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      1 /*
      2  * Copyright (C) 2009 The Android Open Source Project
      3  *
      4  * Licensed under the Eclipse Public License, Version 1.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.eclipse.org/org/documents/epl-v10.php
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.ide.eclipse.adt.internal.editors.layout.gle2;
     18 
     19 import com.android.annotations.NonNull;
     20 import com.android.ide.common.api.INode.IAttribute;
     21 
     22 import java.util.regex.Matcher;
     23 import java.util.regex.Pattern;
     24 
     25 /**
     26  * Represents one XML attribute in a {@link SimpleElement}.
     27  * <p/>
     28  * The attribute is always represented by a namespace URI, a name and a value.
     29  * The name cannot be empty.
     30  * The namespace URI can be empty for an attribute without a namespace but is never null.
     31  * The value can be empty but cannot be null.
     32  * <p/>
     33  * For a more detailed explanation of the purpose of this class,
     34  * please see {@link SimpleXmlTransfer}.
     35  */
     36 public class SimpleAttribute implements IAttribute {
     37     private final String mName;
     38     private final String mValue;
     39     private final String mUri;
     40 
     41     /**
     42      * Creates a new {@link SimpleAttribute}.
     43      * <p/>
     44      * Any null value will be converted to an empty non-null string.
     45      * However it is a semantic error to use an empty name -- no assertion is done though.
     46      *
     47      * @param uri The URI of the attribute.
     48      * @param name The XML local name of the attribute.
     49      * @param value The value of the attribute.
     50      */
     51     public SimpleAttribute(String uri, String name, String value) {
     52         mUri = uri == null ? "" : uri;
     53         mName = name == null ? "" : name;
     54         mValue = value == null ? "" : value;
     55     }
     56 
     57     /**
     58      * Returns the namespace URI of the attribute.
     59      * Can be empty for an attribute without a namespace but is never null.
     60      */
     61     @Override
     62     public @NonNull String getUri() {
     63         return mUri;
     64     }
     65 
     66     /** Returns the XML local name of the attribute. Cannot be null nor empty. */
     67     @Override
     68     public @NonNull String getName() {
     69         return mName;
     70     }
     71 
     72     /** Returns the value of the attribute. Cannot be null. Can be empty. */
     73     @Override
     74     public @NonNull String getValue() {
     75         return mValue;
     76     }
     77 
     78     // reader and writer methods
     79 
     80     @Override
     81     public String toString() {
     82         return String.format("@%s:%s=%s\n", //$NON-NLS-1$
     83                 mName,
     84                 mUri,
     85                 mValue);
     86     }
     87 
     88     private static final Pattern REGEXP =
     89         Pattern.compile("[^@]*@([^:]+):([^=]*)=([^\n]*)\n*");       //$NON-NLS-1$
     90 
     91     static SimpleAttribute parseString(String value) {
     92         Matcher m = REGEXP.matcher(value);
     93         if (m.matches()) {
     94             return new SimpleAttribute(m.group(2), m.group(1), m.group(3));
     95         }
     96 
     97         return null;
     98     }
     99 
    100     @Override
    101     public boolean equals(Object obj) {
    102         if (obj instanceof SimpleAttribute) {
    103             SimpleAttribute sa = (SimpleAttribute) obj;
    104 
    105             return mName.equals(sa.mName) &&
    106                     mUri.equals(sa.mUri) &&
    107                     mValue.equals(sa.mValue);
    108         }
    109         return false;
    110     }
    111 
    112     @Override
    113     public int hashCode() {
    114         long c = mName.hashCode();
    115         // uses the formula defined in java.util.List.hashCode()
    116         c = 31*c + mUri.hashCode();
    117         c = 31*c + mValue.hashCode();
    118         if (c > 0x0FFFFFFFFL) {
    119             // wrap any overflow
    120             c = c ^ (c >> 32);
    121         }
    122         return (int)(c & 0x0FFFFFFFFL);
    123     }
    124 }
    125