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The file management component of a Catalog and Archive Service. This component purposefully separates data stores and metadata stores as standard interfaces, and provides some out of the box backend implementations of them (including one based on the javax.sql.DataSource interface). This component provides everything that you need to catalog, archive and manage files, and directories, and their associated metadata.

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.oodt.cas.filemgr.structs;

//JDK imports
import java.util.List;
import java.util.Vector;

//OODT imports
import org.apache.oodt.cas.filemgr.structs.exceptions.QueryFormulationException;

/**
 * @author woollard
 * @author bfoster
 * @version $Revision$
 * 
 * 
 * A Boolean Query Citeria that allows combination of a number of terms into a
 * query with a boolean operator (AND, OR, NOT). The NOT operator can only be
 * applied to one term.
 * 
 * 
 */

public class BooleanQueryCriteria extends QueryCriteria {

    /**
     * Constants
     */
    public static final int AND = 0;

    public static final int OR = 1;

    public static final int NOT = 2;

    private static final long serialVersionUID = 4718948237682772671L;

    private int operator;

    private List terms;

    /**
     * Default constructor. Uses the AND operator.
     */
    public BooleanQueryCriteria() {
        operator = AND;
        terms = new Vector();
    }

    /**
     * Boolean query constructor. This query is a boolean combination of term,
     * range, and other boolean queries. The supported operators are AND, OR and
     * NOT. Note that the NOT operator can only be used with one (1) term. This
     * method throws the QueryFormulationException if more than one term is used
     * with NOT.
     * 
     * @param terms
     *            The criteria onto which to apply the boolean operator
     * @param op
     *            The boolean operator to be applied
     */
    public BooleanQueryCriteria(List terms, int op)
            throws QueryFormulationException {
        operator = op;
        if (op == NOT && terms.size() > 1) {
            throw new QueryFormulationException(
                    "BooleanQueryCriteria: NOT operator "
                            + "cannot be applied to multiple terms");
        } else {
            this.terms = terms;
        }
    }

    /**
     * Method to add a term to the boolean query. Note that a NOT operator can
     * only be applied to one term. Method throws the QueryFormulationException
     * if this rule is violated.
     * 
     * @param t
     *            Term to be added to the query
     */
    public void addTerm(QueryCriteria t) throws QueryFormulationException {
        if (operator == NOT && !terms.isEmpty()) {
            throw new QueryFormulationException(
                    "BooleanQueryCriteria: NOT operator "
                            + "cannot be applied to multiple terms");
        } else {
            terms.add(t);
        }
    }

    /**
     * Accessor method for the list of terms in the query.
     * 
     * @return The list of terms
     */
    public List getTerms() {
        return terms;
    }

    /**
     * Mutator method for the boolean operator. Note that this method throws the
     * QueryFormulationException if the operator is set to NOT and multiple
     * terms are already defined.
     * 
     * @param op
     *            Boolean operator
     */
    public void setOperator(int op) throws QueryFormulationException {
        if (op == NOT && terms.size() > 1) {
            throw new QueryFormulationException(
                    "BooleanQueryCriteria: NOT operator "
                            + "cannot be applied to multiple terms");
        } else {
            operator = op;
        }
    }

    /**
     * Accessor method for the boolean operator.
     * 
     * @return the boolean operator
     */
    public int getOperator() {
        return operator;
    }

    /**
     * Method is not used in this class...
     */
    public String getElementName() {
        return null;
    }

    /**
     * Method is not used in this class...
     */
    public void setElementName(String elementName) {
    }

    /**
     * Method to convert the query to a string.
     * 
     * @return string equivement of the query
     */
    public String toString() {
        String query = new String();
        if (operator == AND)
            query += "AND(";
        else if (operator == OR)
            query += "OR(";
        else
            query += "NOT(";

        for (int i = 0; i < terms.size(); i++) {
            query += ((QueryCriteria) terms.get(i)).toString();
            if (i < (terms.size() - 1))
                query += ", ";
        }
        query += ")";
        return query;
    }
}