requirements extraction is now cleaner

api/buildcraft/api/blueprints/Schematic.java

@@ -77,22 +77,13 @@ public abstract class Schematic {
 		return true;
 	}
 
-	public final LinkedList<ItemStack> getRequirements(IBuilderContext context) {
-		LinkedList<ItemStack> res = new LinkedList<ItemStack>();
-
-		addRequirements(context, res);
-
-		return res;
-	}
-
-
 	/**
-	 * Returns the requirements needed to build this block. When the
-	 * requirements are met, they will be removed all at once from the builder,
-	 * before calling buildBlock.
+	 * Return true if the block should not be placed to the world. Requirements
+	 * will not be asked on such a block, and building will not be called. Post
+	 * processing will still be called on these blocks though.
 	 */
-	public void addRequirements(IBuilderContext context, LinkedList<ItemStack> requirements) {
-
+	public boolean doNotBuild() {
+		return false;
 	}
 
 	/**
@@ -205,6 +196,19 @@ public abstract class Schematic {
 
 	}
 
+	public void readRequirementsFromWorld(IBuilderContext context, int x, int y, int z) {
+
+	}
+
+	/**
+	 * Returns the requirements needed to build this block. When the
+	 * requirements are met, they will be removed all at once from the builder,
+	 * before calling buildBlock.
+	 */
+	public void writeRequirementsToBuilder(IBuilderContext context, LinkedList<ItemStack> requirements) {
+
+	}
+
 	public void writeToNBT(NBTTagCompound nbt, MappingRegistry registry) {
 
 	}

api/buildcraft/api/blueprints/SchematicBlock.java

@@ -26,6 +26,7 @@ public class SchematicBlock extends SchematicBlockBase {
 
 	public Block block = null;
 	public int meta = 0;
+	public BuildingPermission defaultPermission = BuildingPermission.ALL;
 
 	/**
 	 * This field contains requirements for a given block when stored in the
@@ -34,13 +35,8 @@ public class SchematicBlock extends SchematicBlockBase {
 	 */
 	public ItemStack [] storedRequirements = new ItemStack [0];
 
-	/**
-	 * Returns the requirements needed to build this block. When the
-	 * requirements are met, they will be removed all at once from the builder,
-	 * before calling buildBlock.
-	 */
 	@Override
-	public void addRequirements(IBuilderContext context, LinkedList<ItemStack> requirements) {
+	public void writeRequirementsToBuilder(IBuilderContext context, LinkedList<ItemStack> requirements) {
 		if (block != null) {
 			if (storedRequirements.length != 0) {
 				for (ItemStack s : storedRequirements) {
@@ -52,27 +48,16 @@ public class SchematicBlock extends SchematicBlockBase {
 		}
 	}
 
-	/**
-	 * Return true if the block on the world correspond to the block stored in
-	 * the blueprint at the location given by the slot. By default, this
-	 * subprogram is permissive and doesn't take into account metadata.
-	 */
 	@Override
 	public boolean isAlreadyBuilt(IBuilderContext context, int x, int y, int z) {
 		return block == context.world().getBlock(x, y, z) && meta == context.world().getBlockMetadata(x, y, z);
 	}
 
-	/**
-	 * Perform a 90 degree rotation to the slot.
-	 */
 	@Override
 	public void rotateLeft(IBuilderContext context) {
 
 	}
 
-	/**
-	 * Places the block in the world, at the location specified in the slot.
-	 */
 	@Override
 	public void writeToWorld(IBuilderContext context, int x, int y, int z, LinkedList<ItemStack> stacks) {
 		// Meta needs to be specified twice, depending on the block behavior
@@ -80,26 +65,20 @@ public class SchematicBlock extends SchematicBlockBase {
 		context.world().setBlockMetadataWithNotify(x, y, z, meta, 3);
 	}
 
-	/**
-	 * Return true if the block should not be placed to the world. Requirements
-	 * will not be asked on such a block, and building will not be called.
-	 */
 	@Override
 	public boolean doNotBuild() {
 		return false;
 	}
 
-	/**
-	 * Initializes a slot from the blueprint according to an objet placed on {x,
-	 * y, z} on the world. This typically means adding entries in slot.cpt. Note
-	 * that "id" and "meta" will be set automatically, corresponding to the
-	 * block id and meta.
-	 *
-	 * By default, if the block is a BlockContainer, tile information will be to
-	 * save / load the block.
-	 */
 	@Override
 	public void readFromWorld(IBuilderContext context, int x, int y, int z) {
+
+	}
+
+	@Override
+	public void readRequirementsFromWorld(IBuilderContext context, int x, int y, int z) {
+		super.readRequirementsFromWorld(context, x, y, z);
+
 		if (block != null) {
 			ArrayList<ItemStack> req = block.getDrops(context.world(), x,
 					y, z, context.world().getBlockMetadata(x, y, z), 0);
@@ -116,16 +95,18 @@ public class SchematicBlock extends SchematicBlockBase {
 		nbt.setInteger("blockId", registry.getIdForBlock(block));
 		nbt.setInteger("blockMeta", meta);
 
-		NBTTagList rq = new NBTTagList();
+		if (storedRequirements.length > 0) {
+			NBTTagList rq = new NBTTagList();
 
-		for (ItemStack stack : storedRequirements) {
-			NBTTagCompound sub = new NBTTagCompound();
-			stack.writeToNBT(stack.writeToNBT(sub));
-			sub.setInteger("id", registry.getIdForItem(stack.getItem()));
-			rq.appendTag(sub);
+			for (ItemStack stack : storedRequirements) {
+				NBTTagCompound sub = new NBTTagCompound();
+				stack.writeToNBT(stack.writeToNBT(sub));
+				sub.setInteger("id", registry.getIdForItem(stack.getItem()));
+				rq.appendTag(sub);
+			}
+
+			nbt.setTag("rq", rq);
 		}
-
-		nbt.setTag("rq", rq);
 	}
 
 	@Override
@@ -133,33 +114,35 @@ public class SchematicBlock extends SchematicBlockBase {
 		block = registry.getBlockForId(nbt.getInteger("blockId"));
 		meta = nbt.getInteger("blockMeta");
 
-		NBTTagList rq = nbt.getTagList("rq", Constants.NBT.TAG_COMPOUND);
+		if (nbt.hasKey("rq")) {
+			NBTTagList rq = nbt.getTagList("rq", Constants.NBT.TAG_COMPOUND);
 
-		ArrayList<ItemStack> rqs = new ArrayList<ItemStack>();
+			ArrayList<ItemStack> rqs = new ArrayList<ItemStack>();
 
-		for (int i = 0; i < rq.tagCount(); ++i) {
-			try {
-				NBTTagCompound sub = rq.getCompoundTagAt(i);
+			for (int i = 0; i < rq.tagCount(); ++i) {
+				try {
+					NBTTagCompound sub = rq.getCompoundTagAt(i);
 
-				if (sub.getInteger("id") >= 0) {
-					// Maps the id in the blueprint to the id in the world
-					sub.setInteger("id", Item.itemRegistry
-							.getIDForObject(registry.getItemForId(sub
-									.getInteger("id"))));
+					if (sub.getInteger("id") >= 0) {
+						// Maps the id in the blueprint to the id in the world
+						sub.setInteger("id", Item.itemRegistry
+								.getIDForObject(registry.getItemForId(sub
+										.getInteger("id"))));
 
-					rqs.add(ItemStack.loadItemStackFromNBT(sub));
-				} else {
-					// TODO: requirement can't be retreived, this blueprint is
-					// only useable in creative
+						rqs.add(ItemStack.loadItemStackFromNBT(sub));
+					} else {
+						defaultPermission = BuildingPermission.CREATIVE_ONLY;
+					}
+				} catch (Throwable t) {
+					t.printStackTrace();
+					defaultPermission = BuildingPermission.CREATIVE_ONLY;
 				}
-			} catch (Throwable t) {
-				t.printStackTrace();
-				// TODO: requirement can't be retreived, this blueprint is
-				// only useable in creative
 			}
-		}
 
-		storedRequirements = rqs.toArray(new ItemStack [rqs.size()]);
+			storedRequirements = rqs.toArray(new ItemStack[rqs.size()]);
+		} else {
+			storedRequirements = new ItemStack[0];
+		}
 	}
 
 	@Override
@@ -174,4 +157,9 @@ public class SchematicBlock extends SchematicBlockBase {
 			return BuildingStage.SUPPORTED;
 		}
 	}
+
+	@Override
+	public BuildingPermission getBuildingPermission() {
+		return defaultPermission;
+	}
 }

api/buildcraft/api/blueprints/SchematicBlockBase.java

@@ -34,13 +34,4 @@ package buildcraft.api.blueprints;
  */
 public abstract class SchematicBlockBase extends Schematic {
 
-	/**
-	 * Return true if the block should not be placed to the world. Requirements
-	 * will not be asked on such a block, and building will not be called.
-	 * Post processing will still be called on these blocks though.
-	 */
-	public boolean doNotBuild() {
-		return false;
-	}
-
 }

api/buildcraft/api/blueprints/SchematicEntity.java

@@ -19,7 +19,9 @@ import net.minecraft.nbt.NBTTagCompound;
 import net.minecraft.nbt.NBTTagDouble;
 import net.minecraft.nbt.NBTTagFloat;
 import net.minecraft.nbt.NBTTagList;
+
 import net.minecraftforge.common.util.Constants;
+
 import buildcraft.api.core.Position;
 
 public class SchematicEntity extends Schematic {
@@ -36,7 +38,7 @@ public class SchematicEntity extends Schematic {
 	public ItemStack[] storedRequirements = new ItemStack[0];
 
 	@Override
-	public void addRequirements(IBuilderContext context, LinkedList<ItemStack> requirements) {
+	public void writeRequirementsToBuilder(IBuilderContext context, LinkedList<ItemStack> requirements) {
 		for (ItemStack s : storedRequirements) {
 			requirements.add(s);
 		}

api/buildcraft/api/blueprints/SchematicTile.java

@@ -58,15 +58,6 @@ public class SchematicTile extends SchematicBlock {
 		}
 	}
 
-	/**
-	 * Initializes a slot from the blueprint according to an objet placed on {x,
-	 * y, z} on the world. This typically means adding entries in slot.cpt. Note
-	 * that "id" and "meta" will be set automatically, corresponding to the
-	 * block id and meta.
-	 *
-	 * By default, if the block is a BlockContainer, tile information will be to
-	 * save / load the block.
-	 */
 	@Override
 	public void readFromWorld(IBuilderContext context, int x, int y, int z) {
 		super.readFromWorld(context, x, y, z);
@@ -77,6 +68,15 @@ public class SchematicTile extends SchematicBlock {
 			if (tile != null) {
 				tile.writeToNBT(cpt);
 			}
+		}
+	}
+
+	@Override
+	public void readRequirementsFromWorld(IBuilderContext context, int x, int y, int z) {
+		super.readRequirementsFromWorld(context, x, y, z);
+
+		if (block.hasTileEntity(meta)) {
+			TileEntity tile = context.world().getTileEntity(x, y, z);
 
 			if (tile instanceof IInventory) {
 				IInventory inv = (IInventory) tile;

common/buildcraft/builders/schematics/SchematicBed.java

@@ -19,12 +19,17 @@ import buildcraft.api.blueprints.SchematicBlock;
 public class SchematicBed extends SchematicBlock {
 
 	@Override
-	public void addRequirements(IBuilderContext context, LinkedList<ItemStack> requirements) {
+	public void writeRequirementsToBuilder(IBuilderContext context, LinkedList<ItemStack> requirements) {
 		if ((meta & 8) == 0) {
 			requirements.add(new ItemStack(Items.bed));
 		}
 	}
 
+	@Override
+	public void readRequirementsFromWorld(IBuilderContext context, int x, int y, int z) {
+		// cancel requirements reading
+	}
+
 	@Override
 	public void rotateLeft(IBuilderContext context) {
 		int orientation = meta & 7;

common/buildcraft/builders/schematics/SchematicCactus.java

@@ -19,10 +19,15 @@ import buildcraft.api.blueprints.SchematicBlock;
 public class SchematicCactus extends SchematicBlock {
 
 	@Override
-	public void addRequirements(IBuilderContext context, LinkedList<ItemStack> requirements) {
+	public void writeRequirementsToBuilder(IBuilderContext context, LinkedList<ItemStack> requirements) {
 		requirements.add(new ItemStack(Blocks.cactus));
 	}
 
+	@Override
+	public void readRequirementsFromWorld(IBuilderContext context, int x, int y, int z) {
+		// cancel requirements reading
+	}
+
 	@Override
 	public void writeToWorld(IBuilderContext context, int x, int y, int z, LinkedList<ItemStack> stacks) {
 		context.world().setBlock(x, y, z, Blocks.cactus, 0, 3);

common/buildcraft/builders/schematics/SchematicCustomStack.java

@@ -24,8 +24,12 @@ public class SchematicCustomStack extends SchematicBlock {
 	}
 
 	@Override
-	public void addRequirements(IBuilderContext context, LinkedList<ItemStack> requirements) {
+	public void writeRequirementsToBuilder(IBuilderContext context, LinkedList<ItemStack> requirements) {
 		requirements.add(customStack.copy());
 	}
 
+	@Override
+	public void readRequirementsFromWorld(IBuilderContext context, int x, int y, int z) {
+		// cancel requirements reading
+	}
 }

common/buildcraft/builders/schematics/SchematicDirt.java

@@ -20,10 +20,15 @@ import buildcraft.api.blueprints.SchematicBlock;
 public class SchematicDirt extends SchematicBlock {
 
 	@Override
-	public void addRequirements(IBuilderContext context, LinkedList<ItemStack> requirements) {
+	public void writeRequirementsToBuilder(IBuilderContext context, LinkedList<ItemStack> requirements) {
 		requirements.add(new ItemStack(Blocks.dirt));
 	}
 
+	@Override
+	public void readRequirementsFromWorld(IBuilderContext context, int x, int y, int z) {
+		// cancel requirements reading
+	}
+
 	@Override
 	public void writeToWorld(IBuilderContext context, int x, int y, int z, LinkedList<ItemStack> stacks) {
 		context.world().setBlock(x, y, z, Blocks.dirt, meta, 3);

common/buildcraft/builders/schematics/SchematicDoor.java

@@ -28,12 +28,17 @@ public class SchematicDoor extends SchematicBlock {
 	}
 
 	@Override
-	public void addRequirements(IBuilderContext context, LinkedList<ItemStack> requirements) {
+	public void writeRequirementsToBuilder(IBuilderContext context, LinkedList<ItemStack> requirements) {
 		if ((meta & 8) == 0) {
 			requirements.add(stack.copy());
 		}
 	}
 
+	@Override
+	public void readRequirementsFromWorld(IBuilderContext context, int x, int y, int z) {
+		// cancel requirements reading
+	}
+
 	@Override
 	public void rotateLeft(IBuilderContext context) {
 		meta = rotateMeta(meta);

common/buildcraft/builders/schematics/SchematicEnderChest.java

@@ -13,6 +13,7 @@ import java.util.LinkedList;
 import net.minecraft.init.Blocks;
 import net.minecraft.init.Items;
 import net.minecraft.item.ItemStack;
+
 import buildcraft.api.blueprints.IBuilderContext;
 
 public class SchematicEnderChest extends SchematicRotateMeta {
@@ -22,11 +23,16 @@ public class SchematicEnderChest extends SchematicRotateMeta {
 	}
 
 	@Override
-	public void addRequirements(IBuilderContext context, LinkedList<ItemStack> requirements) {
+	public void writeRequirementsToBuilder(IBuilderContext context, LinkedList<ItemStack> requirements) {
 		requirements.add(new ItemStack(Blocks.obsidian, 8));
 		requirements.add(new ItemStack(Items.ender_eye, 1));
 	}
 
+	@Override
+	public void readRequirementsFromWorld(IBuilderContext context, int x, int y, int z) {
+		// cancel requirements reading
+	}
+
 	@Override
 	public boolean isAlreadyBuilt(IBuilderContext context, int x, int y, int z) {
 		return block == context.world().getBlock(x, y, z);

common/buildcraft/builders/schematics/SchematicFarmland.java

@@ -20,10 +20,15 @@ import buildcraft.api.blueprints.SchematicBlock;
 public class SchematicFarmland extends SchematicBlock {
 
 	@Override
-	public void addRequirements(IBuilderContext context, LinkedList<ItemStack> requirements) {
+	public void writeRequirementsToBuilder(IBuilderContext context, LinkedList<ItemStack> requirements) {
 		requirements.add(new ItemStack(Blocks.dirt));
 	}
 
+	@Override
+	public void readRequirementsFromWorld(IBuilderContext context, int x, int y, int z) {
+		// cancel requirements reading
+	}
+
 	@Override
 	public void writeToWorld(IBuilderContext context, int x, int y, int z, LinkedList<ItemStack> stacks) {
 		context.world().setBlock(x, y, z, block, 0, 3);

common/buildcraft/builders/schematics/SchematicFire.java

@@ -12,19 +12,19 @@ import java.util.LinkedList;
 
 import net.minecraft.init.Items;
 import net.minecraft.item.ItemStack;
+
 import buildcraft.api.blueprints.IBuilderContext;
 import buildcraft.api.blueprints.SchematicBlock;
 
 public class SchematicFire extends SchematicBlock {
 
 	@Override
-	public void addRequirements(IBuilderContext context, LinkedList<ItemStack> requirements) {
+	public void writeRequirementsToBuilder(IBuilderContext context, LinkedList<ItemStack> requirements) {
 		requirements.add(new ItemStack (Items.flint_and_steel));
 	}
 
 	@Override
-	public void readFromWorld(IBuilderContext context, int x, int y, int z) {
-		// No specific data to read from the world. Cancels the initialization
-		// of the requirement list.
+	public void readRequirementsFromWorld(IBuilderContext context, int x, int y, int z) {
+		// cancel requirements reading
 	}
 }

common/buildcraft/builders/schematics/SchematicFluid.java

@@ -26,12 +26,17 @@ public class SchematicFluid extends SchematicBlock {
 	}
 
 	@Override
-	public void addRequirements(IBuilderContext context, LinkedList<ItemStack> requirements) {
+	public void writeRequirementsToBuilder(IBuilderContext context, LinkedList<ItemStack> requirements) {
 		if (meta == 0) {
 			requirements.add(bucketStack.copy());
 		}
 	}
 
+	@Override
+	public void readRequirementsFromWorld(IBuilderContext context, int x, int y, int z) {
+		// cancel requirements reading
+	}
+
 	@Override
 	public boolean isAlreadyBuilt(IBuilderContext context, int x, int y, int z) {
 		if (meta == 0) {
@@ -51,11 +56,6 @@ public class SchematicFluid extends SchematicBlock {
 		return meta != 0;
 	}
 
-	@Override
-	public void readFromWorld(IBuilderContext context, int x, int y, int z) {
-		// Cancel storage of requirements
-	}
-
 	@Override
 	public void writeToWorld(IBuilderContext context, int x, int y, int z, LinkedList<ItemStack> stacks) {
 		if (meta == 0) {

common/buildcraft/builders/schematics/SchematicGravel.java

@@ -20,10 +20,15 @@ import buildcraft.api.blueprints.SchematicBlock;
 public class SchematicGravel extends SchematicBlock {
 
 	@Override
-	public void addRequirements(IBuilderContext context, LinkedList<ItemStack> requirements) {
+	public void writeRequirementsToBuilder(IBuilderContext context, LinkedList<ItemStack> requirements) {
 		requirements.add(new ItemStack(Blocks.gravel));
 	}
 
+	@Override
+	public void readRequirementsFromWorld(IBuilderContext context, int x, int y, int z) {
+		// cancel requirements reading
+	}
+
 	@Override
 	public void writeToWorld(IBuilderContext context, int x, int y, int z, LinkedList<ItemStack> stacks) {
 		context.world().setBlock(x, y, z, Blocks.gravel, 0, 3);

common/buildcraft/builders/schematics/SchematicIgnore.java

@@ -18,7 +18,7 @@ import buildcraft.api.blueprints.SchematicBlock;
 public class SchematicIgnore extends SchematicBlock {
 
 	@Override
-	public void addRequirements(IBuilderContext context, LinkedList<ItemStack> requirements) {
+	public void writeRequirementsToBuilder(IBuilderContext context, LinkedList<ItemStack> requirements) {
 
 	}
 
@@ -37,6 +37,11 @@ public class SchematicIgnore extends SchematicBlock {
 
 	}
 
+	@Override
+	public void readRequirementsFromWorld(IBuilderContext context, int x, int y, int z) {
+
+	}
+
 	@Override
 	public boolean doNotBuild() {
 		return true;

common/buildcraft/builders/schematics/SchematicIgnoreMeta.java

@@ -11,16 +11,22 @@ package buildcraft.builders.schematics;
 import java.util.LinkedList;
 
 import net.minecraft.item.ItemStack;
+
 import buildcraft.api.blueprints.IBuilderContext;
 import buildcraft.api.blueprints.SchematicBlock;
 
 public class SchematicIgnoreMeta extends SchematicBlock {
 
 	@Override
-	public void addRequirements(IBuilderContext context, LinkedList<ItemStack> requirements) {
+	public void writeRequirementsToBuilder(IBuilderContext context, LinkedList<ItemStack> requirements) {
 		requirements.add(new ItemStack(block, 1, 0));
 	}
 
+	@Override
+	public void readRequirementsFromWorld(IBuilderContext context, int x, int y, int z) {
+
+	}
+
 	@Override
 	public boolean isAlreadyBuilt(IBuilderContext context, int x, int y, int z) {
 		return block == context.world().getBlock(x, y, z);

common/buildcraft/builders/schematics/SchematicPortal.java

@@ -19,7 +19,12 @@ import buildcraft.api.blueprints.SchematicBlock;
 public class SchematicPortal extends SchematicBlock {
 
 	@Override
-	public void addRequirements(IBuilderContext context, LinkedList<ItemStack> requirements) {
+	public void writeRequirementsToBuilder(IBuilderContext context, LinkedList<ItemStack> requirements) {
+
+	}
+
+	@Override
+	public void readRequirementsFromWorld(IBuilderContext context, int x, int y, int z) {
 
 	}
 

common/buildcraft/builders/schematics/SchematicPumpkin.java

@@ -11,16 +11,22 @@ package buildcraft.builders.schematics;
 import java.util.LinkedList;
 
 import net.minecraft.item.ItemStack;
+
 import buildcraft.api.blueprints.IBuilderContext;
 import buildcraft.api.blueprints.SchematicBlock;
 
 public class SchematicPumpkin extends SchematicBlock {
 
 	@Override
-	public void addRequirements(IBuilderContext context, LinkedList<ItemStack> requirements) {
+	public void writeRequirementsToBuilder(IBuilderContext context, LinkedList<ItemStack> requirements) {
 		requirements.add(new ItemStack(block, 1, 0));
 	}
 
+	@Override
+	public void readRequirementsFromWorld(IBuilderContext context, int x, int y, int z) {
+		// cancel requirements reading
+	}
+
 	@Override
 	public boolean isAlreadyBuilt(IBuilderContext context, int x, int y, int z) {
 		return block == context.world().getBlock(x, y, z);

common/buildcraft/builders/schematics/SchematicRedstoneDiode.java

@@ -19,10 +19,15 @@ import buildcraft.api.blueprints.SchematicBlock;
 public class SchematicRedstoneDiode extends SchematicBlock {
 
 	@Override
-	public void addRequirements(IBuilderContext context, LinkedList<ItemStack> requirements) {
+	public void writeRequirementsToBuilder(IBuilderContext context, LinkedList<ItemStack> requirements) {
 		requirements.add(new ItemStack(Items.repeater));
 	}
 
+	@Override
+	public void readRequirementsFromWorld(IBuilderContext context, int x, int y, int z) {
+
+	}
+
 	@Override
 	public void rotateLeft(IBuilderContext context) {
 		int step = meta - (meta & 3);

common/buildcraft/builders/schematics/SchematicRedstoneWire.java

@@ -24,10 +24,15 @@ public class SchematicRedstoneWire extends SchematicBlock {
 	}
 
 	@Override
-	public void addRequirements(IBuilderContext context, LinkedList<ItemStack> requirements) {
+	public void writeRequirementsToBuilder(IBuilderContext context, LinkedList<ItemStack> requirements) {
 		requirements.add(customStack.copy());
 	}
 
+	@Override
+	public void readRequirementsFromWorld(IBuilderContext context, int x, int y, int z) {
+
+	}
+
 	@Override
 	public void writeToWorld(IBuilderContext context, int x, int y, int z, LinkedList<ItemStack> stacks) {
 		context.world().setBlock(x, y, z, block, 0, 3);

common/buildcraft/builders/schematics/SchematicSeeds.java

@@ -25,10 +25,15 @@ public class SchematicSeeds extends SchematicBlock {
 	}
 
 	@Override
-	public void addRequirements(IBuilderContext context, LinkedList<ItemStack> requirements) {
+	public void writeRequirementsToBuilder(IBuilderContext context, LinkedList<ItemStack> requirements) {
 		requirements.add(new ItemStack(seeds));
 	}
 
+	@Override
+	public void readRequirementsFromWorld(IBuilderContext context, int x, int y, int z) {
+
+	}
+
 	@Override
 	public void writeToWorld(IBuilderContext context, int x, int y, int z, LinkedList<ItemStack> stacks) {
 		context.world().setBlock(x, y, z, block, 0, 3);

common/buildcraft/builders/schematics/SchematicSign.java

@@ -27,10 +27,15 @@ public class SchematicSign extends SchematicTile {
 	}
 
 	@Override
-	public void addRequirements(IBuilderContext context, LinkedList<ItemStack> requirements) {
+	public void writeRequirementsToBuilder(IBuilderContext context, LinkedList<ItemStack> requirements) {
 		requirements.add(new ItemStack(Items.sign));
 	}
 
+	@Override
+	public void readRequirementsFromWorld(IBuilderContext context, int x, int y, int z) {
+		// cancel requirements reading
+	}
+
 	@Override
 	public void rotateLeft(IBuilderContext context) {
 		if (!isWall) {

common/buildcraft/builders/schematics/SchematicStairs.java

@@ -11,16 +11,22 @@ package buildcraft.builders.schematics;
 import java.util.LinkedList;
 
 import net.minecraft.item.ItemStack;
+
 import buildcraft.api.blueprints.IBuilderContext;
 import buildcraft.api.blueprints.SchematicBlock;
 
 public class SchematicStairs extends SchematicBlock {
 
 	@Override
-	public void addRequirements(IBuilderContext context, LinkedList<ItemStack> requirements) {
+	public void writeRequirementsToBuilder(IBuilderContext context, LinkedList<ItemStack> requirements) {
 		requirements.add(new ItemStack(block, 1, 0));
 	}
 
+	@Override
+	public void readRequirementsFromWorld(IBuilderContext context, int x, int y, int z) {
+
+	}
+
 	@Override
 	public boolean isAlreadyBuilt(IBuilderContext context, int x, int y, int z) {
 		return block == context.world().getBlock(x, y, z);

common/buildcraft/builders/schematics/SchematicStone.java

@@ -20,10 +20,15 @@ import buildcraft.api.blueprints.SchematicBlock;
 public class SchematicStone extends SchematicBlock {
 
 	@Override
-	public void addRequirements(IBuilderContext context, LinkedList<ItemStack> requirements) {
+	public void writeRequirementsToBuilder(IBuilderContext context, LinkedList<ItemStack> requirements) {
 		requirements.add(new ItemStack(Blocks.stone));
 	}
 
+	@Override
+	public void readRequirementsFromWorld(IBuilderContext context, int x, int y, int z) {
+
+	}
+
 	@Override
 	public void writeToWorld(IBuilderContext context, int x, int y, int z, LinkedList<ItemStack> stacks) {
 		context.world().setBlock(x, y, z, Blocks.stone, 0, 3);

common/buildcraft/core/blueprints/Blueprint.java

@@ -100,6 +100,7 @@ public class Blueprint extends BlueprintBase {
 
 		try {
 			slot.readFromWorld(context, x, y, z);
+			slot.readRequirementsFromWorld(context, x, y, z);
 			contents[posX][posY][posZ] = slot;
 		} catch (Throwable t) {
 			// Defensive code against errors in implementers

common/buildcraft/core/blueprints/BptBuilderBlueprint.java

@@ -370,7 +370,11 @@ public class BptBuilderBlueprint extends BptBuilderBase {
 		LinkedList<ItemStack> tmpReq = new LinkedList<ItemStack>();
 
 		try {
-			for (ItemStack stk : slot.getRequirements(context)) {
+			LinkedList<ItemStack> req = new LinkedList<ItemStack>();
+
+			slot.writeRequirementsToBuilder(context, req);
+
+			for (ItemStack stk : req) {
 				if (stk != null) {
 					tmpReq.add(stk.copy());
 				}

common/buildcraft/core/blueprints/BuildingSlotBlock.java

@@ -14,7 +14,9 @@ import net.minecraft.item.ItemStack;
 import net.minecraft.nbt.NBTTagCompound;
 import net.minecraft.nbt.NBTTagList;
 import net.minecraft.tileentity.TileEntity;
+
 import net.minecraftforge.common.util.Constants;
+
 import buildcraft.api.blueprints.IBuilderContext;
 import buildcraft.api.blueprints.MappingRegistry;
 import buildcraft.api.blueprints.SchematicBlockBase;
@@ -83,7 +85,11 @@ public class BuildingSlotBlock extends BuildingSlot {
 		if (mode == Mode.ClearIfInvalid) {
 			return new LinkedList<ItemStack>();
 		} else {
-			return getSchematic().getRequirements(context);
+			LinkedList<ItemStack> req = new LinkedList<ItemStack>();
+
+			getSchematic().writeRequirementsToBuilder(context, req);
+
+			return req;
 		}
 	}
 

common/buildcraft/transport/blueprints/SchematicPipe.java

@@ -94,12 +94,6 @@ public class SchematicPipe extends SchematicTile {
 		Pipe pipe = BlockGenericPipe.getPipe(context.world(), x, y, z);
 
 		if (BlockGenericPipe.isValid(pipe)) {
-			ArrayList<ItemStack> items = pipe.computeItemDrop();
-			storedRequirements = new ItemStack [items.size() + 1];
-			items.toArray(storedRequirements);
-			storedRequirements[storedRequirements.length - 1] = new ItemStack(
-					pipe.item);
-
 			tile.writeToNBT(cpt);
 
 			// This overrides the default pipeId
@@ -125,6 +119,20 @@ public class SchematicPipe extends SchematicTile {
 		}
 	}
 
+	@Override
+	public void readRequirementsFromWorld(IBuilderContext context, int x, int y, int z) {
+		TileEntity tile = context.world().getTileEntity(x, y, z);
+		Pipe pipe = BlockGenericPipe.getPipe(context.world(), x, y, z);
+
+		if (BlockGenericPipe.isValid(pipe)) {
+			ArrayList<ItemStack> items = pipe.computeItemDrop();
+			storedRequirements = new ItemStack[items.size() + 1];
+			items.toArray(storedRequirements);
+			storedRequirements[storedRequirements.length - 1] = new ItemStack(
+					pipe.item);
+		}
+	}
+
 	@Override
 	public void postProcessing(IBuilderContext context, int x, int y, int z) {
 		Item pipeItem = context.getMappingRegistry().getItemForId(cpt.getInteger("pipeId"));