PreparedStatementBuilder.java

package org.cagrid.dorian.service.util;

import java.math.BigInteger;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.util.ArrayList;
import java.util.List;


public class PreparedStatementBuilder {
    private List fields;

    private List whereFields;

    private List whereValues;

    private List whereOperators;

    private List clauses;

    private String table;


    public PreparedStatementBuilder(String table) {
        this.fields = new ArrayList();
        this.whereFields = new ArrayList();
        this.whereValues = new ArrayList();
        this.whereOperators = new ArrayList();
        this.clauses = new ArrayList();
        this.table = table;
    }


    public void addSelectField(String field) {
        this.fields.add(field);
    }


    public void addWhereField(String field, String operator, Object value) {
        this.whereFields.add(field);
        this.whereOperators.add(operator);
        this.whereValues.add(value);
    }


    public void addClause(String clause) {
        this.clauses.add(clause);
    }


    public PreparedStatement prepareStatement(Connection c) throws Exception {
        StringBuffer sql = new StringBuffer("select ");
        boolean first = true;
        for (int i = 0; i < fields.size(); i++) {
            if (!first) {
                sql.append(",");
            } else {
                first = false;
            }
            sql.append((String) fields.get(i));
        }
        sql.append(" FROM " + table);

        if ((whereFields.size() > 0) || (clauses.size() > 0)) {
            sql.append(" WHERE ");
        }
        first = true;
        for (int i = 0; i < whereFields.size(); i++) {
            if (!first) {
                sql.append(" AND ");
            } else {
                first = false;
            }
            sql.append((String) whereFields.get(i) + " " + (String) whereOperators.get(i) + " ?");
        }

        for (int i = 0; i < clauses.size(); i++) {
            if (!first) {
                sql.append(" AND");
            } else {
                first = false;
            }
            sql.append((String) clauses.get(i));
        }
        PreparedStatement s = c.prepareStatement(sql.toString());

        for (int i = 0; i < whereValues.size(); i++) {
            Object o = whereValues.get(i);
            int index = i + 1;
            if (o instanceof String) {
                s.setString((index), (String) o);
            } else if (o instanceof Long) {
                s.setLong((index), ((Long) o).longValue());
            } else if (o instanceof BigInteger) {
                s.setLong((index), ((BigInteger) o).longValue());
            } else if (o instanceof Integer) {
                s.setInt((index), ((Integer) o).intValue());
            } else {
                throw new Exception("Unsupported type " + o.getClass().getName());
            }
        }
        // System.out.println(sql.toString());
        return s;
    }

}