Leveraging dynamic queries

FieldComparisonQLToken.java

/**
 * @author <a href="mailto:mpaluch@paluch.biz">Mark Paluch</a>
 * @since 07.11.13 12:36
 */
public class FieldComparisonQLToken implements FieldQLToken {

	private String field;
	private String value;
	private QueryComparator queryComparator = QueryComparator.EQUAL_TO;

	public FieldComparisonQLToken(String field, String value) {
		this.field = field;
		this.value = value;
	}

	public FieldComparisonQLToken(String field, String value, QueryComparator queryComparator) {
		this.field = field;
		this.value = value;
		this.queryComparator = queryComparator;
	}

	@Override
	public String asQLString() {

		switch (queryComparator) {

		case NOT_EQUAL:
			return "-" + field + ":" + value;

		default:
			return field + ":" + value;
		}

	}

	@Override
	public String toString() {
		final StringBuffer sb = new StringBuffer();
		sb.append(getClass().getSimpleName());
		sb.append(" [field='").append(field).append('\'');
		sb.append(", value='").append(value).append('\'');
		sb.append(']');
		return sb.toString();
	}
}

FieldNullComparisonQLToken.java

/**
 * @author <a href="mailto:mpaluch@paluch.biz">Mark Paluch</a>
 * @since 07.11.13 12:36
 */
public class FieldNullComparisonQLToken implements FieldQLToken {

	private String field;
	private boolean mustBeNull;

	public FieldNullComparisonQLToken(String field, boolean mustBeNull) {
		this.mustBeNull = mustBeNull;
		this.field = field;
	}

	@Override
	public String asQLString() {

		if (mustBeNull) {
			return "-" + field + ":[* TO *]";
		}

		return field + ":[* TO *]";
	}

	@Override
	public String toString() {
		final StringBuffer sb = new StringBuffer();
		sb.append(getClass().getSimpleName());
		sb.append(" [field='").append(field).append('\'');
		sb.append(", mustBeNull=").append(mustBeNull);
		sb.append(']');
		return sb.toString();
	}
}

FieldQLToken.java

/**
 * @author <a href="mailto:mpaluch@paluch.biz">Mark Paluch</a>
 * @since 07.11.13 12:36
 */
public interface FieldQLToken extends SolrQLToken {

}

NativeQLToken.java

/**
 * @author <a href="mailto:mpaluch@paluch.biz">Mark Paluch</a>
 * @since 07.11.13 12:53
 */
public class NativeQLToken implements SolrQLToken {

	private String ql;

	public NativeQLToken(String ql) {
		this.ql = ql;
	}

	@Override
	public String asQLString() {
		return ql;
	}

	@Override
	public String toString() {
		final StringBuffer sb = new StringBuffer();
		sb.append(getClass().getSimpleName());
		sb.append(" [ql='").append(ql).append('\'');
		sb.append(']');
		return sb.toString();
	}
}

OperatorToken.java

/**
 * @author <a href="mailto:mpaluch@paluch.biz">Mark Paluch</a>
 * @since 07.11.13 12:37
 */
public enum OperatorToken
		implements SolrQLToken {
	AND,
	OR;

	@Override
	public String asQLString() {
		return name();
	}
}

SolrQLToken.java

/**
 * @author <a href="mailto:mpaluch@paluch.biz">Mark Paluch</a>
 * @since 07.11.13 12:35
 */
public interface SolrQLToken
{
    String asQLString();
}

StackQLToken.java

import java.util.Stack;

/**
 * @author <a href="mailto:mpaluch@paluch.biz">Mark Paluch</a>
 * @since 07.11.13 12:43
 */
public class StackQLToken implements SolrQLToken {

	private Stack<? extends SolrQLToken> stack;

	public StackQLToken(Stack<? extends SolrQLToken> stack) {
		this.stack = stack;
	}

	@Override
	public String asQLString() {
		StringBuilder builder = new StringBuilder();

		SolrQLToken prevToken = null;
		for (SolrQLToken qlToken : stack) {

			if (prevToken != null) {
				if (qlToken == prevToken || qlToken.getClass().equals(prevToken.getClass())) {
					throw new IllegalStateException("Cannot create QL String because two same tokens follow each other: " + prevToken
							+ " and " + qlToken + " (Query: " + this + ")");
				}
			}

			if (builder.length() != 0) {
				builder.append(' ');
			}

			if (qlToken instanceof StackQLToken) {

				StackQLToken stack = (StackQLToken) qlToken;
				if (!stack.stack.empty()) {

					if (stack.stack.size() == 1) {
						builder.append(qlToken.asQLString());
					} else {
						builder.append('(').append(qlToken.asQLString()).append(')');
					}

				}
			} else {
				builder.append(qlToken.asQLString());
			}

			prevToken = qlToken;
		}
		return builder.toString();
	}

	@Override
	public String toString() {
		final StringBuffer sb = new StringBuffer();
		sb.append(getClass().getSimpleName());
		sb.append(" [stack=").append(stack);
		sb.append(']');
		return sb.toString();
	}
}

Usage.java

Stack<SolrQLToken> stack = new Stack<>();

for (Repository repo: query.getRepositories()) {

	Stack<SolrQLToken> repoPredicateStack = new Stack<>();

	repoPredicateStack.push(new FieldComparisonQLToken("ObjectStore", repo.getObjectStoreName()));
	repoPredicateStack.push(OperatorToken.AND);

	
	if (queryRepo.isIncludeSubClasses()) {
		repoPredicateStack.push(new FieldComparisonQLToken("Path", repo.getDocumentClassName()));
	} else {
		repoPredicateStack.push(new FieldComparisonQLToken("Class", repo.getDocumentClassName()));
	}

	ClassDefinition classDefinition = classDefinitionProvider.get(repo.getObjectStoreName(), repo.getDocumentClassName());

	Stack<SolrQLToken> nested = getSearchFieldsStatement(classDefinition, query.getFields());

	if (!nested.isEmpty()) {
		if (!repoPredicateStack.empty()) {
			repoPredicateStack.push(OperatorToken.AND);
		}
		repoPredicateStack.addAll(nested);
	}

	if (!repoPredicateStack.empty()) {
		if (!stack.empty()) {
			stack.push(OperatorToken.OR);
		}
		stack.push(new StackQLToken(repoPredicateStack));
	}
}

if(!stack.empty()) {
	queries.add(new StackQLToken(stack).asQLString());
}