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Diffstat (limited to 'java/util/BasicMapEntry.java')
| -rw-r--r-- | java/util/BasicMapEntry.java | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/java/util/BasicMapEntry.java b/java/util/BasicMapEntry.java new file mode 100644 index 000000000..ea23cefed --- /dev/null +++ b/java/util/BasicMapEntry.java @@ -0,0 +1,128 @@ +///////////////////////////////////////////////////////////////////////////// +// BasicMapEntry.java -- a class providing a plain-vanilla implementation of +// the Map.Entry interface; could be used anywhere in +// java.util +// +// Copyright (c) 1998 by Jon A. Zeppieri (jon@eease.com) +// +// This program is free software; you can redistribute it and/or modify +// it under the terms of the GNU Library General Public License as published +// by the Free Software Foundation, version 2. (see COPYING.LIB) +// +// This program 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 Library General Public License for more details. +// +// You should have received a copy of the GNU Library General Public License +// along with this program; if not, write to the Free Software Foundation +// Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307 USA +///////////////////////////////////////////////////////////////////////////// + +package java.util; + +/** + * a class which implements Map.Entry + * + * @author Jon Zeppieri + * @version $Revision: 1.1 $ + * @modified $Id: BasicMapEntry.java,v 1.1 1998-10-13 00:38:31 jaz Exp $ + */ +class BasicMapEntry implements Map.Entry +{ + /** the key */ + Object key; + /** the value */ + Object value; + + /** + * construct a new BasicMapEntry with the given key and value + * + * @param newKey the key of this Entry + * @param newValue the value of this Entry + */ + BasicMapEntry(Object newKey, Object newValue) + { + key = newKey; + value = newValue; + } + + /** + * returns true if <pre>o</pre> is a Map.Entry and + * <pre> + * (((o.getKey == null) ? (key == null) : + * o.getKey().equals(key)) && + * ((o.getValue() == null) ? (value == null) : + * o.getValue().equals(value))) + * </pre> + * + * NOTE: the calls to getKey() and getValue() in this implementation + * are <i>NOT</i> superfluous and should not be removed. They insure + * that subclasses such as HashMapEntry work correctly + * + * @param o the Object being tested for equality + */ + public boolean equals(Object o) + { + Map.Entry tester; + Object oTestingKey, oTestingValue; + Object oKey, oValue; + if (o instanceof Map.Entry) + { + tester = (Map.Entry) o; + oKey = getKey(); + oValue = getValue(); + oTestingKey = tester.getKey(); + oTestingValue = tester.getValue(); + return (((oTestingKey == null) ? (oKey == null) : + oTestingKey.equals(oKey)) && + ((oTestingValue == null) ? (oValue == null) : + oTestingValue.equals(oValue))); + } + return false; + } + + /** returns the key */ + public Object getKey() + { + return key; + } + + /** returns the value */ + public Object getValue() + { + return value; + } + + /** the hashCode() for a Map.Entry is + * <pre> + * ((getKey() == null) ? 0 : getKey().hashCode()) ^ + * ((getValue() == null) ? 0 : getValue().hashCode()); + * </pre> + * + * NOTE: the calls to getKey() and getValue() in this implementation + * are <i>NOT</i> superfluous and should not be removed. They insure + * that subclasses such as HashMapEntry work correctly + */ + public int hashCode() + { + Object oKey = getKey(); + Object oValue = getValue(); + return ((oKey == null) ? 0 : oKey.hashCode()) ^ + ((oValue == null) ? 0 : oValue.hashCode()); + } + + /** + * sets the value of this Map.Entry + * + * @param newValue the new value of this Map.Entry + */ + public Object setValue(Object newValue) + throws UnsupportedOperationException, ClassCastException, + IllegalArgumentException, NullPointerException + { + Object oVal = value; + value = newValue; + return oVal; + } +} |
