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    1   /*
    2    * $Id: GString.java 4098 2006-10-10 16:09:48Z blackdrag $
    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  import java.util.regex.Pattern;
    43
    44  import org.codehaus.groovy.runtime.DefaultGroovyMethods;
    45  import org.codehaus.groovy.runtime.InvokerHelper;
    46
    47  /***
    48   * Represents a String which contains embedded values such as "hello there
    49   * ${user} how are you?" which can be evaluated lazily. Advanced users can
    50   * iterate over the text and values to perform special processing, such as for
    51   * performing SQL operations, the values can be substituted for ? and the
    52   * actual value objects can be bound to a JDBC statement. The lovely name of
    53   * this class was suggested by Jules Gosnell and was such a good idea, I
    54   * couldn't resist :)
    55   *
    56   * @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
    57   * @version $Revision: 4098 $
    58   */
    59  public abstract class GString extends GroovyObjectSupport implements Comparable, CharSequence, Writable, Buildable {
    60
    61      private Object[] values;
    62
    63      public GString(Object values) {
    64          this.values = (Object[]) values;
    65      }
    66
    67      public GString(Object[] values) {
    68          this.values = values;
    69      }
    70
    71      // will be static in an instance
    72      public abstract String[] getStrings();
    73
    74      /***
    75       * Overloaded to implement duck typing for Strings
    76       * so that any method that can't be evaluated on this
    77       * object will be forwarded to the toString() object instead.
    78       */
    79      public Object invokeMethod(String name, Object args) {
    80          try {
    81              return super.invokeMethod(name, args);
    82          }
    83          catch (MissingMethodException e) {
    84              // lets try invoke the method on the real String
    85              return InvokerHelper.invokeMethod(toString(), name, args);
    86          }
    87      }
    88
    89      public Object[] getValues() {
    90          return values;
    91      }
    92
    93      public GString plus(GString that) {
    94          List stringList = new ArrayList();
    95          List valueList = new ArrayList();
    96
    97          stringList.addAll(Arrays.asList(getStrings()));
    98          valueList.addAll(Arrays.asList(getValues()));
    99
    100         if (stringList.size() > valueList.size()) {
    101             valueList.add("");
    102         }
    103
    104         stringList.addAll(Arrays.asList(that.getStrings()));
    105         valueList.addAll(Arrays.asList(that.getValues()));
    106
    107         final String[] newStrings = new String[stringList.size()];
    108         stringList.toArray(newStrings);
    109         Object[] newValues = valueList.toArray();
    110
    111         return new GString(newValues) {
    112             public String[] getStrings() {
    113                 return newStrings;
    114             }
    115         };
    116     }
    117
    118     public GString plus(String that) {
    119         String[] currentStrings = getStrings();
    120         String[] newStrings = null;
    121         Object[] newValues = null;
    122
    123         newStrings = new String[currentStrings.length + 1];
    124         newValues = new Object[getValues().length + 1];
    125         int lastIndex = currentStrings.length;
    126         System.arraycopy(currentStrings, 0, newStrings, 0, lastIndex);
    127         System.arraycopy(getValues(), 0, newValues, 0, getValues().length);
    128         newStrings[lastIndex] = that;
    129         newValues[getValues().length] = "";
    130
    131         final String[] finalStrings = newStrings;
    132         return new GString(newValues) {
    133
    134             public String[] getStrings() {
    135                 return finalStrings;
    136             }
    137         };
    138     }
    139
    140     public int getValueCount() {
    141         return values.length;
    142     }
    143
    144     public Object getValue(int idx) {
    145         return values[idx];
    146     }
    147
    148     public String toString() {
    149         StringWriter buffer = new StringWriter();
    150         try {
    151             writeTo(buffer);
    152         }
    153         catch (IOException e) {
    154             throw new StringWriterIOException(e);
    155         }
    156         return buffer.toString();
    157     }
    158
    159     public Writer writeTo(Writer out) throws IOException {
    160         String[] s = getStrings();
    161         int numberOfValues = values.length;
    162         for (int i = 0, size = s.length; i < size; i++) {
    163             out.write(s[i]);
    164             if (i < numberOfValues) {
    165                 InvokerHelper.write(out, values[i]);
    166             }
    167         }
    168         return out;
    169     }
    170
    171     /* (non-Javadoc)
    172      * @see groovy.lang.Buildable#build(groovy.lang.GroovyObject)
    173      */
    174     public void build(final GroovyObject builder) {
    175     final String[] s = getStrings();
    176     final int numberOfValues = values.length;
    177
    178         for (int i = 0, size = s.length; i < size; i++) {
    179             builder.getProperty("mkp");
    180             builder.invokeMethod("yield", new Object[]{s[i]});
    181             if (i < numberOfValues) {
    182                 builder.getProperty("mkp");
    183                 builder.invokeMethod("yield", new Object[]{values[i]});
    184             }
    185         }
    186     }
    187
    188     public boolean equals(Object that) {
    189         if (that instanceof GString) {
    190             return equals((GString) that);
    191         }
    192         return false;
    193     }
    194
    195     public boolean equals(GString that) {
    196         return toString().equals(that.toString());
    197     }
    198
    199     public int hashCode() {
    200         return 37 + toString().hashCode();
    201     }
    202
    203     public int compareTo(Object that) {
    204         return toString().compareTo(that.toString());
    205     }
    206
    207     public char charAt(int index) {
    208         return toString().charAt(index);
    209     }
    210
    211     public int length() {
    212         return toString().length();
    213     }
    214
    215     public CharSequence subSequence(int start, int end) {
    216         return toString().subSequence(start, end);
    217     }
    218
    219     /***
    220      * Turns a String into a regular expression pattern
    221      *
    222      * @return the regular expression pattern
    223      */
    224     public Pattern negate() {
    225         return DefaultGroovyMethods.negate(toString());
    226     }
    227 }