SqlParameter.java

/*
 * SqlParameter
 *
 * Copyright (C) 2010  Jaroslav Merxbauer
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */
package notwa.sql;

import java.sql.Timestamp;

/**
 * The <code>class</code> representing the single sql parameter which is build
 * from:
 * <ul>
 * <li>The parameter name</li>
 * <li>The parameter value</li>
 * <li>The relation between the name and the value</li>
 * <ul>
 * This parameter is then build into the SQL Query template where the actual
 * parameter placeholders are replaced with the values and columns as mandated
 * by the {@link ParameterSet} containg a set of instances of this <code>class</code>.
 *
 * @author Jaroslav Merxbauer
 * @version %I% %G%
 */
public class SqlParameter implements SqlFilter {
    private String name;
    private Object value;
    private String relation;
    
    /**
     * The sole constructor allowing to set all of the properties of valid 
     * <code>SqlParameter</code>.
     *
     * @param name The name of the parameter.
     * @param value The value of the parameter.
     * @param relation The relation between the value and the name.
     */
    public SqlParameter(String name, Object value, String relation) {
        this.name = name;
        this.value = value;
        this.relation = relation;
    }

    @Override
    public boolean equals(Object obj) {
        if (obj == null) {
            return false;
        }
        if (getClass() != obj.getClass()) {
            return false;
        }
        final SqlParameter other = (SqlParameter) obj;
        if ((this.name == null) ? (other.name != null) : !this.name.equals(other.name)) {
            return false;
        }
        if (this.value != other.value && (this.value == null || !this.value.equals(other.value))) {
            return false;
        }
        return true;
    }

    @Override
    public int hashCode() {
        int hash = 5;
        hash = 83 * hash + (this.name != null ? this.name.hashCode() : 0);
        hash = 83 * hash + (this.value != null ? this.value.hashCode() : 0);
        return hash;
    }
    
    /**
     * Gets this parameter name.
     * 
     * @return The parameter name.
     */
    public String getName() {
        return name;
    }
    
    /**
     * Sets this parameter name.
     * 
     * @param name The parameter name.
     */
    public void setName(String name) {
        this.name = name;
    }
    
    /**
     * Gets this parameter value.
     * 
     * @return The parameter value.
     */
    public Object getValue() {
        return value;
    }
    
    /**
     * Sets this parameter value.
     *
     * @param value The parameter value.
     */
    public void setValue(String value) {
        this.value = value;
    }
    
    /**
     * Gets this parameter relation between the name and the value.
     *
     * @return The name to value relation.
     */
    public String getRelation() {
        return this.relation;
    }
    
    /**
     * Sets this parameter relation between the name and the value.
     * 
     * @param relation The name to value relation.
     */
    public void setRelation(String relation) {
        this.relation = relation;
    }

    @Override
    public String formatForSql() {
        StringBuilder builder = new StringBuilder("(");
        builder.append("${").append(this.name).append("} ");
        builder.append(this.relation).append(" ");
        builder.append(formatValueForSql());
        return builder.append(")").toString();
    }

    /**
     * Formats the value in the given parameter for the SQL Query. This actually
     * means that the <code>String</code> or the <code>Timestamp</code> will be
     * surrounded with quotas.
     *
     * @param p The parameter which values will be well-formated.
     * @return The well-formated value.
     */
    private String formatValueForSql() {
        StringBuilder sb = new StringBuilder();
        if ((this.value instanceof String) || (this.value instanceof Timestamp)) {
            sb.append("'");
            if (this.value instanceof Timestamp) {
                sb.append(((Timestamp) this.value).toString());
            } else {
                sb.append((String) this.value);
            }
            sb.append("'");
        } else {
            sb.append(this.value);
        }
        return sb.toString();
    }
}