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    1   /*
    2    * $Id: GString.java,v 1.12 2004/05/04 02:54:44 spullara Exp $
    3    *
    4    * Copyright 2003 (C) James Strachan and Bob Mcwhirter. All Rights Reserved.
    5    *
    6    * Redistribution and use of this software and associated documentation
    7    * ("Software"), with or without modification, are permitted provided that the
    8    * following conditions are met: 1. Redistributions of source code must retain
    9    * copyright statements and notices. Redistributions must also contain a copy
    10   * of this document. 2. Redistributions in binary form must reproduce the above
    11   * copyright notice, this list of conditions and the following disclaimer in
    12   * the documentation and/or other materials provided with the distribution. 3.
    13   * The name "groovy" must not be used to endorse or promote products derived
    14   * from this Software without prior written permission of The Codehaus. For
    15   * written permission, please contact info@codehaus.org. 4. Products derived
    16   * from this Software may not be called "groovy" nor may "groovy" appear in
    17   * their names without prior written permission of The Codehaus. "groovy" is a
    18   * registered trademark of The Codehaus. 5. Due credit should be given to The
    19   * Codehaus - http://groovy.codehaus.org/
    20   *
    21   * THIS SOFTWARE IS PROVIDED BY THE CODEHAUS AND CONTRIBUTORS ``AS IS'' AND ANY
    22   * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
    23   * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
    24   * DISCLAIMED. IN NO EVENT SHALL THE CODEHAUS OR ITS CONTRIBUTORS BE LIABLE FOR
    25   * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
    26   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
    27   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
    28   * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
    29   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
    30   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
    31   * DAMAGE.
    32   *
    33   */
    34  package groovy.lang;
    35
    36  import java.io.IOException;
    37  import java.io.StringWriter;
    38  import java.io.Writer;
    39  import java.util.ArrayList;
    40  import java.util.Arrays;
    41  import java.util.List;
    42
    43  import org.codehaus.groovy.runtime.InvokerHelper;
    44
    45  /***
    46   * Represents a String which contains embedded values such as "hello there
    47   * ${user} how are you?" which can be evaluated lazily. Advanced users can
    48   * iterate over the text and values to perform special processing, such as for
    49   * performing SQL operations, the values can be substituted for ? and the
    50   * actual value objects can be bound to a JDBC statement. The lovely name of
    51   * this class was suggested by Jules Gosnell and was such a good idea, I
    52   * couldn't resist :)
    53   *
    54   * @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
    55   * @version $Revision: 1.12 $
    56   */
    57  public abstract class GString extends GroovyObjectSupport implements Comparable, CharSequence, Writable {
    58
    59      private Object[] values;
    60
    61      public GString(Object values) {
    62          this.values = (Object[]) values;
    63      }
    64
    65      public GString(Object[] values) {
    66          this.values = values;
    67      }
    68
    69      // will be static in an instance
    70      public abstract String[] getStrings();
    71
    72      /***
    73       * Overloaded to implement duck typing for Strings
    74       * so that any method that can't be evaluated on this
    75       * object will be forwarded to the toString() object instead.
    76       */
    77      public Object invokeMethod(String name, Object args) {
    78          try {
    79              return super.invokeMethod(name, args);
    80          }
    81          catch (MissingMethodException e) {
    82              // lets try invoke the method on the real String
    83              return InvokerHelper.invokeMethod(toString(), name, args);
    84          }
    85      }
    86
    87      public Object[] getValues() {
    88          return values;
    89      }
    90
    91      public GString plus(GString that) {
    92          List stringList = new ArrayList();
    93          List valueList = new ArrayList();
    94
    95          stringList.addAll(Arrays.asList(getStrings()));
    96          valueList.addAll(Arrays.asList(getValues()));
    97
    98          if (stringList.size() > valueList.size()) {
    99              valueList.add("");
    100         }
    101
    102         stringList.addAll(Arrays.asList(that.getStrings()));
    103         valueList.addAll(Arrays.asList(that.getValues()));
    104
    105         final String[] newStrings = new String[stringList.size()];
    106         stringList.toArray(newStrings);
    107         Object[] newValues = valueList.toArray();
    108
    109         return new GString(newValues) {
    110             public String[] getStrings() {
    111                 return newStrings;
    112             }
    113         };
    114     }
    115
    116     public GString plus(String that) {
    117         String[] currentStrings = getStrings();
    118         String[] newStrings = null;
    119         Object[] newValues = null;
    120
    121         newStrings = new String[currentStrings.length + 1];
    122         newValues = new Object[getValues().length + 1];
    123         int lastIndex = currentStrings.length;
    124         System.arraycopy(currentStrings, 0, newStrings, 0, lastIndex);
    125         System.arraycopy(getValues(), 0, newValues, 0, getValues().length);
    126         newStrings[lastIndex] = that;
    127         newValues[getValues().length] = "";
    128
    129         final String[] finalStrings = newStrings;
    130         return new GString(newValues) {
    131
    132             public String[] getStrings() {
    133                 return finalStrings;
    134             }
    135         };
    136     }
    137
    138     public int getValueCount() {
    139         return values.length;
    140     }
    141
    142     public Object getValue(int idx) {
    143         return values[idx];
    144     }
    145
    146     public String toString() {
    147         StringWriter buffer = new StringWriter();
    148         try {
    149             writeTo(buffer);
    150         }
    151         catch (IOException e) {
    152             throw new StringWriterIOException(e);
    153         }
    154         return buffer.toString();
    155     }
    156
    157     public Writer writeTo(Writer out) throws IOException {
    158         String[] s = getStrings();
    159         int numberOfValues = values.length;
    160         for (int i = 0, size = s.length; i < size; i++) {
    161             out.write(s[i]);
    162             if (i < numberOfValues) {
    163                 InvokerHelper.write(out, values[i]);
    164             }
    165         }
    166         return out;
    167     }
    168
    169     public boolean equals(Object that) {
    170         if (that instanceof GString) {
    171             return equals((GString) that);
    172         }
    173         return false;
    174     }
    175
    176     public boolean equals(GString that) {
    177         return toString().equals(that.toString());
    178     }
    179
    180     public int hashCode() {
    181         return 37 + toString().hashCode();
    182     }
    183
    184     public int compareTo(Object that) {
    185         return toString().compareTo(that.toString());
    186     }
    187
    188     public char charAt(int index) {
    189         return toString().charAt(index);
    190     }
    191
    192     public int length() {
    193         return toString().length();
    194     }
    195
    196     public CharSequence subSequence(int start, int end) {
    197         return toString().subSequence(start, end);
    198     }
    199 }