File	Doc	Category	Size	Date	Package
VMRuntime.java	API Doc	Android 1.5 API	6296	Wed May 06 22:41:02 BST 2009	dalvik.system

VMRuntime

• java.lang.Object

Fields Summary
private static final VMRuntime	THE_ONE Holds the VMRuntime singleton.

Constructors Summary
private VMRuntime() Prevents this class from being instantiated.

Methods Summary
public native void	gcSoftReferences() Requests that the virtual machine collect available memory, and collects any SoftReferences that are not strongly-reachable.
public native long	getExternalBytesAllocated() Returns the number of externally-allocated bytes being tracked by trackExternalAllocation/Free(). return the number of bytes
public long	getMinimumHeapSize() Returns the minimum heap size, or zero if no minimum is in effect. return the minimum heap size value return nativeMinimumHeapSize(0, false);
public static dalvik.system.VMRuntime	getRuntime() Returns the object that represents the VM instance's Dalvik-specific runtime environment. return the runtime object return THE_ONE;
public native float	getTargetHeapUtilization() Gets the current ideal heap utilization, represented as a number between zero and one. After a GC happens, the Dalvik heap may be resized so that (size of live objects) / (size of heap) is equal to this number. return the current ideal heap utilization
private native long	nativeMinimumHeapSize(long size, boolean set) If set is true, sets the new minimum heap size to size; always returns the current (or previous) size. param size the new suggested minimum heap size, in bytes param set if true, set the size based on the size parameter, otherwise ignore it return the old or current minimum heap size value
private native void	nativeSetTargetHeapUtilization(float newTarget) Implements setTargetHeapUtilization(). param newTarget the new suggested ideal heap utilization. This value may be adjusted internally.
public native void	runFinalizationSync() Does not return until any pending finalizers have been called. This may or may not happen in the context of the calling thread. No exceptions will escape.
public synchronized long	setMinimumHeapSize(long size) Sets the desired minimum heap size, and returns the old minimum size. If size is larger than the maximum size, the maximum size will be used. If size is zero or negative, the minimum size constraint will be removed. Synchronized to make the order of the exchange reliable. param size the new suggested minimum heap size, in bytes return the old minimum heap size value return nativeMinimumHeapSize(size, true);
public float	setTargetHeapUtilization(float newTarget) Sets the current ideal heap utilization, represented as a number between zero and one. After a GC happens, the Dalvik heap may be resized so that (size of live objects) / (size of heap) is equal to this number. param newTarget the new suggested ideal heap utilization. This value may be adjusted internally. return the previous ideal heap utilization throws IllegalArgumentException if newTarget is <= 0.0 or >= 1.0 if (newTarget <= 0.0 || newTarget >= 1.0) { throw new IllegalArgumentException(newTarget + " out of range (0,1)"); } /* Synchronize to make sure that only one thread gets * a given "old" value if both update at the same time. * Allows for reliable save-and-restore semantics. */ synchronized (this) { float oldTarget = getTargetHeapUtilization(); nativeSetTargetHeapUtilization(newTarget); return oldTarget; }
public native boolean	trackExternalAllocation(long size) Asks the VM if <size> bytes can be allocated in an external heap. This information may be used to limit the amount of memory available to Dalvik threads. Returns false if the VM would rather that the caller did not allocate that much memory. If the call returns false, the VM will not update its internal counts. May cause one or more GCs as a side-effect. Called by JNI code. {@hide} param size The number of bytes that have been allocated. return true if the VM thinks there's enough process memory to satisfy this request, or false if not.
public native void	trackExternalFree(long size) Tells the VM that <size> bytes have been freed in an external heap. This information may be used to control the amount of memory available to Dalvik threads. Called by JNI code. {@hide} param size The number of bytes that have been freed. This same number should have been passed to trackExternalAlloc() when the underlying memory was originally allocated.