build query using java 8 features

QueryBuilder.java

package com.my.crawler;

import java.util.HashMap;
import java.util.Map;
import java.util.function.Supplier;

public class QueryBuilder {

	private Map<String, Object> parameterMap = new HashMap<>();

	private StringBuilder querySBuilder;

	public QueryBuilder() {
		querySBuilder = new StringBuilder();
	}

	public QueryBuilder(String initialSQL) {
		querySBuilder = new StringBuilder(initialSQL);
	}
	/**
	* addQuery(" and user = :username", "username", "John");
	*/
	public <R> QueryBuilder addQuery(String query, String parameterName, R parameterValue) {

		querySBuilder.append(query);
		parameterMap.put(parameterName, parameterValue);

		return this;
	}

	/**
	* String userName = "John";
	* addQuery(" and user = :username", "username", () -> userName.toUpperCase());
	*/
	
	public <T> QueryBuilder addQuery(String query, String parameterName, Supplier<T> parameterValue) {

		querySBuilder.append(query);
		parameterMap.put(parameterName, parameterValue.get());

		return this;
	}
	/**
	* String userName = "John";
	* addQuery(" and user = :username", "username", () -> userName.toUpperCase(), () -> userName != null && !userName.equals("baduser"));
	*/
	public <T> QueryBuilder addQuery(String query, String parameterName, Supplier<T> parameterValue,
			Supplier<Boolean> successCondition) {

		if (successCondition.get()) {
			querySBuilder.append(query);
			parameterMap.put(parameterName, parameterValue.get());
		}

		return this;
	}

	/**
	* String userName = "John";
	* addQuery(" and user = :username", "username", () -> userName.toUpperCase(), 
	* () -> userName != null && !userName.equals("baduser"),
	* () -> new IOException());
	*/
	public <T> QueryBuilder addQuery(String query, String parameterName, Supplier<T> parameterValue,
			Supplier<Boolean> successCondition, Supplier<Exception> failureException) throws Exception {

		if (successCondition.get()) {
			querySBuilder.append(query);
			parameterMap.put(parameterName, parameterValue.get());
		} else {
			throw failureException.get();
		}

		return this;
	}

	public Query build() {

		return new Query(querySBuilder.toString(), parameterMap);
	}

}