src/main/java/org/codehaus/groovy/runtime/DefaultGroovyMethodsSupport.java

/*
 *  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.codehaus.groovy.runtime;

import groovy.lang.EmptyRange;
import groovy.lang.IntRange;
import groovy.lang.Range;
import org.codehaus.groovy.runtime.typehandling.DefaultTypeTransformation;

import java.io.Closeable;
import java.io.IOException;
import java.io.OutputStream;
import java.io.Writer;
import java.lang.reflect.Array;
import java.nio.charset.Charset;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Comparator;
import java.util.Hashtable;
import java.util.IdentityHashMap;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.PriorityQueue;
import java.util.Properties;
import java.util.Queue;
import java.util.Set;
import java.util.SortedMap;
import java.util.SortedSet;
import java.util.Stack;
import java.util.TreeMap;
import java.util.TreeSet;
import java.util.Vector;
import java.util.WeakHashMap;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.ConcurrentSkipListMap;
import java.util.concurrent.ConcurrentSkipListSet;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.CopyOnWriteArraySet;
import java.util.concurrent.DelayQueue;
import java.util.concurrent.LinkedBlockingDeque;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.PriorityBlockingQueue;
import java.util.concurrent.SynchronousQueue;
import java.util.logging.Logger;

/**
 * Support methods for DefaultGroovyMethods and PluginDefaultMethods.
 */
public class DefaultGroovyMethodsSupport {

    private static final Logger LOG = Logger.getLogger(DefaultGroovyMethodsSupport.class.getName());
    private static final Object[] EMPTY_OBJECT_ARRAY = new Object[0];

    // helper method for getAt and putAt
    protected static RangeInfo subListBorders(int size, Range range) {
        if (range instanceof IntRange) {
            return ((IntRange)range).subListBorders(size);
        }
        int from = normaliseIndex(DefaultTypeTransformation.intUnbox(range.getFrom()), size);
        int to = normaliseIndex(DefaultTypeTransformation.intUnbox(range.getTo()), size);
        boolean reverse = range.isReverse();
        if (from > to) {
            // support list[1..-1]
            int tmp = to;
            to = from;
            from = tmp;
            reverse = !reverse;
        }
        return new RangeInfo(from, to + 1, reverse);
    }

    // helper method for getAt and putAt
    protected static RangeInfo subListBorders(int size, EmptyRange range) {
        int from = normaliseIndex(DefaultTypeTransformation.intUnbox(range.getFrom()), size);
        return new RangeInfo(from, from, false);
    }

    /**
     * This converts a possibly negative index to a real index into the array.
     *
     * @param i    the unnormalized index
     * @param size the array size
     * @return the normalised index
     */
    protected static int normaliseIndex(int i, int size) {
        int temp = i;
        if (i < 0) {
            i += size;
        }
        if (i < 0) {
            throw new ArrayIndexOutOfBoundsException("Negative array index [" + temp + "] too large for array size " + size);
        }
        return i;
    }

    /**
     * Close the Closeable. Logging a warning if any problems occur.
     *
     * @param closeable the thing to close
     */
    public static void closeWithWarning(Closeable closeable) {
        tryClose(closeable, true); // ignore result
    }

    /**
     * Attempts to close the closeable returning rather than throwing
     * any Exception that may occur.
     *
     * @param closeable the thing to close
     * @param logWarning if true will log a warning if an exception occurs
     * @return throwable Exception from the close method, else null
     */
    static Throwable tryClose(AutoCloseable closeable, boolean logWarning) {
        Throwable thrown = null;
        if (closeable != null) {
            try {
                closeable.close();
            } catch (Exception e) {
                thrown = e;
                if (logWarning) {
                    LOG.warning("Caught exception during close(): " + e);
                }
            }
        }
        return thrown;
    }

    /**
     * Close the Closeable. Ignore any problems that might occur.
     *
     * @param c the thing to close
     */
    public static void closeQuietly(Closeable c) {
        if (c != null) {
            try {
                c.close();
            } catch (IOException e) {
                /* ignore */
            }
        }
    }

    @SuppressWarnings("unchecked")
    protected static <T> Collection<T> cloneSimilarCollection(Collection<T> orig, int newCapacity) {
        Collection<T> answer = (Collection<T>) cloneObject(orig);
        if (answer != null) return answer;

        // fall back to creation
        answer = createSimilarCollection(orig, newCapacity);
        answer.addAll(orig);
        return answer;
    }

    private static Object cloneObject(Object orig) {
        if (orig instanceof Cloneable) {
            try {
                return InvokerHelper.invokeMethod(orig, "clone", EMPTY_OBJECT_ARRAY);
            } catch (Exception ex) {
                // ignore
            }
        }
        return null;
    }

    protected static Collection createSimilarOrDefaultCollection(Object object) {
        if (object instanceof Collection) {
            return createSimilarCollection((Collection<?>) object);
        }
        return new ArrayList();
    }

    protected static <T> Collection<T> createSimilarCollection(Iterable<T> iterable) {
        if (iterable instanceof Collection) {
            return createSimilarCollection((Collection<T>) iterable);
        } else {
            return new ArrayList<T>();
        }
    }

    protected static <T> Collection<T> createSimilarCollection(Collection<T> collection) {
        return createSimilarCollection(collection, collection.size());
    }

    protected static <T> Collection<T> createSimilarCollection(Collection<T> orig, int newCapacity) {
        if (orig instanceof Set) {
            return createSimilarSet((Set<T>) orig);
        }
        if (orig instanceof List) {
            return createSimilarList((List<T>) orig, newCapacity);
        }
        if (orig instanceof Queue) {
            return createSimilarQueue((Queue<T>) orig);
        }
        return new ArrayList<T>(newCapacity);
    }

    protected static <T> List<T> createSimilarList(List<T> orig, int newCapacity) {
        if (orig instanceof LinkedList)
            return new LinkedList<T>();

        if (orig instanceof Stack)
            return new Stack<T>();

        if (orig instanceof Vector)
            return new Vector<T>();

        if (orig instanceof CopyOnWriteArrayList)
            return new CopyOnWriteArrayList<T>();

        return new ArrayList<T>(newCapacity);
    }

    @SuppressWarnings("unchecked")
    protected static <T> T[] createSimilarArray(T[] orig, int newCapacity) {
        Class<T> componentType = (Class<T>) orig.getClass().getComponentType();
        return (T[]) Array.newInstance(componentType, newCapacity);
    }

    @SuppressWarnings("unchecked")
    protected static <T> Set<T> createSimilarSet(Set<T> orig) {
        if (orig instanceof SortedSet) {
            Comparator comparator = ((SortedSet) orig).comparator();
            if (orig instanceof ConcurrentSkipListSet) {
                return new ConcurrentSkipListSet<T>(comparator);
            } else {
                return new TreeSet<T>(comparator);
            }
        } else {
            if (orig instanceof CopyOnWriteArraySet) {
                return new CopyOnWriteArraySet<T>();
            } else {
                // Do not use HashSet
                return new LinkedHashSet<T>();
            }
        }
    }

    @SuppressWarnings("unchecked")
    protected static <T> Queue<T> createSimilarQueue(Queue<T> orig) {
        if (orig instanceof ArrayBlockingQueue) {
            ArrayBlockingQueue queue = (ArrayBlockingQueue) orig;
            return new ArrayBlockingQueue<T>(queue.size() + queue.remainingCapacity());
        } else if (orig instanceof ArrayDeque) {
            return new ArrayDeque<T>();
        } else if (orig instanceof ConcurrentLinkedQueue) {
            return new ConcurrentLinkedQueue<T>();
        } else if (orig instanceof DelayQueue) {
            return new DelayQueue();
        } else if (orig instanceof LinkedBlockingDeque) {
            return new LinkedBlockingDeque<T>();
        } else if (orig instanceof LinkedBlockingQueue) {
            return new LinkedBlockingQueue<T>();
        } else if (orig instanceof PriorityBlockingQueue) {
            return new PriorityBlockingQueue<T>();
        } else if (orig instanceof PriorityQueue) {
            return new PriorityQueue<T>(11, ((PriorityQueue) orig).comparator());
        } else if (orig instanceof SynchronousQueue) {
            return new SynchronousQueue<T>();
        } else {
            return new LinkedList<T>();
        }
    }

    @SuppressWarnings("unchecked")
    protected static <K, V> Map<K, V> createSimilarMap(Map<K, V> orig) {
        if (orig instanceof SortedMap) {
            Comparator comparator = ((SortedMap) orig).comparator();
            if (orig instanceof ConcurrentSkipListMap) {
                return new ConcurrentSkipListMap<K, V>(comparator);
            } else {
                return new TreeMap<K, V>(comparator);
            }
        } else {
            if (orig instanceof ConcurrentHashMap) {
                return new ConcurrentHashMap<K, V>();
            } else if (orig instanceof Hashtable) {
                if (orig instanceof Properties) {
                    return (Map<K, V>) new Properties();
                } else {
                    return new Hashtable<K, V>();
                }
            } else if (orig instanceof IdentityHashMap) {
                return new IdentityHashMap<K, V>();
            } else if (orig instanceof WeakHashMap) {
                return new WeakHashMap<K, V>();
            } else {
                // Do not use HashMap
                return new LinkedHashMap<K, V>();
            }
        }
    }

    @SuppressWarnings("unchecked")
    protected static <K, V> Map<K ,V> cloneSimilarMap(Map<K, V> orig) {
        Map<K, V> answer = (Map<K, V>) cloneObject(orig);
        if (answer != null) return answer;

        // fall back to some defaults
        if (orig instanceof SortedMap) {
            if (orig instanceof ConcurrentSkipListMap) {
                return new ConcurrentSkipListMap<K, V>(orig);
            } else {
                return new TreeMap<K, V>(orig);
            }
        } else {
            if (orig instanceof ConcurrentHashMap) {
                return new ConcurrentHashMap<K, V>(orig);
            } else if (orig instanceof Hashtable) {
                if (orig instanceof Properties) {
                    Map<K, V> map = (Map<K, V>) new Properties();
                    map.putAll(orig);
                    return map;
                } else {
                    return new Hashtable<K, V>(orig);
                }
            } else if (orig instanceof IdentityHashMap) {
                return new IdentityHashMap<K, V>(orig);
            } else if (orig instanceof WeakHashMap) {
                return new WeakHashMap<K, V>(orig);
            } else {
                // Do not use HashMap
                return new LinkedHashMap<K, V>(orig);
            }
        }
    }

    /**
     * Determines if all items of this array are of the same type.
     *
     * @param cols an array of collections
     * @return true if the collections are all of the same type
     */
    @SuppressWarnings("unchecked")
    protected static boolean sameType(Collection[] cols) {
        List all = new LinkedList();
        for (Collection col : cols) {
            all.addAll(col);
        }
        if (all.isEmpty())
            return true;

        Object first = all.get(0);

        //trying to determine the base class of the collections
        //special case for Numbers
        Class baseClass;
        if (first instanceof Number) {
            baseClass = Number.class;
        } else if (first == null) {
            baseClass = NullObject.class;
        } else {
            baseClass = first.getClass();
        }

        for (Collection col : cols) {
            for (Object o : col) {
                if (!baseClass.isInstance(o)) {
                    return false;
                }
            }
        }
        return true;
    }

    protected static void writeUTF16BomIfRequired(final Writer writer, final String charset) throws IOException {
        writeUTF16BomIfRequired(writer, Charset.forName(charset));
    }

    protected static void writeUTF16BomIfRequired(final Writer writer, final Charset charset) throws IOException {
        if ("UTF-16BE".equals(charset.name())) {
            writeUtf16Bom(writer, true);
        } else if ("UTF-16LE".equals(charset.name())) {
            writeUtf16Bom(writer, false);
        }
    }

    protected static void writeUTF16BomIfRequired(final OutputStream stream, final String charset) throws IOException {
        writeUTF16BomIfRequired(stream, Charset.forName(charset));
    }

    protected static void writeUTF16BomIfRequired(final OutputStream stream, final Charset charset) throws IOException {
        if ("UTF-16BE".equals(charset.name())) {
            writeUtf16Bom(stream, true);
        } else if ("UTF-16LE".equals(charset.name())) {
            writeUtf16Bom(stream, false);
        }
    }

    private static void writeUtf16Bom(OutputStream stream, boolean bigEndian) throws IOException {
        if (bigEndian) {
            stream.write(-2);  // FE
            stream.write(-1);  // FF
        } else {
            stream.write(-1);  // FF
            stream.write(-2);  // FE
        }
    }

    private static void writeUtf16Bom(Writer writer, boolean bigEndian) throws IOException {
        if (bigEndian) {
            writer.write(-2);  // FE
            writer.write(-1);  // FF
        } else {
            writer.write(-1);  // FF
            writer.write(-2);  // FE
        }
    }
}