| // Copyright 2006 The Apache Software Foundation |
| // |
| // Licensed 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.apache.tapestry5.internal.util; |
| |
| import java.util.Arrays; |
| |
| /** |
| * Combines multiple values to form a single composite key. MultiKey can often be used as an alternative to nested |
| * maps. |
| */ |
| public final class MultiKey |
| { |
| private static final int PRIME = 31; |
| |
| private final Object[] values; |
| |
| private final int hashCode; |
| |
| /** |
| * Creates a new instance from the provided values. It is assumed that the values provided are good map keys |
| * themselves -- immutable, with proper implementations of equals() and hashCode(). |
| * |
| * @param values |
| */ |
| public MultiKey(Object... values) |
| { |
| this.values = values; |
| |
| hashCode = PRIME * Arrays.hashCode(this.values); |
| } |
| |
| @Override |
| public int hashCode() |
| { |
| return hashCode; |
| } |
| |
| @Override |
| public boolean equals(Object obj) |
| { |
| if (this == obj) |
| return true; |
| if (obj == null) |
| return false; |
| if (getClass() != obj.getClass()) |
| return false; |
| final MultiKey other = (MultiKey) obj; |
| |
| return Arrays.equals(values, other.values); |
| } |
| |
| @Override |
| public String toString() |
| { |
| StringBuilder builder = new StringBuilder("MultiKey["); |
| |
| boolean first = true; |
| |
| for (Object o : values) |
| { |
| if (!first) |
| builder.append(", "); |
| |
| builder.append(o); |
| |
| first = false; |
| } |
| |
| builder.append("]"); |
| |
| return builder.toString(); |
| } |
| |
| } |