {
            return false;
        }
        UniqueKey other = (UniqueKey) obj;
        return new EqualsBuilder()
                .append(this.columnNameSet, other.columnNameSet)
                .append(this.indexName, other.indexName)
                .isEquals();
    }

    private final String indexName;
    private final Set<String> columnNameSet;
}