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Diffstat (limited to 'libjava/gnu/java/lang/VMCPStringBuilder.java')
-rw-r--r-- | libjava/gnu/java/lang/VMCPStringBuilder.java | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/libjava/gnu/java/lang/VMCPStringBuilder.java b/libjava/gnu/java/lang/VMCPStringBuilder.java new file mode 100644 index 00000000000..8e137cd3fec --- /dev/null +++ b/libjava/gnu/java/lang/VMCPStringBuilder.java @@ -0,0 +1,112 @@ +/* VMCPStringBuilder.java -- Growable strings without locking or copying + Copyright (C) 2008 Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +General Public License for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + +package gnu.java.lang; + +import java.lang.reflect.Constructor; +import java.lang.reflect.InvocationTargetException; + +/** + * This class provides VM support for CPStringBuilder + * by allowing the package-private constructor + * of java.lang.String to be invoked. The default + * implementation uses reflection. VMs may replace + * this class with a more efficient version. + */ +final class VMCPStringBuilder +{ + + /** + * The package-private constructor for String objects without copying. + */ + private static final Constructor cons; + + static + { + try + { + cons = String.class.getDeclaredConstructor(new Class[] { char[].class, + Integer.TYPE, + Integer.TYPE, + Boolean.TYPE }); + cons.setAccessible(true); + } + catch (NoSuchMethodException e) + { + throw (Error) + new InternalError("Could not get no-copy String constructor").initCause(e); + } + } + + /** + * Convert this <code>StringBuilder</code> to a <code>String</code>. The + * String is composed of the characters currently in this StringBuilder. Note + * that the result is not a copy, so the builder will allocate a new array + * if a further write operation is attempted. + * + * @param value the buffered characters. + * @param startIndex the index at which to start taking characters from the buffer. + * @param count the number of characters used in the buffer. + * @return the characters in this StringBuilder + */ + public static String toString(char[] value, int startIndex, int count) + { + try + { + return (String) + cons.newInstance(new Object[] { value, Integer.valueOf(startIndex), + Integer.valueOf(count), + Boolean.valueOf(true) }); + } + catch (InstantiationException e) + { + throw (Error) + new InternalError("Could not instantiate no-copy String constructor").initCause(e); + } + catch (IllegalAccessException e) + { + throw (Error) + new InternalError("Could not access no-copy String constructor").initCause(e); + } + catch (InvocationTargetException e) + { + throw (Error) + new InternalError("Error calling no-copy String constructor").initCause(e); + } + } + +} |