closureutils.java

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     * 
     * @see org.apache.commons.collections.functors.ChainedClosure
     * 
     * @param closure1  the first closure
     * @param closure2  the second closure
     * @return the <code>chained</code> closure
     * @throws IllegalArgumentException if either closure is null
     */
    public static Closure chainedClosure(Closure closure1, Closure closure2) {
        return ChainedClosure.getInstance(closure1, closure2);
    }

    /**
     * Create a new Closure that calls each closure in turn, passing the 
     * result into the next closure.
     * 
     * @see org.apache.commons.collections.functors.ChainedClosure
     * 
     * @param closures  an array of closures to chain
     * @return the <code>chained</code> closure
     * @throws IllegalArgumentException if the closures array is null
     * @throws IllegalArgumentException if any closure in the array is null
     */
    public static Closure chainedClosure(Closure[] closures) {
        return ChainedClosure.getInstance(closures);
    }

    /**
     * Create a new Closure that calls each closure in turn, passing the 
     * result into the next closure. The ordering is that of the iterator()
     * method on the collection.
     * 
     * @see org.apache.commons.collections.functors.ChainedClosure
     * 
     * @param closures  a collection of closures to chain
     * @return the <code>chained</code> closure
     * @throws IllegalArgumentException if the closures collection is null
     * @throws IllegalArgumentException if the closures collection is empty
     * @throws IllegalArgumentException if any closure in the collection is null
     */
    public static Closure chainedClosure(Collection closures) {
        return ChainedClosure.getInstance(closures);
    }

    /**
     * Create a new Closure that calls another closure based on the
     * result of the specified predicate.
     * 
     * @see org.apache.commons.collections.functors.IfClosure
     * 
     * @param predicate  the validating predicate
     * @param trueClosure  the closure called if the predicate is true
     * @return the <code>if</code> closure
     * @throws IllegalArgumentException if the predicate is null
     * @throws IllegalArgumentException if the closure is null
     * @since Commons Collections 3.2
     */
    public static Closure ifClosure(Predicate predicate, Closure trueClosure) {
        return IfClosure.getInstance(predicate, trueClosure);
    }

    /**
     * Create a new Closure that calls one of two closures depending 
     * on the specified predicate.
     * 
     * @see org.apache.commons.collections.functors.IfClosure
     * 
     * @param predicate  the predicate to switch on
     * @param trueClosure  the closure called if the predicate is true
     * @param falseClosure  the closure called if the predicate is false
     * @return the <code>switch</code> closure
     * @throws IllegalArgumentException if the predicate is null
     * @throws IllegalArgumentException if either closure is null
     */
    public static Closure ifClosure(Predicate predicate, Closure trueClosure, Closure falseClosure) {
        return IfClosure.getInstance(predicate, trueClosure, falseClosure);
    }

    /**
     * Create a new Closure that calls one of the closures depending 
     * on the predicates.
     * <p>
     * The closure at array location 0 is called if the predicate at array 
     * location 0 returned true. Each predicate is evaluated
     * until one returns true.
     * 
     * @see org.apache.commons.collections.functors.SwitchClosure
     * 
     * @param predicates  an array of predicates to check, not null
     * @param closures  an array of closures to call, not null
     * @return the <code>switch</code> closure
     * @throws IllegalArgumentException if the either array is null
     * @throws IllegalArgumentException if any element in the arrays is null
     * @throws IllegalArgumentException if the arrays are different sizes
     */
    public static Closure switchClosure(Predicate[] predicates, Closure[] closures) {
        return SwitchClosure.getInstance(predicates, closures, null);
    }

    /**
     * Create a new Closure that calls one of the closures depending 
     * on the predicates.
     * <p>
     * The closure at array location 0 is called if the predicate at array
     * location 0 returned true. Each predicate is evaluated
     * until one returns true. If no predicates evaluate to true, the default
     * closure is called.
     * 
     * @see org.apache.commons.collections.functors.SwitchClosure
     * 
     * @param predicates  an array of predicates to check, not null
     * @param closures  an array of closures to call, not null
     * @param defaultClosure  the default to call if no predicate matches
     * @return the <code>switch</code> closure
     * @throws IllegalArgumentException if the either array is null
     * @throws IllegalArgumentException if any element in the arrays is null
     * @throws IllegalArgumentException if the arrays are different sizes
     */
    public static Closure switchClosure(Predicate[] predicates, Closure[] closures, Closure defaultClosure) {
        return SwitchClosure.getInstance(predicates, closures, defaultClosure);
    }
    
    /**
     * Create a new Closure that calls one of the closures depending 
     * on the predicates. 
     * <p>
     * The Map consists of Predicate keys and Closure values. A closure 
     * is called if its matching predicate returns true. Each predicate is evaluated
     * until one returns true. If no predicates evaluate to true, the default
     * closure is called. The default closure is set in the map with a 
     * null key. The ordering is that of the iterator() method on the entryset 
     * collection of the map.
     * 
     * @see org.apache.commons.collections.functors.SwitchClosure
     * 
     * @param predicatesAndClosures  a map of predicates to closures
     * @return the <code>switch</code> closure
     * @throws IllegalArgumentException if the map is null
     * @throws IllegalArgumentException if the map is empty
     * @throws IllegalArgumentException if any closure in the map is null
     * @throws ClassCastException  if the map elements are of the wrong type
     */
    public static Closure switchClosure(Map predicatesAndClosures) {
        return SwitchClosure.getInstance(predicatesAndClosures);
    }

    /**
     * Create a new Closure that uses the input object as a key to find the
     * closure to call. 
     * <p>
     * The Map consists of object keys and Closure values. A closure 
     * is called if the input object equals the key. If there is no match, the
     * default closure is called. The default closure is set in the map
     * using a null key.
     * 
     * @see org.apache.commons.collections.functors.SwitchClosure
     * 
     * @param objectsAndClosures  a map of objects to closures
     * @return the closure
     * @throws IllegalArgumentException if the map is null
     * @throws IllegalArgumentException if the map is empty
     * @throws IllegalArgumentException if any closure in the map is null
     */
    public static Closure switchMapClosure(Map objectsAndClosures) {
        Closure[] trs = null;
        Predicate[] preds = null;
        if (objectsAndClosures == null) {
            throw new IllegalArgumentException("The object and closure map must not be null");
        }
        Closure def = (Closure) objectsAndClosures.remove(null);
        int size = objectsAndClosures.size();
        trs = new Closure[size];
        preds = new Predicate[size];
        int i = 0;
        for (Iterator it = objectsAndClosures.entrySet().iterator(); it.hasNext();) {
            Map.Entry entry = (Map.Entry) it.next();
            preds[i] = EqualPredicate.getInstance(entry.getKey());
            trs[i] = (Closure) entry.getValue();
            i++;
        }
        return switchClosure(preds, trs, def);
    }

}