FilterWhereBuilder.java

/*
 * ====================
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 *
 * Copyright 2008-2009 Sun Microsystems, Inc. All rights reserved.
 *
 * The contents of this file are subject to the terms of the Common Development
 * and Distribution License("CDDL") (the "License").  You may not use this file
 * except in compliance with the License.
 *
 * You can obtain a copy of the License at
 * http://opensource.org/licenses/cddl1.php
 * See the License for the specific language governing permissions and limitations
 * under the License.
 *
 * When distributing the Covered Code, include this CDDL Header Notice in each file
 * and include the License file at http://opensource.org/licenses/cddl1.php.
 * If applicable, add the following below this CDDL Header, with the fields
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package org.identityconnectors.dbcommon;

import java.util.ArrayList;
import java.util.List;

import org.identityconnectors.common.CollectionUtil;

/**
 * The Filter Where builder is component intended to be used within subclass of
 * <code>AbstractFilterTranslator</code> to help create the database WHERE query
 * clause.
 * <p>
 * The main functionality of this helper class is create SQL WHERE query clause
 * </p>
 * <p>
 * The builder can return a List of params to be used within preparedStatement
 * creation
 * <p>
 *
 * @since 1.0
 */
public class FilterWhereBuilder {

    private boolean in;
    private final List<SQLParam> params = new ArrayList<SQLParam>();
    private final StringBuilder where = new StringBuilder();

    /**
     * Compound join operator.
     *
     * @param operator
     *            AND/OR
     * @param l
     *            left <CODE>FilterQueryBuiler</CODE>
     * @param r
     *            right <CODE>FilterQueryBuiler</CODE>
     */
    public void join(final String operator, final FilterWhereBuilder l, final FilterWhereBuilder r) {
        this.in = true;
        if (l.isIn()) {
            where.append("( ");
        }
        where.append(l.getWhere());
        if (l.isIn()) {
            where.append(" )");
        }
        where.append(" ");
        where.append(operator);
        where.append(" ");
        if (r.isIn()) {
            where.append("( ");
        }
        where.append(r.getWhere());
        if (r.isIn()) {
            where.append(" )");
        }

        // The params
        params.addAll(l.getParams());
        params.addAll(r.getParams());
    }

    /**
     * @return the params
     */
    public List<SQLParam> getParams() {
        return CollectionUtil.asReadOnlyList(params);
    }

    /**
     * @return the where
     */
    public StringBuilder getWhere() {
        return where;
    }

    /**
     * Add name value pair bindings with operator, this is lazy bindings
     * resolved at {@link #getWhereClause()}.
     *
     * @see FilterWhereBuilder#getWhereClause()
     *
     * @param param
     *            value to builder
     * @param operator
     *            an operator to compare
     */
    public void addBind(final SQLParam param, final String operator) {
        if (param == null) {
            throw new IllegalArgumentException("null.param.not.suported");
        }
        where.append(param.getName());
        where.append(" ").append(operator).append(" ?");
        params.add(param);
    }

    /**
     * Add null value.
     *
     * @see FilterWhereBuilder#getWhereClause()
     *
     * @param name
     *            of the column
     */
    public void addNull(final String name) {
        where.append(name);
        where.append(" IS NULL");
    }

    /**
     * There is a need to put the content into brackets.
     *
     * @return boolean a in
     */
    public boolean isIn() {
        return in;
    }

    /**
     * Gets the where clause.
     *
     * @return the where clause as a String
     */
    public String getWhereClause() {
        return this.getWhere().toString();
    }
}