001    /*
002     * Created on Sep 17, 2007
003     *
004     * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
005     * in compliance with the License. You may obtain a copy of the License at
006     *
007     * http://www.apache.org/licenses/LICENSE-2.0
008     *
009     * Unless required by applicable law or agreed to in writing, software distributed under the License
010     * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
011     * or implied. See the License for the specific language governing permissions and limitations under
012     * the License.
013     *
014     * Copyright @2007-2011 the original author or authors.
015     */
016    package org.fest.assertions;
017    
018    import static org.fest.util.Strings.isEmpty;
019    
020    /**
021     * Condition to be met by an <code>{@link Object}</code>.
022     * @param <T> the type of {@code Object} this condition accepts.
023     *
024     * @author Yvonne Wang
025     * @author Alex Ruiz
026     */
027    public abstract class Condition<T> {
028    
029      private String description;
030    
031      /**
032       * Creates a new <code>{@link Condition}</code>.
033       */
034      public Condition() {}
035    
036      /**
037       * Creates a new <code>{@link Condition}</code>.
038       * @param description the description of this condition.
039       */
040      public Condition(String description) {
041        as(description);
042      }
043    
044      /**
045       * Sets the description of this condition.
046       * @param newDescription the description to set.
047       * @return this condition.
048       */
049      public final Condition<T> as(String newDescription) {
050        description = newDescription;
051        return this;
052      }
053    
054      final String addDescriptionTo(String s) {
055        String descriptionToAdd = description();
056        if (isEmpty(descriptionToAdd)) descriptionToAdd = getClass().getSimpleName();
057        return String.format("%s:<%s>", s, descriptionToAdd);
058      }
059    
060      /**
061       * Returns the description of this condition, if any.
062       * @return the description of this condition.
063       */
064      public final String description() { return description; }
065    
066      /**
067       * Verifies that the given value satisfies this condition.
068       * @param value the value to verify.
069       * @return {@code true} if the given value satisfies this condition, {@code false} otherwise.
070       */
071      public abstract boolean matches(T value);
072    }