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30 day Evaluation Version distributed via the Maven Jar Repository. Clover is not free. You have 30 days to evaluate it. Please visit http://www.thecortex.net/clover to obtain a licensed version of Clover | |||||||||||||||||||
Source file | Conditionals | Statements | Methods | TOTAL | |||||||||||||||
IdAllocator.java | 100% | 100% | 100% | 100% |
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// Copyright 2004, 2005 The Apache Software Foundation
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package org.apache.tapestry.util;
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import java.util.HashMap;
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import java.util.Map;
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import org.apache.hivemind.util.Defense;
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/**
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* Used to "uniquify" names within a given context. A base name is passed in, and the return value
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* is the base name, or the base name extended with a suffix to make it unique.
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*
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* @author Howard Lewis Ship
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* @since 3.0
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*/
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public class IdAllocator |
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{ |
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private final Map _generatorMap = new HashMap(); |
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private final String _namespace;
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private static class NameGenerator |
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{ |
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private final String _baseId;
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private int _index; |
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NameGenerator(String baseId) |
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{ |
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_baseId = baseId + "$";
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} |
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public String nextId()
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{ |
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return _baseId + _index++;
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} |
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} |
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public IdAllocator()
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{ |
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this(""); |
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} |
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public IdAllocator(String namespace)
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{ |
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Defense.notNull(namespace, "namespace");
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_namespace = namespace; |
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} |
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/**
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* Allocates the id. Repeated calls for the same name will return "name", "name$0", "name$1",
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* etc.
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*/
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public String allocateId(String name)
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{ |
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String key = name + _namespace; |
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NameGenerator g = (NameGenerator) _generatorMap.get(key); |
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String result = null;
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if (g == null) |
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{ |
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g = new NameGenerator(key);
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result = key; |
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} |
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else
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result = g.nextId(); |
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// Handle the degenerate case, where a base name of the form "foo$0" has been
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// requested. Skip over any duplicates thus formed.
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while (_generatorMap.containsKey(result))
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result = g.nextId(); |
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_generatorMap.put(result, g); |
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return result;
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} |
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/**
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* Clears the allocator, resetting it to freshly allocated state.
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*/
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public void clear() |
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{ |
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_generatorMap.clear(); |
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} |
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} |
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