Example.java

        SelectionQueryBuilder q = new SelectionQueryBuilder()
        .expr("is_awesome", EQ, true)
        .expr("money", GT, 50.0f)
        .expr("speed", LT, 21.1f)
        .or()
        .expr("door_number", EQ, 123)
        .or().expr(
        		new SelectionQueryBuilder()
        		.expr("a", GT, 0)
        		.expr("a", LT, 100)
        )
        .expr(
        		new SelectionQueryBuilder()
        		.opt("b", EQ, 0)
        		.opt("c", EQ, false)
        )
        .opt("apples", EQ, 0);
        
        String[] args = q.getArgsArray();
        String selection = q.toString();

*/
* Produces:
* selection: is_awesome = ? AND money > ? AND speed < ? OR door_number = ? OR (a > ? AND a < ?)
* args: [1, 50.0, 21.1, 123]
*/

SelectionQueryBuilder.java

package com.nike.oneplussdk.sample;

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

/**
 * Example:
 *   SelectionQueryBuilder q = new SelectionQueryBuilder()
 *      .expr("is_awesome", EQ, true)
 *      .expr("money", GT, 50.0f)
 *      .expr("speed", LT, 21.1f)
 *      .expr("door_number", EQ, 123)
 *      .opt("apples", EQ, 0);
 *
 */
public class SelectionQueryBuilder {
	public interface Op {
		public String EQ = " = ";
		public String NEQ = " != ";
		public String GT = " > ";
		public String LT = " < ";
		public String GTEQ = " >= ";
		public String LTEQ = " <= ";
		public String LIKE = " LIKE ";
		public String IS = " IS ";
		public String ISNOT = " IS NOT ";
		public String REGEXP = " REGEXP ";
	}
	
	private static final String AND = " AND ";
	private static final String OR = " OR ";
	
	
	private StringBuilder mBuilder;
	private List<String> mArgs = new ArrayList<String>();
	private String mNextOp = null;
	
	public List<String> getArgs() {
		return mArgs;
	}
	
	public String[] getArgsArray() {
		return mArgs.toArray(new String[0]);
	}
	
	public SelectionQueryBuilder() {
		mBuilder = new StringBuilder();
	}
	
	public SelectionQueryBuilder expr(String column, String op, String arg) {
		ensureOp();
		mBuilder.append(column).append(op).append("?");
		mArgs.add(arg);
		mNextOp = null;
		
		return this;
	}
	
	public SelectionQueryBuilder expr(SelectionQueryBuilder builder) {

		List<String> args = builder.getArgs();
		
		
		if(args.size() > 0) {
			ensureOp();
			mBuilder.append("(").append(builder).append(")");
			mArgs.addAll(args);
		}
		
		mNextOp = null;
		
		return this;
	}
	
	public SelectionQueryBuilder expr(String column, String op, boolean arg) {
		return expr(column, op, arg ? "1" : "0");
	}
	
	public SelectionQueryBuilder expr(String column, String op, int arg) {
		return expr(column, op, String.valueOf(arg));
	}
	
	public SelectionQueryBuilder expr(String column, String op, long arg) {
		return expr(column, op, String.valueOf(arg));
	}
	
	public SelectionQueryBuilder expr(String column, String op, float arg) {
		return expr(column, op, String.valueOf(arg));
	}
	
	public SelectionQueryBuilder expr(String column, String op, double arg) {
		return expr(column, op, String.valueOf(arg));
	}
	

	
	public SelectionQueryBuilder optExpr(String column, String op, String arg) {
		if(arg == null) {
			return this;
		}
		
		return expr(column, op, arg);
	}
	
	public SelectionQueryBuilder optExpr(String column, String op, boolean arg) {
		if(!arg) {
			return this;
		}
		
		return expr(column, op, arg ? "1" : "0");
	}
	
	public SelectionQueryBuilder opt(String column, String op, int arg) {
		if(arg == 0) {
			return this;
		}
		return expr(column, op, String.valueOf(arg));
	}
	
	public SelectionQueryBuilder opt(String column, String op, boolean arg) {
		if(!arg) {
			return this;
		}
		return expr(column, op, String.valueOf(arg));
	}
	
	public SelectionQueryBuilder opt(String column, String op, long arg) {
		if(arg == 0) {
			return this;
		}
		return expr(column, op, String.valueOf(arg));
	}
	
	public SelectionQueryBuilder opt(String column, String op, float arg) {
		if(arg == 0) {
			return this;
		}
		return expr(column, op, String.valueOf(arg));
	}
	
	public SelectionQueryBuilder opt(String column, String op, double arg) {
		if(arg == 0) {
			return this;
		}
		return expr(column, op, String.valueOf(arg));
	}
	
	public SelectionQueryBuilder and() {
		mNextOp = AND;
		
		return this;
	}
	
	public SelectionQueryBuilder or() {
		mNextOp = OR;
		
		return this;
	}

	private void ensureOp() {
		if(mBuilder.length() == 0) {
			return;
		}
		
		if(mNextOp == null) {
			mBuilder.append(AND);
		} else {
			mBuilder.append(mNextOp);
			mNextOp = null;
		}
	}
	
	@Override
	public String toString() {
		return mBuilder.toString();
	}
}