From f911ba985aa7fe0096c386c5be385ac5825ea527 Mon Sep 17 00:00:00 2001
From: Tom Tromey <tromey@gcc.gnu.org>
Date: Sat, 16 Jul 2005 00:30:23 +0000
Subject: Initial revision
From-SVN: r102074
---
libjava/classpath/java/util/Map.java | 338 +++++++++++++++++++++++++++++++++++
1 file changed, 338 insertions(+)
create mode 100644 libjava/classpath/java/util/Map.java
(limited to 'libjava/classpath/java/util/Map.java')
diff --git a/libjava/classpath/java/util/Map.java b/libjava/classpath/java/util/Map.java
new file mode 100644
index 0000000..256e988
--- /dev/null
+++ b/libjava/classpath/java/util/Map.java
@@ -0,0 +1,338 @@
+/* Map.java: interface Map -- An object that maps keys to values
+ interface Map.Entry -- an Entry in a Map
+ Copyright (C) 1998, 2001, 2004, 2005 Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING. If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library. Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module. An independent module is a module which is not derived from
+or based on this library. If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so. If you do not wish to do so, delete this
+exception statement from your version. */
+
+
+package java.util;
+
+/**
+ * An object that maps keys onto values. Keys cannot be duplicated. This
+ * interface replaces the obsolete {@link Dictionary} abstract class.
+ * <p>
+ *
+ * The map has three collection views, which are backed by the map
+ * (modifications on one show up on the other): a set of keys, a collection
+ * of values, and a set of key-value mappings. Some maps have a guaranteed
+ * order, but not all do.
+ * <p>
+ *
+ * Note: Be careful about using mutable keys. Behavior is unspecified if
+ * a key's comparison behavior is changed after the fact. As a corollary
+ * to this rule, don't use a Map as one of its own keys or values, as it makes
+ * hashCode and equals have undefined behavior.
+ * <p>
+ *
+ * All maps are recommended to provide a no argument constructor, which builds
+ * an empty map, and one that accepts a Map parameter and copies the mappings
+ * (usually by putAll), to create an equivalent map. Unfortunately, Java
+ * cannot enforce these suggestions.
+ * <p>
+ *
+ * The map may be unmodifiable, in which case unsupported operations will
+ * throw an UnsupportedOperationException. Note that some operations may be
+ * safe, such as putAll(m) where m is empty, even if the operation would
+ * normally fail with a non-empty argument.
+ *
+ * @author Original author unknown
+ * @author Eric Blake (ebb9@email.byu.edu)
+ * @see HashMap
+ * @see TreeMap
+ * @see Hashtable
+ * @see SortedMap
+ * @see Collection
+ * @see Set
+ * @since 1.2
+ * @status updated to 1.4
+ */
+public interface Map
+{
+ /**
+ * Remove all entries from this Map (optional operation).
+ *
+ * @throws UnsupportedOperationException if clear is not supported
+ */
+ void clear();
+
+ /**
+ * Returns true if this contains a mapping for the given key.
+ *
+ * @param key the key to search for
+ * @return true if the map contains the key
+ * @throws ClassCastException if the key is of an inappropriate type
+ * @throws NullPointerException if key is <code>null</code> but the map
+ * does not permit null keys
+ */
+ boolean containsKey(Object key);
+
+ /**
+ * Returns true if this contains at least one mapping with the given value.
+ * In other words, returns true if a value v exists where
+ * <code>(value == null ? v == null : value.equals(v))</code>. This usually
+ * requires linear time.
+ *
+ * @param value the value to search for
+ * @return true if the map contains the value
+ * @throws ClassCastException if the type of the value is not a valid type
+ * for this map.
+ * @throws NullPointerException if the value is null and the map doesn't
+ * support null values.
+ */
+ boolean containsValue(Object value);
+
+ /**
+ * Returns a set view of the mappings in this Map. Each element in the
+ * set is a Map.Entry. The set is backed by the map, so that changes in
+ * one show up in the other. Modifications made while an iterator is
+ * in progress cause undefined behavior. If the set supports removal,
+ * these methods remove the underlying mapping from the map:
+ * <code>Iterator.remove</code>, <code>Set.remove</code>,
+ * <code>removeAll</code>, <code>retainAll</code>, and <code>clear</code>.
+ * Element addition, via <code>add</code> or <code>addAll</code>, is
+ * not supported via this set.
+ *
+ * @return the set view of all mapping entries
+ * @see Map.Entry
+ */
+ Set entrySet();
+
+ /**
+ * Compares the specified object with this map for equality. Returns
+ * <code>true</code> if the other object is a Map with the same mappings,
+ * that is,<br>
+ * <code>o instanceof Map && entrySet().equals(((Map) o).entrySet();</code>
+ * This allows comparison of maps, regardless of implementation.
+ *
+ * @param o the object to be compared
+ * @return true if the object equals this map
+ * @see Set#equals(Object)
+ */
+ boolean equals(Object o);
+
+ /**
+ * Returns the value mapped by the given key. Returns <code>null</code> if
+ * there is no mapping. However, in Maps that accept null values, you
+ * must rely on <code>containsKey</code> to determine if a mapping exists.
+ *
+ * @param key the key to look up
+ * @return the value associated with the key, or null if key not in map
+ * @throws ClassCastException if the key is an inappropriate type
+ * @throws NullPointerException if this map does not accept null keys
+ * @see #containsKey(Object)
+ */
+ Object get(Object key);
+
+ /**
+ * Associates the given key to the given value (optional operation). If the
+ * map already contains the key, its value is replaced. Be aware that in
+ * a map that permits <code>null</code> values, a null return does not
+ * always imply that the mapping was created.
+ *
+ * @param key the key to map
+ * @param value the value to be mapped
+ * @return the previous value of the key, or null if there was no mapping
+ * @throws UnsupportedOperationException if the operation is not supported
+ * @throws ClassCastException if the key or value is of the wrong type
+ * @throws IllegalArgumentException if something about this key or value
+ * prevents it from existing in this map
+ * @throws NullPointerException if either the key or the value is null,
+ * and the map forbids null keys or values
+ * @see #containsKey(Object)
+ */
+ Object put(Object key, Object value);
+
+ /**
+ * Returns the hash code for this map. This is the sum of all hashcodes
+ * for each Map.Entry object in entrySet. This allows comparison of maps,
+ * regardless of implementation, and satisfies the contract of
+ * Object.hashCode.
+ *
+ * @return the hash code
+ * @see Map.Entry#hashCode()
+ */
+ int hashCode();
+
+ /**
+ * Returns true if the map contains no mappings.
+ *
+ * @return true if the map is empty
+ */
+ boolean isEmpty();
+
+ /**
+ * Returns a set view of the keys in this Map. The set is backed by the
+ * map, so that changes in one show up in the other. Modifications made
+ * while an iterator is in progress cause undefined behavior. If the set
+ * supports removal, these methods remove the underlying mapping from
+ * the map: <code>Iterator.remove</code>, <code>Set.remove</code>,
+ * <code>removeAll</code>, <code>retainAll</code>, and <code>clear</code>.
+ * Element addition, via <code>add</code> or <code>addAll</code>, is
+ * not supported via this set.
+ *
+ * @return the set view of all keys
+ */
+ Set keySet();
+
+ /**
+ * Copies all entries of the given map to this one (optional operation). If
+ * the map already contains a key, its value is replaced.
+ *
+ * @param m the mapping to load into this map
+ * @throws UnsupportedOperationException if the operation is not supported
+ * @throws ClassCastException if a key or value is of the wrong type
+ * @throws IllegalArgumentException if something about a key or value
+ * prevents it from existing in this map
+ * @throws NullPointerException if the map forbids null keys or values, or
+ * if <code>m</code> is null.
+ * @see #put(Object, Object)
+ */
+ void putAll(Map m);
+
+ /**
+ * Removes the mapping for this key if present (optional operation). If
+ * the key is not present, this returns null. Note that maps which permit
+ * null values may also return null if the key was removed.
+ *
+ * @param key the key to remove
+ * @return the value the key mapped to, or null if not present.
+ * @throws UnsupportedOperationException if deletion is unsupported
+ * @throws NullPointerException if the key is null and this map doesn't
+ * support null keys.
+ * @throws ClassCastException if the type of the key is not a valid type
+ * for this map.
+ */
+ Object remove(Object key);
+
+ /**
+ * Returns the number of key-value mappings in the map. If there are more
+ * than Integer.MAX_VALUE mappings, return Integer.MAX_VALUE.
+ *
+ * @return the number of mappings
+ */
+ int size();
+
+ /**
+ * Returns a collection (or bag) view of the values in this Map. The
+ * collection is backed by the map, so that changes in one show up in
+ * the other. Modifications made while an iterator is in progress cause
+ * undefined behavior. If the collection supports removal, these methods
+ * remove the underlying mapping from the map: <code>Iterator.remove</code>,
+ * <code>Collection.remove</code>, <code>removeAll</code>,
+ * <code>retainAll</code>, and <code>clear</code>. Element addition, via
+ * <code>add</code> or <code>addAll</code>, is not supported via this
+ * collection.
+ *
+ * @return the collection view of all values
+ */
+ Collection values();
+
+ /**
+ * A map entry (key-value pair). The Map.entrySet() method returns a set
+ * view of these objects; there is no other valid way to come across them.
+ * These objects are only valid for the duration of an iteration; in other
+ * words, if you mess with one after modifying the map, you are asking
+ * for undefined behavior.
+ *
+ * @author Original author unknown
+ * @author Eric Blake (ebb9@email.byu.edu)
+ * @see Map
+ * @see Map#entrySet()
+ * @since 1.2
+ * @status updated to 1.4
+ */
+ interface Entry
+ {
+ /**
+ * Get the key corresponding to this entry.
+ *
+ * @return the key
+ */
+ Object getKey();
+
+ /**
+ * Get the value corresponding to this entry. If you already called
+ * Iterator.remove(), this is undefined.
+ *
+ * @return the value
+ */
+ Object getValue();
+
+ /**
+ * Replaces the value with the specified object (optional operation).
+ * This writes through to the map, and is undefined if you already
+ * called Iterator.remove().
+ *
+ * @param value the new value to store
+ * @return the old value
+ * @throws UnsupportedOperationException if the operation is not supported
+ * @throws ClassCastException if the value is of the wrong type
+ * @throws IllegalArgumentException if something about the value
+ * prevents it from existing in this map
+ * @throws NullPointerException if the map forbids null values
+ */
+ Object setValue(Object value);
+
+
+ /**
+ * Returns the hash code of the entry. This is defined as the
+ * exclusive-or of the hashcodes of the key and value (using 0 for
+ * <code>null</code>). In other words, this must be:
+ *
+<p><pre>(getKey() == null ? 0 : getKey().hashCode())
+^ (getValue() == null ? 0 : getValue().hashCode())</pre>
+ *
+ * @return the hash code
+ */
+ int hashCode();
+
+ /**
+ * Compares the specified object with this entry. Returns true only if
+ * the object is a mapping of identical key and value. In other words,
+ * this must be:
+ *
+<p><pre>(o instanceof Map.Entry)
+&& (getKey() == null ? ((HashMap) o).getKey() == null
+ : getKey().equals(((HashMap) o).getKey()))
+&& (getValue() == null ? ((HashMap) o).getValue() == null
+ : getValue().equals(((HashMap) o).getValue()))</pre>
+ *
+ * @param o the object to compare
+ *
+ * @return <code>true</code> if it is equal
+ */
+ boolean equals(Object o);
+ }
+}
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