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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
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package org.apache.cayenne.validation;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;

import org.apache.cayenne.util.Util;

/**
 * Represents a result of a validation execution. Contains a set of
 * {@link ValidationFailure ValidationFailures}that occured in a given context. All
 * failures are kept in the same order they were added.
 * 
 * @author Fabricio Voznika
 * @since 1.1
 */
public class ValidationResult implements Serializable {

    private List failures;

    public ValidationResult() {
        failures = new ArrayList();
    }

    /**
     * Add a failure to the validation result.
     * 
     * @param failure failure to be added. It may not be null.
     * @see ValidationFailure
     */
    public void addFailure(ValidationFailure failure) {
        if (failure == null) {
            throw new IllegalArgumentException("failure cannot be null.");
        }

        failures.add(failure);
    }

    /**
     * Returns all failures added to this result, or empty list is result has no failures.
     */
    public List getFailures() {
        return Collections.unmodifiableList(failures);
    }

    /**
     * Returns all failures related to the <code>source</code> object, or an empty list
     * if there are no such failures.
     * 
     * @param source it may be null.
     * @see ValidationFailure#getSource()
     */
    public List getFailures(Object source) {

        ArrayList matchingFailures = new ArrayList(5);
        Iterator it = failures.iterator();
        while (it.hasNext()) {
            ValidationFailure failure = (ValidationFailure) it.next();
            if (Util.nullSafeEquals(source, failure.getSource())) {
                matchingFailures.add(failure);
            }
        }

        return matchingFailures;
    }

    /**
     * Returns true if at least one failure has been added to this result. False
     * otherwise.
     */
    public boolean hasFailures() {
        return !failures.isEmpty();
    }

    /**
     * @param source it may be null.
     * @return true if there is at least one failure for <code>source</code>. False
     *         otherwise.
     */
    public boolean hasFailures(Object source) {
        Iterator it = failures.iterator();
        while (it.hasNext()) {
            ValidationFailure failure = (ValidationFailure) it.next();
            if (Util.nullSafeEquals(source, failure.getSource())) {
                return true;
            }
        }

        return false;
    }

    public String toString() {
        StringBuffer ret = new StringBuffer();
        String separator = System.getProperty("line.separator");

        Iterator it = getFailures().iterator();
        while (it.hasNext()) {
            if (ret.length() > 0) {
                ret.append(separator);
            }

            ret.append(it.next());
        }

        return ret.toString();
    }
}
