use @CheckReturnValue for safer pool/Inlist usage

vtm/src/org/oscim/layers/tile/vector/labeling/TextRenderer.java

@@ -92,7 +92,7 @@ class TextRenderer extends ElementRenderer {
 	class LabelPool extends Pool<TextItem> {
 		Label releaseAndGetNext(Label l) {
 			if (l.item != null)
-				TextItem.pool.release(l.item);
+				l.item = TextItem.pool.release(l.item);
 
 			// drop references
 			l.item = null;
@@ -101,6 +101,7 @@ class TextRenderer extends ElementRenderer {
 
 			Label ret = (Label) l.next;
 
+			// ignore warning
 			super.release(l);
 
 			return ret;
@@ -561,7 +562,7 @@ class TextRenderer extends ElementRenderer {
 		}
 
 		// temporary used Label
-		mPool.release(l);
+		l = (Label) mPool.release(l);
 
 		TextLayer tl = mNextLayer.textLayer;
 
@@ -650,8 +651,7 @@ class TextRenderer extends ElementRenderer {
 	}
 
 	/* private */void cleanup() {
-		mPool.releaseAll(mLabels);
+		mLabels = (Label) mPool.releaseAll(mLabels);
-		mLabels = null;
 		mTileSet.releaseTiles();
 		mLabelTask = null;
 	}

vtm/src/org/oscim/renderer/MapRenderer.java

@@ -128,8 +128,7 @@ public class MapRenderer {
 		}
 
 		public void releaseBuffers() {
-			releaseAll(mUsedBuffers);
+			mUsedBuffers = releaseAll(mUsedBuffers);
-			mUsedBuffers = null;
 		}
 	}
 

vtm/src/org/oscim/renderer/atlas/SpriteManager.java

@@ -66,7 +66,7 @@ public abstract class SpriteManager<T> {
 	}
 
 	public void clear() {
-		TextureItem.releaseAll(mTexture);
+		mTexture = TextureItem.pool.releaseAll(mTexture);
 		mAtlas.clear();
 		items = null;
 

vtm/src/org/oscim/renderer/elements/BitmapLayer.java

@@ -146,8 +146,7 @@ public class BitmapLayer extends TextureLayer {
 		TextureItem.releaseTexture(textures);
 		textures = null;
 
-		VertexItem.pool.releaseAll(vertexItems);
+		vertexItems = VertexItem.pool.releaseAll(vertexItems);
-		vertexItems = null;
 	}
 
 	public static final class Renderer {

vtm/src/org/oscim/renderer/elements/ElementLayers.java

@@ -295,7 +295,7 @@ public class ElementLayers {
 			l.vertexItems = null;
 			l.curItem = null;
 		}
-		VertexItem.pool.releaseAll(items);
+		items = VertexItem.pool.releaseAll(items);
 
 		return size;
 	}
@@ -311,8 +311,7 @@ public class ElementLayers {
 				sbuf.put(it.vertices, 0, VertexItem.SIZE);
 		}
 
-		VertexItem.pool.releaseAll(l.vertexItems);
+		l.vertexItems = VertexItem.pool.releaseAll(l.vertexItems);
-		l.vertexItems = null;
 	}
 
 	// cleanup only when layers are not used by tile or overlay anymore!
@@ -321,8 +320,7 @@ public class ElementLayers {
 		// clear line and polygon layers directly
 		for (RenderElement l = baseLayers; l != null; l = l.next) {
 			if (l.vertexItems != null) {
-				VertexItem.pool.releaseAll(l.vertexItems);
+				l.vertexItems = VertexItem.pool.releaseAll(l.vertexItems);
-				l.vertexItems = null;
 				l.curItem = null;
 			}
 			l.verticesCnt = 0;

vtm/src/org/oscim/renderer/elements/ExtrusionLayer.java

@@ -401,16 +401,10 @@ public class ExtrusionLayer extends RenderElement {
 
 		GL.glBindBuffer(GL20.GL_ARRAY_BUFFER, 0);
 
-		for (int i = 0; i < 4; i++)
+		clear();
-			VertexItem.pool.releaseAll(mIndices[i]);
-
-		VertexItem.pool.releaseAll(mVertices);
-
-		mIndices = null;
-		mVertices = null;
-		mClipper = null;
-
 		compiled = true;
+
+		mClipper = null;
 	}
 
 	@Override
@@ -420,11 +414,10 @@ public class ExtrusionLayer extends RenderElement {
 			vboVertices = BufferObject.release(vboVertices);
 		} else {
 			for (int i = 0; i < 4; i++)
-				VertexItem.pool.releaseAll(mIndices[i]);
+				mIndices[i] = VertexItem.pool.releaseAll(mIndices[i]);
 			mIndices = null;
 
-			VertexItem.pool.releaseAll(mVertices);
+			mVertices = VertexItem.pool.releaseAll(mVertices);
-			mVertices = null;
 		}
 	}
 }

vtm/src/org/oscim/renderer/elements/LineLayer.java

@@ -23,9 +23,9 @@ import org.oscim.backend.canvas.Paint.Cap;
 import org.oscim.core.GeometryBuffer;
 import org.oscim.core.MapPosition;
 import org.oscim.core.Tile;
+import org.oscim.renderer.GLState;
 import org.oscim.renderer.GLUtils;
 import org.oscim.renderer.MapRenderer;
-import org.oscim.renderer.GLState;
 import org.oscim.renderer.MapRenderer.Matrices;
 import org.oscim.theme.renderinstruction.Line;
 import org.oscim.utils.FastMath;
@@ -567,8 +567,7 @@ public final class LineLayer extends RenderElement {
 	@Override
 	public void clear() {
 		if (vertexItems != null) {
-			VertexItem.pool.releaseAll(vertexItems);
+			vertexItems = VertexItem.pool.releaseAll(vertexItems);
-			vertexItems = null;
 			curItem = null;
 		}
 		verticesCnt = 0;

vtm/src/org/oscim/renderer/elements/MeshLayer.java

@@ -62,11 +62,8 @@ public class MeshLayer extends RenderElement {
 		Log.d(TAG, "-> " + verticesCnt + " " + numIndices);
 
 		if (numIndices <= 0) {
-			vertexItems.release();
+			vertexItems = VertexItem.pool.releaseAll(vertexItems);
-			vertexItems = null;
+			indiceItems = VertexItem.pool.releaseAll(indiceItems);
-
-			indiceItems.release();
-			indiceItems = null;
 		}
 	}
 
@@ -95,8 +92,7 @@ public class MeshLayer extends RenderElement {
 		for (VertexItem it = indiceItems; it != null; it = it.next)
 			sbuf.put(it.vertices, 0, it.used);
 
-		VertexItem.pool.releaseAll(indiceItems);
+		indiceItems = VertexItem.pool.releaseAll(indiceItems);
-		indiceItems = null;
 
 		sbuf.flip();
 
@@ -109,11 +105,8 @@ public class MeshLayer extends RenderElement {
 	@Override
 	protected void clear() {
 		indicesVbo = BufferObject.release(indicesVbo);
-		VertexItem.pool.releaseAll(indiceItems);
+		indiceItems = VertexItem.pool.releaseAll(indiceItems);
-		VertexItem.pool.releaseAll(vertexItems);
+		vertexItems = VertexItem.pool.releaseAll(vertexItems);
-
-		indiceItems = null;
-		vertexItems = null;
 	}
 
 	public static class Renderer {

vtm/src/org/oscim/renderer/elements/SymbolLayer.java

@@ -174,10 +174,9 @@ public final class SymbolLayer extends TextureLayer {
 		if (pos > 0)
 			sbuf.put(buf, 0, pos);
 
-		VertexItem.pool.release(si);
+		si = VertexItem.pool.release(si);
 
-		TextureItem.releaseAll(prevTextures);
+		prevTextures = TextureItem.pool.releaseAll(prevTextures);
-		prevTextures = null;
 	}
 
 	private TextureItem getTexture(Bitmap bitmap) {
@@ -195,19 +194,16 @@ public final class SymbolLayer extends TextureLayer {
 	}
 
 	public void clearItems() {
-		SymbolItem.pool.releaseAll(symbols);
+		symbols = SymbolItem.pool.releaseAll(symbols);
-		symbols = null;
 		verticesCnt = 0;
 	}
 
 	@Override
 	public void clear() {
-		TextureItem.releaseAll(textures);
+		textures = TextureItem.pool.releaseAll(textures);
-		SymbolItem.pool.releaseAll(symbols);
+		symbols = SymbolItem.pool.releaseAll(symbols);
+		vertexItems = VertexItem.pool.releaseAll(vertexItems);
 
-		textures = null;
-		symbols = null;
-		vertexItems = null;
 		verticesCnt = 0;
 	}
 

vtm/src/org/oscim/renderer/elements/TextLayer.java

@@ -268,18 +268,13 @@ public final class TextLayer extends TextureLayer {
 
 	@Override
 	public void clear() {
-		TextureItem.releaseAll(textures);
+		textures = TextureItem.pool.releaseAll(textures);
-		labels = null;
+		labels = TextItem.pool.releaseAll(labels);
-
+		vertexItems = VertexItem.pool.releaseAll(vertexItems);
-		TextItem.pool.releaseAll(labels);
-		VertexItem.pool.releaseAll(vertexItems);
-		textures = null;
-		vertexItems = null;
 		verticesCnt = 0;
 	}
 
 	public void clearLabels() {
-		TextItem.pool.releaseAll(labels);
+		labels = TextItem.pool.releaseAll(labels);
-		labels = null;
 	}
 }

vtm/src/org/oscim/renderer/elements/TextureItem.java

@@ -105,10 +105,6 @@ public class TextureItem extends Inlist<TextureItem> {
 		}
 	}
 
-	public synchronized static void releaseAll(TextureItem ti) {
-		pool.releaseAll(ti);
-	}
-
 	/**
 	 * Retrieve a TextureItem from pool with default Bitmap with dimension
 	 * TextureRenderer.TEXTURE_WIDTH/HEIGHT.
@@ -191,7 +187,7 @@ public class TextureItem extends Inlist<TextureItem> {
 		}
 	};
 
-	private final static SyncPool<TextureItem> pool = new TextureItemPool();
+	public final static SyncPool<TextureItem> pool = new TextureItemPool();
 
 	private final static ArrayList<Integer> mTextures = new ArrayList<Integer>();
 	private final static ArrayList<Bitmap> mBitmaps = new ArrayList<Bitmap>(10);

vtm/src/org/oscim/renderer/elements/VertexItem.java

@@ -35,17 +35,6 @@ public class VertexItem extends Inlist<VertexItem> {
 		}
 	};
 
-	/**
-	 * Add VertexItems back to pool. Make sure to not use the reference
-	 * afterwards!
-	 * i.e.:
-	 * vertexItem.release();
-	 * vertexItem = null;
-	 * */
-	public void release() {
-		VertexItem.pool.releaseAll(this);
-	}
-
 	public int getSize() {
 		int size = used;
 		for (VertexItem it = next; it != null; it = it.next)

vtm/src/org/oscim/renderer/test/AtlasRenderLayer.java

@@ -106,7 +106,7 @@ public class AtlasRenderLayer extends ElementRenderer {
 		}
 
 		tl.prepare();
-		TextItem.pool.releaseAll(tl.labels);
+		tl.labels = TextItem.pool.releaseAll(tl.labels);
 	}
 
 	boolean initial = true;

vtm/src/org/oscim/tiling/MapTile.java

@@ -225,14 +225,11 @@ public class MapTile extends Tile {
 			// TODO move this to layers clear
 			layers.vbo = BufferObject.release(layers.vbo);
 			layers.clear();
+			layers = null;
 		}
 
-		TextItem.pool.releaseAll(labels);
+		labels = TextItem.pool.releaseAll(labels);
-		SymbolItem.pool.releaseAll(symbols);
+		symbols = SymbolItem.pool.releaseAll(symbols);
-
-		layers = null;
-		labels = null;
-		symbols = null;
 
 		state = STATE_NONE;
 	}

vtm/src/org/oscim/tiling/source/mapnik/TileDecoder.java

@@ -18,6 +18,7 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.util.ArrayList;
 
+import org.oscim.backend.Log;
 import org.oscim.core.GeometryBuffer.GeometryType;
 import org.oscim.core.MapElement;
 import org.oscim.core.Tag;
@@ -27,8 +28,6 @@ import org.oscim.tiling.source.common.PbfDecoder;
 import org.oscim.utils.pool.Inlist;
 import org.oscim.utils.pool.Pool;
 
-import org.oscim.backend.Log;
-
 public class TileDecoder extends PbfDecoder {
 	private final static String TAG = TileDecoder.class.getName();
 
@@ -236,7 +235,7 @@ public class TileDecoder extends PbfDecoder {
 			// FIXME extract layer tag here
 			f.elem.setLayer(5);
 			mMapDataCallback.process(f.elem);
-			mFeaturePool.release(f);
+			f = mFeaturePool.release(f);
 		}
 
 		return true;

vtm/src/org/oscim/utils/pool/Inlist.java

@@ -14,6 +14,8 @@
  */
 package org.oscim.utils.pool;
 
+import javax.annotation.CheckReturnValue;
+
 /**
  * Utility class for making poolable objects.
  * Instead of using an additional list to hold pool items just extend this
@@ -33,6 +35,7 @@ public class Inlist<T extends Inlist<T>> {
 	 * @param item the item
 	 * @return the new head of 'list' (item)
 	 */
+	@CheckReturnValue
 	public static <T extends Inlist<T>> T push(T list, T item) {
 		item.next = list;
 		return item;
@@ -58,6 +61,7 @@ public class Inlist<T extends Inlist<T>> {
 	 * @param item the item
 	 * @return the new head of 'list'
 	 */
+	@CheckReturnValue
 	public static <T extends Inlist<T>> T remove(T list, T item) {
 		if (item == list) {
 			T head = item.next;
@@ -84,6 +88,7 @@ public class Inlist<T extends Inlist<T>> {
 	 * @param i the index
 	 * @return the item or null
 	 */
+	@CheckReturnValue
 	public static <T extends Inlist<T>> T get(T list, int i) {
 		if (i < 0)
 			return null;
@@ -105,6 +110,7 @@ public class Inlist<T extends Inlist<T>> {
 	 * @param item the item
 	 * @return the new head of 'list'
 	 */
+	@CheckReturnValue
 	public static <T extends Inlist<T>> T appendItem(T list, T item) {
 
 		if (item.next != null)
@@ -130,6 +136,7 @@ public class Inlist<T extends Inlist<T>> {
 	 * @param other the other
 	 * @return the head of 'list'
 	 */
+	@CheckReturnValue
 	public static <T extends Inlist<T>> T appendList(T list, T other) {
 
 		if (list == null)
@@ -157,6 +164,7 @@ public class Inlist<T extends Inlist<T>> {
 	 * @param list the list
 	 * @return the last item
 	 */
+	@CheckReturnValue
 	public static <T extends Inlist<T>> T last(T list) {
 		while (list != null) {
 			if (list.next == null)
@@ -174,6 +182,7 @@ public class Inlist<T extends Inlist<T>> {
 	 * @param other the other list
 	 * @return the new head of list
 	 */
+	@CheckReturnValue
 	public static <T extends Inlist<T>> T prependRelative(T list, T item, T other) {
 
 		if (item.next != null)

vtm/src/org/oscim/utils/pool/Pool.java

@@ -14,6 +14,8 @@
  */
 package org.oscim.utils.pool;
 
+import javax.annotation.CheckReturnValue;
+
 public abstract class Pool<T extends Inlist<T>> {
 
 	protected T pool;
@@ -27,33 +29,48 @@ public abstract class Pool<T extends Inlist<T>> {
 		return true;
 	}
 
-	// release 'item' to pool.
+	/**
-	// make sure that item is not in any other Inlist!
+	 * Release 'item' to pool.
-	public void release(T item) {
+	 * <p>
+	 * Usage item = pool.release(item), to ensure to not keep a reference to
+	 * item!
+	 */
+	@CheckReturnValue
+	public T release(T item) {
 		if (item == null)
-			return;
+			return null;
 
 		if (!clearItem(item))
-			return;
+			return null;
-
-		item.next = pool;
-		pool = item;
-	}
-
-	public void releaseAll(T item) {
-		if (item == null)
-			return;
-
-		while (item != null) {
-			T next = item.next;
-
-			clearItem(item);
 
 		item.next = pool;
 		pool = item;
 
-			item = next;
+		return null;
 	}
+
+	/**
+	 * Release 'list' to pool.
+	 * <p>
+	 * Usage list = pool.releaseAll(list), to ensure to not keep a reference to
+	 * list!
+	 */
+	@CheckReturnValue
+	public T releaseAll(T list) {
+		if (list == null)
+			return null;
+
+		while (list != null) {
+			T next = list.next;
+
+			clearItem(list);
+
+			list.next = pool;
+			pool = list;
+
+			list = next;
+		}
+		return null;
 	}
 
 	// remove 'item' from 'list' and add back to pool

vtm/src/org/oscim/utils/pool/SyncPool.java

@@ -14,6 +14,8 @@
  */
 package org.oscim.utils.pool;
 
+import javax.annotation.CheckReturnValue;
+
 public abstract class SyncPool<T extends Inlist<T>> {
 	protected final int maxFill;
 	protected int fill;
@@ -66,14 +68,21 @@ public abstract class SyncPool<T extends Inlist<T>> {
 	 */
 	protected abstract T createItem();
 
-	public void release(T item) {
+	/**
+	 * Release 'item' to pool.
+	 * <p>
+	 * Usage item = pool.release(item), to ensure to not keep a reference to
+	 * item!
+	 */
+	@CheckReturnValue
+	public T release(T item) {
 		if (item == null)
-			return;
+			return null;
 
 		if (!clearItem(item)) {
 			// dont add back to pool
 			freeItem(item);
-			return;
+			return null;
 		}
 		if (fill < maxFill) {
 			synchronized (this) {
@@ -85,17 +94,19 @@ public abstract class SyncPool<T extends Inlist<T>> {
 		} else {
 			freeItem(item);
 		}
+		return null;
 	}
 
 	/**
-	 * Release all items from 'item'. Do not use the
+	 * Release 'list' to pool.
-	 * 'item' reference afterwards!
+	 * <p>
-	 * 
+	 * Usage list = pool.releaseAll(list), to ensure to not keep a reference to
-	 * @param item the item (or list or items)
+	 * list!
 	 */
-	public void releaseAll(T item) {
+	@CheckReturnValue
+	public T releaseAll(T item) {
 		if (item == null)
-			return;
+			return null;
 
 		if (fill > maxFill) {
 			while (item != null) {
@@ -103,7 +114,7 @@ public abstract class SyncPool<T extends Inlist<T>> {
 				freeItem(item);
 				item = item.next;
 			}
-			return;
+			return null;
 		}
 
 		synchronized (this) {
@@ -125,6 +136,7 @@ public abstract class SyncPool<T extends Inlist<T>> {
 				item = next;
 			}
 		}
+		return null;
 	}
 
 	/**