1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 2 <!--NewPage--> 3 <HTML> 4 <HEAD> 5 <!-- Generated by javadoc (build 1.6.0-google-internal) on Mon Jan 04 20:47:57 PST 2010 --> 6 <TITLE> 7 Collections2 (Guava Libraries 2010.01.04) 8 </TITLE> 9 10 <META NAME="date" CONTENT="2010-01-04"> 11 12 <LINK REL ="stylesheet" TYPE="text/css" HREF="../../../../stylesheet.css" TITLE="Style"> 13 14 <SCRIPT type="text/javascript"> 15 function windowTitle() 16 { 17 if (location.href.indexOf('is-external=true') == -1) { 18 parent.document.title="Collections2 (Guava Libraries 2010.01.04)"; 19 } 20 } 21 </SCRIPT> 22 <NOSCRIPT> 23 </NOSCRIPT> 24 25 </HEAD> 26 27 <BODY BGCOLOR="white" onload="windowTitle();"> 28 <HR> 29 30 31 <!-- ========= START OF TOP NAVBAR ======= --> 32 <A NAME="navbar_top"><!-- --></A> 33 <A HREF="#skip-navbar_top" title="Skip navigation links"></A> 34 <TABLE BORDER="0" WIDTH="100%" CELLPADDING="1" CELLSPACING="0" SUMMARY=""> 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HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true" title="class or interface in java.lang">java.lang.Object</A> 96 <IMG SRC="../../../../resources/inherit.gif" ALT="extended by "><B>com.google.common.collect.Collections2</B> 97 </PRE> 98 <HR> 99 <DL> 100 <DT><PRE>public final class <B>Collections2</B><DT>extends <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true" title="class or interface in java.lang">Object</A></DL> 101 </PRE> 102 103 <P> 104 Provides static methods for working with <code>Collection</code> instances. 105 <P> 106 107 <P> 108 <DL> 109 <DT><B>Since:</B></DT> 110 <DD>2010.01.04 <b>stable</b> (imported from Google Collections Library)</DD> 111 <DT><B>Author:</B></DT> 112 <DD>Chris Povirk, Mike Bostock, Jared Levy</DD> 113 </DL> 114 <HR> 115 116 <P> 117 118 <!-- ========== METHOD SUMMARY =========== --> 119 120 <A NAME="method_summary"><!-- --></A> 121 <TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""> 122 <TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"> 123 <TH ALIGN="left" COLSPAN="2"><FONT SIZE="+2"> 124 <B>Method Summary</B></FONT></TH> 125 </TR> 126 <TR BGCOLOR="white" CLASS="TableRowColor"> 127 <TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"> 128 <CODE>static 129 <TABLE BORDER="0" CELLPADDING="0" CELLSPACING="0" SUMMARY=""> 130 <TR ALIGN="right" VALIGN=""> 131 <TD NOWRAP><FONT SIZE="-1"> 132 <CODE><E> <A HREF="http://java.sun.com/javase/6/docs/api/java/util/Collection.html?is-external=true" title="class or interface in java.util">Collection</A><E></CODE></FONT></TD> 133 </TR> 134 </TABLE> 135 </CODE></FONT></TD> 136 <TD><CODE><B><A HREF="../../../../com/google/common/collect/Collections2.html#filter(java.util.Collection, com.google.common.base.Predicate)">filter</A></B>(<A HREF="http://java.sun.com/javase/6/docs/api/java/util/Collection.html?is-external=true" title="class or interface in java.util">Collection</A><E> unfiltered, 137 <A HREF="../../../../com/google/common/base/Predicate.html" title="interface in com.google.common.base">Predicate</A><? super E> predicate)</CODE> 138 139 <BR> 140 Returns the elements of <code>unfiltered</code> that satisfy a predicate.</TD> 141 </TR> 142 <TR BGCOLOR="white" CLASS="TableRowColor"> 143 <TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"> 144 <CODE>static 145 <TABLE BORDER="0" CELLPADDING="0" CELLSPACING="0" SUMMARY=""> 146 <TR ALIGN="right" VALIGN=""> 147 <TD NOWRAP><FONT SIZE="-1"> 148 <CODE><F,T> <A HREF="http://java.sun.com/javase/6/docs/api/java/util/Collection.html?is-external=true" title="class or interface in java.util">Collection</A><T></CODE></FONT></TD> 149 </TR> 150 </TABLE> 151 </CODE></FONT></TD> 152 <TD><CODE><B><A HREF="../../../../com/google/common/collect/Collections2.html#transform(java.util.Collection, com.google.common.base.Function)">transform</A></B>(<A HREF="http://java.sun.com/javase/6/docs/api/java/util/Collection.html?is-external=true" title="class or interface in java.util">Collection</A><F> fromCollection, 153 <A HREF="../../../../com/google/common/base/Function.html" title="interface in com.google.common.base">Function</A><? super F,T> function)</CODE> 154 155 <BR> 156 Returns a collection that applies <code>function</code> to each element of 157 <code>fromCollection</code>.</TD> 158 </TR> 159 </TABLE> 160 <A NAME="methods_inherited_from_class_java.lang.Object"><!-- --></A> 161 <TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""> 162 <TR BGCOLOR="#EEEEFF" CLASS="TableSubHeadingColor"> 163 <TH ALIGN="left"><B>Methods inherited from class java.lang.<A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true" title="class or interface in java.lang">Object</A></B></TH> 164 </TR> 165 <TR BGCOLOR="white" CLASS="TableRowColor"> 166 <TD><CODE><A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true#clone()" title="class or interface in java.lang">clone</A>, <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true#equals(java.lang.Object)" title="class or interface in java.lang">equals</A>, <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true#finalize()" title="class or interface in java.lang">finalize</A>, <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true#getClass()" title="class or interface in java.lang">getClass</A>, <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true#hashCode()" title="class or interface in java.lang">hashCode</A>, <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true#notify()" title="class or interface in java.lang">notify</A>, <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true#notifyAll()" title="class or interface in java.lang">notifyAll</A>, <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true#toString()" title="class or interface in java.lang">toString</A>, <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true#wait()" title="class or interface in java.lang">wait</A>, <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true#wait(long)" title="class or interface in java.lang">wait</A>, <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true#wait(long, int)" title="class or interface in java.lang">wait</A></CODE></TD> 167 </TR> 168 </TABLE> 169 170 <P> 171 172 <!-- ============ METHOD DETAIL ========== --> 173 174 <A NAME="method_detail"><!-- --></A> 175 <TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""> 176 <TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"> 177 <TH ALIGN="left" COLSPAN="1"><FONT SIZE="+2"> 178 <B>Method Detail</B></FONT></TH> 179 </TR> 180 </TABLE> 181 182 <A NAME="filter(java.util.Collection, com.google.common.base.Predicate)"><!-- --></A><H3> 183 filter</H3> 184 <PRE> 185 public static <E> <A HREF="http://java.sun.com/javase/6/docs/api/java/util/Collection.html?is-external=true" title="class or interface in java.util">Collection</A><E> <B>filter</B>(<A HREF="http://java.sun.com/javase/6/docs/api/java/util/Collection.html?is-external=true" title="class or interface in java.util">Collection</A><E> unfiltered, 186 <A HREF="../../../../com/google/common/base/Predicate.html" title="interface in com.google.common.base">Predicate</A><? super E> predicate)</PRE> 187 <DL> 188 <DD>Returns the elements of <code>unfiltered</code> that satisfy a predicate. The 189 returned collection is a live view of <code>unfiltered</code>; changes to one 190 affect the other. 191 192 <p>The resulting collection's iterator does not support <code>remove()</code>, 193 but all other collection methods are supported. The collection's 194 <code>add()</code> and <code>addAll()</code> methods throw an 195 <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/IllegalArgumentException.html?is-external=true" title="class or interface in java.lang"><CODE>IllegalArgumentException</CODE></A> if an element that doesn't satisfy the 196 predicate is provided. When methods such as <code>removeAll()</code> and 197 <code>clear()</code> are called on the filtered collection, only elements that 198 satisfy the filter will be removed from the underlying collection. 199 200 <p>The returned collection isn't threadsafe or serializable, even if 201 <code>unfiltered</code> is. 202 203 <p>Many of the filtered collection's methods, such as <code>size()</code>, 204 iterate across every element in the underlying collection and determine 205 which elements satisfy the filter. When a live view is <i>not</i> needed, 206 it may be faster to copy <code>Iterables.filter(unfiltered, predicate)</code> 207 and use the copy. 208 <P> 209 <DD><DL> 210 </DL> 211 </DD> 212 </DL> 213 <HR> 214 215 <A NAME="transform(java.util.Collection, com.google.common.base.Function)"><!-- --></A><H3> 216 transform</H3> 217 <PRE> 218 public static <F,T> <A HREF="http://java.sun.com/javase/6/docs/api/java/util/Collection.html?is-external=true" title="class or interface in java.util">Collection</A><T> <B>transform</B>(<A HREF="http://java.sun.com/javase/6/docs/api/java/util/Collection.html?is-external=true" title="class or interface in java.util">Collection</A><F> fromCollection, 219 <A HREF="../../../../com/google/common/base/Function.html" title="interface in com.google.common.base">Function</A><? super F,T> function)</PRE> 220 <DL> 221 <DD>Returns a collection that applies <code>function</code> to each element of 222 <code>fromCollection</code>. The returned collection is a live view of <code>fromCollection</code>; changes to one affect the other. 223 224 <p>The returned collection's <code>add()</code> and <code>addAll()</code> methods 225 throw an <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/UnsupportedOperationException.html?is-external=true" title="class or interface in java.lang"><CODE>UnsupportedOperationException</CODE></A>. All other collection 226 methods are supported, as long as <code>fromCollection</code> supports them. 227 228 <p>The returned collection isn't threadsafe or serializable, even if 229 <code>fromCollection</code> is. 230 231 <p>When a live view is <i>not</i> needed, it may be faster to copy the 232 transformed collection and use the copy. 233 <P> 234 <DD><DL> 235 </DL> 236 </DD> 237 </DL> 238 <!-- ========= END OF CLASS DATA ========= --> 239 <HR> 240 241 242 <!-- ======= START OF BOTTOM NAVBAR ====== --> 243 <A NAME="navbar_bottom"><!-- --></A> 244 <A HREF="#skip-navbar_bottom" title="Skip navigation links"></A> 245 <TABLE BORDER="0" WIDTH="100%" CELLPADDING="1" CELLSPACING="0" SUMMARY=""> 246 <TR> 247 <TD COLSPAN=2 BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> 248 <A NAME="navbar_bottom_firstrow"><!-- --></A> 249 <TABLE BORDER="0" CELLPADDING="0" CELLSPACING="3" SUMMARY=""> 250 <TR ALIGN="center" VALIGN="top"> 251 <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../../overview-summary.html"><FONT CLASS="NavBarFont1"><B>Overview</B></FONT></A> </TD> 252 <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-summary.html"><FONT CLASS="NavBarFont1"><B>Package</B></FONT></A> </TD> 253 <TD BGCOLOR="#FFFFFF" CLASS="NavBarCell1Rev"> <FONT CLASS="NavBarFont1Rev"><B>Class</B></FONT> </TD> 254 <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="class-use/Collections2.html"><FONT CLASS="NavBarFont1"><B>Use</B></FONT></A> </TD> 255 <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-tree.html"><FONT CLASS="NavBarFont1"><B>Tree</B></FONT></A> </TD> 256 <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../../deprecated-list.html"><FONT CLASS="NavBarFont1"><B>Deprecated</B></FONT></A> </TD> 257 <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../../index-all.html"><FONT CLASS="NavBarFont1"><B>Index</B></FONT></A> </TD> 258 <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../../help-doc.html"><FONT CLASS="NavBarFont1"><B>Help</B></FONT></A> </TD> 259 </TR> 260 </TABLE> 261 </TD> 262 <TD ALIGN="right" VALIGN="top" ROWSPAN=3><EM> 263 </EM> 264 </TD> 265 </TR> 266 267 <TR> 268 <TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> 269 <A HREF="../../../../com/google/common/collect/ClassToInstanceMap.html" title="interface in com.google.common.collect"><B>PREV CLASS</B></A> 270 <A HREF="../../../../com/google/common/collect/ComparisonChain.html" title="class in com.google.common.collect"><B>NEXT CLASS</B></A></FONT></TD> 271 <TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> 272 <A HREF="../../../../index.html?com/google/common/collect/Collections2.html" target="_top"><B>FRAMES</B></A> 273 <A HREF="Collections2.html" target="_top"><B>NO FRAMES</B></A> 274 <SCRIPT type="text/javascript"> 275 <!-- 276 if(window==top) { 277 document.writeln('<A HREF="../../../../allclasses-noframe.html"><B>All Classes</B></A>'); 278 } 279 //--> 280 </SCRIPT> 281 <NOSCRIPT> 282 <A HREF="../../../../allclasses-noframe.html"><B>All Classes</B></A> 283 </NOSCRIPT> 284 285 286 </FONT></TD> 287 </TR> 288 <TR> 289 <TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2"> 290 SUMMARY: NESTED | FIELD | CONSTR | <A HREF="#method_summary">METHOD</A></FONT></TD> 291 <TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2"> 292 DETAIL: FIELD | CONSTR | <A HREF="#method_detail">METHOD</A></FONT></TD> 293 </TR> 294 </TABLE> 295 <A NAME="skip-navbar_bottom"></A> 296 <!-- ======== END OF BOTTOM NAVBAR ======= --> 297 298 <HR> 299 300 </BODY> 301 </HTML> 302
