| // Copyright 2008 Google Inc. |
| // |
| // 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 com.google.gwtorm.client; |
| |
| import java.io.Serializable; |
| |
| /** |
| * Abstract key type composed of other keys. |
| * |
| * <p>Applications should subclass this type to create their own entity-specific key classes. |
| * |
| * @param <P> the parent key type. Use {@link Key} if no parent key is needed. |
| */ |
| @SuppressWarnings("serial") |
| public abstract class CompoundKey<P extends Key<?>> implements Key<P>, Serializable { |
| /** @return the member key components, minus the parent key. */ |
| public abstract Key<?>[] members(); |
| |
| /** @return the parent key instance; null if this is a root level key. */ |
| @Override |
| public P getParentKey() { |
| return null; |
| } |
| |
| @Override |
| public int hashCode() { |
| int hc = 0; |
| if (getParentKey() != null) { |
| hc = getParentKey().hashCode(); |
| } |
| for (final Key<?> k : members()) { |
| hc *= 31; |
| hc += k.hashCode(); |
| } |
| return hc; |
| } |
| |
| @Override |
| public boolean equals(final Object b) { |
| if (b == null || b.getClass() != getClass()) { |
| return false; |
| } |
| |
| final CompoundKey<P> q = cast(b); |
| if (getParentKey() != null && !getParentKey().equals(q.getParentKey())) { |
| return false; |
| } |
| |
| final Key<?>[] aMembers = members(); |
| final Key<?>[] bMembers = q.members(); |
| if (aMembers.length != bMembers.length) { |
| return false; |
| } |
| for (int i = 0; i < aMembers.length; i++) { |
| if (!aMembers[i].equals(bMembers[i])) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| @Override |
| public String toString() { |
| final StringBuffer r = new StringBuffer(); |
| boolean first = true; |
| if (getParentKey() != null) { |
| r.append(KeyUtil.encode(getParentKey().toString())); |
| first = false; |
| } |
| for (final Key<?> k : members()) { |
| if (!first) { |
| r.append(','); |
| } |
| r.append(KeyUtil.encode(k.toString())); |
| first = false; |
| } |
| return r.toString(); |
| } |
| |
| @Override |
| public void fromString(final String in) { |
| final String[] parts = in.split(","); |
| int p = 0; |
| if (getParentKey() != null) { |
| getParentKey().fromString(KeyUtil.decode(parts[p++])); |
| } |
| for (final Key<?> k : members()) { |
| k.fromString(KeyUtil.decode(parts[p++])); |
| } |
| } |
| |
| @SuppressWarnings("unchecked") |
| private static <A extends Key<?>> CompoundKey<A> cast(final Object b) { |
| return (CompoundKey<A>) b; |
| } |
| } |